A High Catalytic Activity Nanozyme Based on Cobalt-Doped Carbon Dots for Biosensor and Anticancer Cell Effect

Abstract

Nanozyme technology as an emerging field has been successfully applied to chemical sensing, biomedicine, and environmental monitoring. It is very significant for the advance of this field to construct nanozymes with high catalytic activity by a simple method and to develop their multifunctional applications. Here, a new type of cobalt-doped carbon dots (Co-CDs) nanozymes was designed using vitamin B 12 and citric acid as the precursors. The homogeneous cobalt doping at carbon nuclear led the Co-CDs to show significant peroxidase-like activity resembling natural metalloenzymes. Based on the high affinity of Co-CDs to H 2 O 2 (K m = 0.0598 mM), a colorimetric sensor for glucose detection was constructed by combining Co-CDs with glucose oxidase. On account of the high catalytic activity of nanozymes and the cascade strategy, a good linear relationship was obtained from 0.500 to 200 μM, with a detection limit of 0.145 μM. The biosensor has realized the accurate detection of glucose in human serum samples. Moreover, Co-CDs could specifically catalyze H 2 O 2 in cancer cells to generate a variety of reactive oxygen species, leading to the death of cancer cells, which has useful application potential in tumor catalytic therapy. In this work, the catalytic activity of Co-CDs has been adequately exploited, which extends the application of carbon dots in multiple biotechnologies, including biosensing, disease diagnosis, and treatment.

Blood-Glucose-Depleting Hydrogel Dressing as an Activatable Photothermal/Chemodynamic Antibacterial Agent for Healing Diabetic Wounds

“…It is known that Fe 2+ has excellent Fenton reaction activity and catalyzes the oxidation of TMB by hydrogen peroxide (H 2 O 2 ), thereby forming abundant ·OH. , Interestingly, H 2 O 2 was produced by the decomposition of glucose with GOx catalyzed . Therefore, the generation of ·OH could be activated by glucose with the TMB/Fe 2+ /PF127/GOx hydrogel; meanwhile, the chemodynamic property is timely activated for killing bacteria.…”

“…Chemodynamic therapy (CDT) based on the Fenton reaction to catalyze H 2 O 2 to generate highly toxic ROS for efficient killing bacteria, displaying merits of diabetic wound's specificity with cascade catalytic blood glucose, and depth independence. 39,40 Therefore, developing a glucoseactivated multimodal CDT/PTT agent with reducing glucose and monitoring the glucose level simultaneously is imperative for accelerating diabetic wound healing. 41−45 Herein, the Pluronic F-127 (PF127) thermosensitive hydrogel dressing combining the capabilities of colorimetric glucose sensing and glucose-activated chemodynamic/photothermal functions is designed and demonstrated for simultaneous glucose monitoring and antimicrobial therapy to accelerate diabetic wound healing.…”

“…Moreover, photothermal antibacterial efficacy might be restricted to some extent by the low efficiency of photothermal conversion and inhomogeneous distribution of hyperthermia. Chemodynamic therapy (CDT) based on the Fenton reaction to catalyze H 2 O 2 to generate highly toxic ROS for efficient killing bacteria, displaying merits of diabetic wound’s specificity with cascade catalytic blood glucose, and depth independence. , Therefore, developing a glucose-activated multimodal CDT/PTT agent with reducing glucose and monitoring the glucose level simultaneously is imperative for accelerating diabetic wound healing. − …”

Advances and perspectives of nanozymes in respiratory diseases

“…5A). 141 This work extends their application potential to tumor therapy by exploiting metal-doped CDs' catalytic properties. As therapeutic agents, nanozymes can be applied as photosensitizers, sonosensitizers, and radiosensitizers for ROS production under light irradiation, wherein the key role is to generate O 2 to improve efficiency.…”

Nanozymes towards Personalized Diagnostics: A Recent Progress in Biosensing

“…Similar to HRP, SWNTs catalyze the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB), resulting in a change in color that is highly sensitive to changes in pH, temperature, and H 2 O 2 concentration. These intriguing results have encouraged the study of different carbon-based nanomaterials as peroxidase mimics in the field of biosensors, including GQDs [ 49 ], carbon dots [ 50 ], and graphitic carbon nitride [ 51 ].…”