Self-aggregation and thermo-responsive properties of biodegradable poly(ethylene glycol)-poly(L-lactide) amphiphilic diblock copolymers

Transactions - 7th World Biomaterials Congress1034

Screening for 3D Environments That Support Human Mesenchymal Stem Cell Viability Using Hydrogel Arrays

In this study we generated 3D poly(ethylene glycol) (PEG) hydrogel arrays to screen for the individual and combinatorial effects of extracellular matrix (ECM) degradability, cell adhesion ligand type, and cell adhesion ligand density on human mesenchymal stem cell (hMSC) viability. In particular, we explored the influence of two well-characterized ECM-derived cell adhesion ligands: the fibronectin-derived Arg-Gly-Asp-Ser-Pro (RGDSP) sequence, and the laminin-derived Ile-Lys-Val-Ala-Val (IKVAV) sequence. PEG network degradation, the RGDSP ligand, and the IKVAV ligand each individually increased hMSC viability in a dose-dependent manner. The RGDSP ligand also improved hMSC viability in a dose-dependent manner in degradable PEG hydrogels, while the effect of IKVAV was less pronounced in degradable hydrogels. Combinations of RGDSP and IKVAV promoted high viability of hMSCs in nondegradable PEG networks, while the combined effects of the ligands were not significant in degradable PEG hydrogels. Although hMSC spreading was not commonly observed within PEG hydrogels, we qualitatively observed hMSC spreading after 5 days only in degradable PEG hydrogels prepared with 2.5 mM of both RGDSP and IKVAV. These results suggest that the enhanced throughput approach described herein can be used to rapidly study the influence of a broad range of ECM parameters, as well as their combinations, on stem cell behavior

Self-association and micelle formation of biodegradable poly(ethylene glycol)-poly(L-lactic acid) amphiphilic di-block co-polymers

10.1163/156856206777656553Journal of Biomaterials Science, Polymer Edition177747-763JBSE

Subcutaneous tissue response to titanium, poly(epsilon-caprolactone), and carbonate-substituted hydroxyapatite-coated poly(epsilon-caprolactone) plates: a rabbit study

Contains fulltext : 119196.pdf (Publisher’s version ) (Closed access)The aim of this study was to evaluate the soft tissue response to poly(epsilon-caprolactone) (PCL) implants with and without carbonate-substituted hydroxyapatite (CHA) coating compared to the commonly used titanium alloy (Ti-6Al-4V)-machined surface. Experimental materials were implanted subcutaneously in New Zealand white rabbits for 5 weeks. The tissue attachment strength, as evaluated by a tissue peel test, histological and histomorphology analysis, as well as scanning electron microscopy were compared between groups. The peel test result revealed no statistically significant difference between groups. Histological analysis found fibrous capsule formation around all implant materials. The fibrous capsule around PCL implants with and without CHA coating was significantly thinner compared with the capsule thickness around the titanium implants. However, the inflammatory cells, as present at the fibrous capsule-implant interface, were found to be significantly lower in the Ti-group. In conclusion, the current data do not prove that PCL or PCL with a CHA coating results in a superior soft tissue response compared with a machined titanium implant

Functionalization of microparticles with mineral coatings enhances non-viral transfection of primary human cells

Abstract Gene delivery to primary human cells is a technology of critical interest to both life science research and therapeutic applications. However, poor efficiencies in gene transfer and undesirable safety profiles remain key limitations in advancing this technology. Here, we describe a materials-based approach whereby application of a bioresorbable mineral coating improves microparticle-based transfection of plasmid DNA lipoplexes in several primary human cell types. In the presence of these mineral-coated microparticles (MCMs), we observed up to 4-fold increases in transfection efficiency with simultaneous reductions in cytotoxicity. We identified mechanisms by which MCMs improve transfection, as well as coating compositions that improve transfection in three-dimensional cell constructs. The approach afforded efficient transfection in primary human fibroblasts as well as mesenchymal and embryonic stem cells for both two- and three-dimensional transfection strategies. This MCM-based transfection is an advancement in gene delivery technology, as it represents a non-viral approach that enables highly efficient, localized transfection and allows for transfection of three-dimensional cell constructs