Development of cysteine-doped MnO2 quantum dots for spectrofluorimetric estimation of copper: applications in different matrices

Abstract

Copper (Cu) plays a role in maintaining healthy nerve cells and the immune system. Osteoporosis is a high-risk factor for Cu deficiency. In the proposed research, unique green, fluorescent cysteine-doped MnO2 quantum dots (Cys@MnO2 QDs) were synthesized and assessed for the determination of Cu in different food and hair samples. The developed quantum dots were synthesized with the help of cysteine using a straightforward ultrasonic approach to create 3D fluorescent Cys@MnO2 QDs. The resulting QDs’ morphological and optical characteristics were carefully characterized. By adding Cu ions, the intensity of fluorescence for the produced Cys@MnO2 QDs was found to be dramatically reduced. Additionally, the applicability of Cys@MnO2 QDs as a new luminous nanoprobe was found to be strengthened by the quenching effect grounded on the Cu–S bonding. The concentrations of Cu2+ ions were estimated within the range of 0.06 to 7.00 µg mL−1, with limit of quantitation equal to 33.33 ng mL−1 and detection limit equal to 10.97 ng mL−1. The Cys@MnO2 QD technique was applied successfully for the quantification of Cu in a variety of foods, including chicken meat, turkey, and tinned fish, as well as in human hair samples. The chance that this novel technique could be a useful tool for figuring out the amount of cysteine in bio-samples is increased by the sensing system’s remarkable advantages, which include being rapid, simple, and economical. Graphical abstract

Potential in-vitro antioxidant and anti-inflammatory activity of Martynia annua extract mediated Phytosynthesis of MnO2 nanoparticles

“…Some of these benefits include their low cost in terms of workforce and environmental costs, as well as their high luminescence quantum yield. Their wide range of applications, enzymatic-like activity, excellent biocompatibility, advantageous therapeutic qualities, and extremely high theoretical specific capacitance are other appealing variables [ 12 , 13 ]. There are various physicochemical techniques to synthesize MnO 2 NPs like hydrothermal process, Sol-gel process, Wet chemical and photochemical route, Co-precipitation technique, pyrolysis process, and low-temperature solution combustion method [ 14 ].…”