Controlled release of bioactive brain-derived neurotrophic factor (BDNF) via drug delivery system has been showed promise in promoting nerve regeneration after injury. However, some inherited disadvantages limit its application, such as encapsulated protein instability and overdose. In this study, we investigated the potential of chitosan microspheres as an attractive carrier for the controlled release of BDNF. The microspheres were prepared with sodium tripolyphosphate (STPP) by ionic cross-linking. The microspheres showed a spherical shape and relative rough surface morphology as observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The distribution of particle size followed a Gaussian distribution and was not affected by encapsulated protein. The loading content (LC) and encapsulation efficiency (EE) of the microspheres were both affected by the initial amount of BDNF. In vitro release study showed that the release rate of BSA from the microspheres was much faster than that of BDNF. The release profile of the microspheres was over up to 7 days. Weight loss of microspheres after incubation in PBS lasted for 9 weeks. BDNF released from the microspheres was showed to be bioactive, which can be proved by stimulating PC12 cells into a neuronal phenotype in vitro. These data demonstrate that BDNF loaded microspheres offer potential for long-term delivery of bioactive BDNF and could have significant clinical applications for neural tissue regeneration.

通过药物递送系统控制释放生物活性脑源性神经营养因子（BDNF）已显示出促进损伤后神经再生的希望。但是，一些固有的缺点限制了它的应用，例如封装的蛋白质不稳定性和剂量过大。在这项研究中，我们调查了壳聚糖微球作为BDNF控制释放的诱人载体的潜力。用三聚磷酸钠（STPP）通过离子交联制备微球。如通过扫描电子显微镜（SEM）和共聚焦激光扫描显微镜（CLSM）观察到的，微球显示出球形和相对粗糙的表面形态。粒度分布遵循高斯分布，不受封装蛋白质的影响。体外释放研究表明，微球中BSA的释放速率比BDNF快得多。微球的释放曲线长达7天。在PBS中孵育后，微球的重量减轻持续了9周。从微球释放的BDNF被证明具有生物活性，这可以通过体外刺激PC12细胞成为神经元表型来证明。这些数据表明载有BDNF的微球为生物活性BDNF的长期递送提供了潜力，并且对于神经组织再生可能具有重要的临床应用。