Littérature scientifique sur le sujet « Bio-medical Application - Drug Delivery »

Biocompatible hydrotalcite nanohybrids, i.e., layered double hydroxide (LDH) based nanohybrids have attracted significant attention for biomedical functions. Benefiting from good biocompatibility, tailored drug incorporation, high drug loading capacity, targeted cellular delivery and natural pH-responsive biodegradability, hydrotalcite nanohybrids have shown great potential in drug/gene delivery, cancer therapy and bio-imaging. This review aims to summarize recent progress of hydrotalcite nanohybrids, including the history of the hydrotalcite-like compounds for application in the medical field, synthesis, functionalization, physicochemical properties, cytotoxicity, cellular uptake mechanism, as well as their related applications in biomedicine. The potential and challenges will also be discussed for further development of LDHs both as drug delivery carriers and diagnostic agents.

Amorphous calcium phosphate (ACP) has shown significant effects on the biomineralization and promising applications in bio-medicine. However, the limited stability and porosity of ACP material restrict its practical applications. A storage stable highly porous ACP with Brunauer–Emmett–Teller surface area of over 400 m2/g was synthesized by introducing phosphoric acid to a methanol suspension containing amorphous calcium carbonate nanoparticles. Electron microscopy revealed that the porous ACP was constructed with aggregated ACP nanoparticles with dimensions of several nanometers. Large angle X-ray scattering revealed a short-range atomic order of <20 Å in the ACP nanoparticles. The synthesized ACP demonstrated long-term stability and did not crystallize even after storage for over 14 months in air. The stability of the ACP in water and an α-MEM cell culture medium were also examined. The stability of ACP could be tuned by adjusting its chemical composition. The ACP synthesized in this work was cytocompatible and acted as drug carriers for the bisphosphonate drug alendronate (AL) in vitro. AL-loaded ACP released ~25% of the loaded AL in the first 22 days. These properties make ACP a promising candidate material for potential application in biomedical fields such as drug delivery and bone healing.

In recent decades, metal oxide nanoparticles have acquired relevance in biology and medicine due to their unique physicochemical properties. Because of its cheap cost, biodegradability and low toxicity, zinc oxide nanoparticles (ZnO-NPs) have attracted a lot of interest from researchers for therapeutic and diagnostic applications. Zinc oxide (ZnO) has been studied for various biological applications due to its unique semiconducting, optical and piezoelectric characteristics. The growing interest in nano zinc oxide has led to the discovery and development of nanoparticle production technologies. ZnO nanocomposites with varied morphologies have recently been prepared using a physical and chemical method. ZnO NPs have also been employed to deliver different bioactive and chemotherapeutic anticancer medicines to tumour cells in a targeted and sustained manner. This review discusses on the properties, synthesis, drug delivery method for cancer treatment and many other biological uses of ZnO NPs.

Background: Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern. Objective: The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics. Methods: Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models. Results: Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices. Conclusion: The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Topical drug delivery is mostly culled for the local dermatological action, but recently the new technologies are also enhancing its systemic effect. They are generally applied for the purpose as antiseptics, antifungal agents, skin emollients, and protectants. The activity of topical preparation confide in the various factors as drug solubility, its lipophilicity, contact time to skin, its permeability. Many widely used topical agents like ointments, creams, lotions, gel are associated with disadvantages like stability problems, stickiness and lesser spreading coefficient, irritation, allergic reactions, poor permeability, poor absorption and difficulty in absorption of large molecule, to rectify this the new concept of Emulgel has been introduced with the main objective to deliver hydrophobic drug molecule. Emulgel is oil in water or water in oil emulsion carrying drug to be incorporated in gel base to obtain gellified emulsion. Emulgel shows the controlled and better release effect of drug by virtue of combined effect of gel and emulsion with increased stability. Gel having various advantages as non greasy and favors good patient compliance in field of cosmetology and dermatology but are still limited to the deliver hydrophobic drugs. So the Emulgel comes to favour the hydrophobic drugs to give the advantages of gel. Emulgels have several advantages in the field of dermatology such as being thixotropic, greaseless, easily spreadable, easily removable, emollient, nonstaining, long shelf life, bio-friendly, transparent and pleasing appearance. Factors such as gelling agent, oil agent, emulsifiers influence the stability and efficacy of emulgel. So emulgels can be the better semisolid preparation than other conventional systems. At present the emulgel are being used for the delivery of analgesics, anti-inflammatory, anti-fungal, anti-acne drugs and various cosmetic formulations with still wide range to explore.

Ocular drug delivery has been a major challenge for clinical pharmacologists and biomaterial scientists due to intricate and unique anatomical and physiological barriers in the eye. The critical requirement varies from anterior and posterior ocular segments from a drug delivery perspective. Recently, many new drugs with special formulations have been introduced for targeted delivery with modified methods and routes of drug administration to improve drug delivery efficacy. Current developments in nanoformulations of drug carrier systems have become a promising attribute to enhance drug retention/permeation and prolong drug release in ocular tissue. Biodegradable polymers have been explored as the base polymers to prepare nanocarriers for encasing existing drugs to enhance the therapeutic effect with better tissue adherence, prolonged drug action, improved bioavailability, decreased toxicity, and targeted delivery in eye. In this review, we summarized recent studies on sustained ocular drug/gene delivery and emphasized on the nanocarriers made by biodegradable polymers such as liposome, poly lactic-co-glycolic acid (PLGA), chitosan, and gelatin. Moreover, we discussed the bio-distribution of these nanocarriers in the ocular tissue and their therapeutic applications in various ocular diseases.

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components’ basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers—two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take.

: The unique mechanical, electrical, thermal, chemical and optical properties of carbon based nanomaterials (CBNs) like: Fullerenes, Graphene, Carbon nanotubes, and their derivatives made them widely used materials for various applications including biomedicine. Few recent applications of the CBNs in biomedicine include: cancer therapy, targeted drug delivery, bio-sensing, cell and tissue imaging and regenerative medicine. However, functionalization renders the toxicity of CBNs and makes them soluble in several solvents including water, which is required for biomedical applications. Hence, this review represents the complete study of development in nanomaterials of carbon for biomedical uses. Especially, CBNs as the vehicles for delivering the drug in carbon nanomaterials is described in particular. The computational modeling approaches of various CBNs are also addressed. Furthermore, prospectus, issues and possible challenges of this rapidly developing field are highlighted.

Nanoparticle mediated drug delivery approaches provide potential opportunities for targeting and killing of intracellular bacteria. Among them, the porous silica nanoparticles deserve special attention due to their multifunctional properties such as high drug loading, controlled drug release and targeting of organs/cells. A review of the functional requirements of an ideal drug delivery system is provided. A general comparison between different drug delivery carriers and key issues to be addressed for intracellular drug delivery is discussed. Acid catalyzed and acid-base catalyzed, sol-gel derived, silica xerogel systems were investigated for sustained release of an aminoglycosides antimicrobial against salmonella infection in a mouse model. The release of gentamicin from the inner hollow part of the carrier is delayed. Further, the higher porosity of the acidâ base catalyzed silica xerogel allows for high drug loading compared to the acid catalyzed silica xerogel system. Efficacy of these particles in killing intracellular bacteria (salmonella) was determined by administering three doses of porous silica loaded gentamicin. This proved to be useful in reducing the salmonella in the liver and spleen of infected mice. Furthermore, the presence of silanol groups provides the ability to functionalize the silica xerogel system with organic groups, poly (ethylene glycol) (PEG), to further increase the hydrophilicity of the silica xerogel matrix and to modify the drug release properties. Increase in the hydrophilicity of the matrix allows for faster drug release rate. In order to facilitate controlled drug release, magnetic porous silica xerogels were fabricated by incorporating iron particles within the porous silica. The particles were fabricated using an acid-base catalyzed sol-gel technique. The in-vitro drug release studies confirm that the release rate can be changed by the magnetic field "ON-OFF" mechanism. This novel drug release methodology combined with the property of high drug loading capacity proves to be influential in treating salmonella intracellular bacteria. The potential application of any drug delivery carrier relies on the ability to deliver the requisite drug without adversely affecting the cells over the long term. We have developed silica/calcium nanocomposites and evaluated their solubility behavior. The solubility of particles was characterized by particle size measurements for different periods of time. It was found that the solubility behaviour of the silica/calcium particles was dependent on their calcium content. The results obtained demonstrate the potential to use mesoporous silica/calcium nano-composites for drug delivery applications. The significant contribution of this research to drug delivery technology is on design and development of the novel porous core-shell silica nano-structures. This new core-shell nano-structure combines all the above mentioned properties (high drug loading, magnetic field controlled drug release, and solubility). The main aim of preparing these porous core-shell particles is to have a control over the solubility and drug release property, which is a significant phenomenon, which has not been achieved in any other drug delivery systems. The shell layer acts as a capping agent which dissolves at a controllable rate. The rate at which the shell layer dissolves depends on the composition of the particles. This shell prevents the drug â leakageâ from the particles before reaching the target site. The core layer drug loading and release rate was modified by application of a magnetic field. Additionally, inclusion of the calcium ions in the core layer destabilizes the silica network and allows the particles to dissolve at an appropriate rate (which can be controlled by the concentration of the calcium ions).
Ph. D.

Block copolymer nanoparticles (NPs) have gained great attention among researcher for various medical application mainly due to their extraordinary optical, chemical, and biological properties. The current thesis presents design of multifunctional polymeric NPs for imaging and drug delivery system (DDS) with an in-vitro study of their participation in drug release and cell viability. The NPs were synthesized using reversible addition chain fragmentation transfer (RAFT)-mediated emulsion polymerization via polymerization induce self-assembly (PISA) approach. The environment-friendly emulsion polymerization process of n-buytl acrylate (n-BA) in water is highly efficient. The process produced uniform NPs which would have control over the particle size and molecular weight of the compound. Herein we report a novel simultaneous encapsulation of camptothecin (CPT) and Nile red (NR) into poly(ethylene glycol) methyl ether methacrylate-co-N-hydroxyethyl acrylamide-b-poly n-buytlacrylate (PEGA-co-HEAA)-b-P(n-BA) during the particles formation with a small particle size of 66 nm, high conversion ~80% and encapsulation efficiency of ~50%. The In vitro drug release of the CPT from the NPs exhibited an initial burst (70-80%) within 6h. cell viability was evaluated for the NPs against RAW 264.7 cell line, which indicated the designed NPs are biocompatible and not toxic.

The idea of utilizing nanomaterials in bio-related applications has been extensively practiced during the recent decades. Magnetic nanoparticles (MPs), especially superparamagnetic iron oxide nanoparticles have been demonstrated as promising candidates for biomedicine. A protective coating process with biocompatible materials is commonly performed on MPs to further enhance their colloidal and chemical stability in the physiological environment. Mesoporous hollow silica is another class of important nanomaterials that are extensively studied in drug delivery area for their ability to carry significant amount of guest molecules and release in a controlled manner. In this study, different synthetic approaches that are able to produce hybrid nanomaterials, constituting both mesoporous hollow silica and magnetite nanoparticles, are described. In a two-step approach, pre-synthesized magnetite nanoparticles are either covalently conjugated to the surface of polystyrene beads and coated with silica or embedded/enclosed in the porous shell during a nanosized CaCO3 templated condensation of silica precursors, followed by acid dissolution to generate the hollow structure. It was demonstrated that the hollow interior is able to load large amount of hydrophobic drugs such as ibuprofen while the mesoporous shell is capable of prolonged drug. In order to simplify the fabrication procedure, a novel in-situ method is developed to coat silica surface with magnetite nanoparticles. By refluxing the iron precursor with mesoporous hollow silica nanospheres in polyamine/polyalcohol mixed media, one is able to directly form a high density layer of magnetite nanoparticles on silica surface during the synthesis, leaving reactive amine groups for further surface functionalization such as fluorescence conjugation. This approach provides a convenient synthesis for silica nanostructures with promising potential for drug delivery and multimodal imaging. In addition to nanoparticles, nanowires also benefit the research and development of instruments in clinical diagnosis. Semiconductive nanowires have demonstrated their advantage in the fabrication of lab-on-a-chip devices to detect many charge carrying molecules such as antibody and DNA. In our study, In2O3 and silicon nanowire based field effect transistors were fabricated through bottom-up and top-down approaches, respectively, for ultrasensitive bio- detection of toxins such as ricin. The specific binding and non-specific interaction of nanowires with antibodies were also investigated.

The development of a drug delivery system (DDS) is essential to remedy the limitations of free drug molecules. The use of silica as a DDS over other systems (for example, liposomes) can be attributed to it being more robust and versatile. This thesis investigates bio-inspired silica (BIS) and compares it to mesoporous silica nanoparticles (MSN), which have received much attention for drug delivery applications. The BIS synthesis utilised amines to condense silica quicker than MSN, under benign conditions and without the use of hazardous chemicals. With this synthesis method drugs can be loaded in situ and there is potential for amines to have dual function of condensing silica and acting as functionalisation. BIS has also been shown to be more biocompatible than MSN. Due to these reasons it can be argued that BIS has the potential to be a more desirable silica DDS than MSN.Using ibuprofen as a model drug, reaction conditions (e.g. choice of amine additive, synthesis pH and maturation time) were systematically investigated to elucidate their effects upon drug loading and release. BIS synthesised with the amine poly(allylamine hydrochloride) (PAH) (which will henceforth referred to as BIS-PAH) was focused on, as this was the only amine system which released a significant proportion of loaded drug and achieved comparable or improved ibuprofen loading when compared to MCM-41. PAH plays an important role in facilitating the loading of ibuprofen, however if too much is present, release is inhibited greatly. The condensation rate of silica is also an important factor; when condensation rate was increased more drug was able to be released. This is likely due to less of the drug being entrapped within the silica particle and more being phys-adsorbed to the silica surface. Next the use of BIS to deliver hydrocortisone (HC) was investigated. Current treatments for adrenocorticoid insufficiency using hydrocortisone do no mimic the natural circadian variation in levels of blood cortisol. Firstly, the stability of HC during the in situ loading process was measured and data are presented that show that HC must be loaded post-synthesis, to avoid degradation in the reaction mixture. The efficiency of loading was largely unaffected by amine, however, only BIS-PAH allowed for drug release. Longer BIS-PAH maturation times gave lowered loading but the release was improved. Finally, biocompatibility of BIS was also investigated and it was found that, BIS was able to pass through the gut wall into the blood stream, and it was non-haemolytic when compared to MCM-41. There is a potential for bioaccumulation due to silica’s chemical stability. Although the use of BIS for delivery of hydrocortisone was unsuccessful, BIS does have several advantages over MCM-41 (such as quicker synthesis route, involving a one-pot synthesis and drug loading method, simple controllability, lack of hazardous chemicals and superior biocompatibility) and the results presented here show that BIS has similar or improved drug loading and release profiles to MCM-41 when using ibuprofen. With further drug and biocompatibility experiments, these benefits give BIS real potential as a viable DDS to be further investigated.

The goal of this project was to develop a series of nano platforms for single cell analysis and drug delivery. Nanoparticles are a promising option to improve our medical therapies by controlling biodistribution and pharmacokinetics of therapeutics. Nanosystems also offer significant opportunity to improve current imaging modalities. The systems developed during this thesis work can be foundations for developing advanced therapies for obesity and improving our fundamental understandings of single cell behavior. The first of the two systems we attempt to create was a drug delivery system that could selectively target adipose tissue to deliver uncoupling agents and drive browning of adipose tissue and associated weight loss. Protonophores have a history of significant toxic side effects in cardiac and neuronal tissues a recently discovered protonophore, but BAM-15, has been shown to have reduced cytotoxicity. We hypothesized that the altered biodistribution of BAM-15 encapsulated in a nanoparticle could provide systemic weight loss with minimized side effects. The second system developed utilized quantum dots to create a fluorescent barcode that could be repeatedly identified using quantitative fluorescent emission readings. This platform would allow for the tracking of individual cells, allowing repeat interrogation across time and space in complex multicellular environments. Ultimately this work demonstrates the process and complexity involved in developing nanoparticulate systems meant to interact with incredibly complex intracellular environments.

The misassembly of soluble proteins into toxic aggregates, including amyloid fibrils, underlies a large number of human degenerative diseases. Cardiac amyloidoses, which are most commonly caused by aggregation of Immunoglobulin (Ig) light chains or transthyretin (TTR) in the cardiac interstitium and conducting system, represent an important and often underdiagnosed cause of heart failure. Two types of TTR-associated amyloid cardiomyopathies are clinically important. The Val122Ile (V122I) mutation, which alters the kinetic stability of TTR and affects 3% to 4% of African Americans, can lead to development of familial amyloid cardiomyopathy. In addition, aggregation of WT TTR in individuals older than age 65 years causes senile systemic amyloidosis. TTR-mediated amyloid cardiomyopathies are chronic and progressive conditions that lead to arrhythmias, biventricular heart failure, and death. As no Food and Drug Administration-approved drugs are currently available for treatment of these diseases, the development of therapeutic agents that prevent TTR-mediated cardiotoxicity is desired. Here, we report the characterization of AG10 , a potent and selective kinetic stabilizer of TTR. AG10 prevents dissociation of V122I-TTR in serum samples obtained from patients with familial amyloid cardiomyopathy. In contrast to other TTR stabilizers currently in clinical trials, AG10 stabilizes V122I- and WT-TTR equally well and also exceeds their efficacy to stabilize WT and mutant TTR in whole serum. Crystallographic studies of AG10 bound to V122I-TTR give valuable insights into how AG10 achieves such effective kinetic stabilization of TTR, which will also aid in designing better TTR stabilizers. The oral bioavailability of AG10 , combined with additional desirable drug-like features, makes it a very promising candidate to treat TTR amyloid cardiomyopathy. The second part of the thesis discusses harnessing TTR as a platform to enhance in vivo half-life of therapeutic peptides. The tremendous therapeutic potential of peptides has not yet been realized, mainly owing to their short in vivo half-life. Although conjugation to macromolecules has been a mainstay approach for enhancing protein half-life, the steric hindrance of macromolecules often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Here we report a new strategy for enhancing the in vivo half-life of a model peptide Gonadotropin Releasing Hormone (GnRH) and its analog GnRH-A without compromising their potency. Apart from GnRH, we have used other peptides to study their proteolytic stability in vitro . Our approach involves endowing peptides with a small molecule that binds reversibly to the serum protein transthyretin. Although there are a few molecules that bind albumin reversibly, we are unaware of designed small molecules that reversibly bind other serum proteins and are used for half-life extension in vivo . We show here that our strategy was effective in enhancing the half-life of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy.

A literature review of medical implant applications of mesoporous silica films was written, highlighting the advantages and limitations of different film synthesis methods. Both films synthesized through the EISA sol-gel method and particulate films, including those synthesized through the direct growth method, were reviewed and discussed. All films were found to have their strengths and weaknesses, however, the films synthesized through the direct growth method was found to be the most promising type for coating implants. In addition to the literature review, copper-doped mesoporous silica films were synthesized on titanium grade 2 substrates. SEM shows that particles grown on all the films and EDX elemental analysis confirms the presence of copper in the material. Nitrogen physisorption measurements show that particles with incorporated copper have a higher specific surface area, and pore volume compared to un-doped particles. No copper content could be confirmed through FTIR. The particles grown on titanium substrates were more rod-like compared to the ones grown on the silicon substrates as control.

In recent years, a number of reports have focused on the use of polyesters in drug delivery due to their intrinsic biocompatibility and biodegradability. In this thesis, aliphatic polyesters were synthesized by polycondensation reaction and ring opening polymerization reactions. The properties of the polymers and drug delivery potential of the resultant materials were evaluated. In the polycondensation reactions, a series of aliphatic polyesters of similar molecular weight were synthesized by reacting 1,10-decanediol with different ratios of succinic acid/phenylsuccinic acid and the effects of phenyl group side-chain substitution on polymer properties was investigated. A solvent-free melt polycondensation method using scandium (III) triflate as catalyst at an industrially relevant temperature (120 °C) was used. As the phenyl content increased, the polymers changed from semicrystalline to amorphous in state. The loading capability of polymers was checked by formulating nanoparticles containing coumarin 6 as a fluorescent dye analogue of active drugs. A polymer with a 70/30 ratio of succinic acid and phenylsuccinic acid showed the highest dye loading among the set of materials synthesised. This polymer was found to be degradable over time under selected experimental conditions. Amphiphilic block co-polymers from the PluronicTM class were used to stabilize, in PBS, nanoparticles formed from these polyesters by nanoprecipitation routes. The metabolic activity, cell membrane integrity and lysosomal functions of C3A cells dosed with the polymers were determined to observe the cytocompatibility of the highest dye-loaded nanoparticles. Activity relative to undosed C3A cells was retained at more than 80% in the all of the assays. Imaging of Pluronic coated and uncoated nanoparticles in C3A cells suggested that both types of the nanoparticles were endocytosed in the early stage of the study (within 10 min). The internalization of nanoparticles was increased progressively over the study time. These results indicated the possible utility of the selected polymers in diagnostic and delivery applications. Ring opening polymerization (ROP) reactions were used for the synthesis of a diblock (mPEG-b-PεDL) and a triblock (PεDL-b-PEG-b-PεDL) copolymer from a seven membered ε-decalactone (ε-DL) monomer obtained from renewable sources. A diblock (mPEG-b-PεDL) copolymer was compared with structurally similar mPEG-b-PCL copolymer synthesized via ROP of ε-caprolactone (ε-CL) monomer, which can be considered as a non-renewable monomer. A six membered δ-decalactone (δ-DL) was also used for the synthesis of a diblock copolymer (mPEG-b-PδDL) to compare the reaction kinetics and properties of the copolymers. The copolymers were prepared via bulk polymerisation using 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) as a metal-free catalyst to replace the conventionally used stannous octoate [Sn(Oct)2]. A higher polymerization efficiency was achived with TBD compared to Sn(Oct)2 catalyst. However, a notable difference in the reaction temperature required for ε-DL and δ-DL polymerization was observed. The comparison with a structural analogue, i.e. ε-CL, demonstrated that the ε-DL polymerization was inhibited due to the presence of the alkyl chain of ε-DL monomer. However, a higher reaction time (12 h for TBD and 24 h for Sn(Oct)2) in CROP of ε-DL was addressed by using microwave based ring opening polymerization (MROP) reaction. The MROP was adopted as a ‘green’ and cheap heating method alternative to conventional heating (CROP) for the synthesis of mPEG-b-PεDL diblock copolymers using TBD as a catalyst. All the reactions were conducted in bulk. The MROP was designed based on the dielectric properties of all the reacting materials, as it was found that ε-DL monomers showed good absorption of MW radiation (tanδ>0.5). Accordingly, MROP resulted in a higher rate of ε-DL polymerization compared to CROP but comparison of the synthesis of mPEG-b-PCL copolymer by MROP indicated that the presence of the alkyl chain in ε-DL monomer significantly reduced the rate of polymerization. The synthesized mPEG-b-PεDL copolymer was investigated as a potential drug delivery vehicle for solubilization and controlled delivery of indomethacin. The indomethacin loading and release from mPEG-b-PεDL micelles (amorphous core) was compared against well-established mPEG-b-PCL micelles (semicrystalline core). The drug-polymer compatibility was also determined through a predictive computational approach to access the drug solubilisation (or drug loading) into hydrated micelles. The micelles were prepared by solvent evaporation method and characterized for size, morphology, indomethacin (IND) loading and release. Both of the micelle formulations showed a uniform distribution of spherical micelles with size <60 nm. However, a significantly higher size of empty mPEG-b- PεDL micelle was observed compared to mPEG-b-PCL micelles. A higher compatibility of the drug was predicted with PCL core as determined by modified Flory-Huggins interaction parameters (sp) using the Hanson solubility parameter (HSP) approach. The compatibility of the drug was determined for both of the segments (hydrophilic and hydrophobic) of the copolymers and found to be in the order of sp (PεDL)> sp (mPEG)> sp (PCL). The predictions suggested that more IND should encapsulate within the micelles with PCL core compared to PDL core, but the IND loading experiments revealed an overall higher loading in PεDL core (6.55 wt%) compared to PCL core (5.39 wt%) (P < 0.05, unpaired student’s t-test). However, consideration of the IND loading per unit volume of the micelles revealed that the PCL cored micelles was able to load 1.5 times more compared to the PεDL cored micelles. This result illustrated the higher compatibility of the IND with PCL core in accordance with the solubility parameter calculations. These data also suggested that the overall higher IND loading in PεDL core was attributable to the amorphous nature of the core which increased the core volume by 1.81 times compared to the PCL core. Drug release studies showed the sustained release pattern from both of the micelle systems although the semicrystalline PCL core (80% drug release in 110 h) was able to release the drug for a longer period compared to PεDL core (80% drug release in 72 h). Cell viability tests demonstrated the cytocompatibility of the mPEG-b-PεDL polymer. The micelles were internalized effectively in the early stages of the study and progressively increased with time. The results of the present thesis suggested that novel aliphatic polyester can be good candidates for the drug delivery applications and further studies can explore the possible applications of these polymers in the biomedical field.

The recent progresses offered by nanotechnology in the manipulation of matter lead to the development of several nanoparticles (NPs) and nanodevices for medical applications. In oncology, nanosized objects are particularly attractive as drug delivery systems since it is expected that engineered nanovehicles of appropriate size and functionalised with specific ligands/antibodies will improve the efficacy and selectivity of cancer therapies by exploiting both the passive and active mechanism of tumour targeting. The use of delivery systems is particularly appealing in those therapies in which the administration of the drug in aqueous formulations leads to drug aggregation with decreased activity or scarce bioavailability and tumour selectivity. This is the case of most of the photosensitizers used in photodynamic therapy (PDT), which display hydrophobicity and poor selective accumulation in malignant tissues. In the last decades, PDT is emerging as a promising cancer treatment modality in alternative to conventional therapies, which often demonstrate systemic drug toxicity and multidrug-resistance phenomena. PDT is based on the administration of a photosensitizer (PS) that accumulates in the tumour and after activation with light of appropriate wavelengths, reacts with surrounding molecular oxygen leading to the formation of cytotoxic reactive oxygen species (ROS) with consequent cellular and vasculature damages. In this PhD thesis, three different nanosystems, namely, liposomes, poly-(D,L-lactide-co-glycolide) nanoparticles (PLGA NPs) and ORganically Modified SILica nanoparticles (ORMOSIL NPs) were considered for the delivery of the second generation PS meta-tetra(hydroxyphenyl)chlorin (m-THPC, Temoporfin) to cancer cells in vitro. In particular, drug delivery efficiency, dark and phototoxicity of the m-THPC nanoparticle-based formulations were evaluated. To improve m-THPC bioavailability and tumour selectivity, in the design of the nanovehicles PEGylation and targeting of NPs were considered as essential strategies in order to prolong NP circulation in the bloodstream and exploit active mechanisms of tumour targeting. For the delivery of m-THPC using unilamellar liposomes, four different PEGylated liposomal formulations (trade name Fospeg®, provided by Biolitec Research) in which the length (PEG750, PEG2000, PEG5000) and the density (2%, 8%) of PEG were varied, were tested in vitro in normal lung fibroblasts CCD-34Lu and in cancer A549 lung epithelial cells. Compared to drug delivered in the standard solvent (Foscan®, ethanol/PEG 400/water (20:30:50, by vol.)), liposomal m-THPC showed a decreased intracellular uptake in both cell lines, but the presence of the delivery system highly reduced the dark cytotoxicity of the drug. The reduction of the PS dark toxicity increased with the increasing of PEG density on liposome surface, while the length of PEG chains did not affect significantly the toxic effect of m-THPC in the dark. However, photo-toxicity measured in A549 cells was only slightly affected by the reduced uptake of m-THPC delivered by Fospeg®, and the efficiency of PDT-induced cell killing was comparable among the different liposomal formulations. Interestingly, the intracellular localization of m-THPC delivered as Fospeg® or Foscan® was the same (Golgi apparatus and endoplasmic reticulum) suggesting drug release from liposomes, especially in the presence of the serum proteins, being m-THPC only physically entrapped within liposomes. m-THPC release was confirmed by the fact that liposomes covalently labelled with rhodamine were effectively were taken up by cells but, differently from m-THPC, localized in the acidic compartments of the cells. In spite of m-THPC release from liposomes, the Fospeg® formulation was exploited to target actively cancer cells by liposome conjugation with folic acid (FA), being FA-receptors (FRs) over-expressed in several human tumours. Thus, specific uptake and photo-toxicity of FA-targeted liposomes (FA-Fospeg) with respect to liposomes of the same composition but lacking FA (un-targeted Fospeg) was evaluated in KB (FR-positive) and in A549 (FR-negative) cells. The uptake of m-THPC delivered as FA-Fospeg was twice that of un-targeted Fospeg in KB cells; however only a modest fraction (~ 15%) of the targeted vehicle was effectively internalized by FR-mediated endocytosis while nonspecific internalization remained the prevailing mechanism of liposomes uptake in both cell lines. The improved m-THPC uptake obtained with FA-Fospeg in FR over-expressing cells translated into a 1.5 higher photo-induced toxicity. A novel formulation of bare and PEGylated PLGA NPs in which m-THPC was physically entrapped were synthesized (Prof J. Kos, University of Ljubljana) and evaluated in vitro and in vivo for phototherapy and fluorescence-based tumour imaging applications. In vitro studies carried out on A549, MCF10A neo T (breast cancer cells) and U937 (lymphoma derived pro-monocytic cells) cell lines, showed reduced uptake of PEGylated NPs with respect to non PEGylated NPs. As for Fospeg®, the use of the delivery system led to a significant reduction of m-THPC dark toxicity.. As expected for PEGylated NPs, the efficiency of cell internalization of m-THPC entrapped in PEG PLGA was reduced by 50% with respect to that in the standard solvent, but surprisingly cytotoxicity induced in irradiated A549 cells was quite comparable. At 24 h post-injection in vivo biodistribution of bare and PEGylated PLGA NPs compared to Foscan® was assessed in mice, showing very similar drug accumulation in the major organs but reduced skin uptake for both NP formulations. Thus, even if m-THPC release in the presence of serum proteins was measured in vitro, PEGylated PLGA NPs appeared potentially useful as stealth and biodegradable PS delivery systems. The premature release of the PS from the delivery system was completely avoided with the covalent link of m-THPC to the silane matrix of highly PEGylated ORMOSIL NPs (Prof. F. Mancin, University of Padova). This type of NPs exhibited a very low extent of cell internalization in vitro due to their high degree of PEGylation, making NP targeting an essential prerequisite to enhance intracellular drug delivery. In addition to FA, the RGD peptide and the antibody Cetuximab, which bind respectively the integrin α5ß3 receptor and epidermal growth factor receptor (EGFR), were exploited as targeting agents for ORMOSIL NPs and the specific uptake and photo-toxicity of m-THPC delivered by conjugated NPs were evaluated in vitro. The study revealed how the characteristics of the targeting agents are of crucial importance in determining the performances of targeted PEGylated nanosystems. In fact, the hydrophobic FA was very likely buried in the PEG layer and was unable to drive the selective uptake of ORMOSIL NPs while RGD peptide and Cetuximab antibody displayed some selectivity toward cells over-expressing their receptors (HUVEC cells over-expressing integrin α5ß3 receptors and A431 cells over-expressing EGFR). Unfortunately, the enhanced and selective uptake of m-THPC obtained by the two latter targeted ORMOSIL NPs was not accompanied by efficient and selective photo-induced cytotoxicity; it appeared that the selectivity of NP uptake was achieved in scarce drug cell loading conditions, determining only low PDT efficacy. The assessment of the biocompatibility of NPs is of fundamental importance for their safe use in nanomedicine. Since ORMOSIL NPs are not well characterised from this point of view, a toxicological characterization of empty ORMOSIL NPs were carried out in vitro in normal (CCD-34Lu) and cancer (A549, NCIH-2347) lung cells. The study included traditional cell viability and cytotoxicity tests (MTS test, LDH release assay, ROS production, cell membrane permeabilization measurements and electron microscopy analyses) in combination with a genome-wide analysis of gene expression profiles of cells exposed to NPs. The results pointed out that different types of cells respond quite differently to NPs and PEGylation of NPs highly affected the cytotoxicity profiles. PEGylation of ORMOSIL NPs completely abolished the toxicity of the nanosystem in CCD-34Lu and NCIH-2347 cells. On the contrary PEG ORMOSIL NPs induced necrotic cell death of A549 by increasing the permeability of the plasma membrane. At sub-lethal concentrations alteration of gene expression and inflammation were measured in A549 cells exposed to. The different response to PEG NPs is very likely explained considering the peculiarity of the cell type and the particular interaction of NPs with cell and internalization mechanisms. In fact, it was shown clearly that NPs internalized in A549 cells localized in and affected the morphology and the functioning of pulmonary surfactant containing lamellar bodies, peculiar of alveolar type II cells of which A459 cells represents an in vitro models.
Il recente progresso apportato dalla nanotecnologia nella manipolazione della materia ha portato al conseguente sviluppo di diversi tipi di nanoparticelle e nanodevices per applicazioni biomediche. In campo oncologico, oggetti dalle dimensioni nanometriche si sono dimostrati particolarmente interessanti in qualità di sistemi per la veicolazione di farmaci, poiché si presume che l’ingegnerizzazione dei nanoveicoli e la loro funzionalizzazione con specifici ligandi/anticorpi possa portare ad un miglioramento dell’efficacia e della selettività delle terapie antitumorali sfruttando meccanismi di targeting del tumore sia passivi che attivi. L’utilizzo di sistemi di veicolazione è particolarmente importante nel caso di terapie nelle quali la somministrazione dei farmaci in formulazioni acquose conduce a fenomeni di aggregazione con conseguente diminuzione di attività e di disponibilità nel circolo sanguineo, o nel caso di farmaci con scarsa selettività per il tumore. Appartengono a queste categorie la maggior parte dei fotosensibilizzanti utilizzati in terapia fotodinamica (PDT), poiché farmaci di natura idrofobica e con scarsa selettività di accumulo nei tessuti maligni. Negli ultimi decenni, la PDT si è dimostrata una promettente tecnica di trattamento del cancro in alternativa alle terapie convenzionali che invece generalmente dimostrano alta tossicità sistemica e fenomeni di farmaco-resistenza. La PDT si basa sulla somministrazione di un fotosensibilizzante (PS) che accumulatosi nel tumore, e dopo essere stato attivato con opportune lunghezze d’onda di luce, è in grado di reagire con l’ossigeno molecolare che lo circonda generando specie reattive dell’ossigeno (ROS) altamente citotossiche con conseguente danno cellulare e vascolare. In questa tesi di dottorato, tre diversi nanosistemi quali liposomi, nanoparticelle PLGA (poly-(D,L-lactide-co-glycolide)) e nanoparticelle di silice organicamente modificata (ORMOSIL), sono stati presi in considerazione per la veicolazione del fotosensibilizzante di seconda generazione meta-tetra(hydroxyphenyl)chlorin (m-THPC, Temoporfin) in cellule tumorali in vitro. In particolare, sono state valutate l’efficienza di veicolazione del farmaco, la tossicità buia e fotoindotta delle diverse formulazioni di m-THPC. Per migliorare la biodisponibilità e la selettività per il tumore della m-THPC, nella progettazione dei nanoveicoli sono state considerate quali strategie essenziali la pegilazione e il targeting delle particelle, in modo da prolungare la circolazione dei nanosistemi nel flusso sanguineo e in modo da sfruttare meccanismi attivi di targeting del tumore. Per la veicolazione della m-THPC utilizzando liposomi unilamellari sono state saggiate in vitro quattro diverse formulazioni liposomiali pegilate (Fospeg®, fornito dalla ditta Biolitec Research) con lunghezza (PEG750, PEG2000, PEG5000) e densità del PEG (2%, 8%) variabili, utilizzando come linee cellulari fibroblasti di polmone normali (CCD-34Lu) e cellule tumorali di epitelio polmonare (A549). Se paragonate al farmaco somministrato in forma libera in soluzione (Foscan®, etanolo/PEG 400/acqua (20:30:50, vol/vol)), le formulazioni liposomiali di m-THPC hanno mostrato una ridotta internalizzazione in entrambe le linee cellulari, ma nello stesso tempo la presenza del sistema di veicolazione ha portato alla significativa riduzione della tossicità buia del farmaco. La riduzione della tossicità buia del farmaco è risultata proporzionale all’aumento della densità di PEG sulla superficie del liposoma mentre la lunghezza delle catene di PEG sembra essere ininfluente nel limitare l’effetto tossico della m-THPC al buio. Comunque, la ridotta internalizzazione della m-THPC veicolata tramite Fospeg® influenza in modo solo parziale la fototossicità misurata in cellule A549, mentre l’efficienza d’induzione di mortalità in seguito a trattamento fotodinamico è risultata paragonabile tra le diverse formulazioni saggiate. Indipendentemente dalla veicolazione tramite Fospeg® o Foscan®, è stata riscontrata la medesima localizzazione intracellulare della m-THPC (apparato del Golgi e reticolo endoplasmatico) suggerendo il possibile rilascio del farmaco dalla formulazione liposomiale in presenza di proteine del siero, essendo la m-THPC solamente fisicamente intrappolata all’interno dei liposomi. Il rilascio della m-THPC è stato confermato dal fatto che liposomi nei quali viene legata covalentemente rodamina vengono effettivamente internalizzati dalle cellule e, differentemente dalla m-THPC, si accumulano nei compartimenti acidi intracellulari. Nonostante il rilascio del fotosensibilizzante dai liposomi, la formulazione Fospeg® è comunque stata utilizzata per veicolare selettivamente la m-THPC in cellule cancerose tramite la coniugazione dei liposomi con acido folico, essendo i recettori del folato sovraespressi in diversi tumori umani. Quindi sono state valutate l’internalizzazione specifica e la fototossicità di liposomi coniugati con folato (liposomi folato) rispetto a liposomi della stessa composizione ma privi di acido folico (liposomi non coniugati) in cellule KB e A549, rispettivamente positive e negative per l’espressione di recettori del folato. In cellule KB, l’internalizzazione della m-THPC si è rivelata doppia in caso di veicolazione con liposomi folato, malgrado solo una modesta parte (~15%) dei nanosistemi coniugati con folato siano effettivamente internalizzati tramite meccanismi di endocitosi mediata da recettore, essendo invece un’internalizzazione di tipo aspecifico il meccanismo prevalente per l’internalizzazione dei liposomi in entrambe le linee cellulari saggiate. In ogni caso, all’aumentato accumulo di m-THPC ottenuto tramite la veicolazione con Fospeg coniugato con folato in cellule che sovra esprimono il recettore, ne è conseguita una tossicità dopo irradiamento aumentata di circa 1.5 volte. Riguardo invece la veicolazione di m-THPC tramite particelle PLGA, formulazioni nude o pegilate sono state sintetizzate (Prof. J. Kos, Università di Lubiana) e saggiate sia in vitro che in vivo per la loro potenziale applicazione in fototerapia o in diagnosi dei tumori, sfruttando la fluorescenza del fotosensibilizzante fisicamente intrappolato all’interno delle particelle. Studi in vitro condotti su cellule A549, MCF10A neo T (derivate da tumore del seno) e U937 (cellule pro-monocitiche derivate da linfoma), hanno mostrato una ridotta internalizzazione della formulazione di m-THPC pegilata rispetto a quella nuda. Anche con particelle PLGA e come già visto per il Fospeg®, l’utilizzo di un sistema di veicolazione porta alla significativa riduzione della citotossicità buia della m-THPC. L’efficienza d’internalizzazione del fotosensibilizzante veicolato tramite particelle PLGA pegilate viene ridotta circa del 50% rispetto alla sua veicolazione nella formulazione standard ma sorprendentemente l’effetto citotossico indotto in cellule A549 irradiate è quasi paragonabile. La biodistribuzione della m-THPC (veicolata tramite nanoparticelle PLGA nude o pegilate o nella formulazione standard) è stata valutata 24 ore dopo la sua iniezione in topi, mostrando una simile distribuzione nei vari organi ma una significativa riduzione dell’accumulo a livello epidermico per entrambe le formulazioni nanoparticellari. Quindi, nonostante anche per le particelle PLGA pegilate sia stato misurato il rilascio di m-THPC in presenza di proteine sieriche, esse appaiono un buon sistema di veicolazione di fotosensibilizzanti soprattutto per le loro caratteristiche ‘stealth’ e per la loro biodegradabilità. Il rilascio prematuro del fotosensibilizzante è stato invece completamente limitato con il legame covalente della m-THPC alla matrice silanica di particelle ORMOSIL altamente pegilate (Prof. F. Mancin, Università di Padova). Tuttavia questo tipo di particelle ha mostrato un’internalizzazione intracellulare estremamente bassa derivata dall’elevato grado di pegilazione, ponendo come requisito essenziale il targeting delle particelle. In qualità di agenti di targeting per le particelle ORMOSIL pegilate sono stati valutati, oltre al folato, anche il peptide ciclico RGD e l’anticorpo Cetuximab, essendo questi ultimi in grado di legarsi rispettivamente ad integrine α5ß3 e al recettore del fattore di crescite dell’epidermide (EGFR). L’internalizzazione selettiva e la fototossicità della m-THPC veicolata tramite le tre diverse nanoparticelle funzionalizzate sono state valutate in vitro in opportuni sistemi cellulari. Tale studio ha mostrato come le caratteristiche dell’agente di targeting influenzino in modo sostanziale la selettività di tali nanosistemi pegilati. Infatti, mentre il folato altamente idrofobico si ripiega verosimilmente verso la corona di PEG rendendosi inefficace nel guidare selettivamente le particelle ORMOSIL, il peptide RGD e l’anticorpo Cetuximab hanno mostrato una certa selettività nei confronti di cellule sovraesprimenti i rispettivi recettori (cellule HUVEC sovraesprimenti recettori per le integrine α5ß3 e cellule A431 sovraesperimenti EGFR). Tuttavia, l’aumentato accumulo selettivo della m-THPC ottenuto tramite la coniugazione delle nanoparticelle con RGD e Cetuximab non ha portato ad una conseguente aumentata efficienza e selettività nell’induzione di citotossicità in seguito ad irradiamento. Tale risultato è verosimilmente imputabile al fatto che la selettività di accumulo delle nanoparticelle viene raggiunta in condizioni nelle quali la disponibilità del farmaco nelle cellule è troppo bassa, con conseguente scarsa efficacia dopo trattamento fotodinamico. La valutazione della biocompatibilità delle nanoparticelle risulta di fondamentale importanza per un’applicazione sicura della nanotecnologia in campo medico. Quindi, poiché le nanoparticelle ORMOSIL non sono ancora state ben caratterizzate da tale punto di vista, un loro profilo tossicologico è stato tracciato in vitro in cellule polmonari normali (CCD-34Lu) e tumorali (A549, NCIH-2347). Nello studio sono stati combinati esperimenti tradizionali di valutazione della vitalità cellulare e della citotossicità (test MTS, saggio del rilascio di LDH, valutazione della produzione di ROS, misure di permeabilizzazione di membrana, analisi di microscopia elettronica) con un’analisi dei profili di espressione genica estesa all’intero genoma di cellule esposte alle nanoparticelle. I risultati hanno mostrato come diversi tipi di cellule rispondono in modo abbastanza differente all’esposizione alle nanoparticelle e come la pegilazione influisce fortemente sui profili di citotossicità. Infatti, la pegilazione delle particelle ORMOSIL è in grado di abolire completamente la tossicità dei nanosistemi in cellule CCD-34Lu e NCIH-2347 mentre le stesse particelle pegilate inducono morte per necrosi in cellule A549, aumentandone la permeabilità di membrana. Inoltre nelle medesime cellule, concentrazioni sub-letali di nanoparticelle inducono infiammazione e alterazione dell’espressione genica. La differente risposta all’esposizione alle nanoparticelle pegilate delle cellule A549 è spiegabile considerando la peculiarità di questo tipo cellulare, e in particolare l’interazione delle particelle stesse con le cellule e il loro meccanismo d’internalizzazione. Infatti, è stato mostrato in modo chiaro che le nanoparticelle vengono internalizzate in corpi lamellari contenenti il surfattante polmonare, peculiari di cellule alveolari di tipo II, delle quali le cellule A549 rappresentano un modello in vitro. Tale accumulo delle nanoparticelle nei corpi lamellari porta alla modifica della morfologia degli stessi e una pesante alterazione della loro funzionalità.

Near-field optics (NFO) overcomes the diffraction limit of light microscopes and permits single molecules to be imaged. Current NFO systems are designed to scan over the object being imaged and has found many applications in the physical sciences. However, there is a lack of tools that allow one to view intracellular processes, which would have many applications in the neurosciences, cancer studies and drug delivery fields. In this work, the authors have developed near-field optical probes, with nanometer apertures, that achieve much higher light throughput than conventional near-field fiber probes. The probes are designed to penetrate a living cell without destroying it. In parallel to this work, a microfluidic device has been designed and fabricated which is part of a high resolution imaging system the authors are developing. The microfluidic device or “CellTray” contains over 7000 individual wells that contain multiple cells. Together the optical probe and CellTray bring us a step closer to a lab-on-a-chip device for biomedical research.

The magnetic nanoparticles (MNPs) based micro- nanorobots are emerging drug carriers. Controllability by an external magnetic field is the major advantage of these drug carriers. However, they are facing several challenges including controllability of the individual motion of MNPs under a global magnetic field. The microswarm control where collective MNPs were guided by a magnetic field was proposed as a solution [1]. Steering the MNPs as a microswarm to the targeted region has many advantages which include increasing the delivered drug to the site, preserving the healthy organs from drug penetration, and decreasing the negative side effects. In recent studies, particle swarms were guided using a rotating/oscillating magnetic field [2], [3]. A simulation platform for steering the aggregated MNPs based on the gradient field was developed [4]. Despite studies on the separation, no computational platform for predicting changes in particle dispersion under different magnetic field conditions has been introduced. After reaching the position of interest, the aggregates also had to be separated to ensure successful drug delivery. In this study using mathematical modelling, a separation platform has been developed. More details on the mathematical model used here can be found in [5]. The paper is divided into two sections. First, the accuracy of the simulation platform is discussed and then the effective parameters have been studied.

Abstract Convection-enhanced delivery (CED) through an arborizing microneedle catheter system is an experimental drug delivery technique used to treat glioblastoma by providing a higher drug volume dispersed (Vd) of therapeutics directly to larger regions of brain tissue. A convection-enhanced thermo-chemotherapy catheter system (CETCS) can simultaneously deliver fluid and thermal energy to the infected area. The CETCS developed in our Medical Device Design lab comprises a bundle of 6 microneedles made from fiber optic capillary tubing, passed through a rigid cannula and individually arborized (branch-out). We are preparing CETCS for regulatory pathway application to advance it further toward clinical and human trials. In this paper, we performed three performance tests: infusion pressure, leakage, and constant pressure flow rate tests required by the FDA to file a traditional 510(K) based upon a potential predicate device. The high-pressure burst and leakage test showed that the CETCS can withstand an internal pressure of 100 psi with no leakage or failure in any connections and attachments, resulting in a substantial equivalency to the predicate devices. The constant pressure flow rate test showed a flow rate average of 0.64 ml/h under 0.7 psi and 1.69 ml/h under 2.1 psi of constant pressure using distilled water column, resulting in substantial equivalency to the predicate devices.

Intrathecal (IT) drug delivery is a preferred treatment for chronic pain, brain cancers and spasticity. However, the application of IT drug delivery treatment is still limited by the large patient-to-patient variations and numerous kinds of rare genetic diseases. A fast, relatively cheap and subject-specific in-vitro method to study the drug bio-dispersion mechanism and optimize the intrathecal drug therapies for individual patients is in great need. In this study, we will investigate the model design and additive manufacturing process for producing a subject-specific spine model, which will simulate the interaction of the real human spine with cerebrospinal fluid (CSF). Research issues including watertight 3D printable model construction and 3D printing of anatomical accurate, physiological functional spine models are discussed in this paper. A pipeline of additive manufacturing in-vitro subject-specific models for study of cerebrospinal fluid and drug transport in spine is presented.

Abstract Additive manufacturing is a growing field, but its application in the fabrication of medical microdevices has not been fully explored. Traditionally, medical microdevices are manufactured via a combination of techniques such as photolithography, laser-cutting, and micromolding, which collectively have challenges such as multiple fabrication steps, limited design freedom, high fabrication cost, and significant fabrication time. Micro vat photopolymerization is presented here as an alternative method to produce four different microscale medical devices that have applications in microfluidics, drug delivery, and bioscaffolding. In terms of minimum feature size and resolution, the presented structures are comparable, if not superior, to literature quoted parts fabricated through conventional manufacturing methods. The fabrication steps, process parameters, design considerations, learnings, and future research directions are outlined.

In this paper, we designed and fabricated High-throughput Microfluidic device for membrane protein polyhedral. Protein is the most important functional element in our human body and also it could be applied to the key application areas of drug bonding and drug delivery. However protein stucture is difficult to be analyzed due to the complex and variable geometry of protein stucture which can be randomly formed by 20 amino acids and also plused 3D folding of stucture possibly. Based on this, we could imagine it would be a huge variable number of protein stucture, let’s say billion possibilities. Therefore if we can successful discover protein stucture, then we can expect that will improve drug delivery of medical technology forward to a big step.

Poly(L-lactic acid) (PLLA) has been shown to have potential medical usage such as in drug delivery because it can degrade into bioabsorbable products in physiological environments, and its degradation is affected by crystallinity. In this paper, the effect of film formation method and annealing on the crystallinity of PLLA are investigated. The films are made through solvent casting and spin coating methods, and subsequent annealing is conducted. The resulting crystalline morphology, structure, conformation, and intermolecular interaction are examined using optical microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. It is observed that solvent casting produces category 1 spherulites while annealed spin coated films leads to spherulites of category 2. Distinct lamellar structures and intermolecular interactions in the two kinds of films have been shown. The results enable better understanding of the crystallinity in PLLA, which is essential for its drug delivery application.