Biofilm‐Sensitive Photodynamic Nanoparticles for Enhanced Penetration and Antibacterial Efficiency

Abstract

Efficient antimicrobials are urgently needed for the treatment of bacterial biofilms due to their resistance to traditional drugs. Photodynamic therapy (PDT) is a new strategy that has been used to combat bacteria and biofilms. Cationic photosensitizers, particularly cationic photodynamic nanoagents, are usually chosen to enhance photodynamic antimicrobial activity. However, positively charged nanoparticles (NPs) are beneficial to cellular internalization, which causes increased cell cytotoxicity. Herein, a pH‐sensitive photodynamic nanosystem is designed. Rose Bengal (RB) polydopamine (PDA) NPs are decorated in a layer‐by‐layer fashion with polymyxin B (PMB) and gluconic acid (GA) to generate functionally adaptive NPs (RB@PMB@GA NPs). RB@PMB@GA NPs remain negative at physiological pH and exhibit good biocompatibility. When RB@PMB@GA NPs are exposed to an acidic infectious environment, the surface charge of the NPs is, in turn, positively charged as a result of pH‐sensitive electrostatic interactions. This surface charge conversion allows the RB@PMB@GA to effectively bind to the surfaces of bacteria and enhance photoinactivation efficiency against gram‐negative bacteria. Most importantly, RB@PMB@GA NPs exhibit good biofilm penetration and eradication under acidic conditions. Furthermore, RB@PMB@GA NPs efficiently eliminate biofilm infections in vivo. This study provides a promising strategy for safely treating biofilm‐associated infections in vivo.

Bee Bread as a Promising Source of Bioactive Molecules and Functional Properties: An Up-To-Date Review

“…Gluconic acid, a main organic acid in bee bread, exhibited potent antibacterial activities against anaerobic (Porphyromonasgingivalis ), Gram-negative ( Escherichia coli ), and Gram-positive bacteria ( Staphylococcus aureus ), as well as achieved effective biofilm penetration. Importantly, polymyxin B associated with gluconic acid exhibited good biofilm penetration and high antibacterial action [ 37 ]. In addition, acetic acid, another valuable component found in bee products, has been documented to have anti-fungal effects against toxigenic Aspergillus flavus [ 38 ].…”

Metabolism‐Driven Disassembly of Nanoprobes for Bacterial Detection, Imaging, and Photo‐Inactivation

“…Chronic infection is often closely associated with bacterial biofilm formation. [ 40 ] Conventional bactericidal agents are less effective in dealing with such infections because the biofilm matrix inhibits the drug penetration and prevent drugs from reaching embedded cells. [ 41 ] As advantages of HF‐D‐Ala NPs in bacterial targeting and killing were already demonstrated, we therefore assessed whether it could accurately image and kill bacteria in biofilms, by choosing S. aureus biofilm as a proof‐of‐concept model ( Figure a).…”

Smart Polymeric Delivery System for Antitumor and Antimicrobial Photodynamic Therapy

“…Hence, decreased side effect is expected. Herein we presented some typical examples of activatable polymeric delivery systems for anti-bacteria PDT ( Radovic-Moreno et al, 2012 ; Li F. et al, 2018 ; Zhao et al, 2019 ; Broenstrup et al, 2021 ; Wu et al, 2021 ; Ye et al, 2021 ).…”

“…Another pH-sensitive charge reversible nanoparticle system was constructed for enhanced penetration and antibacterial PDT efficiency ( Wu et al, 2021 ). As shown in Figure 14A , the photosensitizer Rose Bengal is dangled with dopamine, and then decorated with polymyxin B (PMB) and gluconic acid (GA) layer-by-layer.…”

“… (A) Schematic illustration of the preparation process of photodynamic NPs for enhanced penetration and antibacterial efficiency in biofilms; (B) antibacterial activities against E. coli at pH 7.4 and pH 5.0, with or without irradiation; (C) photographs of E. coli labeled with the red protein and S. aureus colonies incubated together with the different treatments; (D) typical photographs of the incision areas and implanted catheters from mice under different treatments on Days 1, 3, and 7; (E) photographs of P. aeruginosa bacterial colonies, and (F) quantitative analysis of bacterial colony-forming units obtained from the tissues and catheters in each group. Reprinted with permission from Wu et al (2021) . …”