Combinations of Antimicrobial Polymers with Nanomaterials and Bioactives to Improve Biocidal Therapies

Abstract

The rise of antibiotic-resistant microorganisms has become a critical issue in recent years and has promoted substantial research efforts directed to the development of more effective antimicrobial therapies utilizing different bactericidal mechanisms to neutralize infectious diseases. Modern approaches employ at least two mixed bioactive agents to enhance bactericidal effects. However, the combinations of drugs may not always show a synergistic effect, and further, could also produce adverse effects or stimulate negative outcomes. Therefore, investigations providing insights into the effective utilization of combinations of biocidal agents are of great interest. Sometimes, combination therapy is needed to avoid resistance development in difficult-to-treat infections or biofilm-associated infections treated with common biocides. Thus, this contribution reviews the literature reports discussing the usage of antimicrobial polymers along with nanomaterials or other inhibitors for the development of more potent biocidal therapies.

Kinetic Investigations of Quaternization Reactions of Poly[2‐(dimethylamino)ethyl methacrylate] with Diverse Alkyl Halides

“…The obtained results revealed that lower E a 's are required to perform these quaternization reaction for halides with shorter alkyl chain lengths (i.e., E a = 54.544 kJ mol −1 for BuI, 64.997 kJ mol −1 for HeI, and 65.390 kJ mol −1 for DeI). The herein described experimental method and the obtained kinetic parameters can be used as a reference for optimizing the conditions of quaternization reactions of polymers with amino pedant groups to access cationic polymeric materials, which, either pristine or in combination with other (nano‐)compounds (e.g., nanoparticles), can be useful as novel antimicrobial or fungicidal systems [ 8,12 ] or in other biological applications (e.g., DNA/RNA delivery systems). [ 22 ] Future contributions in this direction will include the kinetic analysis and comparison of similar quaternization reactions utilizing other series of alkyl halides (e.g., alkyl bromides).…”

“…Poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) has a tertiary amine structure as pendant group, which in an acidic medium or as a quaternary ammonium salt acquires a cationic character. [ 7 ] Quaternized PDMAEMA is a versatile polymer that can be applied in antimicrobial systems, [ 8 ] such as films with porous surfaces of narrow size, [ 9 ] cationic coatings for silica nanoparticles, [ 10 ] recognition elements against bacteria, [ 11 ] tandem systems based on polymer‐nanoparticles Ca(OH) 2 ‐Mg(OH) 2 with fungicide properties, [ 12 ] or functionalized cellulose surfaces for preparation of fibers or nanocrystals. [ 13,14 ] Among different synthetic techniques, RAFT polymerization has been utilized for the synthesis of PDMAEMA, where reaction parameters such as the chemical nature of the chain transfer agent (CTA), concentration of reagents, and reaction medium have significant effects on the control of molar mass, Ð , and chemical structure of derived polymers.…”

“…The quaternization reactions were carried out at different temperatures to obtain the corresponding polymeric ammonium salts as well as the following kinetic parameters: Order of the reaction ( n ), Arrhenius pre‐exponential factor ( A ), and activation energy ( E a ). These estimated parameters can provide useful kinetic information for optimizing quaternization reactions for the preparation of well‐defined cationic PDMAEMAs, which could find interesting applications mainly in biological systems such as antimicrobial agents [ 8,12 ] or DNA/RNA delivery systems. [ 22 ]…”

Antimicrobial Polymeric Structures Assembled on Surfaces

“…These halogens can be slowly released into the environment and lead to generating ROS ( Figure 3 d) that can kill faster a broad spectrum of bacteria. In general, the biocidal activity of N-halamines can be restored using halogen-donor compounds (sodium hypochlorite/hypobromite) [ 97 ]. The mechanism of action of N-halamines has been described in two different ways: either the halogen is directly transferred to the microbial cell wall, followed by oxidation, or the dissociation into water is followed by diffusion over the bacteria.…”

“…For instance, antimicrobial polymers, such as PEG [ 114 ], PEI [ 188 ], zwitterionic PCBMA [ 189 ] or cationic poly(2-(tert-butylaminoethyl) methacrylate) (PTBAM) [ 190 ] can be utilized along with biocidal metallic NPs (Ag [ 74 ], copper/Cu [ 191 ], etc.) or carbon-based nanostructures [ 97 ] to develop highly biocidal nanocomposites ( Table 6 ). Metallic NPs are increasingly used as an alternative to antibiotics for a myriad of purposes, including antibacterial coatings for implantable devices, to prevent infections [ 41 ].…”