Biomaterials and regulatory science

The fast development of both biomaterials and regulatory science calls for a convergence,which is addressed in this article via their link through medical products of biomaterials and related safety and efficacy evaluation.The updated definition of biomaterials,and concepts of biomaterials-related medical products and so-called medical-grade and implantable materials are firstly introduced.Then a brief overview of the concept and history of regulatory science and its assessment of safety and efficacy of medical products,as well as the currently ongoing biomaterials-related regulatory science programs are presented.Finally,the opportunities provided by regulatory science for biomaterials as well as challenges on how to develop a biomaterials-based regulatory science system are discussed.As the first article in the field to elucidate the relationship between biomaterials and regulatory science,key take-home messages include(1)biomaterials alone are not medical products;(2)regulatory authorities approve/clear final medical products,not biomaterials;(3)there is no definition/regulation on the so-called medical-grade or implantable materials;and(4)safety and efficacy refer to final medical products,not biomaterials alone.

Dynamic mechanical loading facilitated chondrogenic differentiation of rabbit BMSCs in collagen scaffolds

Mechanical signals have been played close attention to regulate chondrogenic differentiation of bone marrow mesenchymal stem cells(BMSCs).In this study,dynamic mechanical loading simulation with natural frequencies and intensities were applied to the 3D cultured BMSCs–collagen scaffold constructs.We investigated the effects of dynamic mechanical loading on cell adhesion,uniform distribution,proliferation,secretion of extracellular matrix(ECM)and chondrogenic differentiation of BMSCs–collagen scaffold constructs.The results indicated that dynamic mechanical loading facilitated the BMSCs adhesion,uniform distribution,proliferation and secretion of ECM with a slight contraction,which significantly improved the mechanical strength of the BMSCs–collagen scaffold constructs for better mimicking the structure and function of a native cartilage.Gene expression results indicated that dynamic mechanical loading contributed to the chondrogenic differentiation of BMSCs with higher levels of AGG,COL2A1 and SOX9 genes,and prevented of hypertrophic process with lower levels of COL10A1,and reduced the possibility of fibrocartilage formation due to down-regulated COL1A2.In conclusion,this study emphasized the important role of dynamic mechanical loading on promoting BMSCs chondrogenic differentiation and maintaining the cartilage phenotype for in vitro reconstruction of tissue-engineered cartilage,which provided an attractive prospect and a feasibility strategy for cartilage repair.

The effect of LyPRP/collagen composite hydrogel on osteogenic differentiation of rBMSCs

Although platelet-rich plasma(PRP)plays a significant role in the orthopedic clinical application,it still faces two major problems,namely,uncontrollable factors release,frequent preparation and extraction processes as well as the inconvenient form of usage.To overcome these shortcomings,freeze-dried PRP(LyPRP)was encapsulated into bioactive Col I hydrogel to induce osteogenic dif-ferentiation of rabbit bone marrow mesenchymal stem cells(rBMSCs).And PRP/Col I composite hydrogel was prepared as a control.Compared with Col I hydrogel,the introduction of platelets significantly improved the mechanical properties of hydrogels.Meanwhile,platelets were evenly distributed in the composite hydrogels network.The sustainable release of related factors in the composite hydrogels could last for more than 14days to maintain its long-term biological activity.Further cell experiments confirmed that PRP and LyPRP could effectively alleviate the contraction of collagen hydrogel in vitro,and promote the adhesion,proliferation and osteogenesis differentia-tion of rBMSCs.The results of osteogenic gene expression indicated that the 10%LyPRP/Col I composite hydrogel could facilitate the early expression of BMP-2 and late osteogenic associated protein formation with higher expression of alkaline phosphatase and Osteocalcin(OCN).These results might provide new insights for the clinical application of 10%LyPRP/Col I composite hydro-gel as practical bone repair injection.