来自西北大学的Chen等研究人员采用1μg的低剂量BMP2来功能化聚多巴胺(PD)修饰的聚乳酸(PLA)植入物PLA-PD。首次采用抗原-抗体反应来分析BMP2修饰PD涂层的绑定效率。获得的PLA-PD-BMP表面结合的低剂量BMP2能够增强材料表面的细胞黏附性和成骨能力。另外，通过小鼠异位骨模型来证实体内PLA-PD-BMP2支架的骨诱导能力，这被誉为骨诱导活性的"黄金法则"。采用Micro-CT、杨氏模量和组织学分析等方法证实1 μg BMP2修饰的PLA-PD-BMP支架能够诱导骨形成。因此，本文采用的方法能够被当做模板用于结合其他生长因子到不同类型的高分子聚合物表面。这种高效的方法能够以一种温和、安全且高效的方式促进临床高分子聚合物医用植入物的应用。
Osteoinductive activity of the implant in bone healing and regeneration is still a challenging research topic. Therapeutic application of recombinant human bone morphogenetic protein-2 (BMP-2) is a promising approach to enhance osteogenesis. However, high dose and uncontrolled burst release of BMP-2 may introduce edema, bone overgrowth, cystlike bone formation, and inflammation.
Chen et al. from Northwest University, low-dose BMP-2 of 1 μg was used to design PLA-PD-BMP for functionalization of polylactic acid (PLA) implants via musselinspired polydopamine (PD) assist. For the first time, the binding property and efficiency of the PD coating with BMP-2 were directly demonstrated and analyzed using an antigen-antibody reaction. The obtained PLA-PD-BMP surface immobilized with this low BMP-2 dose can endow the implants with abilities of introducing strong stem cell adhesion and enhanced osteogenicity. Furthermore, in vivo osteoinduction of the PLA-PD-BMP-2 scaffolds was confirmed by a rat ectopic bone model, which is marked as the "gold standard" for the evidence of osteoinductive activity. The microcomputed tomography, Young's modulus, and histology analyses were also employed to demonstrate that PLA-PD-BMP grafted with 1 μg of BMP-2 can induce bone formation. Therefore, the method in this study can be used as a model system to immobilize other growth factors onto various different types of polymer substrates. The highly biomimetic mussel-derived strategy can therefore improve the clinical outcome of polymer-based medical implants in a facile, safe, and effective way.