RGD modified PLGA/gelatin microspheres as microcarriers for chondrocyte delivery

Abstract

Poly(lactide-co-glycotide) (PLGA)/gelatin composite microspheres were prepared by an emulsion solvent evaporation technique. RGDS peptides were further immobilized under the catalyzation of water soluble carbodiimide (EDAC). Confocal laser scanning microscopy and transmission electron microscopy revealed that the gelatin was entrapped in the PLGA/gelatin microspheres with a manner of separated domains. The contents of the entrapped gelatin and immobilized RGDS peptides were quantified as 0.9 mg/20 mg and approximately 2.1 microg/20 mg microspheres by hydroxyproline analysis and bicinchoninic acid protein assay, respectively. Moreover, difference in morphology of PLGA, PLGA/gelatin and RGDS modified PLGA/gelatin (PLGA/gelatin-RGDS) microspheres was observed by scanning electron microscopy. The PLGA/gelatin and PLGA/gelatin-RGDS microspheres lost their weight rapidly in PBS, but slowly in DMEM/fetal bovine serum. Rabbit auricular chondrocytes were seeded onto the microspheres in vitro to assess their biological performance and applicability as cell carriers. Results show that amongst the PLGA, PLGA/gelatin and PLGA/gelatin-RGDS microspheres, the latter ones have the best performance in terms of chondrocyte attachment, proliferation, viability and sulfated glycosaminoglycans secretion.

Facile control of RGD-alginate/hyaluronate hydrogel formation for cartilage regeneration

“…The number of integrins on the surface of primary chondrocytes was less than those on immortalized cells (Loeser, Sadiev, Tan, & Goldring, 2000). This may explain why primary chondrocytes do not form a cross-linked structure with the RGD-alginate, even though primary chondrocytes are known to interact with RGD peptides (Tan, Huang, Lao, & Gao, 2009). Surprisingly, G was higher than G when the mixture of RGD-alginate/hyaluronate solution ([polymer] = 2.5 wt%; alginate/hyaluronate = 4/1, w/w) and chondrocytes ([cell] = 1.25 × 10 7 cells/ml) were measured (squares in Fig.…”

Biodegradable insulin-loaded PLGA microspheres fabricated by three different emulsification techniques: Investigation for cartilage tissue engineering

“…3D cell expansion in a bioreactor preserves the chondrocyte phenotype while allowing extensive cell expansion under controlled cultivation conditions [67,68]. Chondrocyte adhesion can be assured by producing microspheres with a positive surface charge (see above) and by distinct surface modifications [69]. As injectable scaffolds cell-microsphere composites offer minimal surgical invasiveness during transplantation and assemble in situ into a 3D scaffold to induce tissue regeneration [70].…”

Poly(α-hydroxy Acids)-Based Cell Microcarriers

“…These peptides can be easily incorporated via the carbodiimide chemistry on the surface of microparticles bearing carboxylic groups [77] or previously functionalized with gelatin [78]. In these two examples, incorporation of RGD peptide clearly improved the initial adhesion and subsequent proliferation of chondrocytes.…”

“…In contrast, after functionalization with REDV the adhesion and proliferation of cells was significantly improved, and similar to that obtained in Cytodex 1, which was used as a positive control. In order to avoid conformational changes associated with large biomacromolecules (i.e., proteins), short peptides can also be incorporated on the surface of microparticles to provide active domains for cell binding [77,78]. These peptides can be easily incorporated via the carbodiimide chemistry on the surface of microparticles bearing carboxylic groups [77] or previously functionalized with gelatin [78].…”