Abstract

The aim of this comparative study was focused on the surface chemistry, in vitro biodegradation and biocompatibility of poly(L-lactic acid) (PLLA) scaffolds incorporated with poly(amidoamine) (PAMAM) and poly(propylene imine) (PPI) dendrimers. The functionality of these two types of dendrimers from second, third and fifth generations (G2, G3 and G5) onto the surface of PLLA film and electrospun scaffolds was investigated and characterized by a series of analyses including X-ray photoelectron spectroscopy, atomic force microscope, Fourier transform infrared spectroscopy, contact angle, scanning electron microscope, weight loss, water uptake and pH changes after degradation in different media. The successful incorporation of dendrimers into the surface of PLLA scaffolds was observed. PPI-G5 could further increase the hydrophilicity and surface roughness of PLLA scaffolds compared to PPI-G3 and PPI-G2. Further improvement on PLLA surface chemistry was observed when PAMAM-G5 was applied compared to PPI-G5. The pH value of Roswell Park Memorial Institute Medium (RPMI) media containing raw electrospun PLLA scaffold decreased to 5.2 from its original value of 7.2. However, the local acidity of RPMI medium caused by PLLA hydrolysis was greatly reduced on the surface of PLLA/PAMAM-G5 and PLLA/PPI-G5 with pH values of 7.8 and 7.5, respectively. Moreover, the viability of fibroblast cells on the surface of PLLA/dendrimer scaffolds was considerably increased compared to raw PLLA. Fibroblasts showed higher attachment and homogeneous spread morphology on the surface of PLLA/PAMAM-G5 and PLLA/PPI-G5. These observations underline the favorable surface properties of PLLA scaffolds incorporated with dendrimers, to be used as a biodegradable biocompatible scaffold tailored for biomedical applications.

摘要

这项比较研究的目的是关注与聚（酰胺胺）（PAMAM）和聚（丙烯亚胺）（PPI）树枝状大分子结合的聚（L-乳酸）（PLLA）支架的表面化学、体外生物降解和生物相容性。通过X射线光电子能谱、原子力显微镜等一系列分析，研究并表征了这两种来自第二代、第三代和第五代（G2、G3和G5）的树枝状聚合物在PLLA薄膜和电纺支架表面上的功能、傅里叶变换红外光谱、接触角、扫描电镜、失重、吸水率和在不同介质中降解后pH值的变化。观察到树枝状聚合物成功掺入到 PLLA 支架的表面。与 PPI-G3 和 PPI-G2 相比，PPI-G5 可以进一步增加 PLLA 支架的亲水性和表面粗糙度。与 PPI-G5 相比，当应用 PAMAM-G5 时，观察到 PLLA 表面化学的进一步改进。含有原始电纺 PLLA 支架的罗斯威尔公园纪念研究所培养基 (RPMI) 培养基的 pH 值从其原始值 7.2 降至 5.2。然而，在pH值分别为7.8和7.5的PLLA/PAMAM-G5和PLLA/PPI-G5表面上，由PLLA水解引起的RPMI培养基的局部酸度大大降低。此外，与原始 PLLA 相比，PLLA/树枝状聚合物支架表面的成纤维细胞的存活率显着增加。成纤维细胞在 PLLA/PAMAM-G5 和 PLLA/PPI-G5 的表面上表现出更高的附着和均匀的扩散形态。