Academic literature on the topic 'Cell-free scaffolds'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Cell-free scaffolds.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Cell-free scaffolds"
1
Kwan, Haowen, Emanuele Chisari, and Wasim S. Khan. "Cell-Free Scaffolds as a Monotherapy for Focal Chondral Knee Defects." Materials 13, no. 2 (January 9, 2020): 306. http://dx.doi.org/10.3390/ma13020306.
Full textAbstract:
Chondral knee defects have a limited ability to be repaired. Current surgical interventions have been unable to regenerate articular cartilage with the mechanical properties of native hyaline cartilage. The use of a scaffold-based approach is a potential solution. Scaffolds are often implanted with cells to stimulate cartilage regeneration, but cell-based therapies are associated with additional regulatory restrictions, an additional surgical procedure for cell harvest, time for cell expansion, and the associated costs. To overcome these disadvantages, cell-free scaffolds can be used in isolation allowing native cells to attach over time. This review discusses the optimal properties of scaffolds used for chondral defects, and the evidence for the use of hydrogel scaffolds and hydrogel–synthetic polymer hybrid scaffolds. Preclinical and clinical studies have shown that cell-free scaffolds can support articular cartilage regeneration and have the potential to treat chondral defects. However, there are very few studies in this area and, despite the many biomaterials tested in cell-based scaffolds, most cell-free studies focused on a specific type I collagen scaffold. Future studies on cell-free scaffolds should adopt the modifications made to cell-based scaffolds and replicate them in the clinical setting. More studies are also needed to understand the underlying mechanism of cell-free scaffolds.
2
Valdoz, Jonard Corpuz, Benjamin C. Johnson, Dallin J. Jacobs, Nicholas A. Franks, Ethan L. Dodson, Cecilia Sanders, Collin G. Cribbs, and Pam M. Van Ry. "The ECM: To Scaffold, or Not to Scaffold, That Is the Question." International Journal of Molecular Sciences 22, no. 23 (November 24, 2021): 12690. http://dx.doi.org/10.3390/ijms222312690.
Full textAbstract:
The extracellular matrix (ECM) has pleiotropic effects, ranging from cell adhesion to cell survival. In tissue engineering, the use of ECM and ECM-like scaffolds has separated the field into two distinct areas—scaffold-based and scaffold-free. Scaffold-free techniques are used in creating reproducible cell aggregates which have massive potential for high-throughput, reproducible drug screening and disease modeling. Though, the lack of ECM prevents certain cells from surviving and proliferating. Thus, tissue engineers use scaffolds to mimic the native ECM and produce organotypic models which show more reliability in disease modeling. However, scaffold-based techniques come at a trade-off of reproducibility and throughput. To bridge the tissue engineering dichotomy, we posit that finding novel ways to incorporate the ECM in scaffold-free cultures can synergize these two disparate techniques.
3
Xu, Shanglong, Yue Yang, Xibin Wang, and Chaofeng Wang. "Branched Channel Scaffolds Fabricated by SFF for Direct Cell Growth Observations." Journal of Bioactive and Compatible Polymers 24, no. 1_suppl (May 2009): 63–74. http://dx.doi.org/10.1177/0883911509103602.
Full textAbstract:
A β-TCP scaffold with a branched channel system was designed to create a novel micro-device that allowed culture perfusion and direct time observation of the cells attached. The scaffold was made by indirect solid free form fabrication (SFF) technology. The flow channel structure was exposed so that the perfusion of the mesenchymal stem cell (MSC) culture could be viewed directly. The cell-seeded scaffolds were continuously perfused for 7 days in the micro-device; during this time, it was possible to observe the dynamic culture processes with cells adhering to the scaffolds and real time cell growth directly. This concept has great potential for use in bone tissue engineering and for versatile fabrication of enhanced scaffolds.
4
Barreto, Rodrigo SN, Patricia Romagnolli, Paula Fratini, Andrea Maria Mess, and Maria Angelica Miglino. "Mouse placental scaffolds: a three-dimensional environment model for recellularization." Journal of Tissue Engineering 10 (January 2019): 204173141986796. http://dx.doi.org/10.1177/2041731419867962.
Full textAbstract:
The rich extracellular matrix (ECM) and availability make placenta eligible as alternative biomaterial source. Herein we produced placental mouse scaffolds by decellularization, and structure, composition, and cytocompatibility were evaluated to be considered as a biomaterial. We obtained a cell-free scaffold containing 9.42 ± 5.2 ng dsDNA per mg of ECM, presenting well-preserved structure and composition. Proteoglycans were widespread throughout ECM without cell nuclei and cell remnants. Collagen I, weak in native placenta, clearly appears in the scaffold after recellularization, opposite distribution was observed for collagen III. Fibronectin was well-observed in placental scaffolds whereas laminin and collagen IV were strong expressed. Placental scaffolds recellularization potential was confirmed after mouse embryonic fibroblasts 3D dynamic culture, resulting in massive scaffold repopulation with cell–cell interactions, cell-matrix adhesion, and maintenance of natural morphology. Our small size scaffolds provide a useful tool for tissue engineering to produce grafts and organ fragments, as well as for cellular biology purposes for tridimensional culture substrate.
5
Khandaker, Morshed, Hembafan Nomhwange, Helga Progri, Sadegh Nikfarjam, and Melville B. Vaughan. "Evaluation of Polycaprolactone Electrospun Nanofiber-Composites for Artificial Skin Based on Dermal Fibroblast Culture." Bioengineering 9, no. 1 (January 6, 2022): 19. http://dx.doi.org/10.3390/bioengineering9010019.
Full textAbstract:
The study’s aim was to develop a dermal equivalent scaffold that can mimic the architecture and biological performance of the human dermis. Poly ε-caprolactone (PCL) electrospun nanofiber material (ENF) was assembled with polyethylene glycol diacrylate (PEGDA), sodium alginate (SA) and type I collagen (CG1) to develop three groups of dermal equivalent scaffolds. These scaffolds were named PEGDA-PCL, SA-PCL and CG1-PCL. Scanning electron microscopy (SEM) images of cell-free scaffolds’ top and cross-sectional surface were collected and analyzed to examine internal morphology, specifically the adhesiveness of PCL fibers with the different scaffolds. Human dermal fibroblasts were cultured on each of the scaffolds. Cell viability studies including cell adhesion, cell differentiation and stress fiber production were conducted on each scaffold. Furthermore, the architectural integrity of each scaffold was verified by degradation analysis for 2 weeks by soaking each scaffold in phosphate-buffered saline (PBS) solution. Finally, we conducted rheological characteristics of each scaffold. Based on our results from the above analysis, the study concluded that CG1-PCL is best suitable for the dermal equivalent model and has potential to be used as a graft for skin repair.
6
Soares, D. G., E. A. F. Bordini, E. S. Bronze-Uhle, F. B. Cassiano, I. S. P. Silva, M. O. Gallinari, H. R. Matheus, et al. "Chitosan-Calcium-Simvastatin Scaffold as an Inductive Cell-Free Platform." Journal of Dental Research 100, no. 10 (July 27, 2021): 1118–26. http://dx.doi.org/10.1177/00220345211024207.
Full textAbstract:
The development of biomaterials based on the combination of biopolymers with bioactive compounds to develop delivery systems capable of modulating dentin regeneration mediated by resident cells is the goal of current biology-based strategies for regenerative dentistry. In this article, the bioactive potential of a simvastatin (SV)–releasing chitosan-calcium-hydroxide (CH-Ca) scaffold was assessed. After the incorporation of SV into CH-Ca, characterization of the scaffold was performed. Dental pulp cells (DPCs) were seeded onto scaffolds for the assessment of cytocompatibility, and odontoblastic differentiation was evaluated in a microenvironment surrounded by dentin. Thereafter, the cell-free scaffold was adapted to dentin discs positioned in artificial pulp chambers in direct contact with a 3-dimensional (3D) culture of DPCs, and the system was sealed to simulate internal pressure at 20 cm/H2O. In vivo experiments with cell-free scaffolds were performed in rats’ calvaria defects. Fourier-transform infrared spectroscopy spectra proved incorporation of Ca and SV into the scaffold structure. Ca and SV were released upon immersion in a neutral environment. Viable DPCs were able to spread and proliferate on the scaffold over 14 d. Odontoblastic differentiation occurred in the DPC/scaffold constructs in contact with dentin, in which SV supplementation promoted odontoblastic marker overexpression and enhanced mineralized matrix deposition. The chemoattractant potential of the CH-Ca scaffold was improved by SV, with numerous viable and dentin sialoprotein–positive cells from the 3D culture being observed on its surface. Cells at 3D culture featured increased gene expression of odontoblastic markers in contact with the SV-enriched CH-Ca scaffold. CH-Ca-SV led to intense mineralization in vivo, presenting mineralization foci inside its structure. In conclusion, the CH-Ca-SV scaffold induces differentiation of DPCs into a highly mineralizing phenotype in the presence of dentin, creating a microenvironment capable of attracting pulp cells to its surface and inducing the overexpression of odontoblastic markers in a cell-homing strategy.
7
Lahner, Matthias, Christian Duif, Andreas Ficklscherer, Christian Kaps, Lukas Kalwa, and Tobias Seidl. "Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study." BioMed Research International 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/717912.
Full textAbstract:
This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10 mm × 15 mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds(P=0.03752, P=0.03078, P=0.00512, P=0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation.
8
Mattioli-Belmonte, Monica, Francesca Montemurro, Caterina Licini, Iolanda Iezzi, Manuela Dicarlo, Giorgia Cerqueni, Florinda Coro, and Giovanni Vozzi. "Cell-Free Demineralized Bone Matrix for Mesenchymal Stem Cells Survival and Colonization." Materials 12, no. 9 (April 26, 2019): 1360. http://dx.doi.org/10.3390/ma12091360.
Full textAbstract:
Decellularized bone matrix is receiving much attention as biological scaffolds and implantable biomaterials for bone tissue regeneration. Here, we evaluated the efficacy of a cell-free demineralized bone matrix on mesenchymal stem cells (MSCs) survival and differentiation in vitro. The seeding of human umbilical cord-derived MSCs (hUC-SCs) on decellularized bone matrices up to 14 days was exploited, assessing their capability of scaffold colonization and evaluating gene expression of bone markers. Light and Scanning Electron Microscopies were used. The obtained cell-free decalcified structures showed elastic moduli attributable to both topology and biochemical composition. Morphological observation evidenced an almost complete colonization of the scaffolds after 14 days of culture. Moreover, in hUC-SCs cultured on decalcified scaffolds, without the addition of any osteoinductive media, there was an upregulation of Collagen Type I (COL1) and osteonectin (ON) gene expression, especially on day 14. Modifications in the expression of genes engaged in stemness were also detected. In conclusion, the proposed decellularized bone matrix can induce the in vitro hUC-SCs differentiation and has the potential to be tested for in in vivo tissue regeneration.
9
Huang, Zhao, Benjamin Kohl, Maria Kokozidou, Stephan Arens, and Gundula Schulze-Tanzil. "Establishment of a Cytocompatible Cell-Free Intervertebral Disc Matrix for Chondrogenesis with Human Bone Marrow-Derived Mesenchymal Stromal Cells." Cells Tissues Organs 201, no. 5 (2016): 354–65. http://dx.doi.org/10.1159/000444521.
Full textAbstract:
Tissue-engineered intervertebral discs (IVDs) utilizing decellularized extracellular matrix (ECM) could be an option for the reconstruction of impaired IVDs due to degeneration or injury. The objective of this study was to prepare a cell-free decellularized human IVD scaffold and to compare neotissue formation in response to recellularization with human IVD cells (hIVDCs) or human bone marrow-derived (hBM) mesenchymal stromal cells (MSCs). IVDs were decellularized via freeze-thaw cycles, detergents and trypsin. Histological staining was performed to monitor cell removal and glycosaminoglycan (GAG) removal. The decellularized IVD was preconditioned using bovine serum albumin and fetal bovine serum before its cytocompatibility for dynamically cultured hBM-MSCs (chondrogenically induced or not) and hIVDCs was compared after 14 days. In addition, DNA, total collagen and GAG contents were assessed. The decellularization protocol achieved maximal cell removal, with only few remaining cell nuclei compared with native tissue, and low toxicity. The DNA content was significantly higher in scaffolds seeded with hIVDCs compared with native IVDs, cell-free and hBM-MSC-seeded scaffolds (p < 0.01). The GAG content in the native tissue was significantly higher compared to the others groups except for the scaffolds reseeded with chondrogenically induced hBM-MSCs (p < 0.05). In addition, there was a significantly increased total collagen content in the chondrogenically induced hBM-MSCs group (p < 0.01) compared with the native IVDs, cell-free and hIVDC-seeded scaffolds (p < 0.01); both recolonizing cell types were more evenly distributed on the scaffold surface, but only few cells penetrated the scaffold. The resulting decellularized ECM was cytocompatible and allowed hBM-MSCs/hIVDCs survival and ECM production.
10
Salerno, Aurelio, Giuseppe Cesarelli, Parisa Pedram, and Paolo Antonio Netti. "Modular Strategies to Build Cell-Free and Cell-Laden Scaffolds towards Bioengineered Tissues and Organs." Journal of Clinical Medicine 8, no. 11 (November 1, 2019): 1816. http://dx.doi.org/10.3390/jcm8111816.
Full textAbstract:
Engineering three-dimensional (3D) scaffolds for functional tissue and organ regeneration is a major challenge of the tissue engineering (TE) community. Great progress has been made in developing scaffolds to support cells in 3D, and to date, several implantable scaffolds are available for treating damaged and dysfunctional tissues, such as bone, osteochondral, cardiac and nerve. However, recapitulating the complex extracellular matrix (ECM) functions of native tissues is far from being achieved in synthetic scaffolds. Modular TE is an intriguing approach that aims to design and fabricate ECM-mimicking scaffolds by the bottom-up assembly of building blocks with specific composition, morphology and structural properties. This review provides an overview of the main strategies to build synthetic TE scaffolds through bioactive modules assembly and classifies them into two distinct schemes based on microparticles (µPs) or patterned layers. The µPs-based processes section starts describing novel techniques for creating polymeric µPs with desired composition, morphology, size and shape. Later, the discussion focuses on µPs-based scaffolds design principles and processes. In particular, starting from random µPs assembly, we will move to advanced µPs structuring processes, focusing our attention on technological and engineering aspects related to cell-free and cell-laden strategies. The second part of this review article illustrates layer-by-layer modular scaffolds fabrication based on discontinuous, where layers’ fabrication and assembly are split, and continuous processes.
Dissertations / Theses on the topic "Cell-free scaffolds"
1
Hulsart, Billström Gry. "Bone Regeneration with Cell-free Injectable Scaffolds." Doctoral thesis, Uppsala universitet, Ortopedi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-234846.
Full textAbstract:
Bone is a remarkable multifunctional tissue with the ability to regenerate and remodel without generating any scar tissue. However, bone loss due to injury or diseases can be a great challenge and affect the patient significantly. Transplanting bone graft from one site in the patient to the site of fracture or bone void, i.e. autologous bone grafting is commonly used throughout the world. The transplanted bone not only fills voids, but is also bone inductive, housing the particular cells that are needed for bone regeneration. Nevertheless, a regenerative complement to autograft is of great interest and importance because the benefits from an off-the-shelf product with as good of healing capacity as autograft will circumvent most of the drawbacks with autograft. With a regenerative-medicine approach, the use of biomaterials loaded with bioactive molecules can avoid donor site morbidity and the problem of limited volume of material. Two such regenerative products that utilize bone morphogenetic protein 7 and 2 have been used for more than a decade in the clinic. However, some severe side effects have been reported, such as severe swelling due to inflammation and ectopic bone formation. Additionally, the products require open surgery, use of supra physiological doses of the BMPs due to poor localization and retention of the growth factors. The purpose of this thesis was to harness the strong inductive capability of the BMP-2 by optimizing the carrier of this bioactive protein, thereby minimizing the side effects that are associated with the clinical products and facilitating safe and localized bone regeneration at the desired site. We focused on an injectable hyaluronan-based carrier. The strategy was to use the body’s own regenerative pathway to stimulate and enhance bone healing in a manner similar to the natural bone-healing process. The hyaluronan-based carrier has a similar composition to the natural extracellular matrix and is degraded by resident hyaluronidase enzymes. Earlier studies have shown a more controlled release and improved mechanical properties when adding a weight of 25 percent of hydroxyapatite, a calcium phosphate that constitutes the inorganic part of the bone matrix. In Paper I, the aim was to improve the carrier by adding other forms of calcium phosphate. The results indicated that the bone formation was enhanced when using nano-sized hydroxyapatite. We wished to further develop the carrier system but were lacking an animal model with high output and easy access. We also wanted to provide paired data and were committed to the 3 Rs of refinement, reduction and replacement. To meet these challenges, we developed and refined an animal model, and this is described in Paper II. In Paper III, we characterized and optimized the handling properties of the carrier. In Paper IV, we discovered the importance of crushing the material, thus enhancing permeability and enlarging the surface area. In Paper V, we sought to further optimize biomaterial properties of the hydrogel through covalently bonding of bisphosphonates to the hyaluronan hydrogel. The results demonstrated exceptional retention of the growth factor BMP-2. In Paper VI, the in vivo response related to the release of the growth factor was examined by combining a SPECT/PET/µCT imaging method to visualize both the retention of the drug, and the in-vivo response in terms of mineralization.
2
Hulsart, Billström Gry. "Bone Regeneration with Cell-free Injectable Scaffolds." Doctoral thesis, Uppsala universitet, Ortopedi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-310312.
Full textAbstract:
Bone is a remarkable multifunctional tissue with the ability to regenerate and remodel without generating any scar tissue. However, bone loss due to injury or diseases can be a great challenge and affect the patient significantly. Autologous bone grafting is commonly used throughout the world. Autograft both fills the void and is bone inductive, housing the particular cells that are needed for bone regeneration. However, a regenerative complement to autograft is of great interest as the use of biomaterials loaded with bioactive molecules can avoid donor site morbidity and the problem of a limited volume of material. Two such regenerative products that utilise bone morphogenetic protein (BMP)-7 and -2 have been used for more than a decade clinically. Unfortunately, several side effects have been reported, such as severe swelling due to inflammation and ectopic bone formation. Additionally, the products require open surgery and use of supra physiological doses of the BMPs due to poor localisation and retention of the growth factor. The purpose of this thesis was to harness the strong inductive capacity of the BMP-2 by optimising the carrier of this bioactive protein, thereby minimising the side effects that are associated with the clinical products and facilitating safe and localised bone regeneration. We focused on an injectable hyaluronan-based carrier developed through polymer chemistry at the University of Uppsala. The strategy was to use the body’s own regenerative pathway to stimulate and enhance bone healing in a manner similar to the natural bone-healing process. The hyaluronan-based carrier has a similar composition to the natural extracellular matrix and is degraded by resident enzymes. Earlier studies have shown improved properties when adding hydroxyapatite, a calcium phosphate that constitutes the inorganic part of the bone matrix. In Paper I, the aim was to improve the carrier by adding other forms of calcium phosphate. The results indicated that bone formation was enhanced when using nano-sized hydroxyapatite. In Paper II, we discovered the importance of crushing the material, thus enhancing permeability and enlarging the surface area. We wished to further develop the carrier system, but were lacking an animal model with relatively high throughput, facilitated access, paired data, and we were also committed to the 3Rs of refinement, reduction, and replacement. To meet these challenges, we developed and refined an animal model, and this is described in Paper III. In Paper IV, we sought to further optimise the biomaterial properties of the hydrogel through covalent bonding of bisphosphonates to the hyaluronan hydrogel. This resulted in exceptional retention of the growth factor BMP-2. In Paper V, SPECT/PET/µCT was combined as a tri-modal imaging method to allow visualisation of the biomaterial’s in situ action, in terms of drug retention, osteoblast activity and mineralisation. Finally, in Paper VI the correlation between existing in vitro results with in vivo outcomes was observed for an array of biomaterials. The study identified a surprisingly poor correlation between in vitro and in vivo assessment of biomaterials for osteogenesis.
3
Rice, Maryjoe Kathryn. "Programmable Microparticle Scaffolds for Enhanced Diagnostic Devices." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78267.
Full textAbstract:
Microrobotics is an emerging discipline with the potential to radically affect fields ranging from medicine to environmental stewardship. Already, there have been remarkable breakthroughs; small scale robots have been made that can selectively traverse the gastrointestinal tract, and others have been built that can fly in a manner inspired from bees. However, there are still significant challenges in microrobotics, and it remains difficult to engineer reliable power sources, actuators, and sensors to create robust, modular designs at the microscale. The miniaturization of the robotic system makes design and efficiency of these components particularly difficult. However, biological systems demonstrate the key features of robotics " sensing, actuation, processing" and are remarkably complex at the microscale. As such, many researchers have turned to biology for inspiration and living robotic components. In our laboratory we have engineered an Escherichia coli (E. coli) capable of producing surface display proteins to either anchor the cells, bind to functionalized nanoparticles, or capture small molecules from the environment, all complex actuation features. Additionally, we have created a processing unit that can create signals based on biological components, yet is non-living. This thesis focuses on the characterization of the surface display E. Coli system and the creation of programmable microparticle scaffolds that may be controlled by biological circuitry. In particular, by leveraging the strong interaction between biotin and streptavidin, I have created programmable microparticle scaffolds capable of attenuating the intensity of a fluorescent response in response to perturbations in the local environmental conditions. We believe this is an excellent enabling technology to facilitate the creation of complex behaviors at the microscale and can be used as a processing unit for simple decision making on microrobots. We foresee this technology impacting disciplines from medical microrobotics to environmental sensing and remediation.Master of Science
4
Аврунін, О. Г., O. G. Avrunin, М. Ю. Тимкович, M. Tymkovych, B. Glasmacher, and O. Gryshkov. "Ethylene glycol improves cryopreservation of cell-seeded electrospun scaffolds in cryobags." Thesis, Zalozba FE, 2020. http://openarchive.nure.ua/handle/document/13884.
Full textAbstract:
Cryopreservation of functional three-dimensional tissue-engineered constructs described. This work suggests that using controlled cryopreservation steps and EG as a non-toxic CPA, efficient cryopreservation of TECs in cryobags becomes feasible.
5
Ruiter, Floor A. A. "Thermo-responsive electrospun scaffolds for enzymatic-free passage and mammalian cell phenotype support." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49711/.
Full textAbstract:
Current conventional cell culture methods for the expansion of cells to large quantities for tissue engineering and regenerative medicine application relies on the use of enzymatic digestion passaging. However, this method significantly reduces the cell viability, due to the destruction of important cell-surface proteins and therefore considered undesirable for the subsequent cell therapies [1]. Research has led to the development of thermo-responsive surfaces for the continuous culture of cells. These thermo-responsive materials properties can be used to passage cells from the surface when the cell culture temperature is reduced. Conventional cell culture is performed on a 2D platform, however this can result in undesired de-differentiation, due to lack of similarities to the natural extracellular matrix (ECM) environment. This thesis aims to develop a thermo-responsive 3D fibre-based scaffold, fabricated by electrospinning, to create an enzymatic-free 3D cell culture platform for the expansion of mammalian cells with the desired phenotype for clinical use. In particular the expansion of human corneal stromal cells (hCSCs), which have been observed to de-differentiate to their active myofibroblastic phenotype with conventional 2D cell culture methods were examined here. Although experimentally the electrospinning method is relatively simple, at the theoretical level the interactions between process parameters and their influence on the fibre morphology is not yet fully understood. In this study a design of experiments (DoE) model was proposed to determine combinations of process parameters that result in significant effects on poly-D,L-lactic acid (PDLLA) fibre morphology. The process parameters used in this study were applied voltage, needle-to-collector distance, flow rate and polymer concentration. Data obtained for mean fibre diameter, standard deviation of the fibre diameter (stdev, measure of fibre morphology) and presence of ‘beading’ on the fibres (beads per μm2) were evaluated as a measure of PDLLA fibre morphology. Uniform fibres occurred at standard deviations of ± 500 nm, ‘beads-on-string’ morphologies were apparent between ± 500-1300 nm and large beads were observed at ± 1300-1800 nm respectively. Mean fibre diameter was significantly influenced by the applied voltage and interaction between flow rate and polymer concentration. Fibre morphology was mainly influenced by the polymer concentration, while bead distribution was significantly influenced by the polymer concentration as well as the flow rate. The resultant DoE model regression equations were tested and considered suitable for the prediction of parameter combinations needed for the desired PDLLA fibre diameter and additionally, provided information regarding the expected fibre morphology. The thermo-responsive behaviour of the scaffolds was achieved by blend electrospinning of the thermo-responsive polymer poly(di(ethylene glycol) methyl ether methacrylate (PDEGMA) and the supportive polymer poly-D,L-Lactic Acid (PLA), which gives the support needed for cell culture. PDEGMA was synthesised by free radical polymerisation and has a lower critical solution temperature of 28°C. The optimised electrospinning process was taken forward for the fabrication of the blend electrospun PLA/PDEGMA scaffolds. Different weight (wt) % concentrations to PLA was incorporated and distribution of the PDEGMA was confirmed by fluorescent labeled PBIPDEGMA. Initial thermo-responsive passaging method was investigated with 3T3 fibroblasts (3T3s). No significant detachment of 3T3s was observed below 10 wt% of PDEGMA in the blend electrospun PLA/PDEGMA scaffolds, while a maximum of 25% of cells detached when cooled for 30 mins at 8°C as observed for 10 wt% PDEGMA. An increase in fibre diameter from 900 nm to 2-3 μm and different cooling methods (1 and 3 h at rt and controlled cooling of -1°C per minute) did not result in an increase of 3T3 detachment. These findings indicate possible insufficient presence of the PDEGMA thermo-responsive brushes at the surface of the fibres. However, when hCSCs were cultured on these scaffolds significantly higher cell detachment was observed (approx. 100% compared to 25% for 3T3s). These findings indicate the application of the blend electrospun PLA/PDEGMA scaffolds for the culture and passaging of hCSCs. hCSCs were observed to not adhere and proliferate on the PLA/PDEGMA scaffolds. Therefore, a peptide thermo-responsive co-polymer conjugated by photo-initiated thiolene chemistry was proposed. Poly(di(ethylene glycol) methyl ether methacrylate-copoly(di(ethylene-glycol) vinyl ether (PDEGMA/ PDEGOH) was synthesised by free radical polymerisation and subsequently functionalised with a free thiol group by a condensation reaction. The obtained poly(diethylene glycol) methyl ether methacrylate co-poly(diethylene glycol) thiol (PDEGMA/PDEGSH) was blend electrospun and the presence of free thiols on the electrospun scaffolds were determined by ToF-SIMS and FITC labeling. These free thiol containing scaffolds were functionalised by a norbornene acid functionalised peptide sequence GGG-YIGSR by the photo-initiated thiolene reaction and its presence was confirmed by ToF-SIMS and ATTO labeling. The biocompatibility of the peptide containing scaffolds was assessed by the adhesion, proliferation and immuno-staining of hCSCs. Significant increase in hCSCs adherence and proliferation was observed on the peptide containing scaffolds. Immuno-staining showed maintained expression of the desired phenotypic markers ALDH, CD34 and CD105, while showing no or low expression of the undesired phenotype expressing a-SMA marker. This desired expression was observed to be maintained after thermo-responsive passaging and observed higher when cells were cultured on PLA scaffolds with 10 wt% PDEGMA/4 mole% PDEGS-Nor-GGG-YIGSR. In this thesis, the fabrication and application of a first generation, biocompatible thermo-responsive peptide conjugate fibrous scaffolds is described. The ease of fabrication, successful adherence and expansion of a therapeutically relevant cell type make these scaffolds a promising new class of materials for the application of cell culture expansion platforms. The scaffolds developed and reported in this thesis are believed to represent a promising contribution to the fields of biomaterials and tissue engineering.
6
Lee, Jang-ho. "Cell sheet engineering for scaffold-free cartilage regeneration." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:147ebea9-5c9d-4822-989d-1d94effeaf56.
Full textAbstract:
Osteoarthritis, the most prevalent joint disease in the United Kingdom, is a progressive condition that results in end-stage full-thickness cartilage loss and has important social and economic impacts on society. Since cartilage lacks regenerative capabilities, it is essential to develop approaches to initiate and enhance cartilage regeneration. In this context, tissue engineering is emerging as an attractive approach for the regeneration of cartilage tissue damaged due to disease or trauma. A scaffold-free cartilage construct, analogous to those found during embryonic precartilage condensation, has received much attention as an alternative novel modality for cartilage tissue engineering. Cartilage repair with scaffold-free tissue more closely resembles the natural situation and mimics the features of the original tissue. Moreover, scaffold-free cartilage implants can overcome the complications caused by the use of suboptimal scaffolds by avoiding the need for a foreign scaffold at all. Culturing cells into tissue patches without the requirement for a scaffold can be achieved through cell sheet engineering, which uses thermo-responsive culture dishes. However, the high costs of the tissue culture consumables, and the relatively low cellular yield, makes this process less attractive. This thesis presents a novel method for generating shape-, size- and thickness-adjustable 3-dimensional scaffold-free cell pellet sheets for use as implantable biological cell patches for cartilage tissue engineering. This new technique of bioengineering scaffold-free cell pellet sheets proves to be reproducible, easily applicable, sizable and thickness adjustable. Stem cells have added a new thrust to tissue engineering. Their distinctive self-renewal and plasticity have not only optimized many tissue engineering developments, but also rendered feasible some applications which would otherwise be unattainable with somatic cells. Human mesenchymal stem cells (HMSCs) were used to examine the optimal condition for generating cell pellet sheets with this new method. Furthermore, the resultant differentiated pellet sheets were compared directly with HMSCs, human chondrocytes and human fibroblasts alone to evaluate the feasibility of using this cell pellet sheet for clinical applications in terms of their biological and mechanical properties. The results of this thesis suggest that the engineered scaffold-free, chondrogenic, differentiated MSC pellet sheet not only exhibits desirable biologic features similar to chondrocytes, but also demonstrates good integrative and viscoelastic potential that might offer exciting possibilities for the development of novel biologically-based clinical therapies. In summary the data presented herein indicate the following points:
7
Varghai, Daniel. "Tubular Tissue Engineered Scaffold-Free High-Cell-Density Mesenchymal Condensations For Femoral Defect Regeneration." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1497222797338966.
Full text
8
Kukhta, Dziyana. "Metody přípravy buněčných transplantátů v kardiologii." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-400529.
Full textAbstract:
Tato diplomová práce se zabývá tkáňovým inženýrstvím, zejména tvorbou homogenní, izotropní a planární vrstvy buněk srdečního svalu pomocí dvou technologii:”scaffold-based” a ”scaffold-free”. Nejprve popsaný histologie srdeční stěny, buňky srdečního svalu a buněčné kultury. Následuje popis tkáňového inženýrství, který zahrnuje technologii “cell sheet” a tkáňové inženýrství na bázi scaffoldů. Na konci teoretické části je popsána aplikace tkáňového inženýrství a buněčná vizualizace. Praktická část věnovaná tvorbě planární buněčné vrstvy z kardiomyocytů a fibroblastů s využitím informací z teoretické části.
9
Wen, Yi-Ting, and 溫苡庭. "Biodegradable water-based polyurethane scaffolds with a sequential release function for cell-free cartilage tissue engineering." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/84rb6r.
Full textAbstract:
碩士國立臺灣大學
高分子科學與工程學研究所
107
Three dimensional (3D) printing technology has rapidly developed as a promising technology for manufacturing tissue engineering scaffolds. Cells used in tissue engineering are subjected to the quality management and risk of contamination, while cell-free scaffolds may not have sufficient therapeutic efficacy. In this study, water-based 3D printing ink containing biodegradable polyurethane (PU), chemokine SDF-1, and Y27632 drug-embedding PU microspheres was printed at low temperature (-40 °C) to fabricate tissue engineering scaffolds with sequential drug release function. The scaffolds containing 200 ng/ml SDF-1 and 22 wt% Y27632-encapsulated microspheres (55 ug/ml Y27632 in microspheres) (abbreviated PU/SDF-1/MS_Y scaffolds) had the optimal performance. The structural design of the scaffolds allowed each of SDF-1 and Y27632 to be released sequentially in vitro and reach the effective concentration (~100 ng/ml and 3.38 ug/ml, respectively) after the appropriate time (24 h and 62 h, respectively). Human mesenchymal stem cells (hMSCs) seeded in the scaffolds showed significant GAG deposition in 7 days. Besides, the gradual release of SDF-1 from the PU/SDF-1/MS_Y scaffolds could induce the migration of hMSCs. Implantation of the cell-free PU/SDF-1/MS_Y scaffolds in rabbit articular cartilage defects supported the potential of the scaffolds to promote cartilage regeneration. The 3D printed scaffolds with sequential releases of SDF-1 and Y27632 may have potential in cartilage tissue engineering.
Book chapters on the topic "Cell-free scaffolds"
1
Perdisa, F., A. Sessa, G. Filardo, M. Marcacci, and E. Kon. "Cell-Free Scaffolds for the Treatment of Chondral and Osteochondral Lesions." In Bio-orthopaedics, 139–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54181-4_11.
Full text
2
Romandini, Iacopo, Francesco Perdisa, Giuseppe Filardo, and Elizaveta Kon. "Cell-Free Scaffolds for the Treatment of Chondral and Osteochondral Lesions." In Cartilage Restoration, 297–305. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77152-6_24.
Full text
3
Itoh, Manabu. "Scaffold-Free Autologous Cell-Based Vascular Graft for Clinical Application." In Kenzan Method for Scaffold-Free Biofabrication, 117–25. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-58688-1_9.
Full text
4
Shimomura, Kazunori, Wataru Ando, Hiromichi Fujie, David A. Hart, Hideki Yoshikawa, and Norimasa Nakamura. "Scaffold-Free Stem Cell-Based Tissue Engineering to Repair Cartilage and Its Potential Application to Other Musculoskeletal Tissues." In Bio-orthopaedics, 537–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54181-4_43.
Full text
5
Kumar, Vineet, Shruti D. Vora, Foram A. Asodiya, Naveen Kumar, and Anil K. Gangwar. "Fourier Transform Infrared Spectroscopy of the Animal Tissues." In Real Perspective of Fourier Transforms and Current Developments in Superconductivity. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94582.
Full textAbstract:
Animal tissues are extensively used as scaffolds for tissue engineering and regenerative therapies. They are typically subjected to decellularization process to obtain a cell-free extracellular matrix (ECM) scaffolds. It is important to identify chemical structure of the ECM scaffolds and Fourier transform infrared (FTIR) appears to be a technique of choice. In this chapter, FTIR spectra of native and decellularized buffalo aortae, buffalo diaphragms, goat skin, and native bovine cortical bone are presented. The transmittance peaks are that of organic collagen amide A, amide B, amide I, amide II and amide III chemical functional groups in both native and decellularized aortae, diaphragms and skin. In bone, the transmittance peaks are that of inorganic ν1, ν3 PO43−, OH− in addition to organic collagen amide A, amide B, amide I, amide II and amide III chemical functional groups. These important transmittance peaks of the tissue samples will help researchers in defining the chemical structure of these animal tissues.
6
Kim, Kyungsook, Sophia Bou-Ghannam, and Teruo Okano. "Cell sheet tissue engineering for scaffold-free three-dimensional (3D) tissue reconstruction." In Cell-derived Matrices - Part B, 143–67. Elsevier, 2020. http://dx.doi.org/10.1016/bs.mcb.2019.11.020.
Full text
7
Martin, Frank, Mario Lehmann, and Ursula Anderer. "Generation of Scaffold Free 3-D Cartilage-Like Microtissues from Human Chondrocytes." In Medical Advancements in Aging and Regenerative Technologies, 169–94. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2506-8.ch008.
Full textAbstract:
Since our society is characterized by an increasing age of its people on the one hand and a high number of persons dealing with sports on the other hand, the number of patients suffering from traumatic defects or osteoarthritis is growing. In combination with the articular cartilage specific limited capacity to regenerate, a need for suitable therapies is obvious. Thereby, cell-based therapies are of major interest. This type of clinical intervention was introduced to patients at the beginning of the 1990s. During the last years, a technological shift from simple cell suspensions to more complex 3D structures was performed. In order to optimize the scaffold free generation of cartilage, such as microtissues from human chondrocytes, the authors examine the influence of a static or spinner flask culture with respect to differentiation and architecture of the engineered microtissues. Additionally, the impact of the soluble factors TGF-ß2 and ascorbic acid on this process are investigated. The results demonstrate a positive impact of TGF-ß2 and ascorbic acid supplementation with respect to general Type II Collagen and proteoglycan expression for both the static and spinner flask culture.
Conference papers on the topic "Cell-free scaffolds"
1
Nansai, Ryosuke, Mamoru Ogata, Junichi Takeda, Wataru Ando, Norimasa Nakamura, and Hiromichi Fujie. "Surface and Bulk Stiffness of the Mature Porcine Cartilage-Like Tissue Repaired With a Scaffold-Free, Stem Cell-Based Tissue Engineered Construct (TEC)." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-204404.
Full textAbstract:
Since the healing capacity of articular cartilage is limited, it is important to develop cell-based therapies for the repair of cartilage. Although synthetic or animal-derived scaffolds are frequently used for effective cell delivery long-term safety and efficiency of such scaffolds still remain unclear. We have been developing a new tissue engineering technique for cartilage repair using a scaffold-free tissue engineered construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs) [1]. As the TEC specimen is composed of cells with their native extracellular matrix, we believe that it is free from concern regarding long term immunological effects. Fujie et al. found in a micro indentation test using an atomic force microscope (AFM) that the immature porcine cartilage-like tissue repaired with TEC exhibited lower stiffness as compared with normal cartilage in immature porcine femur [2], although the macro-scale stiffness of the repaired tissue was almost same as that of the normal cartilage [3]. In the present study, we investigated the macro and micro-compressive properties of mature porcine cartilage-like tissue repaired with TEC.
2
Khoda, Bashir, and Bahattin Koc. "Deformation Modeling of Soft Tissue Scaffolds for Wound Healing." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64662.
Full textAbstract:
Within tissue engineering (TE), one of the major research theme is on synthetic scaffold design. Most research emphasis on the material that has to be biocompatible and biodegradable over time and shows proper cell attachment properties. And traditional scaffold fabrication technique use chemical process resulting in uncontrolled porosity along the structure. Development of Solid Free Form (SFF) technique and improvement in some biomaterial properties provides the leverage of using these techniques to fabricate controlled and interconnected porous scaffold structure. These improved membrane/scaffolds are mostly regular porous structure and when applied in wound area various forces like bandage, contraction and self weight act upon that and cause deformation. As a result, the geometry and the designed porosity changes which eventually alters the desired choreographed functionality such as material concentration, design parameters, cytokines distribution over the wound device geometry. This balance often presents a tradeoff between a denser scaffold providing better mechanical function and a more porous scaffold providing better biofactor delivery, cell proliferation, pathways for nutrients and waste transportation. In this work, a novel scaffold modeling approach of “desired porosity with variational filament distance” has been proposed that will minimize the change in effective porosity with the designed porosity and thus will give a better functionality of such membrane providing both structural integrity and proper bioreactor environment. The proposed methodology has been implemented in this paper and illustrative examples are provided. Also a comparison result of measured effective porosity has been presented between proposed design model and conventional fixed filament distance scaffolds membrane.
3
Susa, Tomoya, Ryosuke Nansai, Norimasa Nakamura, and Hiromichi Fujie. "Influence of Permeability on the Compressive Property of Articular Cartilage: A Scaffold-Free, Stem Cell-Based Therapy for Cartilage Repair." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53365.
Full textAbstract:
Since the healing capacity of articular cartilage is limited, it is important to develop cell-based therapies for the repair of cartilage. Although synthetic or animal-derived scaffolds are frequently used for effective cell delivery long-term safety and efficiency of such scaffolds still remain unclear. We have been studying on a scaffold-free tissue engineered construct (TEC) bio-synthesized from synovium-derived mesenchymal stem cells (MSCs) [1]. As the TEC specimen is composed of cells with their native extracellular matrix, we believe that it is free from concern regarding long term immunological effects. our previous studies indicated that a porcine partial thickness chondral defect was successfully repaired with TEC but that the compressive property of the TEC-treated cartilage-like repaired tissue was different from normal cartilage in both immature and mature animals. Imura et al. found that the permeability of the immature porcine cartilage-like tissues repaired with TEC recovered to normal level for 6 months except the superficial layer [2]. Therefore, the present study was performed to determine the depth-dependent permeability of mature porcine cartilage-like tissue repaired with TEC. Moreover, we investigated the effect of difference of permeability on the compressive property of articular cartilage using a finite element analysis (FEM).
4
Baker, Brendon M., Giana Montero, and Robert L. Mauck. "Removal of Sacrificial Fibers Enhances Long Term Cell and Matrix Distribution in Aligned Nanofibrous Scaffolds." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206856.
Full textAbstract:
Given their ability to dictate initial cell alignment and subsequent matrix organization, aligned electrospun scaffolds are a fitting means for engineering fiber-reinforced, anisotropic tissues such as tendon, ligament, the knee meniscus, and the annulus fibrosus [1–3]. However, one commonly observed limitation of such scaffolds is the relatively slow infiltration rates of surface-seeded cells, where the central thicknesses of constructs cultured for 10 weeks remain devoid of cells [2]. This limitation arises from the tight packing of fibers which yields small pore sizes, thereby hampering cell migration. Towards accelerating cell ingress, we have recently reported on two-polymer composite scaffolds containing both slow eroding poly(ε-caprolactone) (PCL) fibers as well as water-soluble poly(ethylene oxide) (PEO) fibers that serve as space holders during scaffold formation [4]. Removal of these PEO fibers prior to seeding resulted in improved cell infiltration after 3 weeks, but the long term maturation of such constructs has yet to be characterized. To assess the effect of sacrificial PEO fiber content on construct growth, a triple-jet electrospinning device was employed to generate PCL/PEO scaffolds with PEO fiber fractions ranging from 0 to 60%. After seeding with mesenchymal stem cells (MSCs), constructs were clamped in custom grips to maintain strip morphology. The mechanical and biochemical maturation of constructs was assessed over 9 weeks of free swelling culture in a chemically defined medium (CDM), along with cell infiltration and matrix distribution. We hypothesized that enhanced pore size in dual-fiber constructs would lead to not only a better distribution of cells, but also larger increases in stiffness resulting from enhanced matrix production and distribution.
5
Kramschuster, Adam, Lih-Sheng Turng, Wan-Ju Li, Yiyan Peng, and Jun Peng. "The Effect of Nano Hydroxyapatite Particles on Morphology and Mechanical Properties of Microcellular Injection Molded Polylactide/Hydroxyapatite Tissue Scaffold." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13290.
Full textAbstract:
The current large demands for transplant organs and tissues has led to extensive research on material synthesis and fabrication methods for biodegradable polymeric scaffolds, which are required to have high porosity, well interconnected pore structure, and good mechanical properties. However, the majority of current scaffold fabrication techniques are either for batch processes or use organic solvents, which can be detrimental to cell survival and tissue growth. The ability to mass produce solvent-free, highly porous, highly interconnected scaffolds with complex geometries is essential to provide off-the-shelf availability [1]. Injection molding has long been used for mass production of complex 3D plastic parts. The low-cost manufacturing, repeatability, and design flexibility inherent in the injection molding process make it an ideal manufacturing process to create 3D scaffolds, as long as high porosity and interconnectivity can be imparted into the finished product.
6
Nathan, Ashwin S., Brendon M. Baker, and Robert L. Mauck. "Cytoskeletal Control of Mesenchymal Stem Cell Nuclear Deformation on Nanofibrous Scaffolds." In ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206855.
Full textAbstract:
Nanofibrous scaffolds hold great potential for tissue engineering as they recapitulate the mechanical and topographic features of fibrous tissues on both the macroscopic and microscopic level [1,2]. When seeded with cells capable of fibrous extracellular matrix (ECM) production such as mesenchymal stem cells (MSCs), the new matrix is deposited in accordance with the underlying topography, and scaffolds develop improved mechanical properties with time in free swelling culture [6]. While promising, the free swelling conditions employed in evaluating in vitro construct maturation have thus far remained insufficient in achieving native-level properties. As most fibrous tissues are subjected to loading in vivo, mechanical conditioning is considered critical in directing tissue development and subsequent homeostasis with normal use. Mechanical signals are translated from the ECM to the nucleus via the cytoskeleton, with signals culminating in the control of biosynthetic activity based upon external loading conditions. Various bioreactor systems have been developed to mimic these in vivo conditions towards enhancing the maturation of engineered constructs, with most focusing on dynamic tensile deformation [3,4]. Towards gaining further insight into the means by which mechanical cues inspire alterations in cellular behavior, this study developed methods for evaluating cell and sub-cellular deformation of MSCs seeded on randomly-oriented and aligned nanofibrous scaffolds. Using a device that enables visualization of cells seeded on nanofibrous scaffolds undergoing static tensile deformation, we examined the effect of applied strain rate on cell adhesion to scaffolds, as well as changes in nuclear shape in the context of viable actin and microtubule sub-cellular networks with applied strain. These data provide new insight into fundamental mechanisms of MSC mechanoregulation on nanofibrous scaffolds, and offer constraints for long-term bioreactor studies.
7
Baker, Brendon M., Amy M. Silverstein, and Robert L. Mauck. "Engineering Dense Connective Tissues via Anisotropic Nanofibrous Scaffolds With High Sacrificial Fiber Content." In ASME 2010 First Global Congress on NanoEngineering for Medicine and Biology. ASMEDC, 2010. http://dx.doi.org/10.1115/nemb2010-13371.
Full textAbstract:
Given their ability to dictate initial cell alignment and subsequent matrix organization, aligned electrospun scaffolds are a fitting means for engineering fiber-reinforced, anisotropic tissues such as tendon, ligament, the knee meniscus, and the annulus fibrosus [1–4]. However, one commonly observed limitation of such scaffolds is the relatively slow infiltration rates of surface-seeded cells, where the central thicknesses of constructs cultured for 10 weeks remain devoid of cells [3]. This limitation arises from the tight packing of fibers which yields small pore sizes, thereby hampering cell migration. Towards accelerating cell ingress, we have recently reported on two-polymer composite scaffolds containing both slow eroding poly(ε-caprolactone) (PCL) fibers as well as water-soluble poly(ethylene oxide) (PEO) fibers that serve as space holders during scaffold formation [5]. Removal of these PEO fibers prior to seeding resulted in improved cell infiltration after 3 weeks, but the long-term maturation of such constructs has yet to be characterized. To assess the effect of sacrificial PEO fiber content on construct growth, a triple-jet electrospinning device was employed to generate PCL/PEO scaffolds with PEO fiber fractions ranging from 0 to 60%. After seeding with human meniscus fibrochondrocytes (hMFCs), constructs were clamped in custom grips to maintain strip morphology. The mechanical and biochemical maturation of constructs was assessed over 12 weeks of free swelling culture in a chemically defined medium (CDM), along with cell infiltration and matrix distribution. We hypothesized that enhanced pore size in dual-fiber constructs would lead to not only to a better distribution of cells, but also to larger increases in stiffness resulting from enhanced matrix production and distribution.
8
Mi, Hao-Yang, Xin Jing, Lih-Sheng Turng, and Xiang-Fang Peng. "Microcellular Injection Molding of Thermoplastic Polyurethane (TPU) Scaffolds Using Carbon Dioxide and Water as Co-Blowing Agents." In ASME 2013 International Manufacturing Science and Engineering Conference collocated with the 41st North American Manufacturing Research Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/msec2013-1154.
Full textAbstract:
In this study, a novel microcellular injection foaming method employing supercritical CO2 (scCO2) and water as co-blowing agents was developed to produce thermoplastic polyurethane (TPU) tissue engineering scaffolds with a uniform porous structure and no solid skin layer. Various characterization techniques were applied to investigate the cell morphology, crystallization behavior, and static and dynamic mechanical properties of solid molded samples, foamed samples using CO2 or water as a single blowing agent, and foamed samples using both CO2 and water as co-blowing agents. Compared with CO2 foamed scaffolds, scaffolds produced by the co-blowing method exhibit much more uniform cell morphologies without a noticeable reduction in mechanical properties. Moreover, these TPU scaffolds have almost no skin layer, which permits free transport of nutrients and waste throughout the samples, which is highly desirable in tissue engineering. The effect of these blowing agents on the shear viscosity of various samples is also reported.
9
Wang, Hai, and Wei Li. "Selective HIFU Foaming to Fabricate Porous Polymer for Tissue Engineering Scaffolds." In ASME 2006 International Manufacturing Science and Engineering Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/msec2006-21043.
Full textAbstract:
A novel technique is presented in this paper for the fabrication of tissue engineering scaffolds using the High Intensity Focused Ultrasound (HIFU). This acoustic method is a solvent-free, highly efficient and low cost process that has the potential in scaffold-based tissue engineering. HIFU fabrication technique is capable of creating hierarchically-structured porous polymeric materials, which have various topographical features at different length scales. This will in turn affect the cellular response and behavior of certain type of cells, such as the integration and growth of smooth muscle cells (SMCs). In this study, the effect of HIFU porous polymer fabrication was investigated. Scanning-mode HIFU insonation was performed in the HIFU polymer foaming experiments. The acoustic power and the scanning speed were chosen as the parameters and varied in different groups of experiments. The created microstructures were characterized using the scanning electron microscopy (SEM). The fabricated samples were used for cell culture studies with human aortic SMCs (Passage 4). It was found that the selective HIFU foaming process could be used to create hierarchical structures by choosing appropriate ultrasound parameters. The SMCs were viable on the HIFU-created porous PMMA specimens, and the topographical nature of a HIFU-created porous structure affected the cellular response of SMCs.
10
Wang, Xiaoxi, Wei Li, and Vipin Kumar. "Solvent Free Fabrication of Biodegradable Porous Polymers." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59553.
Full textAbstract:
Biodegradable porous polymers with interconnected pores of sub-micrometers to a few hundred micrometers find many applications in emerging technology areas such as tissue engineering, controlled drug delivery, and biochemical sensors. However, most of the current fabrication processes involve organic solvents and chemical blowing agents that may cause environmental concerns and leave residues harmful to biological cells. This paper presents a solvent free fabrication approach for biodegradable porous polymers. Ultrasound cavitation is introduced after the solid state foaming process to produce open cell structures. The material used in this study is polylactic acid (PLA). It belongs to a family of biodegradable polymers that can be used for tissue engineering scaffolds. In order to identify suitable conditions to apply ultrasound, a saturation and foaming study is conducted for the PLA-CO2 gas polymer system. The effects of various process variables are discussed.