Antimicrobial Polymers in the Nano-World

Contact-Killing Antibacterial Polystyrene Polymerized Using a Quaternized Cationic Initiator

Contact-killing antibacterial materials are attracting attention owing to their ability for sustained antibacterial activity. However, contact-killing antibacterial polystyrene (PS) has not been extensively studied because its chemically stable structure impedes chemical modification. In this study, we developed an antibacterial PS sheet with a contact-killing surface using PS synthesized from 2,2'-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) as a radical initiator with cationic moieties. The PS sheet synthesized with ADIP (ADIP-PS) exhibited antibacterial activity in contrast to PS synthesized with other azo radical initiators. Surface ζ-potential measurements revealed that only ADIP-PS had a cationic surface, which contributed to its contact-killing antibacterial activity. The ADIP-PS sheets also exhibited antibacterial activity after washing. In contrast, PS sheets containing silver, a typical leachable antibacterial agent, lost all antibacterial activity after the same washing treatment. The antibacterial ADIP-PS sheet demonstrated strong broad-spectrum activity against both Gram-positive and Gram-negative bacteria, including drug-resistant bacteria. Cytotoxicity tests using L929 cells showed that the ADIP-PS sheets were noncytotoxic. This contact-killing antibacterial PS synthesized with ADIP thus demonstrated good prospects as an easily producible antimicrobial material.

Selected strategies to fight pathogenic bacteria

Natural products and analogues are a source of antibacterial drug discovery. Considering drug resistance levels emerging for antibiotics, identification of bacterial metalloenzymes and the synthesis of selective inhibitors are interesting for antibacterial agent development. Peptide nucleic acids are attractive antisense and antigene agents representing a novel strategy to target pathogens due to their unique mechanism of action. Antisense inhibition and development of antisense peptide nucleic acids is a new approach to antibacterial agents. Due to the increased resistance of biofilms to antibiotics, alternative therapeutic options are necessary. To develop antimicrobial strategies, optimised in vitro and in vivo models are needed. In vivo models to study biofilm-related respiratory infections, device-related infections: ventilator-associated pneumonia, tissue-related infections: chronic infection models based on alginate or agar beads, methods to battle biofilm-related infections are discussed. Drug delivery in case of antibacterials often is a serious issue therefore this review includes overview of drug delivery nanosystems.

Photodynamic Eradication of Pseudomonas aeruginosa with Ru-Photosensitizers Encapsulated in Enzyme Degradable Nanocarriers

The development of new approaches for the treatment of the increasingly antibiotic-resistant pathogen Pseudomonas aeruginosa was targeted by enhancing the effect of local antimicrobial photodynamic therapy (aPDT) using poly(ethylene glycol)-block-poly(lactic acid) (PEG114-block-PLAx) nanocarriers that were loaded with a ruthenium-based photosensitizer (PS). The action of tris(1,10-phenanthroline) ruthenium (II) bis(hexafluorophosphate) (RuPhen3) encapsulated in PEG114-block-PLAx micelles and vesicles was shown to result in an appreciable aPDT inactivation efficiency against planktonic Pseudomonas aeruginosa. In particular, the encapsulation of the PS, its release, and the efficiency of singlet oxygen (1O2) generation upon irradiation with blue light were studied spectroscopically. The antimicrobial effect was analyzed with two strains of Pseudomonas aeruginosa. Compared with PS-loaded micelles, formulations of the PS-loaded vesicles showed 10 times enhanced activity with a strong photodynamic inactivation effect of at least a 4.7 log reduction against both a Pseudomonas aeruginosa lab strain and a clinical isolate collected from the lung of a cystic fibrosis (CF) patient. This work lays the foundation for the targeted eradication of Pseudomonas aeruginosa using aPDT in various medical application areas.

Biomaterials and Encapsulation Techniques for Probiotics: Current Status and Future Prospects in Biomedical Applications

Probiotics have garnered significant attention in recent years due to their potential advantages in diverse biomedical applications, such as acting as antimicrobial agents, aiding in tissue repair, and treating diseases. These live bacteria must exist in appropriate quantities and precise locations to exert beneficial effects. However, their viability and activity can be significantly impacted by the surrounding tissue, posing a challenge to maintain their stability in the target location for an extended duration. To counter this, researchers have formulated various strategies that enhance the activity and stability of probiotics by encapsulating them within biomaterials. This approach enables site-specific release, overcoming technical impediments encountered during the processing and application of probiotics. A range of materials can be utilized for encapsulating probiotics, and several methods can be employed for this encapsulation process. This article reviews the recent advancements in probiotics encapsulated within biomaterials, examining the materials, methods, and effects of encapsulation. It also provides an overview of the hurdles faced by currently available biomaterial-based probiotic capsules and suggests potential future research directions in this field. Despite the progress achieved to date, numerous challenges persist, such as the necessity for developing efficient, reproducible encapsulation methods that maintain the viability and activity of probiotics. Furthermore, there is a need to design more robust and targeted delivery vehicles.

Dual functionalized brush copolymers as versatile antifouling coatings

Polymer coatings containing both fouling-resistant and fouling-release components have been reported to show synergistic antifouling properties. However, it remains unclear how the polymer composition influences the antifouling performance, particularly regarding foulants of different sizes and biological natures. Herein, we prepare dual functionalized brush copolymers containing fouling-resistant poly(ethylene glycol) (PEG) and fouling-release polydimethylsiloxane (PDMS) and examine their antifouling performances against different biofoulants. We utilize poly(pentafluorophenyl acrylate) (PPFPA) as a reactive precursor polymer and graft amine-functionalized PEG and PDMS side chains to create PPFPA-g-PEG-g-PDMS brush copolymers of systematically varying compositions. The copolymer films spin-coated on silicon wafers exhibit surface heterogeneity that can be correlated well with the bulk composition of the copolymer. When the copolymer-coated surfaces are examined against protein (human serum albumin and bovine serum albumin) adsorption and cell (lung cancer cells and microalgae) adhesion, they are found to perform better than the homopolymers. The enhanced antifouling properties are attributed to the copolymers having a PEG-rich top layer and a PEG/PDMS mixed bottom layer that work synergistically to resist biofoulant attachment. Furthermore, the composition of the best-performing copolymer is different for different foulants, with PPFPA-g-PEG₃₉-g-PDMS₄₆ exhibiting the best antifouling properties against proteins and PPFPA-g-PEG₅₄-g-PDMS₃₀ exhibiting the best antifouling properties against cells. We explain this difference by considering the changes in the length scale of the surface heterogeneity in relation to the foulant sizes.

Evaluation of the Antibacterial Properties of Polyvinyl Alcohol-Pullulan Scaffolds Loaded with Nepeta racemosa Lam. Essential Oil and Perspectives for Possible Applications

Essential oil of Nepeta racemosa Lam. was extracted and characterized to determine its antimicrobial activity and potential use in applications. The essential oil was loaded on polyvinyl alcohol-pullulan films and gels and characterized by optical microscopy, scanning electron microscopy, and UV-Vis spectroscopy before having its antimicrobial capacities assessed. The essential oil extracted from Nepeta racemosa Lam. was characterized using gas chromatography coupled with mass spectroscopy, which indicated that the most abundant component was nepetalic acid (55.5%), followed by eucalyptol (10.7%) and other compounds with concentrations of about 5% or less. The essential oil, as well as the loaded films and gels, exhibited good antibacterial activity on both gram-positive and gram-negative strains, with growth inhibition zones larger in some cases than for gentamicin, indicating excellent premises for using these essential-oil-loaded materials for applications in the food industry or biomedicine.

Recent advancements and perspective of ciprofloxacin-based antimicrobial polymers

In recent years, microbial pathogens, which are major sources of infections, have become a widespread concern across the world. The number of deaths caused by infectious diseases is continually rising, according to World Health Organization records. Antimicrobial resistance, particularly resistance to several drugs, is steadily growing in percentages of organisms. Ciprofloxacin is a second-generation fluoroquinolone with significant antimicrobial activity and pharmacokinetic characteristics. According to studies, many bacteria are resistant to the antibiotic ciprofloxacin. In this article, we look into polymers as ciprofloxacin macromolecular carriers with a wide range of antibacterial activity. We also discuss the latter form of coupling, in which ciprofloxacin and polymers are covalently bonded. This article also discusses the use of antimicrobial polymers in combination with ciprofloxacin in a various sectors. The current review article provides an overview of publications in the last five years on polymer loaded or modified with ciprofloxacin having applications in numerous sectors.

Hybrid suture coating for dual-staged control over antibacterial actions to match well wound healing progression

Absorbable sutures have moved to the forefront in surgical fields with a huge market. Antibacterial activity is one indispensable feature for the next generation of absorbable sutures. This study develops a simple and cost-effective coating method to endow sutures with staged control over antibacterial actions to achieve enhanced dual stages of the wound healing process. This method is achieved in aqueous solution under mild conditions without the usage of any organic solvent and reserves the fundamental properties of suture materials, based on the pH-dependent reversible self-polymerization of tannic acid (TA) together with the strong adhesion of poly (tannic acid) (PTA) not only toward the suture surface but also with TA. Just by changing pH of TA solution, a hybrid coating (MPTA) composed of PTA and TA could be readily formed on the commercialized sutures originating from synthetic and natural materials. In the initial post-surgery stage, wound sites are susceptible to aseptic and/or bacterial inflammation. The resulting acid conditions induce burst release of antibacterial TA mostly coming from the adsorbed TA monomer. In the later stage, TA release is tailored totally depending on the pH conditions determined by the healing degree of wounds, allowing the sustained antibacterial prevention in a biologically adjustable manner. Thus, antibacterial MPTA coating meets the rigid requirements that differ distinctly during two major wound healing stages. Nontoxic MPTA coating on sutures leads to excellent post-implantation outcomes regarding bacterial prevention/elimination, anti-inflammation, tissue repair and wound healing. Moreover, MPTA coating provides sutures with a robust platform for functional expansion due to the matrix-independent adhesive ability of PTA.

Valuation of rice straw residues: Production of silylated methylcellulose containing propylamine and propylethylenediamine for use as anticorrosion and antibacterial

Green technology is a scientific movement seeking to eliminate industrial chemicals and replace them with natural products by valorizing natural resources or biological waste. In this work, we present the extraction of cellulose from rice straw and chemically modified water-dispersible cellulose (methylcellulose) by performing a methylation process. The methylcellulose is chemically bonded to N-[3-(trimethoxysilyl)propyl]ethylenediamine, and (3-aminopropyl)triethoxysilane compounds to produce a cellulose-organosilane hybrid. The prepared compounds were studied with appropriate techniques such as ¹H NMR, XRD, FTIR, TGA, Raman spectroscopy, FE-SEM, and AFM. The prepared materials were used as corrosion inhibitors of steel in 1 N H₂SO₄ for studies of potentiodynamic polarization measurements and electrochemical impedance spectroscopy. The materials were also studied as antibacterial agents. The results indicate the successful use of a modified extracted cellulose hybrid in the corrosion field and as an antibacterial agent. Quantum chemical assessments based on density functional theory (DFT) of the trimethoxysilyl propylamine and dimethoxymethylsilyl propylethylenediamine grafted methylcellulose were calculated. The results obtained showed the agreement of the theoretical data with the experimental data.

Addressing a future pandemic: how can non-biological complex drugs prepare us for antimicrobial resistance threats?

Loss of effective antibiotics through antimicrobial resistance (AMR) is one of the greatest threats to human health. By 2050, the annual death rate resulting from AMR infections is predicted to have climbed from 1.27 million per annum in 2019, up to 10 million per annum. It is therefore imperative to preserve the effectiveness of both existing and future antibiotics, such that they continue to save lives. One way to conserve the use of existing antibiotics and build further contingency against resistant strains is to develop alternatives. Non-biological complex drugs (NBCDs) are an emerging class of therapeutics that show multi-mechanistic antimicrobial activity and hold great promise as next generation antimicrobial agents. We critically outline the focal advancements for each key material class, including antimicrobial polymer materials, carbon nanomaterials, and inorganic nanomaterials, and highlight the potential for the development of antimicrobial resistance against each class. Finally, we outline remaining challenges for their clinical translation, including the need for specific regulatory pathways to be established in order to allow for more efficient clinical approval and adoption of these new technologies.

Metal-Organic Frameworks in Agriculture

Agrochemicals, which are crucial to meet the world food qualitative and quantitative demand, are compounds used to kill pests (insects, fungi, rodents, or unwanted plants). Regrettably, there are some important issues associated with their widespread and extensive use (e.g., contamination, bioaccumulation, and development of pest resistance); thus, a reduced and more controlled use of agrochemicals and thorough detection in food, water, soil, and fields are necessary. In this regard, the development of new functional materials for the efficient application, detection, and removal of agrochemicals is a priority. Metal-organic frameworks (MOFs) with exceptional sorptive, recognition capabilities, and catalytical properties have very recently shown their potential in agriculture. This Review emphasizes the recent advances in the use of MOFs in agriculture through three main views: environmental remediation, controlled agrochemical release, and detection of agrochemicals.

Antimicrobial Properties of the Triclosan-Loaded Polymeric Composite Based on Unsaturated Polyester Resin: Synthesis, Characterization and Activity

The manufacturing of sanitary and household furniture on a large scale with inherently antimicrobial properties is an essential field of research. This work focuses on the synthesis of polymer composites based on the unsaturated polyester of resin loaded with 5 wt.%-Triclosan produced by a co-mixing approach on automated technological complex with a potential for broad applications. According to findings, the polymer composite has a non-porous structure (surface area < 1.97 m²/g) suitable for sanitary applications to reduce the growth of bacteria. The chemical composition confirmed the presence of major elements, and the inclusion of Triclosan was quantitatively confirmed by the appearance of chlorine on XRF (1.67 wt.%) and EDS (1.62 wt.%) analysis. Thermal analysis showed the difference of 5 wt.% in weight loss, which confirms the loading of Triclosan into the polymer matrix. The polymer composite completely inhibited the strains of S. aureus 6538-P, S. aureus 39, S. epidermidis 12228, and Kl. Pneumoniae 10031 after 5-min contact time. The antimicrobial effects against Kl. pneumoniae 700603, Ps. aeruginosa 9027 and Ps. aeruginosa TA2 strains were 92.7%, 85.8% and 18.4%, respectively. The inhibition activity against C. albicans 10231 and C. albicans 2091 was 1.6% and 82.4%, respectively; while the clinical strain of C. albicans was inhibited by 92.2%. The polymer composite loaded with 5 wt.%-Triclosan displayed a stability over the period that illustrates the possibility of washing the composite surface.

Material Extrusion-Based Additive Manufacturing of Poly(Lactic Acid) Antibacterial Filaments-A Case Study of Antimicrobial Properties

In the era of the coronavirus pandemic, one of the most demanding areas was the supply of healthcare systems in essential Personal Protection Equipment (PPE), including face-shields and hands-free door openers. This need, impossible to fill by traditional manufacturing methods, was met by implementing of such emerging technologies as additive manufacturing (AM/3D printing). In this article, Poly(lactic acid) (PLA) filaments for Fused filament fabrication (FFF) technology in the context of the antibacterial properties of finished products were analyzed. The methodology included 2D radiography and scanning electron microscopy (SEM) analysis to determine the presence of antimicrobial additives in the material and their impact on such hospital pathogens as Staphylococcus aureus, Pseudomonas aeruginosa, and Clostridium difficile. The results show that not all tested materials displayed the expected antimicrobial properties after processing in FFF technology. The results showed that in the case of specific species of bacteria, the FFF samples, produced using the declared antibacterial materials, may even stimulate the microbial growth. The novelty of the results relies on methodological approach exceeding scope of ISO 22196 standard and is based on tests with three different species of bacteria in two types of media simulating common body fluids that can be found on frequently touched, nosocomial surfaces. The data presented in this article is of pivotal meaning taking under consideration the increasing interest in application of such products in the clinical setting.

Challenges and solutions in polymer drug delivery for bacterial biofilm treatment: A tissue-by-tissue account

To tackle the emerging antibiotic resistance crisis, novel antimicrobial approaches are urgently needed. Bacterial communities (biofilms) are a particular concern in this context. Biofilms are responsible for most human infections and are inherently less susceptible to antibiotic treatments. Biofilms have been linked with several challenging chronic diseases, including implant-associated osteomyelitis and chronic wounds. The specific local environments present in the infected tissues further contribute to the rise in antibiotic resistance by limiting the efficacy of systemic antibiotic therapies and reducing drug concentrations at the infection site, which can lead to reoccurring infections. To overcome the shortcomings of systemic drug delivery, encapsulation within polymeric carriers has been shown to enhance antimicrobial efficacy, permeation and retention at the infection site. In this Review, we present an overview of current strategies for antimicrobial encapsulation within polymeric carriers, comparing challenges and solutions on a tissue-by-tissue basis. We compare challenges and proposed drug delivery solutions from the perspective of the local environments for biofilms found in oral, wound, gastric, urinary tract, bone, pulmonary, vaginal, ocular and middle/inner ear tissues. We will also discuss future challenges and barriers to clinical translation for these therapeutics. The following Review demonstrates there is a significant imbalance between the research focus being placed on different tissue types, with some targets (oral and wound biofims) being extensively more studied than others (vaginal and otitis media biofilms and endocarditis). Furthermore, the importance of the local tissue environment when selecting target therapies is demonstrated, with some materials being optimal choices for certain sites of bacterial infection, while having limited applicability in others.

Ionic liquid-based antimicrobial materials for water treatment, air filtration, food packaging and anticorrosion coatings

Efforts to widen the scope of ionic liquids applications across diverse research areas have flourished in the last two decades with developments in understanding and tailoring their physical, chemical, and biological properties. The promising applications of ionic liquids-based materials as antimicrobial systems is due to their ability and flexibility to be tailored in varying sizes, morphologies, and surface charges. Ionic liquids are also considered as greener materials. Common methods for the preparation of ionic liquid-based materials include crosslinking, loading, grafting, and combination of ionic liquids with other polymeric materials. Recent research focuses on the tuning of the biological properties to design novel ionic liquids-based antimicrobial materials. Here, the properties, synthesis and applications of ionic liquids and ionic liquids-based materials are reviewed with focus on antimicrobial activities applied to water treatment, air filtration, food packaging, and anticorrosion.

Engineered topographies and hydrodynamics in relation to biofouling control-a review

Biofouling, the unwanted growth of microorganisms on submerged surfaces, has appeared as a significant impediment for underwater structures, water vessels, and medical devices. For fixing the biofouling issue, modification of the submerged surface is being experimented as a non-toxic approach worldwide. This technique necessitated altering the surface topography and roughness and developing a surface with a nano- to micro-structured pattern. The main objective of this study is to review the recent advancements in surface modification and hydrodynamic analysis concerning biofouling control. This study described the occurrence of the biofouling process, techniques suitable for biofouling control, and current state of research advancements comprehensively. Different biofilms under various hydrodynamic conditions have also been outlined in this study. Scenarios of biomimetic surfaces and underwater super-hydrophobicity, locomotion of microorganisms, nano- and micro-hydrodynamics on various surfaces around microorganisms, and material stiffness were explained thoroughly. The review also documented the approaches to inhibit the initial settlement of microorganisms and prolong the subsequent biofilm formation process for patterned surfaces. Though it is well documented that biofouling can be controlled to various degrees with different nano- and micro-structured patterned surfaces, the understanding of the underlying mechanism is still imprecise. Therefore, this review strived to present the possibilities of implementing the patterned surfaces as a physical deterrent against the settlement of fouling organisms and developing an active microfluidic environment to inhibit the initial bacterial settlement process. In general, microtopography equivalent to that of bacterial cells influences attachment via hydrodynamics, topography-induced cell placement, and air-entrapment, whereas nanotopography influences physicochemical forces through macromolecular conditioning.

Approaches for the inhibition and elimination of microbial biofilms using macromolecular agents

Biofilms are complex three-dimensional structures formed at interfaces by the vast majority of bacteria and fungi. These robust communities have an important detrimental impact on a wide range of industries and other facets of our daily lives, yet their removal is challenging owing to the high tolerance of biofilms towards conventional antimicrobial agents. This key issue has driven an urgent search for new innovative antibiofilm materials. Amongst these emerging approaches are highly promising materials that employ aqueous-soluble macromolecules, including peptides, proteins, synthetic polymers, and nanomaterials thereof, which exhibit a range of functionalities that can inhibit biofilm formation or detach and destroy organisms residing within established biofilms. In this Review, we outline the progress made in inhibiting and removing biofilms using macromolecular approaches, including a spotlight on cutting-edge materials that respond to environmental stimuli for "on-demand" antibiofilm activity, as well as synergistic multi-action antibiofilm materials. We also highlight materials that imitate and harness naturally derived species to achieve new and improved biomimetic and biohybrid antibiofilm materials. Finally, we share some speculative insights into possible future directions for this exciting and highly significant field of research.

Recent Advances in the Development of Antimicrobial and Antifouling Biocompatible Materials for Dental Applications

The risk of secondary bacterial infections resulting from dental procedures has driven the design of antimicrobial and antifouling dental materials to curb pathogenic microbial growth, biofilm formation and subsequent oral and dental diseases. Studies have investigated approaches based primarily on contact-killing or release-killing materials. These materials are designed for addition into dental resins, adhesives and fillings or as immobilized coatings on tooth surfaces, titanium implants and dental prosthetics. This review discusses the recent developments in the different classes of biomaterials for antimicrobial and antifouling dental applications: polymeric drug-releasing materials, polymeric and metallic nanoparticles, polymeric biocides and antimicrobial peptides. With modifications to improve cytotoxicity and mechanical properties, contact-killing and anti-adhesion materials show potential for incorporation into dental materials for long-term clinical use as opposed to short-lived antimicrobial release-based coatings. However, extended durations of biocompatibility testing, and adjustment of essential biomaterial features to enhance material longevity in the oral cavity require further investigations to confirm suitability and safety of these materials in the clinical setting. The continuous exposure of dental restorative and regenerative materials to pathogenic microbes necessitates the implementation of antimicrobial and antifouling materials to either replace antibiotics or improve its rational use, especially in the day and age of the ever-increasing problem of antimicrobial resistance.

Engineering and polymeric composition of drug-eluting suture: A review

Sutures are the most popular surgical implants in the global surgical equipment market. They are used for holding tissues together to achieve wound closure. However, controlling the body's immune response to these "foreign bodies" at site of infection is challenging. Natural polymers such as collagen, silk, nylon, and cotton, and synthetic polymers such as polycaprolactone, poly(lactic-co-glycolic acid), poly(p-dioxanone) and so forth, contribute the robust foundation for the engineering of drug-eluting sutures. The incorporation of active pharmaceutical ingredients (APIs) with polymeric composition of suture materials is an efficient way to reduce inflammatory reaction in the wound site as well as to control bacterial growth, while allowing wound healing. The incorporation of polymeric composition in surgical sutures has been found to add high flexibility as well as excellent physical and mechanical properties. Fabrication processes and polymer materials allow control over drug-eluting profiles to effectively address wound healing requirements. This review outlines and discusses (a) polymer materials and APIs used in suture applications, including absorbable and nonabsorbable sutures; (b) suture structures, such as monofilament, multifilament, barded and smart sutures; and (c) the existing manufacturing techniques for drug-eluting suture production, including electrospinning, melt-extrusion and coating.

Influence of replacing oregano essential oil by ground oregano leaves on chitosan/alginate-based dressings properties

Biopolymers, as chitosan and alginate, have gained prominence in the biomedical area, mainly for application in wound dressings, as partial replacements for synthetic polymers. The present work aimed to compare the influence of the antimicrobial agent incorporation form on the properties of films prepared by casting. The chitosan/alginate-based films were manufactured containing oregano essential oil (OEO) or ground oregano leaves (OR). The OEO was chosen due to its excellent pharmacological properties, and the substitution by OR can represent an advantageous alternative for minimizing the final cost of the product, by removing the oil extraction step. The films, with different amounts of OEO and OR, were characterized in terms of their morphological, physicochemical, mechanical and antimicrobial properties. The films had properties according to desirable for wound dressing application: water vapor flux less than 35 g m^-2 h^-1, moderate liquid absorption capacity, and similar mechanical properties to human skin. All developed films showed antimicrobial activity against the bacteria Escherichia coli and Staphylococcus aureus. Formulations containing OEO presented the largest inhibition zones, although OR showed high potential for the proposed use. These results suggest that films developed, with both OEO and ground oregano leaves, are promising for use as dressings.

Synthesis and antimicrobial activities of chitosan/polypropylene carbonate-based nanoparticles

Antibiotic resistance is an emerging threat to public health. The development of a new generation of antimicrobial compounds is therefore currently required. Here we report a novel antimicrobial polymer of chitosan/polypropylene carbonate nanoparticles (CS/PPC NPs). These were designed and synthesized from readily available chitosan and a reactive oligomer polypropylene carbonate (PPC)-derived epoxy intermediate. By employing a simple and efficient functionalized strategy, a series of micelle-like chitosan-graft-polypropylene carbonate (CS-g-PPC) polymers and chitosan-polypropylene carbonate (CS-PPC) microgels were prepared by reacting mono-/bis-epoxy capped PPC with chitosan. The chemical structure, particle size, and surface charge of the newly synthesized polymers were characterized by infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, dynamic light scattering (DLS), and zeta potential measurements. The antimicrobial activities of these nanoparticles were determined in both Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). Minimum inhibitory concentration (MIC), the nanoparticle concentration needed to completely inhibit the bacterial growth, was found at 128 μg mL-1 to 1024 μg mL-1, strongly depending both on the nature of the epoxy-imine network formed from the functional groups (mono- or bis-capped epoxy groups reacting with amine groups) and the feed ratio of the functional groups (-epoxy/-NH2) between the functionalized PPC and chitosan. No hemolysis was observed at concentrations well in excess of the effective bacteria-inhibiting concentrations. These findings provide a novel strategy to fabricate a new type of nanoantibiotic for antimicrobial applications.

Incorporation of Poly(Itaconic Acid) with Quaternized Thiazole Groups on Gelatin-Based Films for Antimicrobial-Active Food Packaging

Poly(itaconic acid) (PIA) was synthesized via conventional radical polymerization. Then, functionalization of PIA was carried out by an esterification reaction with the heterocyclic groups of 1,3-thiazole and posterior quaternization by N-alkylation reaction with iodomethane. The modifications were confirmed by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H-NMR), as well as ζ-potential measurements. Their antimicrobial activity was tested against different Gram-negative and Gram-positive bacteria. After characterization, the resulting polymers were incorporated into gelatin with oxidized starch and glycerol as film adjuvants, and dopamine as crosslinking agent, to develop antimicrobial-active films. The addition of quaternized polymers not only improved the mechanical properties of gelatin formulations, but also decreased the solution absorption capacity during the swelling process. However, the incorporation of synthesized polymers increased the deformation at break values and the water vapor permeability of films. The antioxidant capacity of films was confirmed by radical scavenging ability and, additionally, those films exhibited antimicrobial activity. Therefore, these films can be considered as good candidates for active packaging, ensuring a constant concentration of the active compound on the surface of the food, increasing products' shelf-life and reducing the environmental impact generated by plastics of petrochemical origin.

Regulatory developments and their impacts to the nano-industry: A case study for nano-additives in 3D printing

Nanotechnology has increasing applications in numerous markets, particularly in additive processing (3D printing) and manufacturing, which is important for consumer products, medical devices, construction, and general research and development across many other industries. Nanomaterials are desirable in many products due to their unique properties, but those same properties have made evaluating the risk and regulation of these materials challenging. For risk-based regulations, new applications and nanomaterials should be assessed for both human and environmental hazards and exposure to ensure protection. In general, many risk assessments to date have focused on the non-nano versions of chemicals. The lack of guidance on assessing the hazard and exposure of nanomaterials in 3D printing is apparent, and these areas of assessment are actively being evaluated. Industry in most cases will now need to provide specific additional information for assessing the risk of nanomaterials in 3D printing. This review paper focuses on the use of nanomaterials in 3D printing for industrial and manufacturing applications, summarizes the current literature on human health and safety related to 3D printing and inhalation exposure, and the regulations relating to 3D printing in the U.S., Canada, and Europe for this industry.

Addressing Antimicrobial Resistance Through Nanoantibiotics

In recent years, the irrational use of antibiotics has escalated the evolution of multidrug-resistant (MDR) bacterial strains. The infectious diseases caused by these MDR bacterial strains remain a major threat to human health and have emerged as the leading cause of morbidity and mortality. The WHO and CDC have expressed serious concern regarding the continued increase in the development of multidrug resistance among bacteria. The antimicrobial resistance (AMR) poses a severe global threat of growing concern to human health and economic burden. Bacteria have developed the ability to resist antimicrobials by altering target site/enzyme, inactivation of the enzyme, decreasing cell permeability, increasing efflux due to over-expression of efflux pumps, target protection, target overproduction, and many other ways. The shortage of new antimicrobials and rapid rise in antibiotic resistance demands pressing need to develop alternate antibacterial agents.

Dendrimers against fungi - A state of the art review

Fungal based diseases currently affect nearly a quarter of the population around the world, which diseases are usually limited to superficial infections. Perversely, along with the development of modern medicine, cases of life-threatening systemic fungi are more and more often encountered. Compared to antibacterial drugs, significantly fewer fungicides are tested and introduced to clinical practice. At the same time, the drug resistance of pathological fungi is constantly growing. In addition to obtaining new derivatives of already-established classes of drugs, such as azoles, there is a growing interest in new compounds with potentially new mechanisms and application possibilities. Polymers are included in the flow of these studies, and among them - dendrimers. Dendrimers are a special type of polymers with a strictly defined structure and a plethora of functionalization possibilities. This allows them to not only be used as effective antifungal drug carriers but also enables them to exhibit antifungal activity per se. In this review, we have introduced to the epidemiology of fungal infections and summarized the aspects related to their control and therapy. Various polymers and dendrimers with antifungal activity were presented. In the subsequent sections antifungal acting dendrimers were discussed within three subchapters, based on their chemical structure: (i) amino acid-based dendrimers, (ii) amino based dendrimers, and (iii) other, which do not share similarities in structure. We have gathered and summarized the reports regarding the direct action of dendrimers on infectious fungi, as well as their effect when used as solubilizers, carriers or adjuvants with currently used antifungals. Use of dendrimers for the sensing of fungi or their metabolites are also considered. Special attention was also paid to the applications of dendrimers together with photosensitizers in antimicrobial photodynamic therapy.

Zingiber zerumbet L. essential oil-based chitosan nanoemulsion as an efficient green preservative against fungi and aflatoxin B1 contamination

The present study envisages the potential application of chitosan-coated Zingiber zerumbet essential oil nanoemulsion (ZEO-CsNE) as green antimicrobial preservative against Aspergillus flavus, aflatoxin B₁ (AFB₁ ), and lipid peroxidation of stored functional foods. GC-MS analysis of ZEO exhibited the abundance of cis-geraniol (15.53%) as the major component. ZEO-CsNE showed biphasic release profile during in vitro release study conducted for 10 days. The ZEO-CsNE inhibited the growth of A. flavus (strain AF-LHP-SH1) and AFB₁ production at 1.0 and 0.8 µL/mL, respectively. Interestingly, considerable reduction in ergosterol biosynthesis followed by enhanced leakage of vital cellular contents and methylglyoxal inhibition represents novel antifungal and antiaflatoxigenic mechanism of action, respectively. Further, ZEO-CsNE inhibited lipid peroxidation and AFB₁ production in postharvest Salvia hispanica seeds during in situ trial and presented favorable safety profile (median lethal dose [LD₅₀ ] = 29,114 µL/kg) for male mice. Based on overall observations, ZEO-CsNE could be recommended as a green antimicrobial substitute of synthetic preservatives for in vitro and in situ protection of functional food samples. PRACTICAL APPLICATION: Food industries are facing enormous amount of burden coming from fungal and aflatoxin contamination that can cause severe adverse effects to humans. Essential oils (EOs) are well known for their food preservative efficacy; however, some limitations such as oxidative instability in open system may limit their application directly into food system. The encapsulation of the EOs into polymeric matrix could provide a barrier that will protect the EOs from degradation. This research could provide a basis for utilization of EO after encapsulation into chitosan nanoemulsion for industrial-scale application for preservation of stored functional foods from fungal and aflatoxin contamination.

Chemical Hydrogels Bearing Thiazolium Groups with a Broad Spectrum of Antimicrobial Behavior

Several hydrogels based on 2-hydroxyethyl methacrylate and a methacrylic monomer containing a thiazole group in its lateral chain have been prepared by thermal polymerization at 60 °C in water solution varying the chemical composition of the gels. The posterior quaternization of the thiazole groups with methyl iodine has rendered positively charged hydrogels with potential antimicrobial activity. This modification has been structurally characterized by infrared spectroscopy, whereas the thermal stability of all hydrogels has been studied by thermal degradation in inert atmosphere. The swelling behavior in distilled water and the rheology of the different hydrogels have been analyzed as a function of 2-(4-methylthiazol-5-yl)ethyl methacrylate (MTA) monomer content as well as its methylation. Finally, the active character of hydrogels against Gram-positive and Gram-negative bacteria and fungi has been evaluated, revealing excellent antimicrobial activity against all tested microorganisms. The methylated hydrogels could be used as potential materials for wound healing or contact lens applications.

Vitamin E as promising adjunct treatment option in the combat of infectious diseases caused by bacterial including multi-drug resistant pathogens - Results from a comprehensive literature survey

The use of antibiotics has provoked an emergence of various multidrug-resistant (MDR) bacteria. Infectious diseases that cannot be treated sufficiently with conventional antibiotic intervention strategies anymore constitue serious threats to human health. Therefore, current research focus has shifted to alternative, antibiotic-independent therapeutic approaches. In this context, vitamin E constitutes a promising candidate molecule due to its multi-faceted modes of action. Therefore, we used the PubMed database to perform a comprehensive literature survey reviewing studies addressing the antimicrobial properties of vitamin E against bacterial pathogens including MDR bacteria. The included studies published between 2010 and 2020 revealed that given its potent synergistic antimicrobial effects in combination with distinct antibiotic compounds, vitamin E constitutes a promising adjunct antibiotic treatment option directed against infectious diseases caused by MDR bacteria such as Pseudomonas aeruginosa, Burkholderia cenocepacia and methicillin-resistant Staphylococcus aureus (MRSA). In conclusion, the therapeutic value of vitamin E for the treatment of bacterial infections should therefore be investigated in future clinical studies.

Biomaterials against Bone Infection

Chronic bone infection is considered as one of the most problematic biofilm-related infections. Its recurrent and resistant nature, high morbidity, prolonged hospitalization, and costly medical care expenses have driven the efforts of the scientific community to develop new therapies to improve the standards used today. There is great debate on the management of this kind of infection in order to establish consistent and agreed guidelines in national health systems. The scientific research is oriented toward the design of anti-infective biomaterials both for prevention and cure. The properties of these materials must be adapted to achieve better anti-infective performance and good compatibility, which allow a good integration of the implant with the surrounding tissue. The objective of this review is to study in-depth the antibacterial biomaterials and the strategies underlying them. In this sense, this manuscript focuses on antimicrobial coatings, including the new technological advances on surface modification; scaffolding design including multifunctional scaffolds with both antimicrobial and bone regeneration properties; and nanocarriers based on mesoporous silica nanoparticles with advanced properties (targeting and stimuli-response capabilities).

Wearable and Flexible Ozone Generating System for Treatment of Infected Dermal Wounds

Wound-associated infections are a significant and rising health concern throughout the world owing to aging population, prevalence of diabetes, and obesity. In addition, the rapid increase of life-threatening antibiotic resistant infections has resulted in challenging wound complications with limited choices of effective therapeutics. Recently, topical ozone therapy has shown to be a promising alternative approach for treatment of non-healing and infected wounds by providing strong antibacterial properties while stimulating the local tissue repair and regeneration. However, utilization of ozone as a treatment for infected wounds has been challenging thus far due to the need for large equipment usable only in contained, clinical settings. This work reports on the development of a portable topical ozone therapy system comprised of a flexible and disposable semipermeable dressing connected to a portable and reusable ozone-generating unit via a flexible tube. The dressing consists of a multilayered structure with gradient porosities to achieve uniform ozone distribution. The effective bactericidal properties of the ozone delivery platform were confirmed with two of the most commonly pathogenic bacteria found in wound infections, Pseudomonas aeruginosa and Staphylococcus epidermidis. Furthermore, cytotoxicity tests with human fibroblasts cells indicated no adverse effects on human cells.

Film Properties and Antimicrobial Efficacy of Quaternized PDMAEMA Brushes: Short vs Long Alkyl Chain Length

Quaternized poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes bearing quaternary ammonium groups of different alkyl chain lengths (ACLs) were prepared and assessed as biocidal coatings. For the synthesis of the antimicrobial brushes, first well-defined PDMAEMA chains were grown by surface-initiated atom transfer radical polymerization on glass and silicon substrates. Next, the tertiary amine groups of the polymer brushes were modified via a quaternization reaction, using alkyl halides, to obtain the cationic polymers. The polymer films were characterized by Fourier-transform infrared spectroscopy, ellipsometry, atomic force microscopy, and water contact angle measurements. The effect of the ACL of the quaternary ammonium groups on the physicochemical properties of the films as well as the contact killing efficiency of the surfaces against representative Gram-positive and Gram-negative bacteria was investigated. A hydrophilic to hydrophobic transition of the surfaces and a significant decrease of the degree of quaternization of the DMAEMA moieties was found upon increasing the ACL of the quaternization agent above six carbon atoms, allowing the wettability, the thickness, and the pH-response of the brushes to be tuned via a facile postpolymerization, quaternization reaction. At the same time, antimicrobial tests revealed that the hydrophilic polymer brushes exhibited enhanced bactericidal activity against Escherichia coli and Bacillus cereus, whereas the hydrophobic surfaces showed a significant deterioration of the in vitro bactericidal performance. Our results elucidate the antimicrobial action of quaternized polymer brushes, dictating the appropriate choice of the ACL of the quaternization agent for the development of coatings that effectively inhibit biofilm formation on surfaces.

Ag NPs-Assisted Synthesis of Stable Cu NPs on PET Fabrics for Antibacterial and Electromagnetic Shielding Performance

In this study, Cu/Ag/polydopamine (PDA)/polyester (PET) fabrics were fabricated for multi-functional textiles. The PET fabrics were firstly modified by dopamine to form a polydopamine (PDA) layer on the fiber surface, then Ag nanoparticles (Ag NPs) were anchored on fiber surface through chelation between PDA and Ag+ ions, and the Ag NPs were further used as catalytic seeds for in situ reduction of Cu nanoparticles (Cu NPs). The surface morphology, chemistry, and crystalline structure of the prepared PET fabrics were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). As expected, Cu NPs were evenly dispersed on the surface of fibers. The Cu/Ag/PDA/PET fabrics showed good antibacterial property against Escherichia coli and exhibited excellent electromagnetic interference (EMI) shielding ability. The Cu/Ag/PDA/PET fabrics with high performance antibacterial and EMI shielding properties can be applied as functional protective textiles.

Citrus Essential Oils (CEOs) and Their Applications in Food: An Overview

Citrus is a genus belonging to the Rutaceae family and includes important crops like orange, lemons, pummelos, grapefruits, limes, etc. Citrus essential oils (CEOs) consist of some major biologically active compounds like α-/β-pinene, sabinene, β-myrcene, d-limonene, linalool, α-humulene, and α-terpineol belonging to the monoterpenes, monoterpene aldehyde/alcohol, and sesquiterpenes group, respectively. These compounds possess several health beneficial properties like antioxidant, anti-inflammatory, anticancer, etc., in addition to antimicrobial properties, which have immense potential for food applications. Therefore, this review focused on the extraction, purification, and detection methods of CEOs along with their applications for food safety, packaging, and preservation. Further, the concerns of optimum dose and safe limits, their interaction effects with various food matrices and packaging materials, and possible allergic reactions associated with the use of CEOs in food applications were briefly discussed, which needs to be addressed in future research along with efficient, affordable, and "green" extraction methods to ensure CEOs as an ecofriendly, cost-effective, and natural alternative to synthetic chemical preservatives.

Preparation and Characterization of Silver(I) Ethylcellulose Thin Films as Potential Food Packaging Materials

Ag(I)-containing ethylcellulose (EC) films suitable as antbacterial packaging materials have been prepared and fully characterized. Different preparation methods, including the use of green casting solvents, are proposed. The Ag(I) acylpyrazolonato complexes, [Ag(Q^py,CF3 )(L)], L=benzylimidazole (Bzim) and L=ethylimidazole (EtimH), used as active additives, display different modes of interactions with EC, depending on their structural features. A thorough investigation of the EC liquid-crystalline lyotropic phase and its changes with the introduction of silver additives, has been conducted, revealing either the inclusion of complex molecules into the inner structure of the EC matrix or their dispersion on its surface. Moreover, the bactericidal activity of the prepared Ag(I) films seems to be related to the interaction between silver additives and the polymeric EC matrix. Indeed, the EC-2b films show a particularly good performance even with a low silver content, with a relative bacterial killing of about 100 %. Tests for Ag(I) migration have been performed by using three food stimulants under two assay conditions. Low values of silver release are recorded, particularly at low concentration of silver content, in the case of all new prepared Ag(I) films.

Antimicrobial Honey-Inspired Glucose-Responsive Nanoreactors by Polymerization-Induced Self-Assembly

The rise of antimicrobial resistance is at the forefront of global healthcare challenges, with antimicrobial infections on track to overtake cancer as a leading cause of death by 2050. The high effectiveness of antimicrobial enzymes used in combination with the protective, inert nature of polymer materials represents a highly novel approach toward tackling microbial infections. Herein, we have developed biohybrid glucose oxidase-loaded semipermeable polymersome nanoreactors, formed using polymerization-induced self-assembly, and demonstrate for the first time their ability to "switch on" their antimicrobial activity in response to glucose, a ubiquitous environmental stimulus. Using colony-counting assays, it was demonstrated that the nanoreactors facilitate up to a seven-log reduction in bacterial growth at high glucose concentrations against a range of Gram-negative and Gram-positive bacterial pathogens, including a methicillin-resistant Staphylococcus aureus clinical isolate. After demonstrating the antimicrobial properties of these materials, their toxicity against human fibroblasts was assessed and the dosage of the nanoreactors further optimized for use as nontoxic agents against Gram-positive bacteria under physiological blood glucose concentrations. It is envisaged that such biohybrid nanomaterials will become an important new class of antimicrobial biomaterials for the treatment of bacterial infections.

In Situ Measurement of Thermodynamic Partitioning in Open Hydrogels

Thermodynamic partitioning dictates solute loading and release from a hydrogel. Design of drug delivery vehicles, cell and tissue matrices, and immunoassay scaffolds that utilize hydrogel materials is informed by an understanding of the thermodynamic partitioning properties of those hydrogels. We develop aberration-compensated laser scanning confocal microscopy (AC-LSCM), a technique that can be applied to all fluorescence microscopy-based equilibrium partition coefficient measurements where the fluorescence is uniformly distributed in the reference material (e.g., many solutes in thermodynamic equilibrium). In this paper, we use AC-LSCM to measure spatially resolved in situ equilibrium partition coefficients of various fluorescently labeled solutes in single-layer and multilayer open hydrogels. In considering a dynamic material, we scrutinize solute interactions with a UV photoactive polyacrylamide gel that incorporates a benzophenone methacrylamide backbone. We observed strong agreement with an adjusted version of Ogston's ideal size-exclusion model for spatially resolved in situ equilibrium partition coefficients across a wide range of polyacrylamide hydrogel densities (R2 = 0.98). Partition coefficients of solutes differing in hydrodynamic radius were consistent with size-based theory in the photoactive hydrogels, but exceed those in unmodified polyacrylamide gels. This observation suggests a deviation from the size-exclusion model and a shift in the thermodynamic equilibrium state of the solutes toward the gel phase. AC-LSCM also resolves differential partitioning behavior of the model solute in two-layer gels, providing insight into the transport phenomena governing the partitioning in multilaminate gel structures. Furthermore, AC-LSCM identifies and quantifies depth-dependent axial aberrations that could confound quantitation, highlighting the need for the "aberration compensated" aspect of AC-LSCM.

Cytotoxicity, Antioxidant, Antibacterial, and Photocatalytic Activities of ZnO-CdS Powders

In this work, ZnO–CdS composite powders synthesized by a simple chemical precipitation method were thoroughly characterized. The morphological, structural, compositional, photocatalytical, and biological properties of the prepared composites were investigated in comparison with those of the pristine components and correlated with the CdS concentration. ZnO–CdS composites contain flower-like structures, their size being tuned by the CdS amount added during the chemical synthesis. The photocatalytic activity of the composites was analyzed under UV irradiation using powders impregnated with methylene blue; the tests confirming that the presence of CdS along the ZnO in composites can improve the dye discoloration. The biological properties such as antioxidant capacity, antibacterial activity, and cytotoxicity of the ZnO, CdS, and ZnO–CdS composites were evaluated. Thus, the obtained composites presented medium antioxidant effect, biocidal activity against Escherichia coli, and no toxicity (at concentrations less than 0.05 mg/mL for composites with a low CdS amount) for human fibroblast cells. Based on these results, such composites can be used as photocatalytic and/or biocidal additives for photoactive coatings, paints, or epoxy floors, which in their turn can provide a cleaner and healthier environment.

Multifunctional PLA Blends Containing Chitosan Mediated Silver Nanoparticles: Thermal, Mechanical, Antibacterial, and Degradation Properties

Poly(lactic acid) (PLA) is one of the most commonly employed synthetic biopolymers for facing plastic waste problems. Despite its numerous strengths, its inherent brittleness, low toughness, and thermal stability, as well as a relatively slow crystallization rate represent some limiting properties when packaging is its final intended application. In the present work, silver nanoparticles obtained from a facile and green synthesis method, mediated with chitosan as a reducing and stabilizing agent, have been introduced in the oligomeric lactic acid (OLA) plasticized PLA in order to obtain nanocomposites with enhanced properties to find potential application as antibacterial food packaging materials. In this way, the green character of the matrix and plasticizer was preserved by using an eco-friendly synthesis protocol of the nanofiller. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results proved the modification of the crystalline structure as well as the crystallinity of the pristine matrix when chitosan mediated silver nanoparticles (AgCH-NPs) were present. The final effect over the thermal stability, mechanical properties, degradation under composting conditions, and antimicrobial behavior when AgCH-NPs were added to the neat plasticized PLA matrix was also investigated. The obtained results revealed interesting properties of the final nanocomposites to be applied as materials for the targeted application.

Microbicidal Dispersions and Coatings from Hybrid Nanoparticles of Poly (Methyl Methacrylate), Poly (Diallyl Dimethyl Ammonium) Chloride, Lipids, and Surfactants

Hybrid and antimicrobial nanoparticles (NPs) of poly (methyl methacrylate) (PMMA) in the presence of poly (diallyl dimethyl ammonium) chloride (PDDA) were previously obtained by emulsion polymerization in absence of surfactant with low conversion. In the presence of amphiphiles such as cetyl trimethyl ammonium bromide (CTAB), dioctadecyl dimethyl ammonium bromide (DODAB) or soybean lecithin, we found that conversion increased substantially. In this work, the effect of the amphiphiles on the NPs core-shell structure and on the antimicrobial activity of the NPs was evaluated. NPs dispersions casted on silicon wafers, glass coverslips or polystyrene substrates were also used to obtain antimicrobial coatings. Methods for characterizing the dispersions and coatings were based on scanning electron microscopy, dynamic light scattering, determination of thickness, rugosity, and wettability for the coatings and determination of colony-forming unities (log CFU/mL) of microbia after 1 h interaction with the coatings or dispersions. The amphiphiles used during PMMA/PDDA/amphiphile NPs synthesis reduced the thickness of the NPs PDDA shell surrounding each particle. The antimicrobial activity of the dispersions and coatings were due to PDDA-the amphiphiles were either washed out by dialysis or remained in the PMMA polymeric core of the NPs. The most active NPs and coatings were those of PMMA/PDDA/CTAB-the corresponding coatings showed the highest rugosity and total surface area to interact with the microbes. The dispersions and coatings obtained by casting of the NPs dispersions onto silicon wafers were hydrophilic and exhibited microbicidal activity against Escherichia coli, Staphylococcus aureus, and Candida albicans. In addition, a major effect of reduction in particle size revealed the suitability of nanometric and cationic NPs (sizes below 100 nm) represented by PMMA/PDDA/CTAB NPs to yield maximal microbicidal activity from films and dispersions against all microbia tested. The reduction of cell viability by coatings and dispersions amounted to 6-8 logs from [PDDA] ≥ minimal microbicidal concentration.

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

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.