Zhang Hangyu, Li Zhe-fei, Snyder Alexandra, Xie Jian, Stanciu Lia A
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Department of Mechanical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN 46202, USA.
Anal Chim Acta. 2014 May 27;827:86-94. doi: 10.1016/j.aca.2014.04.014. Epub 2014 Apr 12.
There is an increasing need to develop biosensors for the detection of harmful pesticide residues in food and water. Here, we report on a versatile strategy to synthesize functionalized graphene oxide nanomaterials with abundant affinity groups that can capture histidine (His)-tagged acetylcholinesterase (AChE) for the fabrication of paraoxon biosensors. Initially, exfoliated graphene oxide (GO) was functionalized by a diazonium reaction to introduce abundant carboxyl groups. Then, Nα,Nα-bis(carboxymethyl)-l-lysine hydrate (NTA-NH2) and Ni(2+) were anchored onto the GO based materials step by step. AChE was immobilized on the functionalized graphene oxide (FGO) through the specific binding between Ni-NTA and His-tag. A low anodic oxidation potential was observed due to an enhanced electrocatalytic activity and a large surface area brought about by the use of FGO. Furthermore, a sensitivity of 2.23 μA mM(-1) to the acetylthiocholine chloride (ATChCl) substrate was found for our composite covered electrodes. The electrodes also showed a wide linear response range from 10 μM to 1mM (R(2)=0.996), with an estimated detection limit of 3 μM based on an S/N=3. The stable chelation between Ni-NTA and His-tagged AChE endowed our electrodes with great short-term and long-term stability. In addition, a linear correlation was found between paraoxon concentration and the inhibition response of the electrodes to paraoxon, with a detection limit of 6.5×10(-10) M. This versatile strategy provides a platform to fabricate graphene oxide based nanomaterials for biosensor applications.
开发用于检测食品和水中有害农药残留的生物传感器的需求日益增长。在此，我们报告了一种通用策略，用于合成具有丰富亲和基团的功能化氧化石墨烯纳米材料，该材料可捕获组氨酸（His）标记的乙酰胆碱酯酶（AChE）以制造对氧磷生物传感器。最初，通过重氮反应对剥离的氧化石墨烯（GO）进行功能化，以引入大量羧基。然后，将Nα，Nα-双（羧甲基）-L-赖氨酸水合物（NTA-NH2）和Ni（2+）逐步锚定在基于GO的材料上。通过Ni-NTA与His标签之间的特异性结合，将AChE固定在功能化氧化石墨烯（FGO）上。由于使用FGO带来的增强的电催化活性和大表面积，观察到低阳极氧化电位。此外，我们的复合覆盖电极对氯化乙酰硫代胆碱（ATChCl）底物的灵敏度为2.23μA mM（-1）。电极还显示出从10μM到1mM的宽线性响应范围（R（2）=0.996），基于S/N=3估计检测限为3μM。Ni-NTA与His标签化的AChE之间的稳定螯合赋予我们的电极极大的短期和长期稳定性。此外，发现对氧磷浓度与电极对对氧磷的抑制反应之间存在线性相关性，检测限为6.5×10（-10）M。这种通用策略提供了一个平台，用于制造基于氧化石墨烯的纳米材料用于生物传感器应用。
