Photo-responsive emissive oxidase-like nanozyme based on-site antioxidant detection sensor from human saliva
Sanskruti Swain1*, Ting-Yi Lin1, Hua-En Chueh1, I-Hsuan Chou2, Yun-Jung Ting1, Hsing-Ying Lin2, Chen-Han Huang1
1Department of Biomedical Sciences and Engineering, National Central University, Zhongli, Taoyuan, Taiwan
2Institute of Biomedical Engineering, National Tsing Hua University, Hsinchu, Taiwan
* Presenter:Sanskruti Swain, email:sanskrutiswain117@gmail.com
Uncontrolled generation of reactive oxygen species (ROS) due to lack of antioxidants in the human body causes free radical damage inducing excessive cell death, which leads to oxidative stress-related disorders like cancer, Alzheimer’s disease, etc. Herein, we prepared dithiothreitol (DTT)-mediated highly fluorescent AuNCs stabilized by BSA (BSA-AuNCs) with red fluorescence under 385nm UV having maximum emission at 690 nm. Upon visible light irradiation, BSA-AuNCs generated free radicals, which oxidized non-fluorescent thiamine to fluorescent thiochrome under neutral conditions rapidly, but in the presence of antioxidants, the quenching of fluorescence was observed. In our study, we have explored the photo-responsive oxidase-mimetic ability of BSA-AuNCs stimulated by light irradiation to detect antioxidants in human saliva and cancer cell lines. The developed nanocluster exhibited excellent stability in a variety of conditions, high selectivity, and sensitivity in detecting the target analyte among various other interferences, thereby satisfying the criteria for an adequate sensor material. Moreover, to extend the clinical feasibility, a portable microfluidic device was developed to evaluate the Total Antioxidant Capacity from human saliva. Since a correlation exists between oxidative stress and COVID-19 pathology, we utilized the detection technique to evaluate TAC in clinical saliva samples from COVID-19 patients employing the nanosensor.
Keywords: antioxidant capacity, fluorescence, gold nanocluster, oxidase-like nanozyme , on-site detection