Nanocurcumin and Curcumin-Loaded Nanoparticles in Antimicrobial Photodynamic Therapy: Mechanisms and Emerging Applications

The growing threat of antimicrobial resistance has necessitated the development of alternative, non-antibiotic therapies for effective microbial control. Antimicrobial photodynamic therapy, which uses photosensitizers activated by light to generate reactive oxygen species, offers a promising solution. Among natural photosensitizers, curcumin, a polyphenolic compound from Curcuma longa, has demonstrated broad-spectrum antimicrobial activity through reactive oxygen species-mediated membrane disruption and intracellular damage. However, curcumin’s poor water solubility, low stability, and limited bioavailability hinder its clinical utility. Nanotechnology has emerged as a transformative strategy to overcome these limitations. This review comprehensively explores advances in nanocurcumin- and curcumin-loaded nanoparticles, highlighting their physicochemical enhancements, photodynamic mechanisms, and antimicrobial efficacy against multidrug-resistant and biofilm-associated pathogens. A range of nanocarriers, including chitosan, liposomes, nanobubbles, hybrid metal composites, metal–organic frameworks, and covalent organic frameworks, demonstrate improved microbial targeting, light activation efficiency, and therapeutic outcomes. Applications span wound healing, dental disinfection, food preservation, water treatment, and medical device sterilization. Conclusions and future directions are given, emphasizing the integration of smart nanocarriers and combinatorial therapies to enhance curcumin’s clinical translation.