Aggregation-Induced Emission Nanoparticles for Single Near-Infrared Light-Triggered Photodynamic and Photothermal Antibacterial Therapy

Abstract

Phototheranostics is a potential area for precision medicine, which has received increasing attention for antibacterial applications. Integrating all phototheranostic modalities in a single molecule and achieving precise spatial colocalization is a challenging task because of the complexity of energy dissipation and molecular design. Here, a type of quaternary amine functionalized aggregation-induced emission (AIE), AIEgen, was synthesized and used to produce singlet oxygen (1O2) and heat, which were used to eradicate the bacteria. With the introduction of the positive charge in AIEgen, AIE nanoparticles (AIE NPs) could selectively target bacteria. Notably, the AIE NPs displayed obvious antibacterial performance against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). The antibacterial rates of AIE NPs were as high as 99.9% and 99.8% for S. aureus and E. coli, respectively. Therefore, our results suggested the potential of AIE NPs acting as broad-spectrum antimicrobial materials, which provided a strategy for treating different microorganisms.

Structure and functions of Aggregation-Induced Emission-Photosensitizers in anticancer and antimicrobial theranostics

“…AIE-phtotosensitizers were used to generate bacteriophage as AIE–PAP bioconjugate with capabilities for real-time tracking by fluorescence imaging and killing of antibiotic-sensitive or multi-drug-resistant bacteria ( He et al, 2020 ). AIE-photosensitizer nanoparticles with an overall positive charge can act as broad spectrum antimicrobials activated by near infrared light to produce singlet oxygen and heat ( Wang et al, 2022b ). Glucose polymer-modified gold nanoparticles were incubated with diverse types of bacteria to be taken up through the ATP-binding cassette (ABC) transporter pathway before laser irradiation to achieve a three-fold increase in the microbicidal activity ( Yang et al, 2022 ).…”

Bioactive AIEgens Tailored for Specific and Sensitive Theranostics of Gram-Positive Bacterial Infection

“…In recent years, large numbers of aggregation-induced emission molecules (AIEgens) have been developed to combat the aggregation-induced quenching effect . Compared with traditional fluorescent molecules, AIEgens usually have a relatively twisted configuration.…”

“…In recent years, large numbers of aggregation-induced emission molecules (AIEgens) have been developed to combat the aggregation-induced quenching effect. 13 Compared with traditional fluorescent molecules, AIEgens usually have a relatively twisted configuration. When in a good solvent, the AIEgens can rotate freely to dissipate energy by a nonradiative way and basically no fluorescence is produced.…”

“…Then, the confined intramolecular 1 H NMR spectra were recorded on a Bruker AVANCE III HD 600 MHz spectrometer (Germany). 13 C NMR spectra were recorded at 151 and 101 MHz. Mass spectra (MS) were obtained on a Thermo Scientific Q Exactive spectrometer (America).…”

“…For "D-bridge-A"-type molecules, the bridging group may play an important role in determining the photophysical properties. According to the D−A molecular engineering strategy, four "D-bridge-A"-type PSs with different bridging groups were prepared and abbreviated to MTPy, were characterized by 1 H NMR, 13 C NMR, and HRMS (Figures S9 and S20). Photophysical, AIE, and Recognition Properties.…”