Green synthesis of yeast cell wall-derived carbon quantum dots with multiple biological activities

Hypothesis: Yeast cell walls are a sustainable biomass source containing carbon and other elements like phosphorus. Converting cell walls into valuable nanomaterials like carbon quantum dots (CQDs) is of interest. Experiments: Cell walls from Saccharomyces cerevisiae were hydrothermally treated in 0.5 M H 2 SO 4 to produce CQDs. Multiple analytical techniques were utilized to confirm phosphorus -doping (PCQDs), characterize the fluorescence properties, determine quantum yield, and evaluate the sensing, antimicrobial, photocatalytic, and antioxidant capacities. Findings: A successful synthesis of P-CQDs was achieved with strong blue fluorescence under UV excitation, 19 % quantum yield, and excellent stability. The P-CQDs showed sensitive fluorescence quenching in response to ferric ions with a 201 nM detection limit. Antibacterial effects against Escherichia coli and Staphylococcus aureus were demonstrated. P-CQDs also exhibited dye degradation under sunlight and antioxidant activity. So, the prepared P-CQDs displayed promising multifunctional capabilities for metal ion detection, disinfection, and environmental remediation. Further research is required to fully realize and implement the multifunctional potential of P-CQDs in real -world applications.