Biphasic Polyurethane/Polylactide Sponges Doped with Nano-Hydroxyapatite (nHAp) Combined with Human Adipose-Derived Mesenchymal Stromal Stem Cells for Regenerative Medicine Applications.

Krzysztof Marycz,Agnieszka Śmieszek,Jakub Grzesiak,Anna Lis,Monika Marędziak

doi:10.3390/polym8100339

Abstract

Cartilage and bone tissue injuries are common targets in regenerative medicine. The degeneration of cartilage tissue results in tissue loss with a limited ability to regenerate. However, the application of mesenchymal stem cells in the course of such condition makes it possible to manage this disorder by improving the structure of the remaining tissue and even stimulating its regeneration. Nevertheless, in the case of significant tissue loss, standard local injection of cell suspensions is insufficient, due to the low engraftment of transplanted cells. Introduction of mesenchymal stem cells on the surface of a compatible biomaterial can be a promising tool for inducing the regeneration by both retaining the cells at the desired site and filling the tissue gap. In order to obtain such a cell-biomaterial hybrid, we developed complex, biphasic polymer blend biomaterials composed of various polyurethane (PU)-to-polylactide (PLA) ratios, and doped with different concentrations of nano-hydroxyapatite (nHAp). We have determined the optimal blend composition and nano-hydroxyapatite concentration for adipose mesenchymal stem cells cultured on the biomaterial. We applied biological in vitro techniques, including cell viability assay, determination of oxidative stress factors level, osteogenic and chondrogenic differentiation potentials as well as cell proteomic analysis. We have shown that the optimal composition of biphasic scaffold was 20:80 of PU:PLA with 20% of nHAp for osteogenic differentiation, and 80:20 of PU:PLA with 10% of nHAp for chondrogenic differentiation, which suggest the optimal composition of final biphasic implant for regenerative medicine applications.

Highlights

Cartilage and bone tissue injuries caused by mechanical factors require surgical intervention due to their sudden and unexpected nature
Synthetic biomaterials composed of polyurethane (PU) and a polymer of lactic acid (PLA) have been recently proposed as an engineered scaffold dedicated for regenerative medicine applications due to their biocompatibility, relative ease of modulation of their microstructure and mechanical properties [6]
We showed the possibility of synthesizing bi-phasic, polymer-based, nanohydroxyapatite-doped scaffolds for mesenchymal stromal cell colonization and differentiation towards osteoblasts and scaffolds for mesenchymal stromal cell colonization and differentiation towards osteoblasts and chondroblasts

Summary

Introduction

Cartilage and bone tissue injuries caused by mechanical factors require surgical intervention due to their sudden and unexpected nature These disorders are caused by a single or multiple traumatic events that usually lead to serious motion limitation, pain, limb stiffness and/or swelling, which seriously reduce the life quality, in elderly patients. HAp can be obtained from different types of sources, e.g. directly from the patient (autologous), another human donor (allogenic), animals (xenogenic) as well as by synthetic production [8]. It is well known, that synthetic hydroxyapatites exhibit very low osteoconductive and osteoinductive potentials [9]. Preparation of such small objects using special synthetic methods provide appropriate equilibrium in the resorption-remineralization cycle and a high affinity for proteins that play an important role in the active forming of osseous and fibrous tissues [11]

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Results

Conclusion