Photodynamic and Photothermal Ce6-Modified Gold Nanorod as a Potent Alternative Candidate for Improved Photoinactivation of Bacteria

Abstract

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.

Spectrum and size controllable synthesis of high-quality gold nanorods using 1,7-dihydroxynaphthalene as a reducing agent

“…Gold nanorods (AuNRs) have broad applications in the fields of biomedicine, 1,2 imaging, 3,4 sensing, 5 and catalysis 6 due to their tunable longitudinal surface plasmon resonance (LSPR). Because the LSPR frequency is directly related to the aspect ratio of AuNRs, 2,7 AuNRs with different aspect ratios and sizes have different application prospects, of which the small-sized AuNRs possessing a high absorption cross section are more attractive for photothermal applications, 8–10 whereas large-sized AuNRs have applications in scattering-related fields. 11 Therefore, the size and spectrum tunable synthesis of AuNRs is particularly important for the study and application of these particles.…”

pH‐Responsive Pt@mSiO2@CaP Core–Shell Nanoplatforms for Synergistic Chemo‐ and Photothermal Therapy

“…Mesoporous silica (mSiO 2 ) is a good drug carrier owing to its intrinsic biocompatibility, abundant porous channels, and large specific surface area. [ 17–19 ] mSiO 2 as nanoshells have been used for encapsulating NIR light‐absorbing NPs such as gold nanocrystals, [ 20–24 ] Pd nanosheets, [ 25 ] Cu 2‐ x Se nanospheres, [ 26 ] and copper chalcogenides. [ 27 ] The mSiO 2 nanoshells not only offer channels for drug loading, but also protect the NPs from uncontrolled aggregation.…”

Methylene Blue/Carbon Dots Composite with Photothermal and Photodynamic Properties: Synthesis, Characterization, and Antibacterial Application

“…After the fifth minute, almost no 1 O 2 was produced in MB. In addition, the 1 O 2 produced by MB may be unreasonably consumed in external media, which weakens its PDT effect (44) [https://doi.org/10.1021/acsabm.1c00474]. However, CQDs-MB maintained a similar singlet oxygen production rate.…”