Photosensitizer
(PS)-mediated photodynamic therapy (PDT) has attracted
more and more attention as an alternative to traditional antibiotic
therapy. Nevertheless, the limitations of traditional photosensitizers
seriously hinder their practical application, as a result, the methods
to improve the antibacterial properties of traditional photosensitizers
have become a hot topic in the field of photomedicine. Herein, a compound
nano-PS system has been constructed with synergistic photodynamic
and photothermal (PTT) antibacterial effects, triggered by a dual-wavelength
illumination. Fluorescent carbon dots (CDs) were synthesized and employed
as carriers for the delivery of curcumin (Cur) to obtain CDs/Cur.
Upon combined near-infrared and 405 nm visible dual-wavelength irradiation,
CDs/Cur could simultaneously generate ROS and a moderate temperature
increase, triggering synergistic antibacterial effects against both
Gram-positive and Gram-negative bacteria. The results of scanning
electron microscopy and fluorescence confocal imaging showed that
the combined effect of CDs/Cur with PDT and PTT caused more serious
damage to the cell membrane. In addition, CDs/Cur exhibited low cytotoxicity
and negligible hemolytic activity, showing great biocompatibility.
Therefore, the construction of CDs/Cur by employing CDs as photosensitizer
delivery carriers provides a strategy for the improvement of the antibacterial
effect of the photosensitizer and the design of next-generation antibacterial
agents in photomedicine.
The
global rise of antibiotic resistance of pathogenic bacteria
has become an increasing medical and public concern, which is further
urging the development of antimicrobial channels for treating infectious
diseases. The combination of photodynamic therapy (PDT) with photothermal
therapy (PTT) has been considered as a promising alternative way for
the replacement of traditional antibiotic therapy. In this research,
the newly fabricated Chlorin-e6 (Ce6) conjugated mesoporous silica-coated
AuNRs, designated AuNR@SiO2-NH2-Ce6, exhibited
synergistic photothermal effects and single oxygen localized generation
property, and showed stronger photoinactivation for bacteria compared
with Ce6. AuNR@SiO2-NH2-Ce6 can anchor to the
cell membrane and accumulate in the interior of cells. Furthermore,
the unique porous structure of AuNR@SiO2NH2 enabled
Ce6 encapsulation in the mesopores and was subsequently released and
activated by photothermic effect, allowing the generated single oxygen
to penetrate into the cytoplasmic membrane or directly enter the interior
of bacteria cells, thus overcoming the inherent defects of single
oxygen. AuNR@SiO2-NH2-Ce6 not only damaged the
integrity of the cell membrane of bacteria but also facilitated the
cellular permeation and accumulation of external nanoagents in the
bacteria upon light irradiation. In addition, AuNR@SiO2-NH2-Ce6 exhibited negligible cytotoxicity toward mammalian
cells and hemolytic activity. Therefore, AuNR@SiO2-NH2-Ce6 may be highly promising candidates as topical antibacterial
agents, and this study has wide implications on the design of next-generation
antimicrobial agents.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.