Recently, surface engineered biomaterials through surface modification are extensively investigated due to its potential to enhance cellular homing and migration which contributes to a successful drug delivery process. This study is focused on osteoblasts response towards surface engineered using a simple sodium hydroxide (NaOH) hydrolysis and growth factors conjugated poly(lactic acid) (PLA) microspheres. In this study, evaluation of the relationship of NaOH concentration with the molecular weight changes and surface morphology of PLA microspheres specifically wall thickness and porosity prior to in vitro studies was investigated. NaOH hydrolysis of 0.1 M, 0.3 M and 0.5 M were done to introduce hydrophilicity on the PLA prior to conjugation with basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Morphology changes showed that higher concentration of NaOH could accelerate the hydrolysis process as the highest wall thickness was observed at 0.5 M NaOH with ~3.52 µm. All surface modified and growth factors conjugated PLA microspheres wells enhanced the migration of the cells during wound healing process as wound closure was 100% after 3 days of treatment. Increase in hydrophilicity of the surface engineered and growth factors conjugated PLA microspheres provides favorable surface for cellular attachment of osteoblast, which was reflected by positive DAPI staining of the cells' nucleus. Surface modified and growth factors conjugated PLA microspheres were also able to enhance the capability of the PLA in facilitating the differentiation process of mesenchymal stem cells (MSCs) into osteogenic lineage since only positive stain was observed on surface engineered and growth factors conjugated PLA microspheres. These results indicated that the surface engineered and growth factors conjugated PLA microspheres were non-toxic for biological environments and the improved hydrophilicity made them a potential candidate as a drug delivery vehicle as the cells can adhere, attach and proliferate inside it.

中文翻译：

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成骨细胞向表面工程和生长因子共轭聚乳酸微球的迁移，附着和人骨髓间充质干细胞向成骨的分化。

最近，由于表面修饰生物材料具有增强细胞归巢和迁移的潜力，这有助于成功的药物递送过程，因此对通过表面修饰的表面工程生物材料进行了广泛研究。这项研究的重点是成骨细胞对表面的响应，该响应使用简单的氢氧化钠（NaOH）水解和生长因子共轭的聚乳酸（PLA）微球进行表面处理。在这项研究中，在进行体外研究之前，研究了NaOH浓度与PLA微球的分子量变化和表面形态，特别是壁厚和孔隙率之间关系的评估。在与碱性成纤维细胞生长因子（bFGF）和表皮生长因子（EGF）结合之前，先进行0.1 M，0.3 M和0.5 M的NaOH水解以在PLA上引入亲水性。形态变化表明，较高浓度的NaOH可以加速水解过程，因为在0.5 M NaOH和〜3.52 µm处观察到最高壁厚。在治疗3天后，伤口闭合率为100％，所有表面修饰的和生长因子缀合的PLA微球孔均增强了伤口愈合过程中的细胞迁移。表面工程和生长因子缀合的PLA微球的亲水性增加为成骨细胞的细胞附着提供了有利的表面，这通过细胞核的DAPI阳性染色得以体现。表面修饰的和生长因子缀合的PLA微球还能够增强PLA促进间充质干细胞（MSCs）分化为成骨细胞谱系的能力，因为在表面工程和生长因子缀合的PLA微球上仅观察到阳性染色。这些结果表明，经表面工程和生长因子缀合的PLA微球对生物环境无毒，亲水性的提高使其成为潜在的候选药物，因为细胞可以在细胞内粘附，附着和增殖。