本篇研究主要配製三組兩種成分之混合單層薄膜：對-巰基苯甲酸/對-甲氧基苯硫酚、對-羧基芐基硫醇/對-甲氧基芐基硫醇與對-羧基芐基硫醇/芐基硫醇，研究與分析混合單層薄膜之結構及分佈情形以製備均分散之羧酸官能基表面，並活化羧酸官能基，使單股DNA可經由醯胺鍵而固定在表面上，並用來偵測互補段DNA。 混合分子薄膜之表面組成與分佈情形及末端官能基化學反應之進行，使用了反射式紅外線光譜(FT-IR)、橢圓儀(Ellipsometer)、與NEXAFS光譜觀測其結果與反應性。 利用經動力學主導吸附之對-羧基芐基硫醇/芐基硫醇混合分子薄膜系統，以NHS/EDC活化羧酸官能基，使其能與修飾了胺基(amine)之單股DNA反應形成醯胺鍵(amide bond)而使DNA能固定於表面上。當固定於表面之探針(probe)DNA與互補段之目標(target)DNA反應，可由螢光光譜觀測到放光強度之變化。觀測到互補段DNA之最大偵測效率為對-羧基芐基硫醇/芐基硫醇混合分子薄膜比例為1: 9時為最佳比例。 In this study three kinds of binary mixed self-assembled monolayers were prepared on gold：p-mercaptobenzoic acid/4-methoxy-benzenethiol, 4-mercaptomethylbenzoic acid/4-mthoxybenzyl mercaptan, and 4-mercaptomethyl-benzoic acid/benzylmercaptan. The surface structure and distribution of the films were analyzed in order to prepare a randomly distributed carboxyl functional groups on surface. The carboxyl groups were used to immobilize ssDNA through amide linkage via chemical transformation. The ssDNA-attached surface was used to capture a complimentary DNA via hybridization. The compositions of mixed-monolayers and the chemical transformation of the surface functional groups were studied by reflection absorption infrared spectroscopy, ellipsometry, NEXAFS. The mixed SAMs prepared from 4-mercaptomethylbenzoic acid/benzylmercaptan by kinetical trapping method was activated by NHS/EDC to form the NHS-ester, which reacted with an amine-modified probe DNA to attach the single strand DNA in various concentrations on surface. Hybridization with a target DNA was measured by fluorimeter. Maximum loading of the target DNA was observed for a surface prepared from a solution containing 4-mercaptomethylbenzoic acid and benzylmercaptan in 1:9 ratio. II
