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 (P-CQDs), 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.