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Artykuły w czasopismach na temat "Potential Scaffolds"
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Chernonosova, Vera, Marianna Khlebnikova, Victoriya Popova, Ekaterina Starostina, Elena Kiseleva, Boris Chelobanov, Ren Kvon, Elena Dmitrienko i Pavel Laktionov. "Electrospun Scaffolds Enriched with Nanoparticle-Associated DNA: General Properties, DNA Release and Cell Transfection". Polymers 15, nr 15 (27.07.2023): 3202. http://dx.doi.org/10.3390/polym15153202.
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Biomaterial-mediated, spatially localized gene delivery is important for the development of cell-populated scaffolds used in tissue engineering. Cells adhering to or penetrating into such a scaffold are to be transfected with a preloaded gene that induces the production of secreted proteins or cell reprogramming. In the present study, we produced silica nanoparticles-associated pDNA and electrospun scaffolds loaded with such nanoparticles, and studied the release of pDNA from scaffolds and cell-to-scaffold interactions in terms of cell viability and pDNA transfection efficacy. The pDNA-coated nanoparticles were characterized with dynamic light scattering and transmission electron microscopy. Particle sizes ranging from 56 to 78 nm were indicative of their potential for cell transfection. The scaffolds were characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, stress-loading tests and interaction with HEK293T cells. It was found that the properties of materials and the pDNA released vary, depending on the scaffold’s composition. The scaffolds loaded with pDNA-nanoparticles do not have a pronounced cytotoxic effect, and can be recommended for cell transfection. It was found that (pDNA-NPs) + PEI9-loaded scaffold demonstrates good potential for cell transfection. Thus, electrospun scaffolds suitable for the transfection of inhabiting cells are eligible for use in tissue engineering.
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D’Amato, Anthony R., Michael T. K. Bramson, David T. Corr, Devan L. Puhl, Ryan J. Gilbert i Jed Johnson. "Solvent Retention in Electrospun Fibers Affects Scaffold Mechanical Properties". Electrospinning 2, nr 1 (1.09.2018): 15–28. http://dx.doi.org/10.1515/esp-2018-0002.
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Abstract Electrospinning is a robust material fabrication method allowing for fine control of mechanical, chemical, and functional properties in scaffold manufacturing. Electrospun fiber scaffolds have gained prominence for their potential in a variety of applications such as tissue engineering and textile manufacturing, yet none have assessed the impact of solvent retention in fibers on the scaffold’s mechanical properties. In this study, we hypothesized that retained electrospinning solvent acts as a plasticizer, and gradual solvent evaporation, by storing fibers in ambient air, will cause significant increases in electrospun fiber scaffold brittleness and stiffness, and a significant decrease in scaffold toughness. Thermogravimetric analysis indicated solvent retention in PGA, PLCL, and PET fibers, and not in PU and PCL fibers. Differential scanning calorimetry revealed that polymers that were electrospun below their glass transition temperature (Tg) retained solvent and polymers electrospun above Tg did not. Young’s moduli increased and yield strain decreased for solventretaining PGA, PLCL, and PET fiber scaffolds as solvent evaporated from the scaffolds over a period of 14 days. Toughness and failure strain decreased for PGA and PET scaffolds as solvent evaporated. No significant differences were observed in the mechanical properties of PU and PCL scaffolds that did not retain solvent. These observations highlight the need to consider solvent retention following electrospinning and its potential effects on scaffold mechanical properties.
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Korpershoek, Jasmijn V., Mylène de Ruijter, Bastiaan F. Terhaard, Michella H. Hagmeijer, Daniël B. F. Saris, Miguel Castilho, Jos Malda i Lucienne A. Vonk. "Potential of Melt Electrowritten Scaffolds Seeded with Meniscus Cells and Mesenchymal Stromal Cells". International Journal of Molecular Sciences 22, nr 20 (18.10.2021): 11200. http://dx.doi.org/10.3390/ijms222011200.
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Meniscus injury and meniscectomy are strongly related to osteoarthritis, thus there is a clinical need for meniscus replacement. The purpose of this study is to create a meniscus scaffold with micro-scale circumferential and radial fibres suitable for a one-stage cell-based treatment. Poly-caprolactone-based scaffolds with three different architectures were made using melt electrowriting (MEW) technology and their in vitro performance was compared with scaffolds made using fused-deposition modelling (FDM) and with the clinically used Collagen Meniscus Implants® (CMI®). The scaffolds were seeded with meniscus and mesenchymal stromal cells (MSCs) in fibrin gel and cultured for 28 d. A basal level of proteoglycan production was demonstrated in MEW scaffolds, the CMI®, and fibrin gel control, yet within the FDM scaffolds less proteoglycan production was observed. Compressive properties were assessed under uniaxial confined compression after 1 and 28 d of culture. The MEW scaffolds showed a higher Young’s modulus when compared to the CMI® scaffolds and a higher yield point compared to FDM scaffolds. This study demonstrates the feasibility of creating a wedge-shaped meniscus scaffold with MEW using medical-grade materials and seeding the scaffold with a clinically-feasible cell number and -type for potential translation as a one-stage treatment.
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Iqbal, Neelam, Thomas Michael Braxton, Antonios Anastasiou, El Mostafa Raif, Charles Kai Yin Chung, Sandeep Kumar, Peter V. Giannoudis i Animesh Jha. "Dicalcium Phosphate Dihydrate Mineral Loaded Freeze-Dried Scaffolds for Potential Synthetic Bone Applications". Materials 15, nr 18 (8.09.2022): 6245. http://dx.doi.org/10.3390/ma15186245.
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Dicalcium Phosphate Dihydrate (DCPD) mineral scaffolds alone do not possess the mechanical flexibility, ease of physicochemical properties’ tuneability or suitable porosity required for regenerative bone scaffolds. Herein, we fabricated highly porous freeze-dried chitosan scaffolds embedded with different concentrations of Dicalcium Phosphate Dihydrate (DCPD) minerals, i.e., 0, 20, 30, 40 and 50 (wt)%. Increasing DCPD mineral concentration led to increased scaffold crystallinity, where the % crystallinity for CH, 20, 30, 40, and 50-DCPD scaffolds was determined to be 0.1, 20.6, 29.4, 38.8 and 69.9%, respectively. Reduction in scaffold pore size distributions was observed with increasing DCPD concentrations of 0 to 40 (wt)%; coalescence and close-ended pore formation were observed for 50-DCPD scaffolds. 50-DCPD scaffolds presented five times greater mechanical strength than the DCPD mineral-free scaffolds (CH). DCPD mineral enhanced cell proliferation for the 20, 30 and 40-DCPD scaffolds. 50-DCPD scaffolds presented reduced pore interconnectivity due to the coalescence of many pores in addition to the creation of closed-ended pores, which were found to hinder osteoblast cell proliferation.
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Ahmad Hariza, Ahmad Mus’ab, Mohd Heikal Mohd Yunus, Mh Busra Fauzi, Jaya Kumar Murthy, Yasuhiko Tabata i Yosuke Hiraoka. "The Fabrication of Gelatin–Elastin–Nanocellulose Composite Bioscaffold as a Potential Acellular Skin Substitute". Polymers 15, nr 3 (3.02.2023): 779. http://dx.doi.org/10.3390/polym15030779.
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Gelatin usage in scaffold fabrication is limited due to its lack of enzymatic and thermal resistance, as well as its mechanical weakness. Hence, gelatin requires crosslinking and reinforcement with other materials. This study aimed to fabricate and characterise composite scaffolds composed of gelatin, elastin, and cellulose nanocrystals (CNC) and crosslinked with genipin. The scaffolds were fabricated using the freeze-drying method. The composite scaffolds were composed of different concentrations of CNC, whereas scaffolds made of pure gelatin and a gelatin–elastin mixture served as controls. The physicochemical and mechanical properties of the scaffolds, and their cellular biocompatibility with human dermal fibroblasts (HDF), were evaluated. The composite scaffolds demonstrated higher porosity and swelling capacity and improved enzymatic resistance compared to the controls. Although the group with 0.5% (w/v) CNC recorded the highest pore size homogeneity, the diameters of most of the pores in the composite scaffolds ranged from 100 to 200 μm, which is sufficient for cell migration. Tensile strength analysis revealed that increasing the CNC concentration reduced the scaffolds’ stiffness. Chemical analyses revealed that despite chemical and structural alterations, both elastin and CNC were integrated into the gelatin scaffold. HDF cultured on the scaffolds expressed collagen type I and α-SMA proteins, indicating the scaffolds’ biocompatibility with HDF. Overall, the addition of elastin and CNC improved the properties of gelatin-based scaffolds. The composite scaffolds are promising candidates for an acellular skin substitute.
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Lari, Alireza, Tao Sun i Naznin Sultana. "PEDOT:PSS-Containing Nanohydroxyapatite/Chitosan Conductive Bionanocomposite Scaffold: Fabrication and Evaluation". Journal of Nanomaterials 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/9421203.
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Conductive poly(3,4-ethylenedioxythiophene)-poly(4-styrene sulfonate) (PEDOT:PSS) was incorporated into nanohydroxyapatite/chitosan (nHA/CS) composite scaffolds through a freezing and lyophilization technique. The bionanocomposite conductive scaffold was then characterized using several techniques. A scanning electron microscope image showed that the nHA and PEDOT:PSS were dispersed homogeneously in the chitosan matrix, which was also confirmed by energy-dispersive X-ray (EDX) analysis. The conductive properties were measured using a digital multimeter. The weight loss and water-uptake properties of the bionanocomposite scaffolds were studiedin vitro. Anin vitrocell cytotoxicity test was carried out using mouse fibroblast (L929) cells cultured onto the scaffolds. Using a freezing and lyophilization technique, it was possible to fabricate three-dimensional, highly porous, and interconnected PEDOT:PSS/nHA/CS scaffolds with good handling properties. The porosity was 74% and the scaffold’s conductivity was9.72±0.78 μS. The surface roughness was increased with the incorporation of nHA and PEDOT:PSS into the CS scaffold. The compressive mechanical properties increased significantly with the incorporation of nHA but did not change significantly with the incorporation of PEDOT:PSS. The PEDOT:PSS-containing nHA/CS scaffold exhibited significantly higher cell attachment. The PEDOT:PSS/nHA/CS scaffold could be a potential bionanocomposite conductive scaffold for tissue engineering.
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Toullec, Clément, Jean Le Bideau, Valerie Geoffroy, Boris Halgand, Nela Buchtova, Rodolfo Molina-Peña, Emmanuel Garcion i in. "Curdlan–Chitosan Electrospun Fibers as Potential Scaffolds for Bone Regeneration". Polymers 13, nr 4 (10.02.2021): 526. http://dx.doi.org/10.3390/polym13040526.
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Polysaccharides have received a lot of attention in biomedical research for their high potential as scaffolds owing to their unique biological properties. Fibrillar scaffolds made of chitosan demonstrated high promise in tissue engineering, especially for skin. As far as bone regeneration is concerned, curdlan (1,3-β-glucan) is particularly interesting as it enhances bone growth by helping mesenchymal stem cell adhesion, by favoring their differentiation into osteoblasts and by limiting the osteoclastic activity. Therefore, we aim to combine both chitosan and curdlan polysaccharides in a new scaffold for bone regeneration. For that purpose, curdlan was electrospun as a blend with chitosan into a fibrillar scaffold. We show that this novel scaffold is biodegradable (8% at two weeks), exhibits a good swelling behavior (350%) and is non-cytotoxic in vitro. In addition, the benefit of incorporating curdlan in the scaffold was demonstrated in a scratch assay that evidences the ability of curdlan to express its immunomodulatory properties by enhancing cell migration. Thus, these innovative electrospun curdlan–chitosan scaffolds show great potential for bone tissue engineering.
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Minden-Birkenmaier, Benjamin A., Rachel M. Neuhalfen, Blythe E. Janowiak i Scott A. Sell. "Preliminary Investigation and Characterization of Electrospun Polycaprolactone and Manuka Honey Scaffolds for Dermal Repair". Journal of Engineered Fibers and Fabrics 10, nr 4 (grudzień 2015): 155892501501000. http://dx.doi.org/10.1177/155892501501000406.
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This study focused on the characterization of Manuka honey-containing poly(ε-caprolactone) (PCL) nanofiber scaffolds with regards to wound healing. Scaffolds were electrospun from 1, 5, 10, and 20% v/v Manuka honey solutions. Scaffolds were subjected to ethanol disinfection and soaked in phosphate-buffered saline (PBS) for various timepoints, and scaffold morphology and honey release was quantified. Scaffolds showed increased water vapor transmission rate (WVTR) with scaffold soak time, indicating an increase in evaporation due to enhanced osmotic potential of the scaffolds. Mechanical testing indicated lower elasticity and strength with honey incorporation, but showed no significant change in material degradation rate with the presence of honey over a 28 day PBS soak. Fibroblast studies showed honey incorporation increased cell infiltration into the scaffold, but scaffold conditioned media did not induce significant chemotaxis towards the scaffold. Honey incorporation also demonstrated an increase in fibroblast proliferation when in direct contact with the scaffolds. Bacterial clearance from pure honey was observed in both Gram positive Streptococcus agalactiae (Group B Streptocococcus) and Gram negative Escherichia coli ( E. coli), but honey scaffolds demonstrated significant clearance in only the Gram negative E. coli. While further investigation is needed, this preliminary study demonstrates the wound-healing potential of Manuka honey-loaded electrospun scaffolds.
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Deng, Xu Liang, M. M. Xu, Dan Li, Gang Sui, X. Y. Hu i Xiao Ping Yang. "Electrospun PLLA/MWNTs/HA Hybrid Nanofiber Scaffolds and Their Potential in Dental Tissue Engineering". Key Engineering Materials 330-332 (luty 2007): 393–96. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.393.
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Novel Poly(l-lactic acid) (PLLA)/ Multi-walled carbon nanotubes (MWNTs)/ hydroxyapatite (HA) nanofibrous scaffolds with high porosity and well-controlled pore architectures were prepared via electrospinning techniques. The structure, morphology, molecular weight change of the scaffolds were investigated using scanning electron microscopy (SEM). The results noticed that the average diameter of hybrid nanofiber was similar to that of PLLA/HA fiber, but the surface of hybrid fibers was much coarser because of the introduction of MWNTs nano-particles. The biocompatibility of the scaffold has been investigated by human Dental Pulp Stem Cells (DPSCs) cell culture on the scaffold. The preliminary results showed that cells were well adhered and proliferated on the hybrid scaffolds as well as PLLA/HA fibers. Based on the experimental observations, the aligned nanofibrous PLLA/ MWNTs /HA scaffold could be used as a potential candidate scaffold in dental tissue engineering.
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Jain, Shubham, Mohammed Ahmad Yassin, Tiziana Fuoco, Hailong Liu, Samih Mohamed-Ahmed, Kamal Mustafa i Anna Finne-Wistrand. "Engineering 3D degradable, pliable scaffolds toward adipose tissue regeneration; optimized printability, simulations and surface modification". Journal of Tissue Engineering 11 (styczeń 2020): 204173142095431. http://dx.doi.org/10.1177/2041731420954316.
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We present a solution to regenerate adipose tissue using degradable, soft, pliable 3D-printed scaffolds made of a medical-grade copolymer coated with polydopamine. The problem today is that while printing, the medical grade copolyesters degrade and the scaffolds become very stiff and brittle, being not optimal for adipose tissue defects. Herein, we have used high molar mass poly(L-lactide-co-trimethylene carbonate) (PLATMC) to engineer scaffolds using a direct extrusion-based 3D printer, the 3D Bioplotter®. Our approach was first focused on how the printing influences the polymer and scaffold’s mechanical properties, then on exploring different printing designs and, in the end, on assessing surface functionalization. Finite element analysis revealed that scaffold’s mechanical properties vary according to the gradual degradation of the polymer as a consequence of the molar mass decrease during printing. Considering this, we defined optimal printing parameters to minimize material’s degradation and printed scaffolds with different designs. We subsequently functionalized one scaffold design with polydopamine coating and conducted in vitro cell studies. Results showed that polydopamine augmented stem cell proliferation and adipogenic differentiation owing to increased surface hydrophilicity. Thus, the present research show that the medical grade PLATMC based scaffolds are a potential candidate towards the development of implantable, resorbable, medical devices for adipose tissue regeneration.
Rozprawy doktorskie na temat "Potential Scaffolds"
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Hed, Yvonne. "Multifunctional Dendritic Scaffolds: Synthesis, Characterization and Potential applications". Doctoral thesis, KTH, Ytbehandlingsteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127429.
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The development of materials for advanced applications requires innovative macromolecules with well-defined structures and the inherent ability to be tailored in a straightforward manner. Dendrimers, being a subgroup of the dendritic polymer family, possess properties which fulfill such demands. They have a highly branched architecture with a high number of functional groups and are one of the most well-defined types of macromolecules ever synthesized. However, despite their well-defined nature and high functional density, traditional dendrimers commonly lack diverse chemical functionalities. Therefore, this thesis focuses on the synthesis of more complex dendritic materials to extend their tailoring capacity by introduction of dualfunctionalities for multipurpose actions. It covers the synthesis of dualfunctional dendrimers, dendritic modification of linear poly(ethylene glycol) polymers and cellulose surfaces, and the synthesis of linear dendritic hybrids. The building blocks enabling this synthesis, AB2C monomers, were also developed during this work. The orthogonal nature between click groups (azide, alkyne and alkene) and hydroxyl groups have efficiently been utilized for postfunctionalization by robust click chemistry and traditional esterification reactions. Furthermore, linear dendritic hybrids were synthesized, merging the properties of linear and dendritic macromolecules. The dendritic frameworks were tailored towards the production of bone fracture adhesives, novel biofunctional dendritic hydrogels, biosensors and micellar drug delivery vehicles.Utveckling av material för avancerade applikationer kräver innovativa makromolekyler med väldefinierade strukturer och som kan skräddarsys på ett enkelt sätt. Dendrimerer är en undergrupp av dendritiska polymerer vars egenskaper uppfyller dessa krav. De har en mycket förgrenad arkitektur med många funktionella grupper och är en av de mest väldefinierade befintliga syntetiska makromolekylerna. Trots dess väldefinierade karaktär och höga funktionalitet saknar ofta traditionella dendrimerer multipla kemiska funktionaliteter. Denna avhandling fokuserar därför på syntesen av mer komplexa dendritiska material för att förbättra deras kapacitet att skräddarsys, detta görs genom att introducera fler funktionaliteter som kan utnyttjas för multipla ändamål . Avhandlingen redogör för syntesen av difunktionella dendrimerer, dendritiska modifikationer av polyetylenglykol och cellulosaytor samt syntes av traditionella dendritiska hybrider. Byggstenarna som möjliggör syntesen, AB2C monomerer, framställdes också under detta arbete. Den ortogonala karaktären mellan klick grupper (azid, alkyn och alkene) och hydroxylgrupper har utnyttjats effektivt för funktionaliseringar genom användande av robust ”Click”-kemi och traditionella esterifikationsreaktioner. Vidare tillverkades de linjära dendritiska hybrider för att kombinera egenskaperna hos både linjära och traditionella dendritiska polymerer i en och samma makromolekyl. Samtliga dendritiska strukturer skräddarsyddes för applikationer så som benlimmer, biofunktionella dendritiska hydrogeler, biosensorer och läkemedels-bärande miceller.
QC 20130830
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Sharp, Duncan McNeill Craig. "Bioactive scaffolds for potential bone regenerative medical applications". Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/9520.
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Fracture non-unions and bone defects represent a recalcitrant problem in the field of orthopaedic surgery. Although the current gold-standard treatment, autologous bone grafting, has a relatively high success rate, the technique is not without serious problems. The emerging field of regenerative medicine may have the potential to provide an alternative treatment. One promising strategy involves the delivery of both cells and multiple growth factors with different release profiles. A range of scaffolds was developed from Poly( -caprolactone) (PCL), Poly(lactideco- glycolide) (PLGA), and two blends of PCL (Mn 42,500) and PLGA. The scaffolds were manufactured utilising a novel modified fused deposition modelling system, using polymer/dichloromethane solutions. The scaffolds were found to have pore sizes suitable for bone regenerative medical applications (373±9.5 μm in the Ydirection and 460±13 μm in the X-direction). However, the scaffolds were found to be only 52±3 μm in height. This means that the two-layer scaffolds were relatively flat. This was undesirable, as direct control of the complete 3D geometry was the favoured strategy, though it may not be a necessary requirement. Five scaffold coatings were also developed from alginate, chitosan (crosslinked using sodium hydroxide or tripolyphosphate), Type-I collagen and Type-A gelatin. The scaffold coatings were screened in vitro for their cell-compatibility with human marrow stromal cells (hMSCs), human osteoblasts and MG63 cells. This was assessed using an assay for cell death, and assessing total cell counts. From these studies, Type-I collagen was found to be the optimum coating. For hMSCs, their death rates were found to be 19.1±6.3% for alginate, 5.3±3.6% and 2.9±1.4% for chitosan crosslinked with tripolyphosphate and sodium hydroxide respectively, compared to 0.11±0.07% for Type-I collagen, and 0.15±0.13% and 0.16±0.12% for 0.1% and 0.2% gelatin respectively. Type-I collagen was found to be the most cellcompatible coating, as it was consistently associated with higher cell counts than Type-A gelatin. Similarly, PCL scaffolds vacuum dried for 1 hr were found to be cell-compatible. No detectable clinically significant difference was found in either total cell counts, or the proportion of cell death in; hMSCs exposed to PCL scaffolds processed with dichloromethane, hMSCs either exposed to scaffolds known to be biocompatible, or hMSCs cultured in the absence of scaffolds. When cell morphology was compared, scaffolds vacuum dried for 1 hr or more were found to have a similar morphology to the cells cultured in the absence of scaffolds. It was therefore concluded that a vacuum drying time of 1 hr was sufficient for cell-compatibility. The scaffold materials were screened both for their encapsulation efficiencies and release characteristics using the model drug, methylene blue. The encapsulation efficiency was found to be both relatively high and consistent for both Mn 42,500 and 80,000 PCL as well as PCL:PLGA 66:33, at 71±6%, 71±5%, and 78±10% respectively, relative to the low efficiencies recorded for both PCL:PLGA 66:33 and PLGA: 57±5% and 38±10% respectively. The release rate of methylene blue from PCL (Mn 42,500), was found to be relatively slow, controlled, and consistent between batches (between 21±2% and 20±3% released in the first 24 hr). Despite the release rate being consistent for PCL (Mn 80,000), the release rate was thought to be too high, since between 29±3% and 39±5% of the test compound was released in the first 24 hr period. The release rate of methylene blue from the PCL/PLGA blends (between 17±2% – 30±7% and 18±4% – 31±6% in the first 24 hr) and PLGA (between 7.1±3.4% – 9.3±2.9% in the first 24 hr) were found to be inconsistent, and low in the case of PLGA, even taking the different loading efficiencies into account. Therefore, PCL (Mn 42,500) was selected as the favoured candidate scaffold material. The loading content and release profiles from methylene blue loaded collagen scaffold coatings were also evaluated. The drug loading capacity was found to be suitable for use as a drug delivery system (65±5 μg/g of methylene blue per unit scaffold mass). The release of methylene blue was observed to be rapid (between 54±10% – 70±17% in the first 24 hr), which was thought to be desirable for the coating delivery system. Recombinant human bone morphogenetic protein-7 (rhBMP-7) was used as a representative growth factor of interest for bone regenerative medical applications. It was loaded in collagen scaffold coatings (CoatBMP 1.25) and encapsulated within PCL (Mn 42,500) scaffolds (ScaffBMP 1.25). Control coatings and scaffolds were designated CoatPBS and ScaffPBS respectively. Both delivery systems were found to release detectable quantities of rhBMP-7 (releasing 2.8±0.2 μg/g and 87±7 ng/g respectively in the first 24 hr), even after 14 days. The release rate of the growth factor from the scaffold coating was higher than that from the encapsulating scaffolds. However, the cumulative release profiles were found to deviate from the desired ideal release profiles, and burst release was observed from both delivery systems. Although differences were observed for the two delivery systems, this difference may not be of clinical significance. Nevertheless, scaffolds with less than ideal delivery properties may still be of potential clinical use. The bioactivity of the rhBMP-7 released from the test scaffolds was therefore assessed by quantifying the area of normalised ALP staining of hMSCs. The release of rhBMP-7 from the collagen coating of the PCL (Mn 42,500) scaffolds (CoatBMP 1.25ScaffPBS) was capable of statistically significantly increasing hMSC normalised ALP expression, although the actual differences were often relatively small. Therefore, at least a proportion of the growth factor released is likely to have been bioactive. The release from scaffolds encapsulating rhBMP-7 (CoatPBSScaffBMP 1.25) did not have this effect on the hMSCs, indicating that either the concentration released was too low, or the growth factor released was no longer bioactive. However, when the cells were seeded directly onto the scaffolds, the activity of ALP, normalised by a DNA assay, was statistically significantly increased for the CoatPBSScaffBMP 1.25 scaffolds, in hMSCs from all three test patient donors (by 35±10% on the control). ALP activity was also significantly increased in hMSCs from two of the three patients seeded onto CoatBMP 1.25ScaffBMP 1.25 scaffolds (by 39±10% on the control). ALP activity was only statistically significantly increased for one of the hMSC patients when seeded onto CoatBMP 1.25ScaffPBS scaffolds (by 35±14% on the control). The functional osteoinductive capacity of Type-I collagen coated PCL (Mn 42,500) scaffolds loaded with rhBMP-7 was assessed using C2C12 cells seeded onto the scaffolds, and quantified using qRT-PCR. The genes of interest were; Type-I collagen (Col1), osteopontin (OP), ALP, osteocalcin (OC) and runt related transcription factor 2 (Runx2). The CoatBMP 1.25ScaffPBS scaffolds had an early osteoinductive effect on the C2C12 cells, as ALP, OC and Runx2 were elevated during the first 2 days only, compared to the control (e.g. by 44±12%, 128±42%, 60±25% and 46±25% respectively at the 24 hr mark). The CoatPBSScaffBMP 1.25 scaffolds also had an osteoinductive effect on the cells, which was more sustained than that observed for the CoatBMP 1.25ScaffPBS group. While OP, ALP and Runx2 were up-regulated in the first 24 hr compared to the control (by 38±10%, 208±82% and 72±31% respectively), statistically significant up-regulation of the late marker OC was delayed until the 48 hr mark (by 73±49%). The effect was found to be sustained until day 7, when OC and Runx2 were both statistically significantly up-regulated compared to the control (by 151±91% and 93±27% respectively). The CoatBMP 1.25ScaffBMP 1.25 scaffolds were found to combine the early effect of the CoatBMP 1.25ScaffPBS scaffolds, with the more sustained effect of the CoatPBSScaffBMP 1.25 scaffolds. ALP, OC and Runx2 were all up-regulated at the 24 hr mark (by 312±56%, 329±39% and 96±25% respectively). This osteoinductive effect was sustained until day 7 when Col1, ALP and Runx2 were still up-regulated compared to the control (by 174±78%, 72±24% and 178±78% respectively). These data suggest that the scaffolds containing rhBMP-7 have a weak osteoinductive effect on the cells seeded onto them. The different delivery systems were found to affect the cells differently. The clinical significance of this was not assessed in these studies. 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) was used as a model drug to assess the feasibility of releasing lipid-soluble active factors from the scaffolds. This was assessed by quantifying the area of normalised ALP staining of hMSCs. The release of 1,25(OH)2D3 from the loaded collagen scaffold coatings and the encapsulating scaffolds significantly increased ALP expression compared to the control scaffold groups (by 115±28% and 69±25% respectively). Furthermore, ALP expression was significantly increased when the two delivery systems were used together, when compared to either delivery system on its own. These data suggest that the delivery of lipid-soluble active factors is feasible from collagen coated PCL scaffolds, and that the coating and encapsulating delivery systems are mutually compatible.
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Aduba, Donald C. Jr. "Multi-platform arabinoxylan scaffolds as potential wound dressing materials". VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3955.
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Biopolymers are becoming more attractive as advanced wound dressings because of their naturally derived origin, abundance, low cost and high compatibility with the wound environment. Arabinoxylan (AX) is a class of polysaccharide polymers derived from cereal grains that are primarily used in food products and cosmetic additives. Its application as a wound dressing material has yet to be realized. In this two-pronged project, arabinoxylan ferulate (AXF) was fabricated into electrospun fibers and gel foams to be evaluated as platforms for wound dressing materials. In the first study, AXF was electrospun with varying amounts of gelatin. In the second study, AXF was dissolved in water, enzymatically crosslinked and lyophilized to form gel foams. The morphology, mechanical properties, porosity, drug release kinetics, fibroblast cell response and anti-microbial properties were examined for both platforms. Carbohydrate assay was conducted to validate the presence of arabinoxylan ferulate in the electrospun GEL-AXF fibers. Swelling and endotoxin quantification studies were done to evaluate the absorptive capacity and sterilization agent efficacy respectively in AXF foams. The results indicated successful fabrication of both platforms which validated the porous, absorptive, biocompatibility and drug release properties. The results also exhibited that silver impregnated AXF scaffolds inhibited growth of Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis bacteria species, anti-microbial properties necessary to function as advanced wound dressing materials. Future work will be done to improve the stability of both platforms as well as evaluate its applications in vivo.
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Mohammadzadehmoghadam, Soheila. "Electrospun Silk Nanofibre Mats and Their Potential as Tissue Scaffolds". Thesis, Curtin University, 2018. http://hdl.handle.net/20.500.11937/77169.
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In this study new electrospun silk fibroin (SF) based scaffolds were developed and their material and biocompatibility characteristics evaluated. Three types of SF based scaffolds were generated: SF/halloysite (HNT), SF/gelatin and SF/collagen. Scaffolds chosen for their material and biocompatibility characteristics were coated with fibroblast extracellular matrix and their efficacy for supporting primary human keratinocyte expansion were investigated. Collectively these data indicated SF/HNT scaffolds have merit for wound healing and tissue engineering applications.
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Sisson, Kristin M. "Investigating the potential of electrospun gelatin and collagen scaffolds for tissue engineering applications". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 133 p, 2010. http://proquest.umi.com/pqdweb?did=1993336301&sid=9&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Carlqvist, K. H. "The potential of muscle-derived progenitors on titanium scaffolds in bone regenerative applications". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1301768/.
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Muscle-derived cells (MDCs) are a heterogeneous population consisting of cells that can undergo myogenic differentiation; however, it has emerged that not all MDCs are restricted to the myogenic lineage. This discovery may have many implications; for example, MDCs may be a suitable alternative source of osteogenic cells for bone repair. The currently accepted treatment for bone repair, bone grafting, is often associated with small amount of obtainable bone. Much of the work published regarding the differential potential of MDCs has not, to date, focused on the osteogenic pathway and even fewer studies have been performed on human cells. In this thesis osteogenic MDCs were isolated by differential adhesion to fibronectin (Fn) i.e. MDCsFn and compared with mesenchymal stem cells (MSCs) in relation to their osteogenic potential. The osteogenic potential was assessed by measuring mineralization and relevant gene- and protein- expression. MSCs and MDCsFn had a similar pattern of ALP activity and expression. Furthermore, MSCs and MDCsFn both showed mineralization after 3 weeks measured by Alizarin Red S. A qPCR Array measuring the activity of 46 osteogenic genes also showed similarities in gene expression between the two cell types; however, the MSCs showed a more consistent pattern between patients, compared to MDCsFn. Titanium (Ti) has previously been used as a bone repair scaffold in humans due to its osteoconductivity. The interaction between Ti, of various roughness and hydrophilicity, and the two cell types, i.e. MSCs and MDCsFn, were assessed with relation to biocompatibility. Interestingly, the hydrophilic, rough surface, which has been described as superior in bone formation applications, showed higher levels of cell death, both apoptosis and necrosis, compared to the other tested surfaces for both cell types. In conclusion, due to the similarities between MDCsFn and MSCs there might be possibilities to use the osteogenic fraction in future bone regenerative applications.
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Bursey, Devan. "Ribosomally Synthesized and Post-Translationally Modified Peptides as Potential Scaffolds for Peptide Engineering". BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8124.
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Peptides are small proteins that are crucial in many biological pathways such as antimicrobial defense, hormone signaling, and virulence. They often exhibit tight specificity for their targets and therefore have great therapeutic potential. Many peptide-based therapeutics are currently available, and the demand for this type of drug is expected to continue to increase. In order to satisfy the growing demand for peptide-based therapeutics, new engineering approaches to generate novel peptides should be developed. Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a group of peptides that have the potential to be effective scaffolds for in vivo peptide engineering projects. These natural RiPP peptides are enzymatically endowed with post-translational modifications (PTMs) that result in increased stability and greater target specificity. Many RiPPs, such as microcin J25 and micrococcin, can tolerate considerable amino acid sequence randomization while still being capable of receiving unique post-translational modifications. This thesis describes how we successfully engineered E. coli to produce the lasso peptide microcin J25 using a two-plasmid inducible expression system. In addition, we characterized the protein-protein interactions between PTM enzymes in the synthesis of micrococcin. The first step in micrococcin synthesis is the alteration of cysteines to thiazoles on the precursor peptide TclE. This step is accomplished by three proteins: TclI, TclJ, and TclN. We found that a 4-membered protein complex is formed consisting of TclI, TclJ, TclN, and TclE. Furthermore, the TclI protein functions as a central adaptor joining two other enzymes in the Tcl pathway with the substrate peptide.
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Adegoke, Yusuf Adeyemi. "Design and synthesis of new scaffolds as antiproliferative agents and potential hsp90 inhibitors". University of Western Cape, 2020. http://hdl.handle.net/11394/7722.
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Doctor Pharmaceuticae - DPharmNatural products have been an important source of drugs and novel lead compounds in drug discovery. Their unique scaffolds have led to the synthesis of derivatives that continue to give rise to medicinally relevant agents. Thus, natural product-inspired drugs represent a significant proportion of drugs in the market and with several more in development. Cancer is among the leading public health problems and a prominent cause of death globally. Chemotherapy has been important in the management of this disease even though side effects that arise due to lack of selectivity is still an issue.
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Rodriguez, Isaac. "Mineralization Potential of Electrospun PDO-nHA-Fibrinogen Scaffolds Intended for Cleft Palate Repair". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2111.
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The overall goal of this study was to identify mineralized scaffolds which can serve as potential alternatives to bone graft substitutes intended for cleft palate repair. The aim of this preliminary study was to evaluate the role of fibrinogen (Fg) and nano-hydroxyapatite (nHA) in enhancing mineralization potential of polydioxanone (PDO) electrospun scaffolds. Scaffolds were fabricated by blending PDO:nHA:Fg in the following weight ratios: 100:0:0, 50:25:25, 50:50:0, 50:0:50, 0:0:100 and 0:50:50. Scaffolds were immersed in different simulated body fluids for 5 and 14 days to induce mineralization. The inclusion of fibrinogen induced sheet-like mineralization while individual fiber mineralization was noticed in its absence. Modified protocols of alizarin red staining and burn-out test were developed to quantify mineral content of scaffolds. After mineralization, 50:50:0 scaffolds were still porous and contained the most mineral. 50:25:25 scaffolds had the highest mineralization potential but lacked porosity. Therefore, it can be anticipated that these mineralized organic-inorganic electrospun scaffolds will induce bone formation.
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Idahosa, Kenudi Christiana. "Bayliss-Hillman adducts as scaffolds for the construction of novel compounds with medicinal potential". Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1006763.
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This project has focused on exploring the application of Baylis-Hillman (BH) {a.k.a. Morita-Baylis-Hillman (MBH)} scaffolds in the construction of various compounds with medicinal potential. A series of 2-nitrobenzaldehydes has been treated under BH conditions, with two different activated alkenes, viz., (MVK) and methyl acrylate, using (DABCO) or (3-HQ) as catalyst. While most of the BH reactions were carried out at room temperature, some reactions were conducted using microwave irradiation. The resulting BH adducts have been subjected to dehydration, conjugate addition and allylic substitution to obtain appropriate intermediates, which have been used in turn, to synthesize possible lead compounds, viz., cinnamate esters as HIV-1 integrase inhibitors, 3-(aminomethyl)quinolines and quinolones as anti-malarials and cinnamate ester-AZT conjugates as dual-action HIV-1 integrase-reverse transcriptase (IN-RT) inhibitors. Conjugate addition reactions of methyl acrylate-derived BH β-hydroxy esters with the amines, piperidine, propargylamine and 2-amino-5-(diethylamino)pentane, has afforded a range of products as diastereomeric mixtures in moderate to excellent yields. Catalytic hydrogenation of the aminomethy β-hydroxy esters derivatives, using a palladium-oncarbon (Pd-C) catalyst, has afforded the corresponding, novel 3-aminomethyl-2- quinolone derivatives in moderate yields. Effective allylic substitution reactions of the MVK-derived BH β-hydroxy ketones (via a conjugate addition-elimination pathway) using in situ-generated HCl has afforded the corresponding α-chloromethyl derivatives, which have been reacted with various amines, including piperidine, piperazine, propargylamine and 2-amino-5-(diethylamino)pentane, to yield α-aminomethyl derivatives. Catalytic hydrogenation of selected α-aminomethyl derivatives, using a Pd-C catalyst, has afforded the corresponding, novel 3- (aminomethyl)-2-methylquinoline derivatives in low to moderate yields. A bioassay, conducted on a 6-hydroxy-2-methyl-3-[(piperidin-1-yl)methyl]quinoline isolated early in the study indicated anti-malarial activity and prompted further efforts in the synthesis of analogous compounds. Reaction of the methyl acrylate-derived BH adducts with POCl3 has provided access to α-(chloromethyl)cinnamate ester derivatives, which have been aminated to afford α- (aminomethyl)cinnamate ester derivatives as potential HIV-1 integrase inhibitors. The α- (propargylaminomethyl)cinnamates were used, in turn, as substrates for the “click chemistry” reaction with 3'-azido-3'-deoxythymidine (AZT– an azide and an established reverse transcriptase HIV-1 inhibitor) to afford cinnamate ester-AZT conjugates as potential dual-action HIV-1 integrase-reverse transcriptase (IN-RT) inhibitors. Computer modelling and docking studies of a cinnamate ester-AZT conjugate into the HIV-1 integrase and reverse transcriptase active-sites revealed potential hydrogen-bonding interactions with amino acid residues within the receptor cavities. The isolated products have been appropriately characterized using IR, 1- and 2-D NMR and HRMS techniques, while elucidation of the stereochemistry of the double bond in the BH-derived halomethyl derivatives has been assigned on the basis of NOE, computer modelling and X-ray crystallographic data.
Książki na temat "Potential Scaffolds"
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Lapaz Castillo, Jose Luis, Oscar Farrerons Vidal i Noelia Olmedo Torre. Research and Technology in Graphic Engineering and Design at the Universitat Politècnica de Catalunya. OmniaScience, 2022. http://dx.doi.org/10.3926/ege2022.
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The Department of Graphic Engineering and Design (DEGD) of the Polytechnic University of Catalonia has undergone continuous and rapid changes in its teaching and research methods in recent years. The DEGD has pursued continuous improvement in learning techniques in its Undergraduate, Master’s and Doctoral programs, striving for excellence, adapting to the increasingly more varied research needs demanded by society from institutions of higher education. We are experiencing paradigm shifts, to a great extent due to the global change affecting the Earth, and we cannot sit back and wait as a society or a department. It is for this reason that a large part of the research carried out recently is related to improved sustainability, investigating new materials, industrial processes, technologies and mechanisms to repurpose and recycle, as is evident in the chapters of the present book. Graphic Engineering and Design is present in the design methodologies used to design a competition motorcycle, in the study of the potential of cellulose as a sustainable material, in the learning about equidistant curves and the solving of tangency problems, in the quest for an alternative to materials derived from fossil resources, in the new production processes for e-commerce packaging, in additive manufacturing, in 3D printing, in the new design methods for porous scaffolds; cross-curricular and innovative knowledge that forms part of the research at DEGD.
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Butler, Mark James. Design and in vivo evaluation of the angiogenic potential of a poly(butyl methacrylate-co-methacrylic acid) tissue engineering scaffold. 2005.
Znajdź pełny tekst źródłaCzęści książek na temat "Potential Scaffolds"
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Gomes, Nelson G. M., Suradet Buttachon i Anake Kijjoa. "Meroterpenoids from Marine Microorganisms: Potential Scaffolds for New Chemotherapy Leads". W Handbook of Anticancer Drugs from Marine Origin, 323–66. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-07145-9_16.
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Rahaman, Mohamed N., B. Sonny Bal i Lynda F. Bonewald. "Potential of Bioactive Glass Scaffolds as Implants for Structural Bone Repair". W Advances in Bioceramics and Porous Ceramics VIII, 1–15. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119211624.ch1.
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Frejd, Fredrik Y. "Novel Alternative Scaffolds and Their Potential Use for Tumor Targeted Radionuclide Therapy". W Targeted Radionuclide Tumor Therapy, 89–116. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-8696-0_6.
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Montufar, Edgar B., Lucy Vojtova, Ladislav Celko i Maria-Pau Ginebra. "Calcium Phosphate Foams: Potential Scaffolds for Bone Tissue Modeling in Three Dimensions". W Methods in Molecular Biology, 79–94. New York, NY: Springer New York, 2017. http://dx.doi.org/10.1007/978-1-4939-7021-6_6.
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Deng, Xu Liang, M. M. Xu, Dan Li, Gang Sui, X. Y. Hu i Xiao Ping Yang. "Electrospun PLLA/MWNTs/HA Hybrid Nanofiber Scaffolds and Their Potential in Dental Tissue Engineering". W Key Engineering Materials, 393–96. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-422-7.393.
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Bölükbas, Deniz A., Martina M. De Santis, Hani N. Alsafadi, Ali Doryab i Darcy E. Wagner. "The Preparation of Decellularized Mouse Lung Matrix Scaffolds for Analysis of Lung Regenerative Cell Potential". W Methods in Molecular Biology, 275–95. New York, NY: Springer New York, 2019. http://dx.doi.org/10.1007/978-1-4939-9086-3_20.
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Witczak, Zbigniew J., Roman Bielski i Tomasz Poplawski. "Functionalized CARB Pharmacophore (FCP) approach to thio and unsaturated carbohydrate scaffolds with potential anticancer activity". W Carbohydrate Chemistry, 130–50. Cambridge: Royal Society of Chemistry, 2020. http://dx.doi.org/10.1039/9781788013864-00130.
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Rodriguez, Alexandra L., David R. Nisbet i Clare L. Parish. "The Potential of Stem Cells and Tissue Engineered Scaffolds for Repair of the Central Nervous System". W Stem Cells and Cancer Stem Cells, Volume 4, 97–111. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-2828-8_10.
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Lotan, E., i S. Einav. "Seeding Human Mesenchymal Stem Cells into Fibrin-Based Scaffolds - A Potential for a Future Angiogenic Therapy?" W IFMBE Proceedings, 260–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-03900-3_75.
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Wang, Wei, Lei Mei, Fan Wang, Baoqing Pei i Xiaoming Li. "The Potential Matrix and Reinforcement Materials for the Preparation of the Scaffolds Reinforced by Fibers or Tubes for Tissue Repair". W Tissue Repair, 25–77. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-3554-8_2.
Pełny tekst źródłaStreszczenia konferencji na temat "Potential Scaffolds"
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Egan, Paul, Stephen J. Ferguson i Kristina Shea. "Design and 3D Printing of Hierarchical Tissue Engineering Scaffolds Based on Mechanics and Biology Perspectives". W ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59554.
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Continued scientific research is crucial for developing new biomedical products, such as tissue engineering scaffolds, that are difficult to optimize due to the complexity of interfacing mechanical and biological systems. In this paper, mechanical and biological perspectives are used to propose and implement an approach for designing hierarchical scaffolds that provide structural support in the body as tissue regenerates. Three sequential steps are proposed for defining design needs, generating design alternatives, and fabricating design prototypes. Design needs are determined by considering mechanical and biological performance requirements, experimental procedures, and fabrication constraints. The primary mechanical requirement is a scaffold’s need to maintain structural integrity, while biologically the scaffold should promote cellular growth. Scaffold design alternatives of four topology types are generated by altering design parameters that describe a scaffold’s structure. Trade-offs are revealed for scaffold porosity and surface area properties that are known to influence mechanical and biological scaffold performance. Scaffolds of each topology type are designed with 80% porosity and fabricated, which enables their potential use in scientific experiments to measure how property trade-offs influence scaffold performance. On the basis of currently available knowledge, a to-scale spinal scaffold implant is designed and fabricated with a graphically maximized surface area to porosity ratio for a hierarchical scaffold, which represents a potentially high performing design from both mechanical and biological perspectives. These results demonstrate the importance of multidisciplinary approaches for designing complex biomedical tissue scaffolds that could significantly improve healthcare through the development of new clinical products.
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Lawrence, Logan, James B. Day, Pier Paolo Claudio i Roozbeh (Ross) Salary. "Investigation of the Regenerative Potential of Human Bone Marrow Stem Cell-Seeded Polycaprolactone Bone Scaffolds, Fabricated Using Pneumatic Microextrusion Process". W ASME 2021 16th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/msec2021-63411.
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Abstract Pneumatic MicroExtrusion (PME) is a direct-write additive manufacturing process, which has emerged as a robust, high-resolution method for the fabrication of a broad spectrum of biological tissues and organs. However, the PME process is intrinsically complex, governed by bio-physio-chemical phenomena as well as material-process interactions. Hence, investigation of the influence of consequential factors on bone scaffold fabrication as well as investigation of cell-scaffold interactions would be an inevitable need. The objective of the work is to investigate the biocompatibility as well as the histological properties of PME-fabricated porous bone scaffolds, composed of polycaprolactone (PCL). To achieve this objective, a media extraction of the scaffold material was tested for cytostatic or cytotoxic activity with the aim to: (i) assess the fabricated scaffolds’ feasibility of use in regenerative medicine, and (ii) determine their structural integrity in a modelled in-vivo environment. In addition, the scaffolds were inoculated with an established osteosarcoma cell line (SAOS-2) and cultured for seven days to investigate the scaffold architecture and cell integration potential. A histological examination was performed on the seeded scaffolds for further in-depth analysis of cell-scaffold interaction. Overall, the results of this study pave the way for future investigation of stem cell incorporation into PME-fabricated PCL scaffolds toward the treatment of osseous fractures and defects.
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Nowlin, John, Md Maksudul Islam, Yingge Zhou i George Z. Tan. "Cone Electrospinning Polycaprolactone / Collagen Scaffolds With Microstructure Gradient". W ASME 2019 14th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/msec2019-2871.
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Abstract Polycaprolactone (PCL) is a synthetic biomaterial that has been widely used for tissue engineering scaffolds. Collagen, a natural polymer found in various tissues in the human body, can be electrospun in combination with PCL to improve the scaffold’s biological characteristics for cell attachment, growth and differentiation. Recreating the physical structure which mimics the extracellular matrix of musculoskeletal tissues generally requires fibrous patterns, including aligned, random, or a mixture of both to form a gradient structure. This study introduced a novel cone rotation electrospinning technique for nanofiber scaffold with microstructure gradient. The effects of key process parameters on nanofiber attributes were evaluated through a factorial design of experiment. We found that changing the rotation speed, electrospinning distance, and position on the cone had significant effects on the structure gradient of nanofiber mats. This cone rotation technique extends the capability of conventional electrospinning to create tunable anisotropic nanofiber scaffolds as potential biomimetic solutions for tissue regeneration.
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Lu, Lin, David Wootton, Peter I. Lelkes i Jack Zhou. "Study of Structured Porogen Method for Bone Scaffold Fabrication". W ASME 2008 International Manufacturing Science and Engineering Conference collocated with the 3rd JSME/ASME International Conference on Materials and Processing. ASMEDC, 2008. http://dx.doi.org/10.1115/msec_icmp2008-72134.
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The increasing demand on bone scaffolds has promoted the development of tissue engineering fabrication technique for manufacturing bone scaffold. In this study, a novel structured porogen method for bone scaffold fabrication has been explored. This method has demonstrated highly efficient and reproducible fabrication of structured bone scaffolds which mimics the bone structure. By using commercially available Drop on Demand (DDP) system and three dimensional printer (3-DP) system, at first designed structured porogens can be manufactured, and then bone scaffolds can be fabricated by injecting the biocomposite materials into the porogens. The mechanical properties of the fabricated scaffolds using DDP system have been characterized. The biocompatibility of our fabricated scaffolds using 3-DP has been examined. With incorporating of bioactive calcium phosphate into the composite materials, the mechanical strength and bioactivity of the scaffolds made by the structured porogen method can be improved significantly. This structured porogen method has a potential to be used on various Solid Freeform Fabrication systems which allows each system to use a single ubiquitous building material to fabricate multiple biomaterial scaffolds with sufficient mechanical integrity.
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Gilbert, Thomas W., James H. C. Wang, Stephen F. Badylak i Savio L. Y. Woo. "Development of a Novel Model System to Study Remodeling of ECM Scaffolds in Response to Cyclic Stretching". W ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41444.
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In an effort to better understand the role of mechanical loading on the healing and remodeling of biological tissues, a number of in vitro models have been developed to apply either static or cyclic mechanical load to cell-seeded scaffolds (Huang 1993, Langelier 1999, Cacou 2000). The current study describes the validation of a new system designed to facilitate the study of matrix remodeling in cell seeded scaffolds, as well as the formation of tissue engineered scaffolds for potential use in repair of healing ligaments and tendons. Our objective was to develop a system that would allow a cell seeded scaffold to remain viable under cyclic loading for long periods of time, with the capability to apply complex loading regimes to the scaffold while monitoring the load in the scaffold.
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Lee, Se-Jun, Wei Zhu i Lijie Grace Zhang. "Development of Novel 3D Scaffolds With Embedded Core-Shell Nanoparticles for Nerve Regeneration". W ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51595.
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Neural tissue engineering has emerged as a promising alternative to address various nerve injuries. Particularly, advancement in both 3D biomimetic scaffold fabrication strategies and nanotechnology has inspired this field into a new era. In this study, we fabricated a novel 3D biomimetic scaffold, which has tunable porous structure and embedded core-shell nanoparticles with neurogenic factor delivery system, using stereolithography (SL) based 3D printing and core-shell electrospraying techniques. Our results indicated that scaffolds with higher porosity significantly improve PC-12 neural cell adhesion compared to ones with smaller porosity. Furthermore, scaffolds embedded bovine serum albumin (BSA) containing nanoparticles showed an enhancement in cell proliferation relative to bared control scaffolds. In addition, confocal microscopy images illustrated that the scaffold with nerve growth factor (NGF) nanoparticles increased the length of neuritis and directed neurite extension of PC-12 cells along the fiber. The results in this study demonstrate the potential of this 3D scaffold in improving neural cell function and nerve growth.
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Tourlomousis, Filippos, Houzhu Ding, Antonio Dole i Robert C. Chang. "Towards Resolution Enhancement and Process Repeatability With a Melt Electrospinning Writing Process: Design and Protocol Considerations". W ASME 2016 11th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/msec2016-8774.
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With recent advancements in the direct electrostatic printing of highly viscous thermoplastic polymers onto an automated collector, melt electrospinning writing technology (MEW) has shown great potential for addressing the fundamental effects of an engineered scaffold’s dimensional parameters (e.g. fiber diameter, apparent pore size, and pore shape) on cultured cell–scaffold interactions. The superior resolution obtainable with MEW compared to conventional extrusion-based 3D printing technologies and its ability for toolpath-controlled fiber printing can facilitate the creation of a complex cell microenvironment or niche. Such a cell niche would provide the microscale fiber diameter and pore size for a scaffold substrate to present dimensional cues that affect downstream cellular function. In this study, the authors present in detail the design of a custom MEW system that allows simultaneous thermal management in the material, spin-line, and collector regimes using a heat gun. The complex interplay of process and instrument-based parameters is clarified with respect to stable jet formation allowing the printing of scaffolds with various microstructural patterned cues and consistent fiber diameter in a reproducible manner. Current fabrication of high fidelity scaffolds requires that the ratio of inter-fiber distance to fiber diameter to be an approximate value of 10. Since this manufacturing challenge yields pore sizes that are prohibitively large for 3D cell culture studies, particular emphasis is given in this paper to address the underlying physical mechanisms that will enable the fabrication of pore sizes with MEW scaffolds at cellular-relevant fiber diameters (10 – 50 μm). The authors show that appropriate toolpath planning that takes into account the different modes of the process can improve the inter-fiber distance resolution and thus the scaffold’s apparent pore size.
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Wu, Y., J. Y. H. Fuh, Y. S. Wong i J. Sun. "Fabrication of 3D Scaffolds via E-Jet Printing for Tendon Tissue Repair". W ASME 2015 International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/msec2015-9367.
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Current clinical grafts used in tendon treatment are subject to several restrictions and there is a significant demand for alternative engineered tissue. The previously reported tendon scaffolds mainly based on electrospinning and textile technologies showed promising results for tendon regeneration. However, limitations, such as small pore size, nutrition transmission, cell attachment, exist universally in such scaffolds. In this work, a novel tissue engineered polycaprolactone (PCL) tendon scaffold based on electrohydrodynamic jet printing (E-Jetting) was developed for investigation. In preliminary in-vitro study, human tenocytes were seeded in scaffolds with pore size of ∼106 μm to investigate the cell attachment, morphology and alignment. This study suggested that E-jetted tendon scaffold highly mimicked hierarchical construction from fiber to fascicle level of the native tendon, and has potential to be an alternative tendon regeneration tool.
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Chinnasami, H., i R. Devireddy. "Osteo-Induction of Human Adipose Derived Stem Cells Cultured on Poly (L-Lactic Acid) Scaffolds Prepared by Thermally Induced Phase Separation Method". W ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51906.
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Bio-degradable Poly (l-lactic acid) (PLLA) scaffolds synthesized using thermally induced phase separation (TIPS) method was used to load cryo-preserved human adipose derived stem cells (hASCs). To make the scaffolds, PLLA-Dioxane solutions were formed by dissolving PLLA in 1,4-Dioxane with three different compositions (wt/vol). These PLLA-Dioxane solutions, frozen in three different cooling rates were lyophilized at 0.037bar and −70°C for 48hrs resulting in porous PLLA scaffolds. Based on the porosity, pore size and compressive strength, a suitable scaffold was chosen to investigate its bio-compatibility and osteo-inductive potential.
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Shanjani, Yaser, Naveen Chandrashekar i Ehsan Toyserkani. "Prediction of Biomechanical Properties of Bone Implant Scaffolds". W ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43001.
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This work is concerned with the 3D finite element modeling of porous implants in which the pore characteristics and distribution are taken into account. The analysis is conducted for scaffolds composed of various biocompatible materials such as Hydroxyapatite, PMMA, PEEK, Ti-6Al-4V, Silicon Nitride, Zirconia and Alumina. Furthermore, the potential of bone growth within the scaffolds is investigated using principal strain histograms of loaded scaffolds. The results show that the histogram of the principal strain resembles a top hat distribution while the porosity (void fraction) decreases. For a specific porosity, the principal strain distribution falls within the desired region (for optimal bone growth) by selecting materials with some particular Poisson’s ratio, although stress-shielding possibility rises due to an increase in the apparent stiffness of the scaffold. The increase in the apparent stiffness is a result of high Young modulus of the above-mentioned materials. The model will provide a platform for designers to adjust internal architecture features (e.g., the porosity level, shape/size/orientation of pores and the material properties) based on the host bone data prior to the scaffold fabrication.
Raporty organizacyjne na temat "Potential Scaffolds"
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Hassan, Mozan, Abbas Khaleel, Sherif Karam, Ali Al-Marzouqi, Ihtesham Ur Rehman i Sahar Mohsin. Bacterial inhibition and osteogenic potentials of Sr/Zn co-doped nano-hydroxyapatite-PLGA composite scaffold for bone tissue engineering applications. Peeref, czerwiec 2023. http://dx.doi.org/10.54985/peeref.2306p7862520.
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Morrison, Mark, Joshuah Miron, Edward A. Bayer i Raphael Lamed. Molecular Analysis of Cellulosome Organization in Ruminococcus Albus and Fibrobacter Intestinalis for Optimization of Fiber Digestibility in Ruminants. United States Department of Agriculture, marzec 2004. http://dx.doi.org/10.32747/2004.7586475.bard.
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Improving plant cell wall (fiber) degradation remains one of the highest priority research goals for all ruminant enterprises dependent on forages, hay, silage, or other fibrous byproducts as energy sources, because it governs the provision of energy-yielding nutrients to the host animal. Although the predominant species of microbes responsible for ruminal fiber degradation are culturable, the enzymology and genetics underpinning the process are poorly defined. In that context, there were two broad objectives for this proposal. The first objective was to identify the key cellulosomal components in Ruminococcus albus and to characterize their structural features as well as regulation of their expression, in response to polysaccharides and (or) P AA/PPA. The second objective was to evaluate the similarities in the structure and architecture of cellulosomal components between R. albus and other ruminal and non-ruminal cellulolytic bacteria. The cooperation among the investigators resulted in the identification of two glycoside hydrolases rate-limiting to cellulose degradation by Ruminococcus albus (Cel48A and CeI9B) and our demonstration that these enzymes possess a novel modular architecture specific to this bacterium (Devillard et al. 2004). We have now shown that the novel X-domains in Cel48A and Cel9B represent a new type of carbohydrate binding module, and the enzymes are not part of a ceiluiosome-like complex (CBM37, Xu et al. 2004). Both Cel48A and Cel9B are conditionally expressed in response to P AA/PPA, explaining why cellulose degradation in this bacterium is affected by the availability of these compounds, but additional studies have shown for the first time that neither PAA nor PPA influence xylan degradation by R. albus (Reveneau et al. 2003). Additionally, the R. albus genome sequencing project, led by the PI. Morrison, has supported our identification of many dockerin containing proteins. However, the identification of gene(s) encoding a scaffoldin has been more elusive, and recombinant proteins encoding candidate cohesin modules are now being used in Israel to verify the existence of dockerin-cohesin interactions and cellulosome production by R. albus. The Israeli partners have also conducted virtually all of the studies specific to the second Objective of the proposal. Comparative blotting studies have been conducted using specific antibodies prepare against purified recombinant cohesins and X-domains, derived from cellulosomal scaffoldins of R. flavefaciens 17, a Clostridium thermocellum mutant-preabsorbed antibody preparation, or against CbpC (fimbrial protein) of R. albus 8. The data also suggest that additional cellulolytic bacteria including Fibrobacter succinogenes S85, F. intestinalis DR7 and Butyrivibrio fibrisolvens Dl may also employ cellulosomal modules similar to those of R. flavefaciens 17. Collectively, our work during the grant period has shown that R. albus and other ruminal bacteria employ several novel mechanisms for their adhesion to plant surfaces, and produce both cellulosomal and non-cellulosomal forms of glycoside hydrolases underpinning plant fiber degradation. These improvements in our mechanistic understanding of bacterial adhesion and enzyme regulation now offers the potential to: i) optimize ruminal and hindgut conditions by dietary additives to maximize fiber degradation (e.g. by the addition of select enzymes or PAA/PPA); ii) identify plant-borne influences on adhesion and fiber-degradation, which might be overcome (or improved) by conventional breeding or transgenic plant technologies and; iii) engineer or select microbes with improved adhesion capabilities, cellulosome assembly and fiber degradation. The potential benefits associated with this research proposal are likely to be realized in the medium term (5-10 years).