New Smart Antimicrobial Hydrogels, Nanomaterials, and Coatings: Earlier Action, More Specific, Better Dosing?

Abstract

To fight against antibiotic‐resistant bacteria adhering and developing on medical devices, which is a growing problem worldwide, researchers are currently developing new “smart” materials and coatings. They consist in delivery of antimicrobial agents in an intelligent way, i.e., only when bacteria are present. This requires the use of new and sophisticated tools combining antimicrobial agents with lipids or polymers, synthetic and/or natural. In this review, three classes of innovative materials are described: hydrogels, nanomaterials, and thin films. Moreover, smart antibacterial materials can be classified into two groups depending on the origin of the stimulus used: those that respond to a nonbiological stimulus (light, temperature, electric and magnetic fields) and those that respond to a biological stimulus related to the presence of bacteria, such as changes in pH or bacterial enzyme secretion. The bacteria presence can induce a pH change that constitutes a first potential biological trigger allowing the system to become active. A second biological trigger signal consists in enzymes produced by bacteria themselves. A complete panel of recent studies will be given focusing on the design of such innovative smart materials that are sensitive to biological triggers.

Surface Design for Antibacterial Materials: From Fundamentals to Advanced Strategies

“…[ 185 ] We believe that bacterial responsiveness and targeting capabilities are promising for the design of antimicrobial materials such as nanoparticles with bacterial targeting, [ 186 ] antibacterial micro–nano robots, [ 187 ] and smart hydrogel materials. [ 188 ] These antibacterial materials are promising for the treatment of clinical infections: 1) Targeting materials with bacterial‐related selectivity can largely avoid the bactericidal effects of antibacterial materials interfering with normal tissue cells. [ 186 ] Most of these targets are based on the inherent structure of bacteria, which makes it difficult for the bacteria to develop drug resistance.…”

“…[ 191 ] Moreover, the surface of micro/nanorobots can be modified with various coating to endow the robots with multifunction such as drug delivery, blood cleaning, and unique movement patterns; [ 192 ] 3) Smart hydrogels that obtain usage widely in drug carrier, tissue engineering, and wearable smart devices, are characterized with unique rich water content, 3D network structure, and various molecular designs. [ 188 ] These smart‐hydrogels can achieve specific responses to the various micro‐environment in the treatment of diabetic foot ulcers causing high amputation rates. [ 193 ] Through the functionalization design of a 3D network, the construction of multifunctional intelligent hydrogel can be realized to treat diabetic foot ulcers from many aspects such as antibacterial, wound cleaning, and insulin‐responsive release.…”

Antimicrobial Peptides and Their Applications in Biomedical Sector

“…AMPs, though capable enough to prevent various biological and medical issues, still have limited commercial applications. The release of antimicrobial molecules in the presence or absence of infections (i.e., uncontrolled release) is one of the major concerns [ 210 ]. Novel drug delivery systems include smart and intelligent mechanisms that are capable of adjusting the release rate of drugs according to the physiological conditions of the patients [ 211 ].…”

Physically Switchable Antimicrobial Surfaces and Coatings: General Concept and Recent Achievements

“…Several strategies for surface protection were developed and experimentally tested, including prevention of bacterial adhesion, killing of adhering bacteria or all surrounding bacteria as well as destroying of actually formed bacterial biofilm [12][13][14]. One simple solution proposed many years before consists in the incorporation of antimicrobial agents in the protective coating structure and achievement of protection against bacterial colonization through a gradual release of these agents or contact killing of bacteria [9,12,14].…”

“…Several strategies for surface protection were developed and experimentally tested, including prevention of bacterial adhesion, killing of adhering bacteria or all surrounding bacteria as well as destroying of actually formed bacterial biofilm [12][13][14]. One simple solution proposed many years before consists in the incorporation of antimicrobial agents in the protective coating structure and achievement of protection against bacterial colonization through a gradual release of these agents or contact killing of bacteria [9,12,14]. However, nowadays, this solution cannot be considered effective because the doped coatings lose their efficiency with time, which represents a high risk for the development of resistant bacterial strains as well as undesired environmental contamination by the released antimicrobials [15,16].…”