HCl-Protonated Metal-Organic Framework-Confined Au Nanoclusters with Enhanced Catalytic Activity and Specificity for
Yuxin Song1,2, Chengyi Zhu1,2, Pengyou Zhou1,2
1Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing100069, China.
Abstract:
Development of nanozymes with enhanced activity and specificity can be profitable for sensitive and anti-interference biosensing. Herein, we developed a protonation strategy to fabricate metal-organic framework-confined Au nanoclusters with enhanced catalytic activity and specificity. Organic acid acetic acid (HAc), tannins (TA), and inorganic acid hydrochloric acid (HCl) were used to etch the UiO-66-NH2 skeleton, and only HCl can introduce reasonable protonation on UiO-66-NH2 without structural damage. The peroxidase (POD)- and glucose oxidase-mimic catalytic activities of UiO-66-NH2@Au can be improved simultaneously. Mechanism study revealed that the surface protonation can regulate the charge density and binding energy of the Au nanocluster growth on the surface of UiO-66-NH2, resulting in an improved catalytic activity to H2O2 and glucose molecules simultaneously. Interestingly, the oxidase-mimic activity of protonated UiO-66-NH2@Au was absolutely suppressed; thus, the POD-specific catalytic activity can be used as anti-interference colorimetric tags in colorectal cancer (CRC) biomarker biosensing. Combined with the lateral flow assay, a detection limit of 17 pg/mL for carcinoembryonic antigen (CEA) and 0.11 U/mL for carbohydrate antigen 19-9 (CA19-9) can be visually detected simultaneously within 15 min. For clinical diagnosis, CRC patients can be differentiated from healthy controls with better accuracy than by using commercial ELISA kits. Moreover, protonated UiO-66-NH2@Au can specifically catalyze glucose and did not respond to the glucose analogues and can hence be directly used for salivary glucose detection. In addition, we found that HCl-protonated UiO-66-NH2 can be a universal method to improve the POD-mimic catalytic activity of UiO-66-NH2 confined with other catalytic metals such as Pt, Ru, and Pd. It highlights that HCl-protonated nanozymes can be a simple strategy to fabricate UiO-66-NH2 confined nanozymes with enhanced catalytic activity and specificity.
