Honeycomb-Structured Films by Multifunctional Amphiphilic Biodegradable Copolymers: Surface Morphology Control and Biomedical Application as Scaffolds for Cell Growth

Abstract

Recently, fabrication of functional porous polymer films with patterned surface structures at the scale from nanometer to micrometer has been attracting increasing interests in material science and nanobiotechnology. In this work, we present new preparation of two series of multifunctional amphiphilic copolymers and preparation of their microporous thin films on solid substrates. First, diblock dendritic poly(l-lysine)-b-poly(l-lactide)s and triblock dendritic poly(l-lysine)-b-poly(l-lactide)-b-dendritic poly(l-lysine)s (C1-C6) were synthesized through 4-dimethylaminopyridine (DMAP)-catalyzed living ring-opening polymerization of (l-)-lactide with (l-)-lysine dendron initiators, and their structures were characterized by nuclear magnetic resonance spectrometer (NMR), gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization Fourier-transformed mass spectra (MALDI-FTMS). Employing the breath-figure (BF) fabrication strategy, thin films of the synthesized amphiphiles (C1-C6) were drop-cast, and their surface topologies were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the effects of new amphiphile structure and drop-casting parameters of amphiphile concentration, humidity and temperature on self-assembly of ordered porous surface were studied. Furthermore, the influence of surface energy of drop-casting substrates was additionally investigated. With a human cervical epithelial carcinoma cell line (HeLa), cytotoxicity of the prepared honeycomb-structured films by new amphiphile C6 was evaluated by thiazoyl-blue-tetrazolium-bromide (MTT) assay, and HeLa cell growth behavior with microporous amphiphile films as the scaffolds was also examined. It was found that tunable micropore diameter sizes and well ordered surface topologies of BF films could be achieved for the new prepared amphiphiles, and utilization of the honeycomb-like microporous films as scaffolds indicated favorable enhancement in cell proliferation. Therefore, the honeycomb-structured films by these biocompatible multifunctional amphiphiles may provide new materials as 3D-scaffold materials for potential application in tissue engineering and regeneration.