# Photothermic Release of Curcumin for Antimicrobial Photodynamic Therapy

## TL;DR

This paper introduces a light-responsive drug delivery system that uses curcumin to effectively kill bacteria through controlled release triggered by near-infrared light.

## Contribution

A novel nanocarrier combining photothermal activation and light-controlled drug delivery for antimicrobial photodynamic therapy.

## Key findings

- NIR irradiation triggered ~90% curcumin release from the nanocarriers.
- The system reduced CFUs of S. aureus and P. aeruginosa by over 3 log10 in planktonic cultures.
- Higher curcumin concentrations improved efficacy against bacterial biofilms.

## Abstract

Drug delivery systems (DDS) are promising tools to enhance
antimicrobial
Photodynamic Therapy (aPDT) by improving the targeted delivery and
controlled release of photosensitizers. In this study, we introduce
a light-responsive DDS based on curcumin-loaded mesoporous silica
nanoparticles featuring a gold nanostar core and paraffin capping,
designed specifically for near-infrared (NIR)-triggered photothermal
release. This multicomponent nanoplatform uniquely combines photothermal
activation with light-controlled drug delivery for antimicrobial applications.
The synthesized nanoparticles exhibited a mean diameter below 500
nm, a polydispersity index of 0.154, and a surface charge of −21.9
mV. Upon NIR irradiation at 1200 J/cm2, curcumin release
was approximately 90%. In planktonic bacterial cultures, aPDT mediated
by this system led to reductions of 3.16 log1
0 and 2.18 log1
0 in colony-forming units (CFUs)
for Staphylococcus aureus and Pseudomonas aeruginosa, respectively. For bacterial
biofilms, a higher curcumin concentration (1000 μg/mL) resulted
in CFU reductions of 2.16 log1
0 and 1.77 log1
0 for S. aureus and P. aeruginosa, respectively. This study demonstrated
a NIR-activated nanocarrier for the controlled release of curcumin
and effective inactivation of both planktonic and biofilm-associated
bacteriaoffering a new approach to improve the precision and
efficacy of aPDT.