Wang Tingting, Muthuswamy Jit
Harrington Department of Bioengineering, Arizona State University, Tempe, Arizona 85287, USA.
Anal Chem. 2008 Nov 15;80(22):8576-82. doi: 10.1021/ac801463a. Epub 2008 Oct 24.
A piezoelectric immunosensor for sensing the low molecular weight neurotransmitter gamma-aminobutyric acid (GABA), one of two major inhibitory neurotransmitters in the central nervous system, is described. The sensing interface consists of a dextran layer covalently attached to a self-assembled monolayer of thiolamine compound on the surface of gold electrodes of the crystals. The dextran layer is further modified with GABA molecules to act as the biosensing layer. The affinity binding of monoclonal anti-GABA antibody on the modified piezoelectric crystals is studied in real time without any additional labels. The equilibrium association constant, K(eq) for binding between anti-GABA antibody and GABA molecules is 14.5 microg x mL (-1). The detection limit for anti-GABA is approximately 10 nM. The sensitivity of the sensor at a concentration corresponding to half-maximal response is 13.6 ng/mL x Hz. The functionalized sensor substrate is subsequently used for competitive determination of different concentrations of free GABA (range of 5 microM-50 mM) in PBS-BSA buffer. The detection limit of the immunosensor for sensing GABA with maximum sensitivity is approximately 42 microM.
本文描述了一种用于检测低分子量神经递质γ-氨基丁酸（GABA）的压电免疫传感器，GABA是中枢神经系统中两种主要的抑制性神经递质之一。传感界面由共价连接到晶体金电极表面硫醇胺化合物自组装单分子层上的葡聚糖层组成。葡聚糖层进一步用GABA分子修饰，用作生物传感层。在没有任何额外标记的情况下，实时研究了修饰后的压电晶体上抗GABA单克隆抗体的亲和结合。抗GABA抗体与GABA分子结合的平衡缔合常数K(eq)为14.5μg×mL(-1)。抗GABA的检测限约为10 nM。传感器在对应于最大响应一半浓度时的灵敏度为13.6 ng/mL×Hz。随后将功能化的传感器底物用于在PBS-BSA缓冲液中竞争性测定不同浓度的游离GABA（范围为5μM-50 mM）。具有最大灵敏度的用于检测GABA的免疫传感器的检测限约为42μM。
