Stachowiak Timothy B, Mair Dieudonne A, Holden Tyler G, Lee L James, Svec Frantisek, Fréchet Jean M J
Department of Chemical Engineering, University of California, Berkeley, CA 94720-1460, USA.
J Sep Sci. 2007 May;30(7):1088-93. doi: 10.1002/jssc.200600515.
The plastic material known as cyclic olefin copolymer (COC) is a useful substrate material for fabricating microfluidic devices due to its low cost, ease of fabrication, excellent optical properties, and resistance to many solvents. However, the hydrophobicity of native COC limits its use in bioanalytical applications. To increase surface hydrophilicity and reduce protein adsorption, COC surfaces were photografted with poly(ethylene glycol) methacrylate (PEGMA) using a two-step sequential approach: covalently-bound surface initiators were formed in the first step and graft polymerization of PEGMA was then carried out from these sites in the second step. Contact angle measurements were used to monitor and quantify the changes in surface hydrophilicity as a function of grafting conditions. As water droplet contact angles decreased from 88 degrees for native COC to 45 degrees for PEGMA-grafted surfaces, protein adsorption was also reduced by 78% for the PEGMA-modified COC microchannels as determined by a fluorescence assay. This photografting technique should enable the use of COC microdevices in a variety of bioanalytical applications that require minimal nonspecific adsorption of biomolecules.
被称为环烯烃共聚物（COC）的塑料材料，因其成本低、易于制造、优异的光学性能以及对多种溶剂的耐受性，成为制造微流控设备的一种有用的基底材料。然而，天然COC的疏水性限制了其在生物分析应用中的使用。为了提高表面亲水性并减少蛋白质吸附，采用两步连续法将聚甲基丙烯酸乙二醇酯（PEGMA）光接枝到COC表面：第一步形成共价结合的表面引发剂，第二步从这些位点进行PEGMA的接枝聚合。通过接触角测量来监测和量化作为接枝条件函数的表面亲水性变化。随着水滴接触角从天然COC的88度降至PEGMA接枝表面的45度，通过荧光测定法确定，PEGMA修饰的COC微通道的蛋白质吸附也减少了78%。这种光接枝技术应能使COC微器件用于各种需要生物分子非特异性吸附最小化的生物分析应用中。
