Department of Regenerative Biomaterials, Radboud University Medical Center, Philips van Leydenlaan 25, 6525 EX, Nijmegen, The Netherlands.
CAM Bioceramics B.V., Zernikedreef 6, 2333 CL, Leiden, The Netherlands.
J Biomed Mater Res B Appl Biomater. 2019 Oct;107(7):2216-2228. doi: 10.1002/jbm.b.34306. Epub 2019 Feb 1.
Injectable, self-setting calcium phosphate cements (CPCs) are synthetic bone substitutes considered favorable for the repair and regeneration of bone due to their osteocompatibility and unique handling properties. However, their clinical applicability can be compromised due to insufficient cohesion upon injection into the body coupled with poor degradation rates that restricts new bone formation. Consequently, carboxymethyl cellulose (CMC) was incorporated into CPC formulations to improve their cohesion and injectability while poly ( -lactic-co-glycolic acid) (PLGA) porogens were added to introduce macroporosity and improve their biodegradation rate. Like most biomaterials, CPCs are gamma irradiated before clinical use to ensure sufficient sterilization. However, it is well known that gamma irradiation also reduces the molecular weight of CMC and PLGA via chain scission, which affects their material properties. Therefore, the aim of this study is to measure the effect that gamma irradiation has on the molecular weight of CMC at varying doses of 15, 40, or 80 kGy and investigate how this affects the handling (i.e., injectability, cohesion, washout, and setting times) and in vitro degradation behavior of CPC formulations. Results reveal that the molecular weight of CMC decreases with increasing gamma irradiation dose, thereby reducing the viscosifying capabilities of CMC, which causes CPCs to deteriorate more readily. Further, the addition of CMC seems to inhibit the degree of phase transformation during cement setting while the subsequent reduction in molecular weight of PLGA after gamma irradiation improves the in vitro degradation rate of CPCs due to the faster degradation rate of low molecular weight PLGA. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2216-2228, 2019.
可注射自固化磷酸钙骨水泥（CPCs）被认为是一种合成的骨替代物，由于其骨相容性和独特的处理性能，有利于骨骼的修复和再生。然而，由于其在注入体内时的内聚性不足，以及降解率低，限制了新骨的形成，其临床应用可能会受到影响。因此，羧甲基纤维素（CMC）被掺入 CPC 配方中，以提高其内聚性和可注射性，同时添加聚（-乳酸-共-乙醇酸）（PLGA）致孔剂以引入大孔并提高其生物降解率。与大多数生物材料一样，CPC 在临床使用前要经过伽马辐照，以确保充分灭菌。然而，众所周知，伽马辐照也会通过链断裂降低 CMC 和 PLGA 的分子量，从而影响它们的材料性能。因此，本研究的目的是测量伽马辐照对 CMC 分子量的影响，辐照剂量分别为 15、40 或 80 kGy，并研究这如何影响 CPC 配方的处理（即可注射性、内聚性、冲洗和凝固时间）和体外降解行为。结果表明，CMC 的分子量随伽马辐照剂量的增加而降低，从而降低 CMC 的增稠能力，导致 CPC 更容易恶化。此外，CMC 的添加似乎抑制了水泥凝固过程中的相转变程度，而伽马辐照后 PLGA 分子量的随后降低则提高了 CPC 的体外降解率，因为低分子量 PLGA 的降解速度更快。© 2019 Wiley Periodicals， Inc. J 生物医学材料 Res 部分 B：应用生物材料 107B：2216-2228，2019。
