Synergistic Photodynamic and Photothermal Antibacterial Activity of In Situ Grown Bacterial Cellulose/MoS₂-Chitosan Nanocomposite Materials with Visible Light Illumination

Abstract

Owing to the rise in prevalence of multidrugresistant pathogens attributed to the overuse of antibiotics, infectious diseases caused by the transmission of microbes from contaminated surfaces to new hosts are an ever-increasing threat to public health. Thus, novel materials that can stem this crisis, while also functioning via multiple antimicrobial mechanisms so that pathogens are unable to develop resistance to them, are in urgent need. Toward this goal, in this work, we developed in situ grown bacterial cellulose/MoS 2 -chitosan nanocomposite materials (termed BC/MoS 2 -CS) that utilize synergistic membrane disruption and photodynamic and photothermal antibacterial activities to achieve more efficient bactericidal activity. The BC/ MoS 2 -CS nanocomposite exhibited excellent antibacterial efficacy, achieving 99.998% (4.7 log units) and 99.988% (3.9 log units) photoinactivation of Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, respectively, under visible-light illumination (xenon lamp, 500 W, λ ≥ 420 nm, and 30 min). Mechanistic studies revealed that the use of cationic chitosan likely facilitated bacterial membrane disruption and/or permeability, with hyperthermia (photothermal) and reactive oxygen species (photodynamic) leading to synergistic pathogen inactivation upon visiblelight illumination. No mammalian cell cytotoxicity was observed for the BC/MoS 2 -CS membrane, suggesting that such composite nanomaterials are attractive as functional materials for infection control applications.

Phase-Dependent 1T/2H-MoS2 Nanosheets for Effective Photothermal Killing of Bacteria

“…As a result of enhanced photothermal performance by 1T-MoS 2 NSs under NIR laser irradiation, the cell division Z-ring and penicillinbinding proteins were inactivated, showing that E. coli could survive for a short period of time. 79 A large amount of damage to the bacterial cell walls (red arrows), full annihilation of the bacteria (yellow arrows), and aberrant growth of bacteria (blue…”

Biofilm Microenvironment-Mediated MoS2 Nanoplatform with Its Photothermal/Photodynamic Synergistic Antibacterial Molecular Mechanism and Wound Healing Study

“…Intracellular Photothermal and Photodynamic Activity. We further investigated the photothermal effects of the materials under in vitro bacterial growth environment by coincubating the activated bacterial broth with different concentrations of MQC@ZIF-8 (9,19,38,75,150, and 300 μg mL −1 ), followed by irradiation with an 808 nm NIR laser at a power of 1 W cm −2 . The results were recorded with a photothermal imager at 0, 3, and 6 min.…”

Prussian Blue Nanocubes Decorated with Ag Nanoparticles for Near-Infrared Triggered Release of Bactericidal Ag+, Fe2+, and Fe3+ Ions

“…3,10 Therefore, the dual-mode antibacterial treatment strategy combined with PTA and PDA is a particularly promising approach to supply the possible synergistic benefits without triggering drug resistance and conquer respective shortcomings. 11−13 So far, a variety of high-efficiency nanocomposite materials combined with PTA and PDA have been developed, such as BC/MoS 2 -CS, 3 PB@HA, 9 CDs/Cur, 13 Au@Bi 2 WO 6 , 14 PDA-Cur, 15 and PB@MOF. 16 However, the application of photothermal therapy (PTT) and photodynamic therapy (PDT) in bacterial treatment is still facing huge challenges.…”

“…In recent years, the strategies of photo-triggered photothermal antibacterial therapy (PTA) and photodynamic antibacterial therapy (PDA) have attracted great interest in seeking new antibiotic alternatives because of their high bactericidal activity and low sensitivity to the multidrug-resistant mechanism. − However, both single-mode PTA and PDA have underlying limitations, for example, it is difficult to obtain efficient bacterial ablation without damaging the surrounding healthy cells and tissues through the photothermal effect alone. Only at high temperatures over 70 °C, bacteria can be completely eradicated .…”

“…When the ambient temperature reaches about 50 °C, bacterial resistance is reduced obviously, allowing them to be inactivated more quickly by reactive oxygen species (ROS), without causing damage to normal tissue cells in a short period of time. , Therefore, the dual-mode antibacterial treatment strategy combined with PTA and PDA is a particularly promising approach to supply the possible synergistic benefits without triggering drug resistance and conquer respective shortcomings. − So far, a variety of high-efficiency nanocomposite materials combined with PTA and PDA have been developed, such as BC/MoS 2 -CS, PB@HA, CDs/Cur, Au@Bi 2 WO 6 , PDA-Cur, and PB@MOF …”