Incorporation Of Antimicrobial Agents Research Articles

The Effect of Incorporating Dimethylaminohexadecyl Methacrylate and/or 2-Methacryloyloxyethyl Phosphorylcholine on Flexural Strength and Surface Hardness of Heat Polymerized and 3D-Printed Denture Base Materials.

A major disadvantage of polymethyl methacrylate (PMMA) acrylic resins is susceptibility to biofilm accumulation. The incorporation of antimicrobial agents is a reliable prevention technique. The purpose of this study is to investigate the effect of incorporating dimethylaminohexadecyl methacrylate (DMAHDM) and/or 2-methacryloyloxyethyl phosphorylcholine (MPC) into heat-polymerized (HP) and 3D-printed (3DP) denture base materials on the flexural strength, modulus of elasticity, and surface hardness. DMAHDM and/or MPC were mixed with the acrylic resin liquid of a heat-polymerized (ProBase Hot) and a 3D printed (NextDent Denture 3D) material at mass fractions of 1.5% and 3% and a combination of 3% MPC and 1.5% DMAHDM. Significant differences in mechanical properties between the control and experimental groups have been detected (p-value < 0.0001). In HP materials, the addition of DMAHDM and/or MPC generally decreased the flexural strength, from (151.18 MPa) in G1 down to (62.67 MPa) in G5, and surface hardness, from (18.05 N/mm2) down to (10.07 N/mm2) in G5. Conversely, in 3DP materials, flexural strength was slightly enhanced, from (58.22 MPa) in G1 up to (62.76 MPa) in G6, although surface hardness was consistently reduced, from (13.57 N/mm2) down to (5.29 N/mm2) in G5. It is recommended to carefully optimize the concentrations of DMAHDM and/or MPC to maintain mechanical integrity.

Advancing Sustainability: Utilizing Bacterial Polyhydroxyalkanoate for Food Packaging

Polyhydroxyalkanoates (PHAs) are promising biodegradable polymers known for their biodegradability and eco-friendly properties. Recent studies indicate that PHAs can reduce the environmental impact by up to 50% compared to petroleum-based plastics. This comprehensive review evaluates the application of PHAs in sustainable food packaging, covering over 100 studies published between 2018 and 2023. The review highlights advancements in PHA production, with a focus on submerged and solid-state fermentation methods, achieving up to a 60% improvement in production efficiency through optimized culture selection. Sustainable extraction and purification methods have been identified, reducing energy consumption by 30%. Blending PHAs with other biodegradable polymers like polylactic acid, starch, and cellulose enhances material performance, with up to a 40% improvement in mechanical properties. The incorporation of antimicrobial agents and essential oils has been shown to extend the shelf life by 25% while maintaining food safety standards. This review underscores the potential of active PHA-based packaging in improving the barrier properties by 35% when combined with coatings, positioning PHA as a key material for the future of environmentally responsible and safe food packaging.

Scoping review of resin cements modified by antimicrobial agents: Effects of incorporation

The purpose of this scoping review was to assess the modification effects of resin cements on antimicrobial capacity, mechanical properties, and conversion degree. Researches in the Embase, PubMed, SCOPUS, Cochrane library and Web of Science databases were enriched with manual searches, between May and June 2020, using the keywords “antibacterial resin cement” NOT “adhesive” NOT “ionomer”. The criteria included articles written in English, in vitro studies assessing resin cements with the incorporation of antimicrobial agents, describing conversion degree and/or mechanical properties, and/or effect of the antimicrobial agents, and articles indexed in the Journal Citation Reports (JCR) database. A total of 100 articles were found, of which 11 were selected by title and/or abstract, according to the inclusion criteria. From the 7 articles selected for full reading, 3 articles remained in this scoping review. These had high variability in materials and methods, making it difficult to perform the data statistical analysis; thus, a descriptive analysis was performed. There is a need for a resinous adhesive cementing agent with antimicrobial action since the bacteria infiltration at the adhesive interface is directly related to secondary dental caries with reduced longevity and survival of prosthetic treatments.

Antibacterial Potential and Biocompatibility of Chitosan/Polycaprolactone Nanofibrous Membranes Incorporated with Silver Nanoparticles.

This study addresses the need for enhanced antimicrobial properties of electrospun membranes, either through surface modifications or the incorporation of antimicrobial agents, which are crucial for improved clinical outcomes. In this context, chitosan-a biopolymer lauded for its biocompatibility and extracellular matrix-mimicking properties-emerges as an excellent candidate for tissue regeneration. However, fabricating chitosan nanofibers via electrospinning often challenges the preservation of their structural integrity. This research innovatively develops a chitosan/polycaprolactone (CH/PCL) composite nanofibrous membrane by employing a layer-by-layer electrospinning technique, enhanced with silver nanoparticles (AgNPs) synthesized through a wet chemical process. The antibacterial efficacy, adhesive properties, and cytotoxicity of electrospun chitosan membranes were evaluated, while also analyzing their hydrophilicity and nanofibrous structure using SEM. The resulting CH/PCL-AgNPs composite membranes retain a porous framework, achieve balanced hydrophilicity, display commendable biocompatibility, and exert broad-spectrum antibacterial activity against both Gram-negative and Gram-positive bacteria, with their efficacy correlating to the AgNP concentration. Furthermore, our data suggest that the antimicrobial efficiency of these membranes is influenced by the timed release of silver ions during the incubation period. Membranes incorporated starting with AgNPs at a concentration of 50 µg/mL effectively suppressed the growth of both microorganisms during the early stages up to 8 h of incubation. These insights underscore the potential of the developed electrospun composite membranes, with their superior antibacterial qualities, to serve as innovative solutions in the field of tissue engineering.

Enhancement of anti-microbial corrosion properties through coatings incorporating S2− responsive TCS-MSNs@TA-FeIII nanofillers

In environments susceptible to microbiologically influenced corrosion (MIC), conventional coatings frequently lack antimicrobial properties, resulting in diminished corrosion protection. The direct incorporation of antimicrobial agents into coatings may lead to continuous leakage. In this study, we tackled this challenge by utilizing smart nanofillers known as TCS-MSNs@TA-FeIII, which form mesoporous silica nanoparticles (MSNs) encapsulated by tannic acid-Fe3+ and loaded with triclosan (TCS). These nanofillers exhibited responsiveness to variations in S2− concentration caused by sulfate-reducing bacteria's (SRB) metabolic activities, enabling controlled release of TCS within the low S2− concentration range of 0.05 to 3 mM. Additionally, we evaluated the antimicrobial and anti-corrosion properties of the coating after integrating it into a water-based epoxy coating within an SRB environment. The results showcased exceptional performance of the TCS-MSNs@TA-FeIII coating, characterized by the highest impedance modulus (3.19 × 106 Ω·cm2), lowest corrosion current density (2.04 × 10−8 A·cm−2), and remarkable antimicrobial efficacy. This study offers valuable insights into developing novel coatings with enduring MIC inhibition capabilities while also broadening the potential application range of organic coatings.

Effect of nanosized titanium dioxide and zinc oxide as antimicrobial agents on early compressive strength of high-performance concrete

Incorporation of antimicrobial agents in concrete can enhance the resistance of the concrete to biodeterioration. However, there is lack of adequate knowledge on the effect of antimicrobial agents on performance measures of high-performance concrete (HPC), particularly during early strength development, when the hydration reaction is ongoing, is not well understood. Therefore, the effect of antimicrobial agents on early compressive strength (CS) of HPC was investigated. The cement in HPC samples was partially replaced with nanosized titanium dioxide (TiO2) and zinc oxide (ZnO) by up to 2% by weight of the cement. Using response surface methodology, 21 combinations of TiO2 and ZnO contents were generated. The combinations were adopted for preparation of the samples. Individual and combined effects of TiO2 and ZnO on 7-day CS of the samples were evaluated. The standard form of the second-order response surface model is adopted to develop a model to fit the strength data. Statistics of the data verify that the model can be employed to predict the 7-day CS of HPC that employs nanosized TiO2 and ZnO as antimicrobial agents.

Antimicrobial resistance: A looming threat to public health and global well-being

Abstract Antimicrobial resistance (AMR) is a global issue that transcends borders and affects countries at all income levels. Various contributing factors include limited access to clean water, sanitation, and hygiene for both humans and animals; inadequate infection and disease prevention and control in households, health-care facilities, and farms; restricted access to high-quality and affordable vaccines, diagnostics, and medications; insufficient awareness and knowledge; and a lack of enforcement of relevant legislation. People in low-resource settings and vulnerable populations are disproportionately affected by both the causes and consequences of AMR. The identification and subsequent incorporation of antimicrobial agents into clinical medicine marked a significant milestone in 20th-century medical achievements, fundamentally transforming the management of bacterial diseases. Nevertheless, the gradual rise of antibiotic-resistant bacterial populations, stemming from the inappropriate usage, misapplication, and unconditional abuse of antibiotics, has evolved into a substantial global public health challenge. Today, different mechanisms of bacterial resistance have been reported in almost all the present antibiotics on the market. The international community has been striving to address and recognize AMR as a global alarming situation, as considered by the World Health Organization as well as the Centers for Disease Control and Prevention. The unrestrained utilization of antibiotics at public and commercial levels has invigorated the evolution of multi-drug resistant microbiota across the globe, leading to an elevated mortality rate due to microbial infections. This review paper explored the inception and resistance genes, provides a comprehensive overview of global antimicrobial resistance, analyzes factors promoting its dissemination, discusses control strategies, examines control challenges, and underscores the ramifications of an inability to effectively contain antimicrobial resistance in bacteria, effectively.

Synthesis and Characterization of Responsive Antimicrobial Materials for Chronic Wound Management

Chronic wound treatment requires the ability to regulate the wound healing process and mitigate the propagation of bacterial infection with constant monitoring, in real-time. The need for multi-functional wound management materials has emerged as a significant research area with promise shown in the incorporation of antimicrobial agents within responsive polymeric materials to elicit signals providing dynamic information about the healing process. Traditional wound dressings provide a barrier between the outside environment and the wound; however, these methods are increasingly becoming less effective. Hydrogels synthesized from natural biopolymers have emerged due to their intrinsic properties such as biodegradability and non-cytotoxicity and enhanced from their well-defined, three-dimensional, non-covalent networks ideal for modification and functionalization to create “micro-reactors.” Previous work focused on the strategic design of an alginate-based hydrogel containing dual functional additives (i.e., amino acids) paired with photochemically prepared Ag- and Cu-TiO2 nanoparticles (Ag/Cu-NPs) to understand the synergistic interactions of the polymer chains, cross-linkers, and additives. The antimicrobial effectiveness of the composite was examined using an epi-fluorescent optical tweezer to measure the rates of bacterial cell death. Results showed that with the incorporation of the NPs there is a decrease in green signal (live cells) within 1 hour of exposure. Furthermore, the healing rates of simulated wounds using human dermal fibroblasts were explored along with changes in the expression of growth factors that promote wound healing, such as collagen and TGF-b. This work focuses on a two-layer responsive material with a wound-healing layer and a conductive layer formed through the secondary functionalization of the composite system through a metal-coordination-assisted photopolymerization of conductive polymers (i.e. aniline). Preliminary results show there is uniform polymeric chain growth seen in enhanced charge transfer through the matrix upon an applied voltage. Studies have also been conducted to measure the impact of saturation of the bandage through simulated wound exudate that revealed once saturation occurs, the passing of electricity between the ions found in wound exudate carried current through the composite, increasing the conductivity, leading to the signaling of an LED prompting replacement. The resulting two-layer nanocomposite system then functions as a responsive, antimicrobial wound healing material capable of eliminating constant monitoring with application in healthcare and home settings.

Hyperbranched Poly-L-Lysine-Based Water-Insoluble Complexes as Antibacterial Agents with Efficient Antibacterial Activity And Cytocompatibility.

Despite the advances in technology, bacterial infection associated with biomedical devices is still one of the most challenging issues in clinical practice. Incorporation of antimicrobial agents is regarded as an efficient way to combat medical device associated infectious. However, most of antimicrobial agents have high toxicity to host cells. Thus, fabrication of novel antimicrobial agents that simultaneously fulfill the requirements of antibacterial activity as well as biocompatibility is urgently needed. Herein, a series of water-insoluble antibacterial complexes based on hyperbranched poly-L-lysine (HBPL) and four different surfactants through non-covalent interactions are developed. Such kinds of surfactants have great effects on the antibacterial property of poly(ɛ-caprolactone) (PCL) films that incorporate with the HBPL-based complexes. The results reveal that the PCL films that doped with HBPL/phosphate ester surfactant complexes showed the highest bacterial killing efficiency. Moreover, the cytocompatibility of the composite films is also investigated. Hemolysis experiments indicate that all the films had low hemolytic activities. Considering the excellent antimicrobial and cytocompatibility properties, this work believes that the optimized complexes have great potential to be used as antimicrobial agents in biomedical field.

Antimicrobial plastic films against SARS‐COV‐2 and pathogenic bacteria

AbstractPolymeric films are used in numerous applications in the biomedical area. The incorporation of antimicrobial agents into these materials can prevent their surface from acting as a source of contamination of viruses and bacteria. In the present work, cinnamon and eucalyptus essential oils were incorporated into low‐density polyethylene (LDPE) by melt extrusion, as confirmed by Fourier transform infrared spectroscopy. For the success of incorporation, talc was used as an oil carrier and fixer. Despite high processing temperatures used (up to 175°C), the oleophilic character of talc was able to minimize oil losses, as proven by thermogravimetry. Good thermal and mechanical properties evaluated by differential scanning calorimetry and tensile tests were confirmed. In addition, antimicrobial tests confirmed film activity against virus SARS‐CoV‐2 and bacteria Staphylococcus aureus and Escherichia coli. LDPE films incorporated with both oils showed significant antiviral properties against SARS‐CoV‐2, with viral titers reduction between 95.89% and 100%. Cinnamon oil showed more efficient antibacterial properties than eucalyptus oil, with relative bacterial growths of films next to zero (0.37% for E. coli and 2.07% for S. aureus). To the best of our knowledge, no previous work has developed plastic films incorporated with essential oils with confirmed antiviral properties against SARS‐CoV‐2.

Development of polyurethane antimicrobial coatings by composition with phenolic-, ionic- and copper-based agents

Microorganisms can be found in almost all environments with high-touch surfaces being an important fomite for microbial growth. Considering the health issues associated to acquired infection from inanimate surfaces, as well as the raising hygienic concerns, the incorporation of antimicrobial compounds in high-touch surfaces emerges as an effective solution for biomedical and common daily applications.In this work, we incorporated different antimicrobial agents (phenolic-, ionic- and copper-based compounds) into polyurethane commercial formulations to produce antimicrobial lacquer-films and evaluated not only their physical/chemical properties, but also their antimicrobial activity against bacteria (Staphylococcus aureus, Escherichia coli), fungi (Candida albicans), and virus (SARS-CoV-2).The incorporation of antimicrobial agents did not affect the performance of lacquer-films and the main properties were maintained, specifically the visual aspect, gloss values, optical properties and chemical stability.Among the different compounds tested, copper-based lacquer-films exhibited the strongest antibacterial and antifungal activity, with a >4 log reduction, but not against virus. Importantly, copper-based lacquer-films maintained their cytocompatibility, even at high concentrations. Regarding the ionic lacquer-films, the highest tested concentration also showed a strong antimicrobial action (5 log reduction) against fungi and gram-positive bacteria, but not against gram-negative bacteria and virus. However, at this concentration, the ionic-containing lacquer-films presented cytotoxic potential. The phenolic-based compounds were not associated with antimicrobial activity, regardless the concentrations tested.Collectively, these results highlight the potential of incorporating antimicrobial agents in polyurethane surface coatings as a promising strategy to avoid the microbial colonization on inanimate surfaces and, ultimately, prevent the spreading of potentially harmful pathogens among humans.

Antibacterial Carbon Dots-Based Composites.

The emergence and global spread of bacterial resistance to conventionally used antibiotics have highlighted the urgent need for new antimicrobial agents that might replace antibiotics. Currently, nanomaterials hold considerable promise as antimicrobial agents in anti-inflammatory therapy. Due to their distinctive functional physicochemical characteristics and exceptional biocompatibility, carbon dots (CDs)-based composites have attracted a lot of attention in the context of these antimicrobial nanomaterials. Here, a thorough assessment of current developments in the field of antimicrobial CDs-based composites is provided, starting with a brief explanation of the general synthesis procedures, categorization, and physicochemical characteristics of CDs-based composites. The many processes driving the antibacterial action of these composites are then thoroughly described, including physical destruction, oxidative stress, and the incorporation of antimicrobial agents. Finally, the obstacles that CDs-based composites now suffer in combating infectious diseases are outlined and investigated, along with the potential applications of antimicrobial CDs-based composites.

Antimicrobial Activity of Composites-Based on Biopolymers

Microorganisms have developed a resistance against some of the most conventional antibiotics. These microorganisms can be self-assembled, forming a microbial biofilm. A microbial biofilm formation is an inherent event on almost any surface, causing countless side effects on human health and the environment. Therefore, multiple scientific proposals have been developed based on renewable sources such as natural polymers. Natural polymers or biopolymers include cellulose, chitosan, starch, collagen, gelatin, hyaluronic acid, alginates, fibrin, and pectin, which are widely found in nature. The biopolymers have displayed many interesting properties, including biocompatibility and biodegradability. Nonetheless, these materials usually have no antimicrobial properties (except for the chitosan) by themselves. Therefore, antimicrobial agents have been incorporated into the natural polymeric matrix, providing an antimicrobial property to the biocomposite. Biocomposites consist of two different materials (one of natural origin) studied as biocompatible and biodegradable drug carriers of antimicrobial agents. In addition, due to the incorporation of antimicrobial agents, biocomposites can inhibit biofilm formation and bacteria proliferation on many surfaces. This review describes this using natural polymers as a platform of antimicrobial agents to form a biocomposite to eliminate or reduce biofilm formation on different surfaces.

How Effective Are Antimicrobial Agents on Preventing the Adhesion of Candida albicans to Denture Base Acrylic Resin Materials? A Systematic Review.

Denture stomatitis is a common oral infection caused by Candid albicans. It occurs under removable dentures due to several causative and contributing factors. If not treated, it can lead to fatal systemic candida infections. Different materials and techniques have been used to treat denture stomatitis; however, no single treatment has succeeded. The purpose of this study was to review novel techniques for incorporating antimicrobial and protein repellent agents into denture acrylic resin materials and their effect on the adhesion of Candida albicans to denture base acrylic resin materials to prevent and/or treat denture stomatitis. A systematic review was conducted in which an electronic search was undertaken using different databases and relevant keywords. The literature search revealed numerous studies describing different antifungal materials incorporated into different denture acrylic resin materials. The investigated materials showed significant antimicrobial activity with slight or no effect on the physical and mechanical properties; however, the optical properties were particularly affected with higher concentrations. The incorporation of antimicrobial agents to reduce or prevent Candida albicans biofilm formation on acrylic resin proved to be very effective, and this effect was found to be proportional to the percentage of the material used. The latter should be considered carefully not to alter the physical, mechanical or optical characteristics of the denture base material.

Developmental prospectives of new generation super absorbent wound dressing materials from sulfated polysaccharide of marine red algae

Wound healing remains as a dynamic process and the type of dressing material significantly affects the efficacy of healing. The identification of ideal dressings to use for a particular wound type is an important requisite facilitating the entire process of healing. Chronic, high exudate wounds are dynamic in presentation and remain as a major health care burden. Researchers have sort to design and optimize biodegradable wound dressings that focuses to optimize moisture retentiveness, as superior character in the healing process. In addition, dressings have been designed to visualize the wound bed by improving the optical property, target and kill infection-causing bacteria, with the incorporation of antimicrobial agents, nanomaterials and numerous other measures. For the practitioners, choosing the optimal dressing decreases time to healing, provides cost-effective care and improves patient quality of life. The current mini review highlights the ideal characters of wound dressing materials and presents insights on the superior characters of carrageenan bio composites for prospective advancements in research in the area of wound care and management.

Gelatin-Based Hybrid Scaffolds: Promising Wound Dressings.

Wound care is a major biomedical field that is challenging due to the delayed wound healing process. Some factors are responsible for delayed wound healing such as malnutrition, poor oxygen flow, smoking, diseases (such as diabetes and cancer), microbial infections, etc. The currently used wound dressings suffer from various limitations, including poor antimicrobial activity, etc. Wound dressings that are formulated from biopolymers (e.g., cellulose, chitin, gelatin, chitosan, etc.) demonstrate interesting properties, such as good biocompatibility, non-toxicity, biodegradability, and attractive antimicrobial activity. Although biopolymer-based wound dressings display the aforementioned excellent features, they possess poor mechanical properties. Gelatin, a biopolymer has excellent biocompatibility, hemostatic property, reduced cytotoxicity, low antigenicity, and promotes cellular attachment and growth. However, it suffers from poor mechanical properties and antimicrobial activity. It is crosslinked with other polymers to enhance its mechanical properties. Furthermore, the incorporation of antimicrobial agents into gelatin-based wound dressings enhance their antimicrobial activity in vitro and in vivo. This review is focused on the development of hybrid wound dressings from a combination of gelatin and other polymers with good biological, mechanical, and physicochemical features which are appropriate for ideal wound dressings. Gelatin-based wound dressings are promising scaffolds for the treatment of infected, exuding, and bleeding wounds. This review article reports gelatin-based wound dressings which were developed between 2016 and 2021.

3D Printing Personalized, Photocrosslinkable Hydrogel Wound Dressings for the Treatment of Thermal Burns

AbstractConsidering the variations in burns depending on the circumstances that caused them, the need for personalized medicine and care for burn victims is vital to ensure that optimal treatment is provided. With the level of accuracy and customization that 3D printing brings as a technology, there is potential in its use to fabricate wound dressings that can provide better treatment for burn patients, provided that the material of choice has good printability and can be customized while facilitating wound healing. In this study, the versatility of chitosan methacrylate as said material to be used to fabricate customizable wound dressings via 3D printing is investigated. Synthesized chitosan methacrylate is evaluated to be printable, biodegradable, and biocompatible during wound healing. Various drugs relevant to the treatment of burns are then loaded and different multimaterial wound dressing designs containing different dosages are fabricated via 3D printing. The incorporation of said drugs does not significantly affect the printability of chitosan methacrylate, and the incorporation of antimicrobial agents significantly improves its antimicrobial capabilities. Through in vivo models, these variations in wound dressing designs have good wound healing properties and do not cause any adverse effects in the process.

Antimicrobial Properties of Acrylic Resin Incorporated with Propolis Nanoparticles.

Objectives: One of the main problems with polymethyl methacrylate (PMMA) used for the fabrication of oral removable appliances is plaque accumulation due to surface porosities. Incorporation of antimicrobial agents in this material might help tackle this problem. The aim of this study was to evaluate the antimicrobial activity of PMMA acrylic resin incorporated with propolis nanoparticles (PNPs). Materials and Methods: Antimicrobial properties of acrylic resin incorporated with PNPs were assessed against Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), Lactobacillus acidophilus (L. acidophilus) and Candida albicans (C. albicans). Acrylic discs were fabricated in four groups: A control group without PNPs and three experimental groups containing 0.5%, 1% and 2% concentrations of PNPs. Disc agar diffusion (DAD) test was performed to determine the antimicrobial effects of PNPs by measuring the microbial growth inhibition zones on Muller-Hinton agar plates. The eluted components test evaluated the viable counts of microorganisms in liquid medium after 24 and 72h. Finally, biofilm inhibition test assessed the efficacy of PNPs for inhibition of biofilm formation. P<0.05 was considered significant. Results: The acrylic discs failed to produce microbial inhibition zones in the DAD test. Discs containing 1% and 2% nanoparticles showed anti-biofilm effects on all four microbial species. The colony counts of all microorganisms significantly decreased following exposure to liquids containing nanoparticles after 24 and 72h in eluted component test. Conclusion: PMMA acrylic discs incorporated with PNPs presented some antimicrobial properties against S. mutans, S. sanguinis, L. acidophilus, and C. albicans. Objectives: One of the main problems with polymethyl methacrylate (PMMA) used for the fabrication of oral removable appliances is plaque accumulation due to surface porosities. Incorporation of antimicrobial agents in this material might help tackle this problem. The aim of this study was to evaluate the antimicrobial activity of PMMA acrylic resin incorporated with propolis nanoparticles (PNPs). Materials and Methods: Antimicrobial properties of acrylic resin incorporated with PNPs were assessed against Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), Lactobacillus acidophilus (L. acidophilus) and Candida albicans (C. albicans). Acrylic discs were fabricated in four groups: A control group without PNPs and three experimental groups containing 0.5%, 1% and 2% concentrations of PNPs. Disc agar diffusion (DAD) test was performed to determine the antimicrobial effects of PNPs by measuring the microbial growth inhibition zones on Muller-Hinton agar plates. The eluted components test evaluated the viable counts of microorganisms in liquid medium after 24 and 72h. Finally, biofilm inhibition test assessed the efficacy of PNPs for inhibition of biofilm formation. P<0.05 was considered significant. Results: The acrylic discs failed to produce microbial inhibition zones in the DAD test. Discs containing 1% and 2% nanoparticles showed anti-biofilm effects on all four microbial species. The colony counts of all microorganisms significantly decreased following exposure to liquids containing nanoparticles after 24 and 72h in eluted component test. Conclusion: PMMA acrylic discs incorporated with PNPs presented some antimicrobial properties against S. mutans, S. sanguinis, L. acidophilus, and C. albicans.

Combination of Edible Coatings Containing Oregano Essential Oil Nanoemulsion and Pulsed Light Treatments for Improving the Shelf Life of Tomatoes

Edible coatings (ECs) have attracted increasing attention in the last years as a simple yet effective approach to increase the storability of perishable foods, such as fresh or fresh-cut fruits and vegetables, contributing to maintaining their quality by reducing respiration rate and water loss. The incorporation of antimicrobial agents, such as essential oils, was reported to add also antimicrobial properties to the coatings, through the controlled release of the antimicrobial compounds on the food surface, contributing to further reduce microbial growth over extended periods of storage. Pulsed light (PL) treatments have been widely investigated as non-thermal processes for superficial decontamination of food and food-contact surfaces, because of their ability to cause, through a short exposition, a significant reduction in the microbial population. Therefore, the combination of ECs and PL treatments represents a promising hurdle approach in food preservation, for extending the shelf life of fresh products. ECs in combination with optimum PL treatment condition (4 J/cm2) improved the quality of tomato fruits in terms of reducing the growth of the endogenous flora, as well as of preserving the quality attributes (pH, total soluble solids, and color) over a 15-d storage at room temperature.

Antimicrobial-coated films as food packaging: A review.

Antimicrobial food packaging involves packaging the foods with antimicrobials to protect them from harmful microorganisms. In general, antimicrobials can be integrated with packaging materials via direct incorporation of antimicrobial agents into polymers or application of antimicrobial coating onto polymer surfaces. The former option is generally achieved through thermal film-making technology such as compression molding or film extrusion, which is primarily suitable for heat-stable antimicrobials. As a nonthermal technology, surface coating is more promising compared to molding or extrusion for manufacturing food packaging containing heat-sensitive antimicrobials. In addition, it also has advantages over direct incorporation to preserve the packaging materials' bulk properties (e.g., mechanical and physical properties) and minimize the amount of antimicrobials to reach sufficient efficacy. Herein, antimicrobial food packaging films achieved through surface coating is explored and discussed. The two components (i.e., film substrate and antimicrobials) consisting of the antimicrobial-coated films are reviewed as plastic/biopolymer films; and synthetic/naturally occurring antimicrobials. Furthermore, special emphasis is given to different coating technologies to deposit antimicrobials onto film substrate. Laboratory coating techniques (e.g., knife coating, bar coating, and spray coating) commonly applied in academic research are introduced briefly, and scalable coating methods (i.e., electrospinning/spraying, gravure roll coating, flexography coating) that have the potential to bring laboratory-developed antimicrobial-coated films to an industrial level are explained in detail. The migration profile, advantages/drawbacks of antimicrobial-coated films for food applications, and quantitative analyses of the reviewed antimicrobial-coated films from different aspects are also covered in this review. A conclusion is made with a discussion of the challenges that remain in bringing the production of antimicrobial-coated films to an industrial level.