Science Program, Department of General Education, Faculty of Liberal Arts, Rajamangala University of Technology Srivijaya, Songkhla 90000, Thailand.
Division of Biotechnology, Lund University, P.O. Box 124, 221 00 Lund, Sweden.
Sensors (Basel). 2021 Dec 24;22(1):99. doi: 10.3390/s22010099.
A capacitive biosensor for the detection of protein A was developed. Gold electrodes were fabricated by thermal evaporation and patterned by photoresist photolithography. A layer-by-layer (LbL) assembly of thiourea (TU) and HAuCl and chemical reduction was utilized to prepare a probe with a different number of layers of TU and gold nanoparticles (AuNPs). The LbL-modified electrodes were used for the immobilization of human IgG. The binding interaction between human IgG and protein A was detected as a decrease in capacitance signal, and that change was used to investigate the correlation between the height of the LbL probe and the sensitivity of the capacitive measurement. The results showed that the initial increase in length of the LbL probe can enhance the amount of immobilized human IgG, leading to a more sensitive assay. However, with thicker LbL layers, a reduction of the sensitivity of the measurement was registered. The performance of the developed system under optimum set-up showed a linearity in response from 1 × 10 to 1 × 10 M, with the limit detection of 9.1 × 10 M, which could be interesting for the detection of trace amounts of protein A from affinity isolation of therapeutic monoclonal antibodies.
一种用于检测蛋白质 A 的电容式生物传感器已经被开发出来。金电极通过热蒸发和光刻胶光刻技术制造。采用层叠（LbL）组装的硫脲（TU）和 HAuCl 以及化学还原法，制备了具有不同 TU 层数和金纳米粒子（AuNPs）的探针。LbL 修饰的电极用于固定人 IgG。通过检测电容信号的降低来检测人 IgG 与蛋白质 A 之间的结合相互作用，并且利用该变化来研究 LbL 探针的高度与电容测量的灵敏度之间的相关性。结果表明，LbL 探针长度的初始增加可以增强固定化人 IgG 的量，从而使测定更加灵敏。然而，随着 LbL 层更厚，测量的灵敏度会降低。在最佳设置下，所开发系统的性能表现出从 1×10 到 1×10 M 的响应线性度，检测限为 9.1×10 M，这对于从治疗性单克隆抗体的亲和分离中检测痕量蛋白质 A 可能很有趣。
