Theyagarajan Kandaswamy, Yadav Sangeeta, Satija Jitendra, Thenmozhi Kathavarayan, Senthilkumar Sellappan
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology (VIT), Vellore 632014, India.
School of Biosciences and Technology, Vellore Institute of Technology (VIT), Vellore 632014, India.
ACS Biomater Sci Eng. 2020 Nov 9;6(11):6076-6085. doi: 10.1021/acsbiomaterials.0c00807. Epub 2020 Oct 21.
Creation of interfaces with a prudent design for the immobilization of biomolecules is substantial in the construction of biosensors for real-time monitoring. Herein, an adept biosensing interface was developed using a nanoconjugated matrix and has been employed toward the electrochemical determination of hydrogen peroxide (HO). The anionic gold nanoparticle (AuNP) was electrostatically tethered to cationic redox ionic liquid (IL), to which the horseradish peroxidase (HRP) enzyme was covalently immobilized to form a nanobioconjugate. The anthracene-substituted, aldehyde-functionalized redox IL (CHO-AIL) was judiciously designed with the (i) imidazolium cation for electrostatic interaction with AuNPs, (ii) anthracene moiety to mediate the electron transfer, and (iii) free aldehydic group for covalent bonding with a free amine group of the enzyme. Thus, the water-soluble HRP is effectively bonded to the CHO-AIL on a glassy carbon electrode (GCE) via imine bond formation, which resulted in the formation of the HRP-CHO-AIL/GCE. Electrochemical investigations on the HRP-CHO-AIL/GCE reveal highly stable and distinct redox peaks for the anthracene/anthracenium couple at a formal potential (°') of -0.47 V. Electrostatic tethering of anionic AuNPs to the HRP-CHO-AIL promotes the electron transfer process in the HRP-CHO-AIL/AuNPs/GCE, as observed by the reduction in the formal potential to -0.42 V along with the enhancement in peak currents. The HRP-CHO-AIL/AuNPs/GCE has been explored toward the electrocatalytic detection of HO, and the modified electrode demonstrated a linear response toward HO in the concentration range of 0.02-2.77 mM with a detection limit of 3.7 μM. The developed biosensor ascertained predominant selectivity and sensitivity in addition to remarkable stability and reproducibility, corroborating the suitableness of the platform for the effectual biosensing of HO. The eminent performance realized with our biosensor setup is ascribed to the multifunctional efficacy of this newly designed nanobioconjugate.
设计合理的生物分子固定化界面对于构建用于实时监测的生物传感器至关重要。在此，利用纳米共轭基质开发了一种灵敏的生物传感界面，并将其用于过氧化氢（HO）的电化学测定。阴离子金纳米颗粒（AuNP）通过静电作用与阳离子氧化还原离子液体（IL）相连，辣根过氧化物酶（HRP）共价固定在该离子液体上，形成纳米生物共轭物。精心设计了蒽取代、醛功能化的氧化还原离子液体（CHO-AIL），其中（i）咪唑阳离子用于与AuNP进行静电相互作用，（ii）蒽部分用于介导电子转移，（iii）游离醛基用于与酶的游离胺基共价结合。因此，水溶性HRP通过亚胺键的形成有效地结合到玻碳电极（GCE）上的CHO-AIL上，从而形成了HRP-CHO-AIL/GCE。对HRP-CHO-AIL/GCE的电化学研究表明，在-0.47 V的形式电位（°'）下，蒽/蒽鎓对具有高度稳定且明显的氧化还原峰。阴离子AuNP与HRP-CHO-AIL的静电连接促进了HRP-CHO-AIL/AuNPs/GCE中的电子转移过程，形式电位降低至-0.42 V，同时峰电流增强。HRP-CHO-AIL/AuNPs/GCE已用于HO的电催化检测，修饰电极在0.02-2.77 mM的浓度范围内对HO表现出线性响应，检测限为3.7 μM。所开发的生物传感器除了具有出色的稳定性和可重复性外，还具有主要的选择性和灵敏度，证实了该平台对HO进行有效生物传感的适用性。我们的生物传感器装置所实现的卓越性能归因于这种新设计的纳米生物共轭物的多功能功效。
