GRGDSPC

Scaffolds that can achieve cell adhesion and controlled release of protein drugs are very promising in bone tissue engineering. Due to their biocompatibility and injectablity, poly(lactide-co-glycolide acid) (PLGA) porous microspheres (PLGA-pMS) present potential scaffolds in bone tissue engineering. However, their application is hampered by the burst release of protein drugs and hydrophobicity that leads to poor cell adhesion. To overcome these drawbacks, we developed novel PLGA-pMS by incorporating bovine serum albumin (BSA) loaded chitosan microspheres (CS-MS) in Gly-Arg-Gly-Asp-Ser-Pro-Cys (GRGDSPC) modified PLGA-pMS (CS-MS/PLGA-pMS). GRGDSPC was used to enhance the hydrophilicity and cell affinity of the porous microspheres. Results showed that PLGA-pMS had a size of 446.77±19.46μm, with an average surface pore size of 21.56±3.02μm, whereas CS-MS had a size of 15.98±0.96μm and 16.35±0.38μm (5% and 10% TPP-prepared CS-MS, respectively). A scanning electron microscope (SEM) and a confocal laser scanning microscope (CLSM) revealed that CS-MS were partly embedded in the PLGA matrices and the integrity of CS-MS was retained. Thermogravimetry analyzer (TGA) also demonstrated that CS-MS were incorporated into PLGA-pMS. The CS-MS/PLGA-pMS had a size of 454.02±16.09μm, with a BSA encapsulation efficiency of 53.19±1.67% and 62.16±3.44% (5% and 10% TPP-prepared CS-MS, respectively). CS-MS/PLGA-pMS exhibited a sustained FITC-BSA release for 28 days. Modification of GRGDSPC significantly improved adhesion of MG-63 cells on the porous microspheres. In conclusion, CS-MS/PLGA-pMS may act as potential bifunctional scaffolds for bone tissue engineering.

Engineering of functional vascularized pancreatic tissues offers an alternative way to solve the perpetual shortage of organs for transplantation. However, revascularization remains a major bottleneck in biological engineering, which limited the further clinical applications of this strategy. In this study, an efficient approach for enhancing re-endothelialization of rat decellularized pancreatic scaffolds (DPS) was presented, by conjugating with GRGDSPC peptide to maximize coverage of the vessel walls with human umbilical vein endothelial cells (HUVECs). First, pancreas was perfused with 1% Triton X-100 and 0.1% ammonium hydroxide to remove the cellular components. Subsequently, GRGDSPC was covalently coupled to the vasculature of DPS and re-seeded with HUVECs via perfusion of the portal vein in the bioreactor. After the re-endothelialized scaffolds were created, in vitro and in vivo experiments were undertaken to evaluate the angiogenesis. Our results demonstrated that GRGDSPC-conjugated scaffolds could support the survival and accelerated the proliferation of HUVECs; angiogenesis was also significantly improved over untreated scaffolds. In conclusion, GRGDSPC-conjugated scaffolds showed great potential for the generation of functional bioengineered pancreatic tissue suitable for long-term transplantation.

Ligament reconstruction is an effective therapy for anterior cruciate ligament (ACL) rupture. Polyethylene terephthalate (PET) artificial ligaments have recently gained popularity in clinical ACL reconstruction for its advantage in the improvement of keen function. However, the application of PET in clinical treatment is limited by its poor bioactivity and biocompatibility. Recently, bone marrow-derived mesenchymal stem cells (BMSCs) have been widely studied in regenerative medical therapy due to their multi-lineage differentiation. Previous study also indicated that BMSCs may promote the healing of tendon-bone interface of injured ligament. We speculate that BMSCs may enhance the curative effect of PET artificial ligament on the tendon-bone-healing in ligament reconstruction. In this study, the PET materials were first modified with sodium hydroxide hydrolysis and GRGDSPC peptide which was able to improve its bioactivity and biocompatibility. Then, the effects of modified PET materials on the adhesion, proliferation and differentiation of BMSCs were examined. The in vitro co-culture of BMSCs and modified PET showed the modified PET promoted the adhesion, proliferation and differentiation of BMSCs. Further, the effect of culture complex of BMSCs and modified PET artificial ligament co-culture system on the injured ligament reconstruction was investigated in vivo. Results showed not only better growth and differentiation of BMSCs but also satisfactory healing of the injured ligament was observed after implantation of this culture complex into the injured ligament of rabbits. Our study provides a brand-new solution for ACL reconstruction.