Magnetoelectric Polymer Membrane-Based Electrical Microenvironment with Magnetically Controlled Antibacterial Activity

Abstract

The “hard to clean” parts of food processing devices (e.g., the corners of pipes) are difficult to disinfect. This challenge might be overcome through the application of a positive electrical environment. However, the chemical modification of a material surface is complex and difficult. In this work, we developed a smart electroactive Tb x Dy1–x Fe alloy/poly­(vinylidene fluoride-trifluoroethylene) (TD/P­(VDF-TrFE)) magnetoelectric coating to endow stainless steel with the function of a smart adjustable electrical environment, which was realized by the introduction of a magnetic field of various intensities (0–1800 Oe). An antibacterial assay showed that the polarized coating@stainless steel (P-CS) exhibited antibacterial effects, with the highest antibacterial effect observed at 1800 Oe. Furthermore, in this study, we have, for the first time, explored the antibacterial mechanism of TD/P­(VDF-TrFE)-assisted electrical stimulation based on the bacterial intracellular reactive oxygen species (ROS) level, cell respiratory chain, and membrane potential. The results showed that a microelectric field was formed on the P-CS sample in an aqueous solution, which not only generated ROS on the cathode surface but also caused H+ consumption in the electrochemical gradient of the bacterial membrane, leading to OH– production and inhibition of adenosine triphosphate (ATP) synthesis. In addition, the electric field also induced hyperpolarization of the membrane potential in Escherichia coli cells via a K+ efflux, thus inducing rearrangement of the outer membrane. In conclusion, an adjustable surface potential was established through the introduction of magnetoelectric polymer coatings, which endowed stainless steel with magnetically controlled antibacterial effects.

Flexible, Breathable, and Self-Powered Patch Assembled of Electrospun Polymer Triboelectric Layers and Polypyrrole-Coated Electrode for Infected Chronic Wound Healing

“…coli and S. aureus membranes with surface ζ-potentials of −12.7 and −37.1 mV, respectively . When the positively charged PPY surface contacts negatively charged bacteria, the electron exchanges destroy the bacterial cell membranes and eventually kill them (Figure c) .…”

“…39 The protons released from amino acids charge the E. coli and S. aureus membranes with surface ζ-potentials of −12.7 and −37.1 mV, respectively. 40 When the positively charged PPY surface contacts negatively charged bacteria, the electron exchanges destroy the bacterial cell membranes and eventually kill them (Figure 3c). 23 SYTO 9/PI staining after incubation for 16 h visually demonstrates the bactericidal effect of different treatments (Figure 3d), consistent with the plate count results (Figure 3a,b).…”

Design and Properties of Antimicrobial Biomaterials Surfaces

“…To eliminate bacteria on stainless steel, Lai et al. [ 112 ] have prepared an electroactive Tb x Dy 1– x Fe alloy/poly(vinylidene fluoride‐trifluoroethylene) (TD/P(VDF‐TrFE)) magnetoelectric coating which is responsive to a magnetic field ( Figure a). After polarization by electric poling, the stainless steel magnetoelectric coating generates a micro‐electric field with magnetic stimulation to produce ROS and H + consumption in the electrochemical gradient of the bacterial membrane (Figure 13d).…”

“…A K + efflux is also produced by TD/P(VDF-TrFE)-assisted electrical stimulation leading to hyperpolarization of the membrane potential in E. coli, thus causing rearrangement of the outer bacterial membrane. Reproduced with permission [112]. Copyright 2022, ACS Publishing.…”

Magnetic field regulation of mouse bone marrow mesenchymal stem cell behaviours on TiO2 nanotubes via surface potential mediated by Terfenol‐D/P(VDF‐TrFE) film

“…However, direct hyperthermia and electrotherapy have certain limitations. Therefore, numerous responsive materials, for example, light [9], sound [10,11], magnetic [12], and mechanical [13], have been employed to regulate the in vivo antibacterial [14,15], antitumour [6], and osteogenesis [12,16] properties of artificial bones through in vitro stimulation. For instance, graphene and dopamine are typical materials with photothermal or photodynamic effects [17,18].…”