Firkowska-Boden Izabela, Adjiski Ranko, Bautista Andres Cordero, Borowski Andreas, Matziolis Georg, Jandt Klaus D, Kinne Raimund W, Bossert Jörg
Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Jena, Germany.
Chair of Materials Science, Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Jena, Germany.
J Mech Behav Biomed Mater. 2021 Mar;115:104285. doi: 10.1016/j.jmbbm.2020.104285. Epub 2020 Dec 23.
Incorporation of biodegradable poly(lactic-co-glycolic acid; PLGA) fibers into calcium phosphate cements (CPCs) has proven beneficial for their mechanical properties and the targeted delivery of bone morphogenetic proteins (BMPs). However, the deficiency of functional groups on the PLGA surface results in poor fiber-matrix interfacial strength (ISS), limiting the mechanical improvement, and insufficient surface charge to immobilize therapeutic amounts of BMPs. The present study therefore focused on the: i) functionalization of PLGA fibers using polyelectrolyte multilayers (PEMs) of biopolymers; ii) analysis of their impact on the mechanical properties of the CPC in multifilament fiber pull-out tests; and iii) testing of their applicability as carriers for BMPs using chemical-free adsorption of biotinylated recombinant human growth factor (rhGDF-5) and colorimetric assays. The PEMs were created from chitosan (Chi), hyaluronic acid (HA), and gelatin (Gel) via layer-by-layer (LbL) deposition. Four PEM nanocoatings consisting of alternating Chi/Gel and Chi/HA bilayers with a terminating layer of Chi, Gel or HA were tested. Nanocoating of the PLGA fibers with PEMs significantly enhanced the ISS with the CPC matrix to max. 3.55 ± 1.05 MPa (2.2-fold). The increase in ISS, ascribed to enhanced electrostatic interactions between PLGA and calcium phosphate, was reflected in significant improvement of the composites' flexural strength compared to CPC containing untreated fibers. However, only minor effects on the composites' work of fracture were observed. The adsorption of rhGDF-5 on the PLGA surface was supported by PEMs terminating with either positive or negative charges, without significant differences among the nanocoatings. This proof-of-principle rhGDF-5 immobilization study, together with the augmented ISS of the composites, demonstrates that surface modification of PLGA fibers with biopolymers is a promising approach for targeted delivery of BMPs and improved mechanical properties of the fiber-reinforced CPC.
将可生物降解的聚乳酸-乙醇酸共聚物（PLGA）纤维掺入磷酸钙骨水泥（CPC）中已证明对其机械性能和骨形态发生蛋白（BMP）的靶向递送有益。然而，PLGA表面官能团的缺乏导致纤维-基质界面强度（ISS）较差，限制了机械性能的改善，并且表面电荷不足以固定治疗量的BMP。因此，本研究重点关注：i）使用生物聚合物的聚电解质多层膜（PEM）对PLGA纤维进行功能化；ii）在多丝纤维拔出试验中分析它们对CPC机械性能的影响；iii）通过生物素化重组人生长因子（rhGDF-5）的无化学吸附和比色法测试它们作为BMP载体的适用性。PEM是通过层层（LbL）沉积由壳聚糖（Chi）、透明质酸（HA）和明胶（Gel）制成的。测试了四种由交替的Chi/Gel和Chi/HA双层以及Chi、Gel或HA终止层组成的PEM纳米涂层。用PEM对PLGA纤维进行纳米涂层显著增强了与CPC基质的ISS，最高可达3.55±1.05MPa（2.2倍）。ISS的增加归因于PLGA与磷酸钙之间增强的静电相互作用，与含有未处理纤维的CPC相比，复合材料的弯曲强度有显著提高。然而，对复合材料的断裂功仅观察到轻微影响。带有正电荷或负电荷终止层的PEM均支持rhGDF-5在PLGA表面的吸附，纳米涂层之间没有显著差异。这项原理验证的rhGDF-5固定化研究，连同复合材料增强的ISS，表明用生物聚合物对PLGA纤维进行表面改性是一种有前景的方法，可用于BMP的靶向递送和改善纤维增强CPC的机械性能。
