Zhang Juanjuan, Chen Shihong, Ruo Yuan, Zhong Xia, Wu Xiaoping
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China.
Anal Bioanal Chem. 2015 Jan;407(2):447-53. doi: 10.1007/s00216-014-8290-x. Epub 2014 Nov 30.
A highly sensitive electrochemiluminescent (ECL) biosensor was designed for the detection of concanavalin A (ConA) based on glucose oxidase (GOx) as a recognition element by carbohydrate-lectin biospecific interaction, and poly(ethylenimine) (PEI) reduced graphene and hollow gold nanoparticles (HAuNPs) as supporting matrix and signal amplifier. The modification process and detection principle of the biosensor are briefly described as follows. First, PEI reduced graphene oxide with abundant amino groups was cast onto the surface of glassy carbon electrode to adsorb HAuNPs for improving the signal intensity in luminol/H2O2 ECL system. Next, GOx was further assembled onto the electrode by the interaction between Au and -NH2. In the presence of glucose in the detection solution, GOx catalyzed glucose to generate H2O2 in situ, which served as a co-reactant of luminol to enhance ECL signal of luminol. Based on the fact that ConA could result in a decrease in ECL signal when immobilized on the electrode, an ECL biosensor was prepared for the determination of ConA. The ECL signal intensity was linear with the logarithm of ConA concentration and the linear range was from 1.0 to 20 ng/mL with a low detection limit of 0.31 ng/mL (signal to noise ratio =3). This strategy led to a nearly 1000-fold improvement in detection limit for ConA assays compared with previously reported method, thus exhibiting a great potential application in sensitive bioassays of ConA.
基于葡萄糖氧化酶（GOx）作为识别元件，利用碳水化合物-凝集素生物特异性相互作用，以及聚乙烯亚胺（PEI）还原石墨烯和中空金纳米粒子（HAuNPs）作为支撑基质和信号放大器，设计了一种用于检测伴刀豆球蛋白A（ConA）的高灵敏度电化学发光（ECL）生物传感器。该生物传感器的修饰过程和检测原理简述如下。首先，将具有丰富氨基的PEI还原氧化石墨烯浇铸到玻碳电极表面以吸附HAuNPs，从而提高鲁米诺/H2O2 ECL体系中的信号强度。接下来，通过Au与-NH2之间的相互作用将GOx进一步组装到电极上。在检测溶液中存在葡萄糖的情况下，GOx催化葡萄糖原位生成H2O2，H2O2作为鲁米诺的共反应物增强鲁米诺的ECL信号。基于ConA固定在电极上时会导致ECL信号降低这一事实，制备了用于测定ConA的ECL生物传感器。ECL信号强度与ConA浓度的对数呈线性关系，线性范围为1.0至20 ng/mL，检测限低至0.31 ng/mL（信噪比=3）。与先前报道的方法相比，该策略使ConA检测的检测限提高了近1000倍，因此在ConA的灵敏生物测定中显示出巨大的潜在应用价值。
