School of Pharmacy, University of Nottingham, Nottingham, UK.
School of Molecular and Cellular Biology, University of Leeds, Leeds, UK.
J Mater Chem B. 2021 May 26;9(20):4120-4133. doi: 10.1039/d1tb00129a.
Effective regenerative medicine requires delivery systems which can release multiple components at appropriate levels and at different phases of tissue growth and repair. However, there are few biomaterials and encapsulation techniques that are fully suitable for the loading and controlled release of multiple proteins. In this study we describe how proteins were physically and chemically loaded into a single coaxial electrospun fibre scaffold to obtain bi-phasic release profiles. Cyto-compatible polymers were used to construct the scaffold, using polyethylene oxide (PEO) for the core and polycaprolactone (PCL) reacted or mixed with (bis-aminopropyl)polyether (Jeffamine ED2003; JFA) for the shell. Horseradish peroxidase (HRP), a model protein, was loaded in the core and functionalised onto the scaffold surface by coupling of protein carboxyl groups to the available polymer amine groups. Fibre morphologies were evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and functional group content was determined using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF SIMS). Hydrophobicity profiles of the fibres before and after protein loading were evaluated by water contact angle (WCA) and the mechanical properties of the electrospun scaffolds were determined by performing tensile tests. The electrospun fibre scaffolds generated by reacting PEO/PCL with 1,6-diaminohexane and those from mixing PEO/PCL with JFA were further characterised for protein conjugation and release. Fibres prepared by the mixed PEO/PCL/JFA system were found to be the most appropriate for the simultaneous release of protein from the core and the immobilisation of another protein on the shell of the same scaffold. Moreover, JFA enhanced scaffold properties in terms of porosity and elasticity. Finally, we successfully demonstrated the cytocompatibility and cell response to protein-loaded and -conjugated scaffolds using HepG2 cells. Enhanced cell attachment (2.5 fold) was demonstrated using bovine serum albumin (BSA)-conjugated scaffolds, and increased metabolic activity observed with retinoic acid (RA)-loaded scaffolds (2.7 fold).
有效的再生医学需要能够以适当的水平和在组织生长和修复的不同阶段释放多种成分的输送系统。然而，很少有生物材料和封装技术完全适合于多种蛋白质的加载和控制释放。在本研究中，我们描述了如何将蛋白质物理和化学加载到单个同轴电纺纤维支架中以获得双相释放曲线。使用聚环氧乙烷（PEO）作为芯，聚己内酯（PCL）与（双氨基丙基）聚醚（Jeffamine ED2003；JFA）反应或混合作为壳，构建了细胞相容性聚合物支架。辣根过氧化物酶（HRP），一种模型蛋白，被加载到芯中，并通过将蛋白羧基偶联到可用的聚合物胺基上，将其功能化到支架表面上。通过扫描电子显微镜（SEM）和透射电子显微镜（TEM）评估纤维形态，通过 X 射线光电子能谱（XPS）和飞行时间二次离子质谱（TOF SIMS）测定官能团含量。通过水接触角（WCA）评估纤维在蛋白质负载前后的疏水性曲线，并通过进行拉伸试验来确定电纺支架的机械性能。通过 1,6-二氨基己烷反应的 PEO/PCL 和 PEO/PCL 与 JFA 混合制备的电纺纤维支架进一步用于蛋白质结合和释放的表征。发现由 PEO/PCL/JFA 混合体系制备的纤维最适合从芯中同时释放蛋白质并将另一种蛋白质固定在同一支架的壳上。此外，JFA 增强了支架的多孔性和弹性。最后，我们使用 HepG2 细胞成功地证明了负载蛋白质和结合蛋白质的支架的细胞相容性和细胞反应。使用牛血清白蛋白（BSA）结合的支架，证明了增强的细胞附着（2.5 倍），并且观察到负载维甲酸（RA）的支架的代谢活性增加（2.7 倍）。
