State Key Laboratory of Bioelectronics, School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing 211189, PR China.
Biosens Bioelectron. 2012 Oct-Dec;38(1):79-85. doi: 10.1016/j.bios.2012.05.007. Epub 2012 May 15.
A novel label-free immunosensing strategy for sensitive detection of tumor necrosis factor-alpha antigen (TNF-α) via surface-initiated atom transfer radical polymerization (SI-ATRP) was proposed. In this strategy, the Au electrode was first modified by consecutive SI-ATRP of ferrocenylmethyl methacrylate (FMMA) and glycidyl methacrylate (GMA), and TNF-α antibody was coupled to the copolymer segment of GMA (PGMA) by aqueous carbodiimide coupling reaction. Subsequently, the target TNF-α antigen was captured onto the Au electrode surface through immunoreaction. The whole process was confirmed by scanning electron microscopy (SEM) and surface plasmon resonance (SPR) measurements. With introduction of redox polymer segment of FMMA (PFMMA) as electron-transfer mediator, the antigen-coupled Au electrode exhibited well electrochemical behavior, as revealed by cyclic voltammetry measurement. This provided a sensing platform for sensitive detection of TNF-α with a low detection limit of 3.9 pg mL(-1). Furthermore, the "living" characteristics of the ATRP process can not only be readily controlled but also allow further surface functionalization of the electrodes, thus the proposed method presented a way for label-free and flexible detection of biomolecules.
一种通过表面引发原子转移自由基聚合（SI-ATRP）灵敏检测肿瘤坏死因子-α抗原（TNF-α）的新型无标记免疫传感策略被提出。在该策略中，首先通过连续的 ferrocenylmethyl methacrylate（FMMA）和甲基丙烯酸缩水甘油酯（GMA）的表面引发原子转移自由基聚合（SI-ATRP）对 Au 电极进行修饰，并通过水相碳二亚胺偶联反应将 TNF-α 抗体偶联到 GMA 的共聚物段（PGMA）上。随后，通过免疫反应将目标 TNF-α 抗原捕获到 Au 电极表面。整个过程通过扫描电子显微镜（SEM）和表面等离子体共振（SPR）测量得到确认。通过引入 FMMA（PFMMA）的氧化还原聚合物段作为电子转移介质，抗原偶联的 Au 电极表现出良好的电化学行为，这通过循环伏安法测量得到证实。这为 TNF-α 的灵敏检测提供了一个传感平台，其检测限低至 3.9 pg mL(-1)。此外，ATRP 过程的“活”特性不仅可以容易地控制，还可以进一步对电极进行表面功能化，从而为生物分子的无标记和灵活检测提供了一种方法。
