Spatial modulation of biomolecules immobilization by fabrication of hierarchically structured PEG-derived brush micropatterns: An versatile cellular microarray platform

Abstract

Microarray technology holds enormous promise in the development of various fields ranging from tissue engineering, regenerative medicine to high-throughput screening. Here, based on the digital micromirror device (DMD)-based spatiotemporal regulation of surface-initiated photoinduced atom transfer radical polymerization (Photo-ATRP) process, a flexible and versatile methodology was developed to fabricate a hierarchical microarray structure constituted with a homogeneous hyperbranched polyethylene glycol (PEG)-derived brush layer as anti-fouling background and an extension layer of square-grid poly(2-(2-azido-2-methyl-1-oxopropoxy) ethyl methacrylate) (PAMEMA) brushes micropatterns on the silicon substrate. The terminal azido groups on the side chains of PAMEMA brushes provide abundant reactive sites to realize the covalent immobilization of target biomolecules, including RGD peptide, fibronectin, BSA and streptavidin. The TOF-SIMS and fluorescence characterizations demonstrated the feasibility and efficiency of spatially modulating the density of surface-bound biomolecules through regulating the 3D architecture parameters of the PAMEMA brush micropatterns and consequentially the azido chemical functionality. Moreover, culture experiments of human bone-derived marrow stromal cells (BMSCs) and mouse L929 cells were conducted on the obtained hierarchical microarray structure in a high-throughput manner. The presented hierarchical microarray structure holds excellent potential as a high-throughput screening platform, allowing for the parallel assessment of cell-surface interactions.