Cerruti Marta, Jaworski Justyn, Raorane Digvijay, Zueger Chris, Varadarajan John, Carraro Carlo, Lee Seung-Wuk, Maboudian Roya, Majumdar Arun
Department of Chemical Engineering, University of California at Berkeley, Berkeley, California 94720, USA.
Anal Chem. 2009 Jun 1;81(11):4192-9. doi: 10.1021/ac8019174.
The selective detection of a specific target molecule in a complex environment containing potential contaminants presents a significant challenge in chemical sensor development. Utilizing phage display techniques against trinitrotoluene (TNT) and dinitrotoluene (DNT) targets, peptide receptors have previously been identified with selective binding capabilities for these molecules. For practical applications, these receptors must be immobilized onto the surface of sensor platforms at high density while maintaining their ability to bind target molecules. In this paper, a polymeric matrix composed of poly(ethylene-co-glycidyl methacrylate) (PEGM) has been prepared. A high density of receptors was covalently linked through reaction of amino groups present in the receptor with epoxy groups present in the co-polymer. Using X-ray photoelectron spectroscopy (XPS) and gas-chromatography/mass spectroscopy (GC/MS), this attachment strategy is demonstrated to lead to stably bound receptors, which maintain their selective binding ability for TNT. The TNT receptor/PEGM conjugates retained 10-fold higher TNT binding ability in liquid compared to the lone PEGM surface and 3-fold higher TNT binding compared to non-specific receptor conjugates. In contrast, non-target DNT exposure yielded undetectable levels of binding. These results indicate that this polymeric construct is an effective means of facilitating selective target interaction both in an aqueous environment. Finally, real-time detection experiments were performed using a quartz crystal microbalance (QCM) as the sensing platform. Selective detection of TNT vs DNT was demonstrated using QCM crystals coated with PEGM/TNT receptor, highlighting that this receptor coating can be incorporated as a sensing element in a standard detection device for practical applications.
在包含潜在污染物的复杂环境中选择性检测特定目标分子，是化学传感器开发中的一项重大挑战。利用针对三硝基甲苯（TNT）和二硝基甲苯（DNT）目标的噬菌体展示技术，先前已鉴定出对这些分子具有选择性结合能力的肽受体。对于实际应用，这些受体必须以高密度固定在传感器平台表面，同时保持其结合目标分子的能力。本文制备了一种由聚（乙烯 - 甲基丙烯酸缩水甘油酯）（PEGM）组成的聚合物基质。通过受体中存在的氨基与共聚物中存在的环氧基反应，将高密度的受体共价连接起来。使用X射线光电子能谱（XPS）和气相色谱/质谱（GC/MS），证明这种连接策略可导致受体稳定结合，从而保持其对TNT的选择性结合能力。与单独的PEGM表面相比，TNT受体/PEGM缀合物在液体中的TNT结合能力高10倍，与非特异性受体缀合物相比，TNT结合能力高3倍。相比之下，非目标DNT暴露产生的结合水平无法检测到。这些结果表明，这种聚合物构建体是在水性环境中促进选择性目标相互作用的有效手段。最后，使用石英晶体微天平（QCM）作为传感平台进行了实时检测实验。使用涂有PEGM/TNT受体的QCM晶体证明了对TNT与DNT的选择性检测，突出表明这种受体涂层可作为传感元件纳入标准检测设备中用于实际应用。
