Optimized growth of dendritic Au nanostructures with multi-cross-linked glucose oxidase for highly catalytic activity of salivary glucose

Abstract

We aim to develop a system that prominently features glucose oxidase (GOx) as the catalyst, integrated with a dendritic Au nanostructures electrode as the core component. The dendritic Au (DenAu) nanostructures are optimally electro-deposited on a flexible substrate without the use of any surfactant, template, or stabilizer, demonstrating their potential through highly sensitive flexible glucose sensor application. To determine the optimal condition for the growth of dendritic Au nanostructures, we meticulously investigated the concentration of the precursor, deposition potential/time, and stirring rate. Subsequently, the glucose oxidase (GOx) was immobilized on the fabricated sensor with dendritic Au nanostructures. Due to the effective high loading of GOx onto the dendritic Au and its high catalytic activity, the fabricated flexible glucose sensor was capable of detecting glucose over an ultra-wide dynamic range from 0.001 to 10,000 μM without any mediator. It exhibited an exceptionally high sensitivity of 678 μAmM？1 cm？2 and a low limit of detection of 0.1 μM, surpassing the performance of the sensor with bare Au. Furthermore, the fabricated flexible sensor with dendritic Au nanostructure showed practical feasibility and possibility for the detection of salivary glucose, which was evidenced by a strong correlation coefficient of 0.9935 in artificial saliva.