基于聚合物刷微图案的生物素化梯度表面制备研究

Fabrication of Biotinylated Gradient Surface Based on the Micropatterned Polymer Brushes

提出了基于叠氮功能化聚合物刷微图案制备生物素化梯度表面的方法.通过数字微镜器件(DMD)调控光辐照引发表面原子转移自由基聚合(ATRP)反应,制备叠氮功能化的聚(2-(2-叠氮-2-甲基丙氧基)甲基丙烯酸乙酯)(PAMEMA)聚合物刷微图案,采用X射线光电子能谱仪(XPS)和飞行时间二次离子质谱仪(TOF-SIMS)对PAMEMA聚合物刷微图案的化学组成及分布进行表征,表明叠氮基团在聚合物刷图案化表面的区域选择性分布;以叠氮基团为反应位点,通过点击化学反应实现PAMEMA聚合物刷微图案表面的生物素化,借助荧光标记的链霉亲和素染色实验表征生物素在微图案表面的分布情况;以具有厚度变化的PAMEMA聚合物刷微图案为模板制备生物素表面,结果表明通过控制聚合物刷的厚度可以对微图案表面固定生物素分子的空间密度进行调控以实现具有复杂结构的生物素化梯度表面的成功制备.

The biotin-avidin reaction system has shown remarkable advantages in immunoassays and biomedical fields due to its high specificity,excellent sensitivity and stability.The ability to generate biotinylated surface with gradient features would further promote the potential application of the biotin-avidin system in various fields ranging from high-throughput analysis to multifunctional biological surface.Here,based on the micropatterned polymer brushes functionalized with azido groups,a promising method was presented for fabricating the biotinylated gradient surfaces.Micropatterned poly(2-(2-azido-2-methyl-1-oxopropoxy)ethyl methacrylate)(PAMEMA)brushes bearing azido groups were fabricated through employing a digital mirror device(DMD)-based light modulation technique to regulate a surface-initiated photoinduced atom transfer radical polymerization(Photo-ATRP)process.X-ray photoelectron spectroscopy(XPS)and time of flight-secondary ion mass spectrometry(TOF-SIMS)measurements were performed to characterize the surface elemental composition of silicon substrates micropatterned with PAMEMA brushes,whose results indicate the spatially selective distribution of azido groups.The terminal azido groups of PAMEMA brushes could provide reactive sites for covalent immobilization of DBCO-PEG4-biotin through the highly specific orthogonal“click”reaction,leading to the biotinylation of PAMEMA brushes micropatterned surface.The streptavidin-fluorophore conjugate binding experiment was performed to characterize the distribution of biotins on the patterned surface.The fluorescence characterizations demonstrated the functionality of the micropatterned PAMEMA brushes with various thicknesses to regulate the spatial density of immobilized biotins,which resulted in the successful creation of biotinylated gradient surfaces with various complicated structures.The research extends the application of polymer brush micropattern in functional gradient surfaces preparation,and provides fundamental technical support for expanding biotinylated gradient surfaces applications in high-throughput detection chips and combinatorial chemistry.