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Bio‐active ethylcellulose (EC) polymeric films have been obtained by incorporating curcumin (curc) and Ag(I)‐based compounds, known for their antioxidant and antimicrobial activity, respectively, within the polymeric matrix. The recently reported Ag(I) coordination polymer, in both its structural forms (α‐[(bpy)Ag(OTf)]∞ and β‐{[(bpy)Ag][OTf]}∞), and the [(bpy)Ag(OTf)]∞‐curc polymeric co‐crystal (bpy=2,2′‐bipyridine; OTf=trifluoromethanesulfonate) have been selected as Ag(I) species. The hybrid composite films have been prepared through the simple solvent casting method and characterized through Powder X‐Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), UV‐vis spectroscopy. The deep investigation of the film samples highlighted the non‐inert behaviour of EC towards these specific active ingredients. Antimicrobial tests showed that EC films embedding the Ag(I)‐based compounds present good antimicrobial performance, in particular against Staphylococcus aureus, used as a model of Gram‐positive bacteria. In addition, Silver migration tests, performed on the Ag(I)‐incorporating EC films, evidenced low values of silver release particularly in the case of the EC films incorporating [(bpy)Ag(OTf)]∞‐curc. [ABSTRACT FROM AUTHOR]

Antimicrobial pectin/chitosan composite films have potential as wound dressing and food packaging. However, almost biofilms were synthesized through chemical routes, causing eco-unfriendliness, and negative impacts on the environment and human health. Green synthesis of composite films incorporating with biosynthesized AgNPs is therefore necessary to enhance mechanical and antimicrobial activities. This study focused on the influence of biosynthesized AgNPs on characteristics of passion fruit peel pectin/chitosan (P/CH) biofilms. Characterization, mechanical, antimicrobial activities of P/CH/AgNPs biofilms were evaluated. Incorporating AgNPs into P/CH-based films significantly exerted apparent color and optical properties of biofilms. As AgNPs concentration increased, P/CH/AgNPs biofilms had higher water content (20.1%), better water vapor permeability (1.28 × 10–9 g/mm h Pa), but lower mechanical, water solubility (43.98%), swelling (630.29 ± 11.79%) indexes. P/CH/AgNPs biofilms exhibited outstanding antibacterial properties against S. aureus, B. cereus, P. aeruginosa, K. pneumonia. As expected, in vivo results consolidated the evidence of excellent wound closure (100%) of P/CH/AgNPs biofilms after 15 days. Our findings recommend P/CH/AgNPs antibacterial biofilms have promising biomedical applications.

Abstract Biomaterials developed with biopolymers contribute to the healing process of healthy or diabetic patients. The objective of the present study was to evaluate the effect of honey incorporation (0.3, 0.6, and 1.2 g/100 mL) in chitosan/collagen/glycerol composite films. The Ch/Coll/1.2H films revealed the greatest percentage of elongation (27.10%) and Young´s modulus (65.58 MPa). The barrier properties (WVTR and WVP) exhibited a significant increase when the honey was incorporated into the films. The absorption capacity, solubility, and enzymatic biodegradability were lower in films containing honey. The chemical interactions between the functional groups of the films were verified by FTIR. The morphology studied by SEM confirmed the mixture’s homogeneity. Finally, all formulations exhibited antibacterial properties against Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, and Salmonella Typhimurium. The aforementioned properties of formulated dressings are suitable for their potential application in chronic wounds.

The design and engineering of antibacterial materials are key for preventing bacterial adherence and proliferation in biomedical and household instruments. Silver nanoparticles (AgNPs) and chitosan (CHI) are broad-spectrum antibacterial materials with different properties whose combined application is currently under optimization. This study proposes the formation of antibacterial films with AgNPs embedded in carboxymethylcellulose/chitosan multilayers by the layer-by-layer (LbL) method. The films were deposited onto nanoporous silicon (nPSi), an ideal platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. We focused on two alternative multilayer deposition processes: cyclic dip coating (CDC) and cyclic spin coating (CSC). The physicochemical properties of the films were the subject of microscopic, microstructural, and surface–interface analyses. The antibacterial activity of each film was investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria strains as model microorganisms. According to the findings, the CDC technique produced multilayer films with higher antibacterial activity for both bacteria compared to the CSC method. Bacteria adhesion inhibition was observed from only three cycles. The developed AgNPs–multilayer composite film offers advantageous antibacterial properties for biomedical applications. [ABSTRACT FROM AUTHOR]

Antimicrobial pectin/chitosan composite films have potential as wound dressing and food packaging. However, almost biofilms were synthesized through chemical routes, causing eco-unfriendliness, and negative impacts on the environment and human health. Green synthesis of composite films incorporating with biosynthesized AgNPs is therefore necessary to enhance mechanical and antimicrobial activities. This study focused on the influence of biosynthesized AgNPs on characteristics of passion fruit peel pectin/chitosan (P/CH) biofilms. Characterization, mechanical, antimicrobial activities of P/CH/AgNPs biofilms were evaluated. Incorporating AgNPs into P/CH-based films significantly exerted apparent color and optical properties of biofilms. As AgNPs concentration increased, P/CH/AgNPs biofilms had higher water content (20.1%), better water vapor permeability (1.28 × 10–9 g/mm h Pa), but lower mechanical, water solubility (43.98%), swelling (630.29 ± 11.79%) indexes. P/CH/AgNPs biofilms exhibited outstanding antibacterial properties against S. aureus , B. cereus, P. aeruginosa, K. pneumonia. As expected, in vivo results consolidated the evidence of excellent wound closure (100%) of P/CH/AgNPs biofilms after 15 days. Our findings recommend P/CH/AgNPs antibacterial biofilms have promising biomedical applications. [ABSTRACT FROM AUTHOR]

Silicone elastomers are widely used in aviation, electronics, automotive, and medical device fields, and their overuse inevitably causes recycled problems. In addition, the elastomers are subject to attack by bacteria and fire during use in some application scenarios, which is a safety hazard. Therefore, there is a great need to prepare silicone elastomers with improved antibacterial, flame retardant, self‐healing, and recyclable functions. A new strategy is proposed to prepare silicone elastomers with bio‐based tannic acid as cross‐linkers to solve this problem by using polydimethylsiloxane as a soft chain segment and 2,2‐bis(hydroxymethyl)propionic acid as an intermediate chain extender. Based on the phenol carbamate bonding and hydrogen bonding interactions, the elastomer has efficient self‐healing ability and can achieve dynamic dissociation at 120 °C for complete recovery. In addition, due to the unique spatial structure and polyphenolic hydroxyl groups of tannic acid, the mechanical properties of the elastomer are greatly improved with an antimicrobial efficiency of over 90% and a final oxygen index of 25.5%. The multifunctional silicone elastomer has great potential applications in recyclable refractory materials and antimicrobial materials. [ABSTRACT FROM AUTHOR]

Chitosan is a biopolymer with great potential as food packaging due to its ability to create a film without additives and its better mechanical and antibacterial qualities compared to other biopolymers. However, chitosan film still has limitations due to its high moisture sensitivity and limited flexibility. Incorporating ZnO nanoparticles (ZnO-NPs) and stearic acid (SA) into chitosan films was expected to improve tensile strength, water vapor barrier, and antibacterial capabilities. This study aims to find the optimal formula for biohybrid nanocomposite films composed of chitosan, ZnO-NPs, and SA. The full factorial design approach—4 × 2 with 3 replicates, i.e., two independent variables, namely %ZnO-NPs at 4 levels (0%, 0.5%, 1%, and 3%, w/w) and %SA at 2 levels (0% and 5%, w/w)—was utilized to optimize chitosan-based biohybrid nanocomposite films, with the primary interests being antibacterial activities, water vapor barrier, and tensile strength. The incorporation of ZnO-NPs into chitosan films could increase antibacterial activity, while SA decreased it. The addition of SA had a good effect only in decreasing water vapor transmission rate (WVTR) values but a detrimental effect on other film properties mentioned above. The incorporation of ZnO-NPs enhanced all functional packaging properties of interest. The suggested solution of the optimization study has been validated. As a result, the formula with the inclusion of 1% ZnO-NPs without SA is optimal for the fabrication of active antibacterial films with excellent multifunctional packaging capabilities. [ABSTRACT FROM AUTHOR]

Nowaday the use of essential oils, having antimicrobial activity, is quite limited in the field of active packaging for the difficulty to retain the active compound for a long time into the material. The paper reports the design and fabrication of a nano-carrier able to incorporate and protect an essential oil (i.e. citral) for targeted applications. The hybrid filler was produced by growing layered double hydroxide (LDH) nanocrystals as plates on halloysite nanotubes (Hal) (Hal@LDH). Such hybrid filler was used as a carrier of citral as an antimicrobial essential oil. The active filler was incorporated into the starch matrix at 5, 10, and 15 wt% and films were produced. The structural organization of the filler was conducted by using Scansion Electron Microscopy (SEM), Thermogravimetric Analysis (TGA) and X-ray Diffraction (XRD) analysis. The obtained bio-composite films were structurally analyzed through XRD and SEM with EDX analysis. The physical performances were evaluated through the analysis of mechanical properties, contact angle, radical scavenging activity and release kinetics of citral, as a function of filler loading. To assess the possibility of using such composites for food packaging applications, tests were carried out on different strains such as Escherichia coli, Listeria monocytogenes, and Salmonella bongori. • A hybrid carrier loaded with citral was prepared to produce starch based active films. • The used methodology to produce the hybrid carrier was ball milling at ambient temperature. • Analysis of structure and physical properties of the composites was carrier out. • Films showed antimicrobial activity against pathogens active in food spoilage. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WPU) and Ag NPs have been applied widely in packaging. However, WPU was susceptible to the contamination due to high moisture absorption, and the stability of Ag NPs in matrix polymers was still low. To resolve this problem, chitosan (CS) was used as the dispersant to synthesize CS/Ag NPs composites in this work, and then they were mixed with WPU to prepare CS/Ag-WPU films. CS macromolecules provided the carriers for Ag NPs with a diameter of about 2.5 nm, and Ag NPs were dispersed stably in WPU. Compared with pure WPU film, as-prepared CS/Ag-WPU films had a higher thermal stability at low temperature, and the crystal size for WPU increased after introducing CS/Ag NPs. Importantly, the water contact angle for CS/Ag-WPU-5 increased to 54.2° from 27.5° implying that the hydrophobicity was improved. In addition, CS/Ag-WPU composites exhibited an excellent inhibitory effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Antibacterial performances of most samples were improved with the crease of the concentration of CS, and the inhibitory effect on S. aureus was preferred. Therefore, as-prepared CS/Ag-WPU films in this paper have a potential application in antibacterial packaging field.

Silver nanoparticles have attracted wide interest in medicine on account of their antibacterial activity. We report in this paper, the antibacterial activity and biocompatibility of a temperature responsive topical film fabricated from pullulan-g-pNIPAM and impregnated with two different concentrations (15 ppm and 30 ppm) of silver nanoparticles (Ag-NPs). The release of silver from the film under the influence of temperature above the LCST has been studied and the in vitro release profile of the films has been compared with a marketed silver nano formulation, 'Meganano gel'. The release of silver from the films has a distinctive profile characterized by a sustained release over a period of 48 hrs, which is comparable to the marketed formulation. The films exhibit excellent swelling properties, making them ideal materials for absorption of exudates from wounds. The antibacterial activity of the films has been established at physiological temperature against gram-positive S. aureus and gram-negative E. coli and compared with the marketed formulation. A cytotoxicity evaluation on HeK293 cells has demonstrated their biocompatibility. The nanocomposite films are thus a new therapeutic device for management of non-healing wounds being constructed from temperature responsive polymers that release Ag-NPs when the temperature of the wound exudate is slightly higher than normal. [ABSTRACT FROM AUTHOR]

It remains a challenge to maintain the antiadhesion properties of superhydrophobic films after exposure to bacterial environments. In this work, superhydrophobic bactericidal polymer films via the simple incorporation of polyvinylpyrrolidone‐iodine (PVP‐I) or iodine into polytetrafluoroethylene (PTFE) are fabricated to improve their antiadhesive and antibacterial capability. Superhydrophobic iodine‐embedded films, polytetrafluoroethylene/polyvinylpyrrolidone‐iodine and polytetrafluoroethylene‐iodine (PTFE/PVP‐I and PTFE‐I), show excellent antiadhesive and bactericidal performances even post exposure to bacterial solutions as compared to iodine‐free counterparts by controlling the release of iodine. Especially, superhydrophobic PTFE/PVP‐I films display a more sustained iodine release profile and significant antibacterial properties against gram‐positive (S. aureus, methicillin‐resistant S. aureus (MRSA)) and gram‐negative (E. coli) bacteria. Such a facile combination of antiseptic agents and superhydrophobic surface could be widely used for antiseptic biomedical applications. [ABSTRACT FROM AUTHOR]

adipate terephthalate (PBAT) as matrix and zinc oxide nanoparticles (ZnONPs) and silver nanoparticles (AgNPs) as antibacterial agents, a series of antibacterial PLA/PBAT films were prepared by melt blending. The weight ratio of PLA, PBAT and nanoparticles in composite films was 70:900:10 (lower loading) or 70:900:20 (higher loading). The results showed that comparing with the PLA/PBAT films, the hydrophilicity, oxygen barrier properties, mechanical performance and antibacterial activities of PLA/PBAT/nanoparticles films were significantly improved (P＜0.05), and influenced by the content and type of nanoparticles. After the addition of nanoparticles, the maximum change of films performance was from 71.3° to 35.8°for water contact angle, from 7.4 × 10−14 cm3 cm.cm−2. s−1. Pa−1 to 5.5 × 10−14 cm3 cm.cm−2. s−1. Pa−1 for oxygen transmission permeability, from 26.4 MPa to 31.4 MPa for tensile strength, and from 0% to 57.8% (Escherichia coli) or 58.6% (Staphylococcus aureus) for antibacterial ratio. The films with higher loading content of nanoparticles showed a better antibacterial activity. For the same nanoparticles content, the antibacterial activity of PLA/PBAT/AgNPs was better than PLA/PBAT/ZnONPs. The overall migration in food simulants involving acetic acid (3%) ethanol (10% and 95%) was below 10 mg/dm2 for most films, however, the overall migration for the films with higher content of AgNPs exceeded the limit value. The fresh noodles packaged by PLA/PBAT/AgNPs films showed the significant lowest total viable count with 4.6 lg (CFU/g) and the best appearance color characterized by L* (lightness), a*(red-green) and b*(yellow-blue) at storage time of 7 d in contrast with PLA/PBAT and PLA/PBAT/ZnONPs films, indicating the potential application of prepared films in active packaging to prolong the shelf life of food. • Developing antibacterial biodegradable films for fresh noodles packaging. • Effect of ZnO or Ag nanoparticles with low or high content on films properties. • Nanoparticles addition improved the performance of films. • The total migration of films meets food safety except higher-Ag loaded films. • The Ag-loaded films showed the best antibacterial and preservative on noodles. [ABSTRACT FROM AUTHOR]

Aimed at decreasing the environmental pollution caused by petroleum-derived packing materials, many efforts have been directed towards fabricating biodegradable substitutes, especially of cellulose-based film with functional properties. In this paper, a totally plant-derived antibacterial film was successfully prepared. Regenerated cellulose films were used as substrate and poacic acid, a decarboxylated product from 8–5-diferulic acid, as fungicides. The physical properties and thermal stability of the prepared plant-derived antibacterial films were characterized, and the antibacterial activity was also assessed as the function poacic acid contents. The morphology showed that the cellulose/poacic acid films exhibited a homogeneous and smooth surface and poacic acid was successfully incorporated into cellulose films as revealed by Fourier-transform infrared (FT-IR) spectroscopy and fluorescent microscopy. It was noted that both the tensile strength and thermal stability of the antibacterial films decreased due to the incorporation of the poacic acid. Remarkably, the prepared cellulose/poacic acid films exhibited superior antibacterial activity against Staphylococcus aureus. The notable properties of the cellulose/poacic acid films are promising for applications in food and medical packaging to enhance their safety. [ABSTRACT FROM AUTHOR]

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(Qpy,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. [ABSTRACT FROM AUTHOR]

In this current work, antimicrobial films based on starch, poly(butylene adipate-co-terephthalate) (PBAT), and a commercially available AgNPs@SiO2 antibacterial composite particle product were produced by using a melt blending and blowing technique. The effects of AgNPs@SiO2 at various loadings (0, 1, 2, 3, and 4 wt%) on the physicochemical properties and antibacterial activities of starch/PBAT composite films were investigated. AgNPs@SiO2 particles were more compatible with starch than PBAT, resulting in preferential distribution of AgNPs@SiO2 in the starch phase. Infusion of starch/PBAT composite films with AgNPs@SiO2 marginally improved mechanical and water vapor barrier properties, while surface hydrophobicity increased as compared with films without AgNPs@SiO2. The composite films displayed superior antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The sample loaded with 1 wt% AgNPs@SiO2 (SPA-1) showed nearly 90% inhibition efficiency on the tested microorganisms. Furthermore, a preliminary study on peach and nectarine at 53% RH and 24 °C revealed that SPA-1 film inhibited microbial spoilage and extended the product shelf life as compared with SPA-0 and commercial LDPE packaging materials. The high-throughput production method and strong antibacterial activities of the starch/PBAT/AgNPs@SiO2 composite films make them promising as antimicrobial packaging materials for commercial application.

Highlights • Preparation of ZnO nanoparticles by in situ generated in carboxymethyl chitosan. • ZnO was incorporated into chitosan multilayer films to improve properties. • Water vapor resistance was improved by the addition of ZnO and sodium alginate. • Mechanical properties and antibacterial activity were improved. • The film with prepared ZnO (0.05 g/g sodium alginate) had a better preservation effect. Abstract To deal with serious environmental pollution resulting from plastic packaging materials, biodegradable films using chitosan (CS) are gaining considerable increase gradually. However, chitosan films lack important properties to meet the preserved demands. This study aimed to develop new bio-based films incorporated with carboxymethyl chitosan-ZnO (CMCS-ZnO) nanoparticles and sodium alginate (SA) to overcome the weakness of CS films. CMCS-ZnO nanoparticles were successfully synthesized in the matrix of CMCS through direct precipitation method, which showed an average diameter of 100 nm. Multilayer films with CS film as the outer layer and SA film as the inner layer were prepared by solution casting method. The addition of CMCS-ZnO nanoparticles led to enhanced tensile strength, and to better water vapor resistance. The as-prepared films exhibited distinctive antibacterial activity against S. aureus and E. coli. The results suggested that the as-prepared film is expected to be a promising material for food packaging. [ABSTRACT FROM AUTHOR]

Here in we present our research on electrospun polyacrylonitrile nanofiber films embedded with titania/AgNP nanoparticles for sustained antibacterial applications. Although silver possesses excellent antimicrobial characteristics and have been extensively exploited in applications where protection from microbial species and bacterial colonization is needed. Recently, it was discovered that silver may be allergic to skin and may induce detrimental side-effects such as argyria and argyrosis . Excess utilization of silver may even cause carcinoma. In continuation of our research on preparation of biologically safe antibacterial materials producing longer timed protection, here we proposed electrospun polyacrylonitrile nanofiber mats containing titania/AgNP composite nanoparticles. The titania/AgNP nanoparticles were prepared using polydopamine hydrochloride (pdopa) as adhesive and reducing agent. The nanoparticles were then added into polyacrylonitrile polymer solution and electrospun to fabricate polyacrylonitrile/titania/AgNP composite nanofiber mats (PTAgNP). The samples were characterized with XRD, TEM, SEM, FT-IR, SEM-EDX and antibacterial assays. Synthesis of the titania/AgNP was confirmed by XRD, TEM and EDX analysis. The nanofibers were studied with SEM, XRD, TEM and antibacterial tests. The SEM observations confirmed regular morphology of the nanofibers. The XRD and TEM analysis evidenced titania/AgNP contents in the polyacrylonitrile nanofibers. The antibacterial assays demonstrated excellent bacterial growth inhibition on agar plates and in the liquid medium. The samples were observed to inhibit growth of E. coli and S. aureus bacteria for up to 120 h. The quantitative bactericidal assay (relative cell viability, %) demonstrated 0% bacteria cell viability by polyacrylonitrile nanofibers containing 10 wt% of titania/AgNP nanoparticles.

In this study, blended films from poly(vinyl alcohol) (PVA) containing chitosan (CS) were prepared via a simple solution casting and electrospraying method. The structures of the PVA-CS films were characterized by Fourier-transform infrared spectroscopy. The morphologies of the films were observed by scanning electron microscopy. The thermal properties of the PVA-CS films were examined by thermogravimetry. The effects of CS contents on the mechanical properties, oxygen permeability values, water vapor permeation levels, and antibacterial behaviors against Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) strains were investigated. Compared to the pure PVA film, the PVA-CS films showed greater elongation at break, lower oxygen permeability, higher water barrier properties, and greater antibacterial activity, especially for the PVA:CS weight ratio of 75:25. The obtained results indicate the PVA-CS film may be a promising material for food packaging applications. [ABSTRACT FROM AUTHOR]

Zn-doped and Cu-doped SiOx films were synthesized by atmospheric pressure plasma chemical vapor deposition to study their antibacterial efficiency against Gram-negative Escherichia coli and their cytotoxic effect on the growth of mouse cells. Zn-rich and Cu-rich particles with diameters up to several microns were found to be homogeneously distributed within the SiOx films. For both doping elements, bacteria are killed within the first three hours after exposure to the film surface. In contrast, mouse cells grow well on the surfaces of both film types, with a slight inhibition present only after the first day of exposure. The obtained results indicate that the films show a high potential for use as effective antibacterial surfaces for medical applications.

BACKGROUND Antibacterial films were prepared using sodium alginate ( SA) and carboxymethyl cellulose ( CMC) as a matrix, glycerin as a plasticizer and CaCl2 as a cross-linking agent, and by incorporating the natural antibacterial agent pyrogallic acid ( PA). The present study describes the microstructure and the physical, barrier, mechanical, optical and antibacterial properties of blended films prepared by incorporating different concentrations of PA into the SA/ CMC matrix. RESULTS The microstructure of the films was investigated by Fourier transform infrared spectroscopy and scanning electron microscopy, which revealed that PA interacts with the SA/ CMC matrix through hydrogen bonding. Moreover, the incorporation of PA increased the moisture content, water vapor permeability and oxygen permeability of SA/ CMC films. Films containing 40 g kg−1 of PA had the highest elongation at break result (39.60%). Compared with pure SA/ CMC films, the incorporation of PA improved the barrier properties against ultraviolet light; however, it decreased the color parameter L* value and increased the a* and b* values of the films. Furthermore, films with PA, especially at higher concentrations, were more effective against Escherichia coli and Staphylococcus aureus. CONCLUSION Antibacterial SA/ CMC films incorporating PA appear to have good potential to enhance the safety of foods and food products. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

With the consumption of disposable electronic devices increasing, it is meaningful but also a big challenge to develop reusable and sustainable materials to replace traditional single-use sensors. Herein, a clever strategy for constructing a multifunctional sensor with 3R circulation (renewable, reusable, pollution-reducing biodegradable) is presented, in which silver nanoparticles (AgNPs) with multiple interactions are introduced into a reversible non-covalent cross-linking network composed of biocompatible and degradable carboxymethyl starch (CMS) and polyvinyl alcohol (PVA) to simultaneously obtain high mechanical conductivity and long-term antibacterial properties by a one-pot method. Surprisingly, the assembled sensor shows high sensitivity (gauge factor up to 4.02), high conductivity (0.1753 S m -1 ), low detection limit (0.5%), long-term antibacterial ability (more than 7 days), and stable sensing performance. Thus, the CMS/PVA/AgNPs sensor can not only accurately monitor a series of human behavior, but also identify handwriting recognition from different people. More importantly, the abandoned starch-based sensor can form a 3R circulation. Especially, the fully renewable film still shows excellent mechanical performance, achieving reusable without sacrificing its original function. Therefore, this work provides a new horizon for multifunctional starch-based materials as sustainable substrates for replacing traditional single-use sensors., (© 2023 Wiley-VCH GmbH.)

Super-elastic Titanium based thin films Ti-23Nb-0.7Ta-2Zr-(O) (TNTZ-O) and Ti-24Nb-(N) (TN-N) (at.%) were deposited by direct current magnetron sputtering (DCMS) in different reactive atmospheres. The effects of oxygen doping (TNTZ-O) and/or nitrogen doping (TN-N) on the microstructure, mechanical properties and biocompatibility of the as-deposited coatings were investigated. Nano-indentation measurements show that, in both cases, 1 sccm of reactive gas in the mixture is necessary to reach acceptable values of hardness and Young’s modulus. Mechanical properties are considered in relation to the films compactness, the compressive stress and the changes in the grain size. Data on Bacterial inactivation and biocompatibility are reported in this study. The biocompatibility tests showed that O-containing samples led to higher cells proliferation. Bacterial inactivation was concomitant with the observed pH and surface potential changes under light and in the dark. The increased cell fluidity leading to bacterial lysis was followed during the bacterial inactivation time. The increasing cell wall fluidity was attributed to the damage of the bacterial outer cell which losing its capacity to regulate the ions exchange in and out of the bacteria. [ABSTRACT FROM AUTHOR]

Insight is provided in this study for the effect of the TiO 2 film densification/compactness on polyethylene (PE-TiO 2 ) by sputtering TiO 2 at two very different energy levels. Uniform, adhesive low energy films were prepared by direct current magnetron sputtering (DCMS) and compared with films sputtered at high energy levels by high power impulse magnetron sputtering (HIPIMS). Nano-particulate TiO 2 films sputtered by HPIMS presented sizes of ∼10.2 nm compared to films sputtered by DCMS with TiO 2 sizes of ∼16.5 nm as determined by X-ray diffraction (XRD). The E. coli inactivation kinetics was three times faster for the samples sputtered by HIPIMS compared to their DCMS counterparts. This is an unexpected finding since the DCMS presenting larger TiO 2 sized nanoparticles released a higher amount of Ti-ions compared to the HIPIMS samples as monitored by inductively coupled plasma mass-spectrometry (ICP-MS). The Ti-ions released do not seem to react through an oligodynamic effect but diffuse through the less compact TiO 2 sputtered by DCMS. The faster bacterial inactivation kinetics observed by the HIPIMS sputtered samples can be understood in terms of the complete of Ti 4+ /Ti 3+ redox conversion during bacterial inactivation detected by X-ray photo-electron spectroscopy (XPS) compared to the smaller Ti 4+ /Ti 3+ effect observed in the DCMS-samples. A higher optical density was detected for the HIPIMS sputtered samples by diffuse reflectance spectroscopy (DRS). Evidence is presented for the shift in surface potential and local pH during bacterial inactivation under aerobic and anaerobic conditions. A reaction mechanism is suggested based on the findings described in this study. The sputtered films present the potential to hinder biofilm formation on flexible thin polymers/textiles widely used in hospitals and health facilities. [ABSTRACT FROM AUTHOR]

In the current approach, antibacterial chitosan-silver nanocomposite films were fabricated through microwave irradiation. During the process, by utilizing chitosan as reducing agent, silver nanoparticles were synthesized within 11 min by microwave irradiation. Further, films were fabricated within 90 min. It involved an energy consumption of just 0.146 kWh to synthesize silver nanoparticles. This is many times less than the energy consumed during conventional methods. The silver nanoparticles were examined through UV–vis spectrum and transmission electron microscopy (TEM). The fabricated films were characterized by using scanning electron microscopy coupled with an energy dispersive spectrometer (SEM–EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and contact angle (CA) measurements. The films exhibited antibacterial properties against both Gram-negative micro-organisms ( Escherichia coli ; E. coli ) and Gram-positive micro-organisms ( Staphylococcus aureus ; S. aureus ). In overall, the procedure adopted for fabricating these antibacterial films is environmental friendly, time-saving and energy-saving. [ABSTRACT FROM AUTHOR]

Over the past decade, there have been many interesting studies in the scientific literature about the interaction of graphene-based polymeric nanocomposites with microorganisms to tackle antimicrobial resistance. These studies have reported variable intensities of biocompatibility and selectivity for the nanocomposites toward a specific strain, but it is widely believed that graphene nanocomposites have antibacterial, antiviral, and antifungal activities. Such antibacterial activity is due to several mechanisms by which graphene nanocomposites can act on cells including stimulating oxidative stress; disrupting membranes due to sharp edges; greatly changing core structure mechanical strength and coarseness. However, the underlying mechanisms of graphene nanocomposites as antiviral and antifungal agents remain relatively scarce. In this review, recent advances in the synthesis, functional tailoring, and antibacterial, antiviral, and antifungal applications of graphene nanocomposites are summarized. The synthesis of graphene materials and graphene-based polymeric nanocomposites with techniques such as pressurized gyration, electrospinning, chemical vapor deposition, and layer-by-layer self-assembly is first introduced. Then, the antimicrobial mechanisms of graphene membranes are presented and demonstrated typical in vitro and in vivo studies on the use of graphene nanocomposites for antibacterial, antiviral, and antifungal applications. Finally, the review describes the biosafety, current limitations, and potential of antimicrobial graphene-based nanocomposites., (© 2023 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH.)

Highlights: [•] Uniform and adhesive sputtered TiON on polyester leading to bactericide films. [•] TiON bacterial inactivation in the minute range under simulated solar irradiation. [•] Repetitive bacterial inactivation by TiON films showing stable performance. [Copyright &y& Elsevier]

Abstract: Anatase-structured TiO2 films were deposited on a commercial fluorinated polymer (FEP) with a treated surface, by means of a sol–gel dip-coating technique. Two different curing temperatures were investigated and the film microstructures were characterized by X-ray diffraction, atomic force microscopy and scanning electron microscopy analyses. The prepared samples presented very high performances in terms of photocatalytic activities, analyzed by the degradation of an organic dye in a liquid medium, and of bactericidal activities, tested on Staphylococcus aureus (S. aureus, a Gram positive bacterium) and Escherichia coli (E. coli, a Gram negative bacterium). [Copyright &y& Elsevier]

[Display omitted] • Preparation of an antibacterial film decorated with silver nanoparticles (AgNPs). • Silver nitrates were in situ reduced to AgNPs by lemon juice during film preparation. • Lemon juice enhanced the mechanical properties of films. • Polyvinyl alcohol can be used as a dispersant in film to make the AgNPs ubiquitous. • The AgNPs films had good bacteriostatic effect. Microorganisms contribute to deterioration of garden stuff after picking. Antibacterial films consisting of polyvinyl alcohol (PVA), soluble starch (SS), and silver nanoparticles (AgNPs) with AgNPs in situ reduced from AgNO 3 by lemon juice (LJ) were developed to combat microbial corruption. PVA/SS/LJ/AgNPs films have better tensile strength and elongation at break, but lower water vapor permeability, moisture absorption, and transmittance compared to PVA/SS and PVA/SS/LJ films. Silver released from PVA/SS/LJ/AgNPs films were 13.55, 18.97, 19.55, 20.19, 20.47, and 20.82 mg/g after submerging samples in water for three seconds and soaking for 1, 2, 3, 4, and 5 days, respectively. PVA/SS/LJ/AgNPs films had good bacteriostatic effects on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Salmonella, as the average diameter of the inhibition circle was 12.12 ± 0.01, 13.04 ± 0.02, 14.79 ± 0.01, 14.20 ± 0.01, and 12.68 ± 0.01 mm, respectively. Therefore, PVA/SS/LJ/AgNPs film has a wide application prospect. [ABSTRACT FROM AUTHOR]

In this current work, antimicrobial films based on starch, poly(butylene adipate-co-terephthalate) (PBAT), and a commercially available AgNPs@SiO2 antibacterial composite particle product were produced by using a melt blending and blowing technique. The effects of AgNPs@SiO2 at various loadings (0, 1, 2, 3, and 4 wt%) on the physicochemical properties and antibacterial activities of starch/PBAT composite films were investigated. AgNPs@SiO2 particles were more compatible with starch than PBAT, resulting in preferential distribution of AgNPs@SiO2 in the starch phase. Infusion of starch/PBAT composite films with AgNPs@SiO2 marginally improved mechanical and water vapor barrier properties, while surface hydrophobicity increased as compared with films without AgNPs@SiO2. The composite films displayed superior antibacterial activities against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The sample loaded with 1 wt% AgNPs@SiO2 (SPA-1) showed nearly 90% inhibition efficiency on the tested microorganisms. Furthermore, a preliminary study on peach and nectarine at 53% RH and 24 °C revealed that SPA-1 film inhibited microbial spoilage and extended the product shelf life as compared with SPA-0 and commercial LDPE packaging materials. The high-throughput production method and strong antibacterial activities of the starch/PBAT/AgNPs@SiO2 composite films make them promising as antimicrobial packaging materials for commercial application. [ABSTRACT FROM AUTHOR]

The aim of the study was to establish the influence of poly(ethylene glycol) (PEG) on the properties of potential biodegradable packaging materials with antibacterial properties, based on polylactide (PLA) and tea tree essential oil (TTO). The obtained polymeric films consisted of PLA, a natural biocide, and tea tree essential oil (5–20 wt. %) was prepared with or without an addition of 5 wt. % PEG. The PLA-based materials have been tested, taking into account their morphology, and their thermal, mechanical and antibacterial properties against Staphylococcus aureus and Escherichia coli. It was established that the introduction of a plasticizer into the PLA–TTO systems leads to an increase in tensile strength, resistance to deformation, as well an increased thermal stability, in comparison to films modified using only TTO. The incorporation of 5 wt. % PEG in the PLA solution containing 5 wt. % TTO allowed us to obtain a material exhibiting a satisfactory antibacterial effect on both groups of representative bacteria. The presented results indicated a beneficial effect of PEG on the antibacterial and functional properties of materials with the addition of TTO. [ABSTRACT FROM AUTHOR]

This study aimed to develop soy protein isolate (SPI)-based active nanocomposite films reinforced with cellulose nanocrystals (CNC), zinc oxide nanoparticles (ZnONP), CNC/ZnONP mixture (physical mixing), or CNC@ZnONP nanohybrids (in situ growth). The tensile strength, oxygen and water vapor barrier properties, water resistance ability, and thermal stability were substantially improved by the incorporation of nano reinforcements, particularly the CNC-containing agents. However, the nanocomposite films displayed a lower elongation at break, surface hydrophobicity, and transmittance compared with the pure SPI-based film. The filling effect of reinforcements and their hydrogen bonds with the film matrix contributed to the formation of a compact and homogeneous film structure. The ZnO-containing films obviously inhibited the growth of foodborne pathogens (Escherichia coli and Staphylococcus aureus) and also reduced the total viable counts and the total volatile basic nitrogen values in a pork sample. Furthermore, the CNC@ZnONP film prevented the migration of zinc from the film into the food system. Therefore, the obtained nanocomposite films have broad application prospects in the field of active food packaging. Image 1 • Cellulose nanocrystals@ZnO nanoparticles (CNC@ZnONP) nanohybrids were synthesized. • Soy protein isolate-based antibacterial nanocomposite films were developed. • CNC improved the tensile strength, barrier ability, and thermal stability of films. • The films containing ZnONP had potential to extend the shelf-life of fresh pork. • The CNC@ZnONP film prevented the migration of zinc from film to the food system. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop active edible coatings based on marine polysaccharide matrices and polyphenols-enriched native plant extracts from arid and semiarid regions of Argentina. Initially, five plant extracts were characterized in terms of antioxidant, antibacterial and antiviral activity and the one with better biological properties and no toxicity or genotoxicity, Larrea nitida (Ln) extract, was incorporated into agar, alginate or agar/alginate matrices. The Ln extract-containing films were characterized in terms of physicochemical and polyphenols release performance in food simulants. The incorporation of Ln extract provided darker films, with a more saturated orange-brownish color and with negligible effects on mechanical and barrier properties. Additionally, all the coatings showed antiviral activity when applied to blueberries against murine norovirus (MNV), a cultivable norovirus surrogate. The coatings of agar and Ln extract was able to reduce the infectivity of MNV below the limit of detection after over-night (ON) incubation at 25 °C and after 4 days at 10 °C storage. These edible polysaccharides coatings containing Ln extract could be an alternative to reduce or eliminate foodborne viruses and protect the food against oxidative process. Image 1 • Polyphenolic plant extracts were used for the development of active edible coatings. • Larrea nitida extract showed the greatest antioxidant and antimicrobial properties. • Ln extract was not toxic or genotoxic at the concentration used (500 μg/mL). • Antioxidant and antimicrobial coatings were formed with agar, alginate and Ln extract. • Ln containing coatings reduced the titers of MNV in artificially contaminated berries. [ABSTRACT FROM AUTHOR]