Enhancement of Antimicrobial Efficacy Through Emodin-Loaded β-Cyclodextrin Nanocarbon Quantum Dots with Photodynamic Therapy

Bacteria are among the main causes of various diseases, which makes the search for safe and effective antimicrobial agents a major focus of research. In this study, nanocarbon quantum dots (Emo-CDs) with photodynamic antimicrobial activity were synthesized from rhodopsin (Emo) and β -cyclodextrin ( β -CD) using a simple hydrothermal method. This system, when combined with photodynamic therapy (PDT), exhibited enhanced antimicrobial properties. The prepared Emo-CDs can efficiently generate singlet oxygen under light irradiation, meeting the requirements for photodynamic antimicrobial activity. The antimicrobial efficacy of Emo-CDs was found to be concentration-dependent. After 10 min of xenon lamp irradiation, Emo-CDs demonstrated significantly greater antibacterial activity than Emo alone, achieving bactericidal rates as high as 99.89% against S. aureus and 97.75% against E. coli . Additionally, the photodynamic bactericidal effect increased with higher concentrations of Emo-CDs. Moreover, the system showed stable photoluminescence and good biocompatibility. In conclusion, the Emo-CDs system demonstrates great potential for improving the bioavailability, biocompatibility and antimicrobial efficacy of Emo, providing new strategies for developing novel dosage forms of active compounds in traditional Chinese medicine.