Johnson Alexander, Madsen Jeppe, Chapman Paul, Alswieleh Abdullah, Al-Jaf Omed, Bao Peng, Hurley Claire R, Cartron Michaël L, Evans Stephen D, Hobbs Jamie K, Hunter C Neil, Armes Steven P, Leggett Graham J
Department of Chemistry , University of Sheffield , Brook Hill , Sheffield S3 7HF , UK . Email:
Department of Physics and Astronomy , University of Sheffield , Sheffield S3 7RH , UK.
Chem Sci. 2017 Jun 1;8(6):4517-4526. doi: 10.1039/c7sc00289k. Epub 2017 Apr 18.
Binary polymer brush patterns were fabricated photodeprotection of an aminosilane with a photo-cleavable nitrophenyl protecting group. UV exposure of the silane film through a mask yields micrometre-scale amine-terminated regions that can be derivatised to incorporate a bromine initiator to facilitate polymer brush growth atom transfer radical polymerisation (ATRP). Atomic force microscopy (AFM) and imaging secondary ion mass spectrometry (SIMS) confirm that relatively thick brushes can be grown with high spatial confinement. Nanometre-scale patterns were formed by using a Lloyd's mirror interferometer to expose the nitrophenyl-protected aminosilane film. In exposed regions, protein-resistant poly(oligo(ethylene glycol)methyl ether methacrylate) (POEGMEMA) brushes were grown by ATRP and used to define channels as narrow as 141 nm into which proteins could be adsorbed. The contrast in the pattern can be inverted by (i) a simple blocking reaction after UV exposure, (ii) a second deprotection step to expose previously intact protecting groups, and (iii) subsequent brush growth surface ATRP. Alternatively, two-component brush patterns can be formed. Exposure of a nitrophenyl-protected aminosilane layer either through a mask or to an interferogram, enables growth of an initial POEGMEMA brush. Subsequent UV exposure of the previously intact regions allows attachment of ATRP initiator sites and growth of a second poly(cysteine methacrylate) (PCysMA) brush within photolithographically-defined micrometre or nanometre scale regions. POEGMEMA brushes resist deposition of liposomes, but fluorescence recovery after photobleaching (FRAP) studies confirm that liposomes readily rupture on PCysMA "corrals" defined within POEGMEMA "walls". This leads to the formation of highly mobile supported lipid bilayers that exhibit similar diffusion coefficients to lipid bilayers formed on surfaces such as glass.
通过对带有可光裂解硝基苯基保护基团的氨基硅烷进行光脱保护，制备了二元聚合物刷图案。通过掩膜对硅烷膜进行紫外线照射，可产生微米级的胺端基区域，该区域可进行衍生化以引入溴引发剂，从而通过原子转移自由基聚合（ATRP）促进聚合物刷的生长。原子力显微镜（AFM）和成像二次离子质谱（SIMS）证实，可以在高空间限制下生长相对较厚的刷子。利用劳埃德镜干涉仪对硝基苯基保护的氨基硅烷膜进行曝光，形成了纳米级图案。在曝光区域，通过ATRP生长了抗蛋白质的聚（寡聚（乙二醇）甲基醚甲基丙烯酸酯）（POEGMEMA）刷，并用于定义窄至141nm的通道，蛋白质可吸附到这些通道中。图案的对比度可以通过以下方式反转：（i）紫外线曝光后的简单封闭反应；（ii）第二个脱保护步骤，以暴露先前完整的保护基团；（iii）随后的刷生长和表面ATRP。或者，可以形成双组分刷图案。通过掩膜或干涉图对硝基苯基保护的氨基硅烷层进行曝光，能够生长初始的POEGMEMA刷。随后对先前完整的区域进行紫外线曝光，允许在光刻定义的微米或纳米级区域内附着ATRP引发剂位点并生长第二种聚（甲基丙烯酸半胱氨酸）（PCysMA）刷。POEGMEMA刷可阻止脂质体的沉积，但光漂白后荧光恢复（FRAP）研究证实，脂质体很容易在POEGMEMA“壁”内定义的PCysMA“围栏”上破裂。这导致形成高度可移动的支撑脂质双层，其扩散系数与在玻璃等表面形成的脂质双层相似。
