Synergistic activity of photoactivated curcumin-derived nanocomplexes in combination with antibiotics against planktonic and biofilm bacterial cells

Alternative antimicrobial strategies such as antimicrobial photodynamic therapy (aPDT) and curcumin-derived nanocomplexes were assessed in this study against biofilm cells of Gram-positive and Gram-negative clinical isolates. Curcumin-derived nanocomplexes (curcumin-chitosan magnetic nanoparticles [Cur-Chi-MNPs], carbon magnetic-nanoparticles [Cur-C-MNPs] and Curcumin-derived carbon quantum dots [Cur-QDs] were synthetized and characterized using scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and dynamic light scattering. The antimicrobial activity of photoactivated curcumin-derived nanocomplexes after blue light (400−470 nm), green light (495−570 nm), and red light (620−750 nm) exposure was assessed on biofilm bacterial cells of clinical isolates of Gram-negative and Gram-positive bacteria. Photoactivation of curcumin by green, red light and blue light increased the antibiofilm activity against Gram-positive isolates and Gram-negative isolates, but the effect was higher in Gram-positive pathogens. Green light photoactivation of Cur-Chi-MNPs and Cur-QDs yielded antibiofilm activity against Staphylococcus lugdunensis , whilst Cur-C-MNPs showed antibiofilm activity only against Stenotrophomonas maltophilia regardless of photoactivation. Photoactivated curcumin-derived nanocomplexes showed antimicrobial and antibiofilm properties against some Gram-positive and Gram-negative bacterial strains. Nanocurcumin-mediated aPDT could be a potential treatment option for biofilm eradication of clinical drug-resistant infections. • Photodynamic therapy and curcumin-derived nanocomplexes were assessed. • Curcumin showed antibiofilm activity in Gram-positive strains. • Cur-Chi-MNPs and Cur-QDs showed antibiofilm activity in S. lugdunensis. • Cur-C-MNPs showed antibiofilm activity against S. maltophilia . • Photoactivated curcumin-derived nanocomplexes showed antimicrobial properties.