Zhou Yansheng, Li Ying, Li Daqing, Yin Yidan, Zhou Fenglei
Institute for Materials Discovery, Faculty of Mathematical Physical Sciences, University College London, 107 Roberts Building, Malet Place, London WC1E 7JE, UK.
Spinal Repair Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK.
J Funct Biomater. 2022 May 13;13(2):58. doi: 10.3390/jfb13020058.
Peripheral nerve injury (PNI) is a neurological disorder that causes more than 9 million patients to suffer from dysfunction of moving and sensing. Using biodegradable polymers to fabricate an artificial nerve conduit that replicates the environment of the extracellular matrix and guides neuron regeneration through the damaged sites has been researched for decades and has led to promising but primarily pre-clinical outcomes. However, few peripheral nerve conduits (PNCs) have been constructed from controllable biodegradable polymeric materials that can maintain their structural integrity or completely degrade during and after nerve regeneration respectively. In this work, a novel PNC candidate material was developed via the electrospinning of polyhydroxy butyrate/chitosan (PHB/CS) composite polymers. An SEM characterisation revealed the resultant PHB/CS nanofibres with 0, 1 and 2 wt/v% CS had less and smaller beads than the nanofibres at 3 wt/v% CS. The water contact angle (WCA) measurement demonstrated that the wettability of PHB/CS electrospun fibres was significantly improved by additional CS. Furthermore, both the thermogravimetric analysis (TGA) and differentiation scanning calorimetry (DSC) results showed that PHB/CS polymers can be blended in a single phase with a trifluoracetic solvent in all compositions. Besides, the reduction in the degradation temperature (from 286.9 to 229.9 °C) and crystallinity (from 81.0% to 52.1%) with increasing contents of CS were further proven. Moreover, we found that the degradability of the PHB/CS nanofibres subjected to different pH values rated in the order of acidic > alkaline > phosphate buffer solution (PBS). Based on these findings, it can be concluded that PHB/CS electrospun fibres with variable blending ratios may be used for designing PNCs with controlled biodegradability.
周围神经损伤（PNI）是一种神经疾病，导致超过900万患者出现运动和感觉功能障碍。几十年来，人们一直在研究使用可生物降解聚合物制造人工神经导管，该导管可复制细胞外基质环境并引导神经元通过受损部位再生，并取得了有前景但主要是临床前的成果。然而，很少有周围神经导管（PNC）是由可控的可生物降解聚合物材料构建的，这些材料能够分别在神经再生期间和之后保持其结构完整性或完全降解。在这项工作中，通过静电纺丝制备聚羟基丁酸酯/壳聚糖（PHB/CS）复合聚合物，开发了一种新型PNC候选材料。扫描电子显微镜（SEM）表征显示，与含3 wt/v% CS的纳米纤维相比，含0、1和2 wt/v% CS的所得PHB/CS纳米纤维的珠粒更少、更小。水接触角（WCA）测量表明，添加CS可显著提高PHB/CS电纺纤维的润湿性。此外，热重分析（TGA）和差示扫描量热法（DSC）结果均表明，PHB/CS聚合物在所有组成中均可与三氟乙酸溶剂以单相混合。此外，随着CS含量的增加，降解温度（从286.9℃降至229.9℃）和结晶度（从81.0%降至52.1%）降低得到进一步证实。此外，我们发现，不同pH值下PHB/CS纳米纤维的降解性顺序为酸性>碱性>磷酸盐缓冲溶液（PBS）。基于这些发现，可以得出结论，具有可变混合比例的PHB/CS电纺纤维可用于设计具有可控生物降解性的PNC。
