Ahmad Habib M N, Dutta Gaurab, Csoros John, Si Bo, Yang Rongfang, Halpern Jeffrey M, Seitz W Rudolf, Song Edward
Department of Electrical and Computer Engineering, University of New Hampshire, Durham, NH 03824, United States.
Department of Chemistry, University of New Hampshire, Durham, NH 03824, United States.
ACS Appl Polym Mater. 2021 Jan 8;3(1):329-341. doi: 10.1021/acsapm.0c01120. Epub 2020 Dec 9.
The use of highly crosslinked molecularly imprinted polymers as a synthetic target receptor has the limitations of restricted accessibility to the binding sites resulting in slow response time. Moreover, such artificial receptors often require additional transduction mechanisms to translate target binding events into measurable signals. Here, we propose the development of a single-chain stimuli-responsive templated polymer, without using any covalent interchain crosslinkers, as a target recognition element. The synthesized polymer chain exhibits preferential binding with the target molecule with which the polymer is templated. Moreover, upon specific target recognition, the polymer undergoes conformation change induced by its particular stimuli responsiveness, namely the target binding event. Such templated single-chain polymers can be attached to the electrode surface to implement a label-free electrochemical sensing platform. A target analyte, 4-nitrophenol (4-NP), was used as a template to synthesize a poly-N-isopropylacrylamide (PNIPAM)-based copolymer chain which was anchored to the electrode to be used as a selective receptor for 4-NP. The electrode surface chemistry analysis and the electrochemical impedance study reveal that the polymer concentration, the interchain interactions, and the Hofmeister effect play a major role in influencing the rate of polymer grafting as well as the morphology of the polymers grafted to the electrode. We also show that the specific binding between 4-NP and the copolymer results in a substantial change in the charge transfer kinetics at the electrode signifying the polymer conformation change.
使用高度交联的分子印迹聚合物作为合成目标受体存在局限性，即结合位点的可及性受限，导致响应时间缓慢。此外，这种人工受体通常需要额外的转导机制，将目标结合事件转化为可测量的信号。在此，我们提出开发一种单链刺激响应模板聚合物，不使用任何共价链间交联剂，作为目标识别元件。合成的聚合物链与作为模板的目标分子表现出优先结合。此外，在特定目标识别时，聚合物因其特定的刺激响应性，即目标结合事件，而发生构象变化。这种模板化单链聚合物可附着在电极表面，以实现无标记电化学传感平台。以目标分析物4-硝基苯酚（4-NP）为模板，合成了一种基于聚N-异丙基丙烯酰胺（PNIPAM）的共聚物链，该共聚物链锚定在电极上，用作4-NP的选择性受体。电极表面化学分析和电化学阻抗研究表明，聚合物浓度、链间相互作用和霍夫迈斯特效应在影响聚合物接枝速率以及接枝到电极上的聚合物形态方面起着主要作用。我们还表明，4-NP与共聚物之间的特异性结合导致电极处电荷转移动力学发生显著变化，这表明聚合物构象发生了变化。
