Bacterial Reduction Rates Research Articles

Photothermal Antibacterial and Osteoinductive Polypyrrole@Cu Implants for Biological Tissue Replacement.

The treatment of bone defects caused by disease or accidents through the use of implants presents significant clinical challenges. After clinical implantation, these materials attract and accumulate bacteria and hinder the integration of the implant with bone tissue due to the lack of osteoinductive properties, both of which can cause postoperative infection and even lead to the eventual failure of the operation. This work successfully prepared a novel biomaterial coating with multiple antibacterial mechanisms for potent and durable and osteoinductive biological tissue replacement by pulsed PED (electrochemical deposition). By effectively regulating PPy (polypyrrole), the uniform composite coating achieved sound physiological stability. Furthermore, the photothermal analysis showcased exceptional potent photothermal antibacterial activity. The antibacterial assessments revealed a bacterial eradication rate of 100% for the PPy@Cu/PD composite coating following a 24 h incubation. Upon the introduction of NIR (near-infrared) irradiation, the combined effects of multiple antibacterial mechanisms led to bacterial reduction rates of 99% for E. coli and 98% for S. aureus after a 6 h incubation. Additionally, the successful promotion of osteoblast proliferation was confirmed through the application of the osteoinductive drug PD (pamidronate disodium) on the composite coating's surface. Therefore, the antimicrobial Ti-based coatings with osteoinductive properties and potent and durable antibacterial properties could serve as ideal bone implants.

Eco-friendly activation of cotton textiles with LiNbO3 nanoparticles for enhanced self-cleaning and antibacterial performance

Cotton textiles play a universal role in everyday life, but they are prone to stain and serve as a primary channel for transmitting viruses and bacteria. The photocatalytic/antibacterial coatings are highly effective in addressing bacterial contamination on fabrics, although their efficacy diminishes with continuous use and washing. Here, insights are provided into the attachment of LiNbO3 on cotton surfaces using eco-friendly chemical activators to promote resistance to washing cycles, self-cleaning, and bactericide textiles. LiNbO3 nanoparticles were synthesized by low-temperature hydrothermal synthesis and directly applied to cotton fabric using immersion. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) N2 adsorption, diffuse reflectance for band gap determination, and Raman spectroscopy. A simple and effective impregnation method was used, promoting an ester-bond attachment between the cotton surface and the activators. Microscopy analysis (SEM) confirmed the successful deposition of the nanoparticles on cotton fabric. The LiNbO3 coating consisted of transparent layers and did not change the properties of cotton. Methylene blue stains are generally eliminated under UV light after 2 h using nanoparticles and activators. Antibacterial properties were evaluated under visible light through direct contact with bacterial suspensions and culturing. The coated cotton fabric that was activated with oxalic acid exhibited significant photocatalytic antibacterial activity against both Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) bacteria, with bacterial reduction rate above 97 %, even after 10 washing cycles. This performance can be attributed to the effective coupling of LiNbO3 with oxalic acid in the cotton’s surface and its resistance to washing out. This study's novel synthesis and coating method offers an environmentally friendly, cost-effective, and straightforward approach for producing LiNbO3 self-cleaning and antibacterial surface-activated cotton.

Production and performance evaluation of chitosan/collagen/honey nanofibrous membranes for wound dressing applications

Persistent bacterial infections are the leading risk factor that complicates the healing of chronic wounds. In this work, we formulate mixtures of polyvinyl alcohol (P), chitosan (CH), collagen (C), and honey (H) to produce nanofibrous membranes with healing properties. The honey effect at concentrations of 0 % (PCH and PCHC), 5 % (PCHC-5H), 10 % (PCHC-10H), and 15 % (PCHC-15H) on the physicochemical, antibacterial, and biological properties of the developed nanofibers was investigated. Morphological analysis by SEM demonstrated that PCH and PCHC nanofibers had a uniform and homogeneous distribution on their surfaces. However, the increase in honey content increased the fiber diameter (118.11–420.10) and drastically reduced the porosity of the membranes (15.79–92.62 nm). The addition of honey reduces the water vapor transmission rate (WVTR) and the adsorption properties of the membranes. Mechanical tests revealed that nanofibers were more flexible and elastic when honey was added, specifically the PCHC-15H nanofibers with the lowest modulus of elasticity (15 MPa) and the highest elongation at break (220 %). Also, honey significantly improved the antibacterial efficiency of the nanofibers, mainly PCHC-15H nanofibers, which presented the best bacterial reduction rates against Staphylococcus aureus (59.84 %), Pseudomonas aeruginosa (47.27 %), Escherichia coli (65.07 %), and Listeria monocytogenes (49.58 %). In vitro tests with cell cultures suggest that nanofibers were not cytotoxic and exhibited excellent biocompatibility with human fibroblasts (HFb) and keratinocytes (HaCaT), since all treatments showed higher or similar cell viability as opposed to the cell control. Based on the findings, PVA-chitosan-collagen-honey nanofibrous membranes have promise as an antibacterial dressing substitute.

Development of UV protective and antimicrobial CVC fabric using colloidal zinc oxide solution with carrot and orange peel extract

AbstractChronic exposure to ultraviolet (UV) radiation can cause degenerative changes in the cells, fibrous tissues and blood vessels. Moreover, microbiological attacks pose severe risks to human health and are a major cause of sickness worldwide. The aim of this work is to develop UV protective and antimicrobial materials using zinc oxide (ZnO) colloidal solution with carrot and orange peel extract. Treated samples were subjected to color strength (K/S value) measurement, scanning electron microscope (SEM) image analysis, attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy analysis, ultraviolet protection factor (UPF) test, bacterial reduction rate analysis and bursting strength measurement. The study revealed that the treated fabric exhibited remarkable UV protection capabilities, as evidenced by low transmission percentages across UV wavelengths and an outstanding UPF rating of 50, signifying excellent defense against harmful ultraviolet radiation. Additionally, antibacterial tests revealed the significant effectiveness of the treatment against common bacterial strains, with impressive reduction rates for Staphylococcus aureus (99.99%) and Escherichia coli (99.17%). Furthermore, the fabric's bursting strength, both in dry and wet conditions, remained nearly unchanged after treatment. ATR‐FTIR analysis and SEM imaging provided insights into the phytochemical compounds that give protection against UV composition (44.63–49.91) and surface morphology of the treated fabric, elucidating the mechanisms behind its enhanced properties. Due to the availability of carrot and orange peel in nature and low cost of raw materials, this process can be considered to apply commercially for further research purposes.Highlights Utilization of carrot and orange peel waste. Successful application of zinc oxide for antibacterial and ultraviolet protective materials. Excellent defense against harmful ultraviolet radiation. Significant effectiveness against common bacterial strains. Low cost and commercially viable functional materials.

Chitosan/Alginate-Based Nanoparticles for Antibacterial Agents Delivery.

Nanoparticle systems integrating alginate and chitosan emerge as a promising avenue to tackle challenges in leveraging the potency of pharmacological active agents. Owing to their intrinsic properties as polysaccharides, alginate and chitosan, exhibit remarkable biocompatibility, rendering them conducive to bodily integration. By downsizing drug particles to the nano-scale, the system enhances drug solubility in aqueous environments by augmenting surface area. Additionally, the system orchestrates extended drug release kinetics, aligning well with the exigencies of chronic drug release requisite for antibacterial therapeutics. A thorough scrutiny of existing literature underscores a wealth of evidence supporting the utilization of the alginate-chitosan nanoparticle system for antibacterial agent delivery. Literature reviews present abundant evidence of the utilization of nanoparticle systems based on a combination of alginate and chitosan for antibacterial agent delivery. Various experiments demonstrate enhanced antibacterial efficacy, including an increase in the inhibitory zone diameter, improvement in the minimum inhibitory concentration, and an enhancement in the bacterial reduction rate. This enhancement in efficacy occurs due to mechanisms involving increased solubility resulting from particle size reduction, prolonged release effects, and enhanced selectivity towards bacterial cell walls, stemming from ionic interactions between positively charged particles and teichoic acid on bacterial cell walls. However, clinical studies remain limited, and there are currently no marketed antibacterial drugs utilizing this system. Hence, expediting clinical efficacy validation is crucial to maximize its benefits promptly.

Comfort Properties and Antimicrobial Activity of Cotton and Nylon/PU Knits Treated with Microcapsules Containing Sea Buckthorn Oil

This study was performed to investigate comfort properties and antimicrobial activity of cotton and nylon knits treated with microcapsules containing sea buckthorn fruit oil reported as having antimicrobial efficacy depending on concentration of microcapsules and treatment types. Chitosan-arabic gum microcapsules containing sea buckthorn fruit oil were prepared and they were treated on cotton and nylon/PU knit respectively by an experimental design of 2 different treatment types (bath immersion method and screen printing method) Χ 5 different concentration levels of microcapsules (20, 30, 40, 50, and 60% on the weight of fabric). As comfort properties, stiffness, water-vapor permeability, and air permeability were measured objectively. Antimicrobial activity was evaluated by calculating the percentage reduction of the bacterium. As results, stiffness values of the treated knits were slightly higher than those of untreated ones, which was thought not to affect touch in wear. The values of water-vapor permeability and air permeability of both cotton and nylon after the treatment were not significantly decreased. These results means that microcapsules loaded on the knits might not worsen their wear comfort. As for antimicrobial activity, more than 90% of bacterial reduction rates against S. Aureus were shown in cotton jersey by screen printing even after repeated laundry while those was found in nylon/PU tricot by bath immersion. From these results, it was concluded that chitosan-arabic gum microcapsule containing sea buckthorn fruit oil could be utilized for textiles to provide antimicrobial activity.

Functionalization of graphene oxide with amphiphilic block copolymer to enhance antibacterial activity

Functionalization of GO with an amphiphilic block copolymer is designed with an aim to enhance its biocompatibility, however, long copolymer chains can screen the blade effect of GO to sacrifice its antimicrobial activities. To solve this problem, low molecular weight of poly(ethylene glycol) (PEG), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and their block copolymer were respectively introduced onto GO via an isophorone diisocyanate modified GO as a intermediate, followed by a solvent evaporation of an oil-in-water emulsion treatment (SE treatment) to induce block copolymer into polymer micelle via phase separation to refresh the sharp edges of GO. Block copolymer modified GO possessed similar dispersibility and stability to PEG modified GO, and even higher loading capacity of the hydrophobic drug than PHBV modified GO, illustrating its superior properties to homopolymer. PEG, PHBV and their block copolymer modified GO were nontoxic towards ATDC5 cells while cultured for 3 days and compatible with erythrocytes within 8 h. SE treatment enhanced greatly the loading capacity of the hydrophobic drug and the accumulative release reached 91.3% within 24 h. The inhibition zone of the block copolymer modified GO was 14.1 mm and 14.8 mm against E. coli and S. aureus, comparable to that of PEG modified GO. The bacterial reduction rate of the copolymer micelle modified GO was 87.1% and 82.7% towards E. coli and S. aureus, much greater than that of PEG, PHBV and their block copolymer modified GO at a concentration of 1 mg/mL. The antibiofilm capacity of the copolymer micelle modified GO were equal to that of PEG modified, demonstrating its great promise in tissue engineering application for repair of infected tissue defects.

Structure and Properties of Cationic Chitosan Derivative Modified Bombyx mori

Abstract Cationic modification of silk fabric can highly improve its antibacterial property, but cationic modification may change the microstructure of silk fiber, and further affect its properties, thus O-methyl acrylamide quaternary ammonium salt of chitosan (NMA-HTCC), which is a kind of strong cationic chitosan derivative, was used for the modification on Bombyx mori silk fiber. The combination structure between NMA-HTCC and silk fiber was characterized by FT-IR. The surface morphology and structure of silk fiber after being treated by NMA-HTCC were investigated by SEM and XPS analysis. The crystalline structure and thermal stability of silk fibers before and after being treated were determined by XRD and DSC analysis, respectively. Then the breaking strength, breaking elongation and antibacterial properties of the silk yarns were also determined. The results indicated that the NMA-HTCC modified silk fiber clearly showed two characteristic absorption peaks at 1535 cm-1 and 1670 cm-1 due to the N-H bending and C=O stretch of the secondary amide in the acrylamidomethyl group of the NMA-HTCC molecule. The successful combination of NMA-HTCC and silk fiber was also confirmed by XPS and SEM analysis. Compared with the untreated silk sample, the diffracted intensity of the characteristic absorption peak and crystallinity of the NMA-HTCC modified silk fiber were both increased; the internal aggregation structure of the silk fiber treated with NMA-HTCC was much closer and its thermal stability was enhanced obviously. The breaking strength and elongation of silk fibers after being treated with NMA-HTCC were also significantly increased. Silk fibers treated with NMA-HTCC had excellent durable antibacterial properties against S. aureus and E. coli, even after 50 repeated launderings, with the bacterial reduction rate of the silk fibers maintained at over 95 %. The results in this research can provide the theoretical basis for the application of NMA-HTCC in the modifications of silk fabric.

Thymol-loaded polylactic acid electrospun fibrous membranes with synergistic biocidal and anti-bacterial adhesion properties via morphology control

Antibiotic resistance is a growing challenge in modern medicine, highlighting the urgent need for alternative antimicrobial strategies. The combination of synergistic sterilization and inhibition of bacterial adhesion presents a promising approach for achieving a long-lasting antibacterial effect. Herein, we report the fabrication of thymol-loaded polylactic acid (Thy-PLA) porous fibrous membranes that exhibit both bacteria-killing and bacteria-repellent functions, accomplished through control of microstructure and morphology during the electrospinning process. Notably, we employed the breath figure method, a humidity-induced morphology control technique, which significantly increased the surface roughness of the Thy-PLA fibers and resulted in a nano-porous structure for bacterial repulsion. Additionally, this method facilitated the enhanced release of thymol, thereby enabling efficient sterilization. By simply modifying the morphology, we achieved bacterial reduction rates of up to 99.92 % and 99.87 % for Escherichia coli and Staphylococcus aureus, respectively, and robust mechanical properties (ultimate tensile stress of 20 MPa and elongation at break of 822.7 %). Furthermore, the fibrous membranes exhibited an impressive oil/water absorption capacity (∼36.7 g/g in 90 s) thanks to the interior and surface porosity. The porous fibrous membranes with synergistic antimicrobial efficiency and tunable mechanical properties demonstrate great potential for diverse applications, particularly in wound dressing and oil/water filtration.

Fabrication and Characterization of Electrospun Chitosan/Polylactic Acid (CH/PLA) Nanofiber Scaffolds for Biomedical Application.

The present study demonstrates a strategy for preparing porous composite fibrous materials with superior biocompatibility and antibacterial performance. The findings reveal that the incorporation of PEG into the spinning solutions significantly influences the fiber diameters, morphology, and porous area fraction. The addition of a hydrophilic homopolymer, PEG, into the Ch/PLA spinning solution enhances the hydrophilicity of the resulting materials. The hybrid fibrous materials, comprising Ch modified with PLA and PEG as a co-solvent, along with post-treatment to improve water stability, exhibit a slower rate of degradation (stable, moderate weight loss over 16 weeks) and reduced hydrophobicity (lower contact angle, reaching 21.95 ± 2.17°), rendering them promising for biomedical applications. The antibacterial activity of the membranes is evaluated against Staphylococcus aureus and Escherichia coli, with PEG-containing samples showing a twofold increase in bacterial reduction rate. In vitro cell culture studies demonstrated that PEG-containing materials promote uniform cell attachment, comparable to PEG-free nanofibers. The comprehensive evaluation of these novel materials, which exhibit improved physical, chemical, and biological properties, highlights their potential for biomedical applications in tissue engineering and regenerative medicine.

Microbial investigation of cleanability of different plastic and metal surfaces used by the food industry

Different conveyor belt materials used by the meat and other food industries were compared, regarding their cleanability as bacterial reduction rates in relation to their surface topography. Eleven thermoplastic polymers, four stainless steels, and five aluminized nanostructured surfaces were investigated under laboratory conditions. Cleanings were conducted with water only, and with an alkaline foam detergent. Overall, scanning electron microscopy revealed remarkable differences in the surface topography of the tested surfaces. Water cleaning results showed that nanostructured aluminized surfaces achieved significantly higher cleanability rates compared to the eight thermoplastic surfaces, as well as the glass-bead blasted rough stainless steel. Thermoplastic surfaces showed overall low cleanability rates when cleaned with alkaline detergent, while stainless steel and nanoporous aluminum showed high variations. Overall, nanoporous aluminum showed promising results as it can be used to coat conveyor belts. However, compatibility with cleaning detergent and sensitivity to scratches must be further investigated. Overall, it can be concluded that cleanability is not only influenced by surface roughness, but also by the overall surface finish, scratches, and defects.

The effect of silver nanoparticle concentration on the antibacterial properties of tri-layer PCL-Ag/PT/PVP wound dressing

To comprehensively manage wound infection, tri-layer fibre membranes have been designed with two antibacterial agents, including silver nanoparticles (AgNPs) and chitosan oligosaccharide (COS), and their antibacterial properties were evaluated using qualitative and quantitative tests. While the first polycaprolactone (PCL) silver layer and the second plasma-treated PCL layer were fabricated by electrospinning, the third COS layer was constructed via coating and heat-vacuum drying. The formation of the membranes and their fibrous and porous structures were examined using scanning electron microscopy (SEM). The antibacterial activities of the membranes against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus were examined by disk diffusion and percentage reduction assays, which were performed simultaneously as per the certificates from the Ministry of Health Institute of Public Health in Ho Chi Minh city. The tri-layer membranes, named PCLAg50/PT (plasma treatment)/COS and PCLAg500/PT/COS, achieved desirable antibacterial results with extensive inhibition zones and bacterial reduction rates ranging from 99-100%. In addition, while the PCLAg500 membrane exhibited broad inhibition zones and reduction rates ranging from 94.6-97%, the PCLAg50 membrane achieved reduction rates ranging from 67.5-82.1% despite the absence of inhibition zones. As a result, the fabricated tri-layer membranes could reduce local and opportunistic infections. Depending on infectious risks, the concentration of silver utilsed as an infection-prevention agent must be adjusted from 50 to 500 ppm to ensure safety.

Fabrication of PVA/graphene nanofibrous membrane infused with neem extraction for packaging and biomedical applications

Graphene nanofibrous membranes have been synthesized in the present study by combining neem with graphene and using polyvinyl alcohol (PVA). The nanofibrous membranes have been synthesized using an electrospinning under optimum processing conditions for food packaging and biomedical applications. The FTIR analysis confirmed the presence of different organic compounds in the materials. XRD analysis confirmed the crystallinity of the fabricated materials. The minimum average diameter of the fibers was 276.9 nm, approved by the SEM images. The fabricated materials contained Al as the maximum atomic percentage confirmed by the EDX analysis. All the samples had the same top absorption rate. The addition of neem increased the thermal stability of the materials, approved by the thermal analysis. The maximum bacterial reduction rate was observed against the gram-negative bacteria strain Escherichia coli in sample R3. The results demonstrated that the synthesized nanofibrous membranes can be used for biomedical applications.

Staphylococcus aureus binding to Seraph® 100 Microbind® Affinity Filter: Effects of surface protein expression and treatment duration.

Extracorporeal blood purification systems represent a promising alternative for treatment of blood stream infections with multiresistant bacteria. The aim of this study was to analyse the binding activity of S. aureus to Seraph affinity filters based on heparin coated beads and to identify effectors influencing this binding activity. To test the binding activity, we used gfp-expressing S. aureus Newman strains inoculated either in 0.9% NaCl or in blood plasma and determined the number of unbound bacteria by FACS analyses after passing through Seraph affinity filters. The binding activity of S. aureus was clearly impaired in human plasma: while a percent removal of 42% was observed in 0.9% NaCl (p-value 0.0472) using Seraph mini columns, a percent removal of only 10% was achieved in human plasma (p-value 0.0934). The different composition of surface proteins in S. aureus caused by the loss of SarA, SigB, Lgt, and SaeS had no significant influence on its binding activity. In a clinically relevant approach using the Seraph® 100 Microbind® Affinity Filter and 1000 ml of human blood plasma from four different donors, the duration of treatment was shown to have a critical effect on the rate of bacterial reduction. Within the first four hours, the number of bacteria decreased continuously and the reduction in bacteria reached statistical significance after two hours of treatment (percentage reduction 64%, p-value 0.01165). The final reduction after four hours of treatment was close to 90% and is dependent on donor. The capacity of Seraph® 100 for S. aureus in human plasma was approximately 5 x 108 cells. The Seraph affinity filter, based on heparin-coated beads, is a highly efficient method for reducing S. aureus in human blood plasma, with efficiency dependent on blood plasma composition and treatment duration.

High antibacterial durability of silver nanoparticles anchored on cotton fiber surfaces by 4‐vinylpyridine polymers synthesized via a “grafting through” strategy

AbstractThis study aims at developing novel methodology to prepare antibacterial cotton fabric with excellent antibacterial durability, and a “grafting through” approach was adopted to enhance affinity of Ag NPs with cotton fiber surfaces. The surface modification was carried out by covalently linking acrylic acid (AA) molecules onto the fibers, then 4‐vinylpyridine was copolymerized with the AA moieties as a polymeric binder. Once the coordination bonds were formed between silver nanoparticles (Ag NPs) and the pyridine nitrogen, Ag NPs could be stably immobilized on the cotton fabric. Experimental results showed that the AA‐co‐PVP grafting copolymer had a significant regulatory effect on the dispersion and particle size of Ag particles, and the resulting cotton fabric presented a high antibacterial property with excellent durability. Even after 120 washing cycles, the bacterial reduction rates of the modified fabric against both Staphylococcus aureus and Escherichia coli retained a level higher than 99%. In addition, other textile attributes, such as vapor transmissibility, water absorbability and flexibility, could be largely retained in the modified fabrics.

Development of g-C3N4/ZnO nanocomposite as a novel, highly effective and durable photocatalytic antibacterial coating for cotton fabric

Photocatalytic antibacterial coats are considered among the best solutions to bacterial contamination of fabrics, with the drawback of reduced efficacy after continued use and washing. In the present study, the g-C3N4/ZnO (CNZ) nanocomposite has been introduced as a novel cotton fabric coating, with high durability, and CNZ nanopowders were synthesized using a two-step thermal synthesis process and directly coated onto cotton fabric using the sonication technique. The synthesized nanoparticles (NPs) were examined using X-ray diffraction (XRD), UV–visible spectroscopy, photoluminescence (PL), Brunauer-Emmett-Teller (BET), and Fourier transform infrared (FTIR) analyzes. Besides, the SEM analysis confirmed the successful deposition of NPs on cotton fabric. The photodegradation of methylene blue (MB) stain was assessed as a functional test for the photocatalytic effectiveness of the coated fabric, then its antibacterial properties were evaluated under visible light, by direct contact with bacterial suspensions and culturing. The results revealed that the CNZ-coated cotton fabric containing 30% ZnO (CNZ-30) has significant photocatalytic antibacterial activity against both Escherichia coli (gram-negative), and Staphylococcus aureus (gram-positive) bacteria. The bacterial reduction rate of CNZ-30 coated fabric for both E. coli and S. aureus was above 98%, even after 18 washing cycles. This excellent performance is attributed to the effective coupling of ZnO with g-C3N4, improved light absorption, and reduced e−/h+ pair recombination rates. This study novel coating method can offer an environmentally friendly, cost-effective, and simple process to manufacture hybrid CNZ antibacterial cotton in the textile industry.

Durably antibacterial cotton fabrics coated by protamine via Schiff base linkages

The development of antibacterial cotton fabrics with an overall performance is critical but remains challenging. In this study, we propose a facile method to prepare durable antibacterial cotton fabric without significant sacrifices of wearing comfortability. Cotton fabric is firstly oxidated to obtain dialdehyde groups, then treated with PM molecules to establish a PM coating on the fiber surfaces via Schiff base linkages. The resultant cotton fabrics show durably antibacterial activity, realizing high bacterial reduction rates against both E. coli and S. aureus higher than 99.99 %, and offering remarkable durabilities tolerable 50 washing cycles and 500 rubbing times. These fabrics also show reliable safety for human skin that proofed by a series of cytotoxicity tests with positive results. This work demonstrates an example of versatile strategy to impart effective antibacterial function with durable activity to cotton textiles, showing great potential for practical applications in functional textile fields.

Antibacterial Properties of Honey Nanocomposite Fibrous Meshes.

Natural substances are increasingly being developed for use in health-related applications. Honey has attracted significant interest, not only for its physical and chemical properties, but also for its antibacterial activity. For the first time, suspensions of Black Forest honeydew honey and manuka honey UMF 20+ were examined for their antibacterial properties against Escherichia coli and Staphylococcus epidermidis using flow cytometry. The inhibitory effect of honey on bacterial growth was evident at concentrations of 10, 20 and 30 v/v%. The minimum inhibitory effects of both honey types against each bacterium were also investigated and reported. Electrospray ionisation (ESI) mass spectrometry was performed on both Black Forest honeydew honey and manuka honey UMF 20+. Manuka honey had a gluconic concentration of 2519 mg/kg, whilst Black Forest honeydew honey had a concentration of 2195 mg/kg. Manuka honey demonstrated the strongest potency when compared to Black Forest honeydew honey; therefore, it was incorporated into nanofiber scaffolds using pressurised gyration and 10, 20 and 30 v/v% manuka honey-polycaprolactone solutions. Composite fibres were analysed for their morphology and topography using scanning electron microscopy. The average fibre diameter of the manuka honey-polycaprolactone scaffolds was found to range from 437 to 815 nm. The antibacterial activity of the 30 v/v% scaffolds was studied using S. epidermidis. Strong antibacterial activity was observed with a bacterial reduction rate of over 90%. The results show that honey composite fibres formed using pressurised gyration can be considered a natural therapeutic agent for various medicinal purposes, including wound-healing applications.

Toward the Scalable Fabrication of Fully Bio-Based Antimicrobial and UVB-Blocking Transparent Polylactic Acid Films That Incorporate Natural Coatings and Nanopatterns.

Microbial transmissions via membrane surface and single-use plastic-induced pollution are two urgent societal problems. This research introduces a scalable fabrication strategy for fully biobased antibacterial and ultraviolet-B block polylactic acid (PLA) films integrating natural coatings and nanopatterns via ultrasonic atomization spray coating and thermal nanoimprinting lithography (TNIL) techniques, respectively. Tannic acid (TA) and gallic acid (GA) were formulated prior to TNIL using anode aluminum oxide template. Results reveal that TA and GA inks display intense adsorption in the UVB region. Plasma increases the hydrophilicity of PLA films for fast spreading of ink droplets. Micron-sized pillars observed on film confirm the successful structural replication. TA-coated PLA films display higher transparency than GA-coated ones. Nanopatterned PLA films have a modest antibacterial resistance of c. 45% against Escherichia coli. TA/GA coatings, however, impart PLA films with a bacterial reduction rate of over 80%. The integration of a TA or GA coating with nanopatterns further promotes the antibacterial rate up to 98%. The cytocompatibility of TA and GA demonstrates that the engineered film can potentially be applied as food packaging. Finally, a continuous mass production strategy is proposed along with an outline of the associated challenges and costs. This study provides a scalable strategy to the sustainable development of eco-benign and functional films.

A high‐speed, salt‐free, and dyebath‐recyclable circular coloration technology inspired by mussel bionic

AbstractWith the current situation of high‐energy consumption and high pollution in the textile industry, developing an eco‐friendly and universal dyeing technology is urgently required. Towards this goal, in this study, the dyeing technology with room temperature, salt‐free, zero release, and rapid cycle dyeing for 20 min was realized using a polymer of catechol and polyethyleneimine as a dye. The dyed fabrics exhibited washing, rubbing, and perspiration fastness characteristics for practical needs, mainly attributing to the hydrogen bonding and π–π interaction between the dye molecules and the fabrics. Benefiting from the unique dyeing technology, the dyed fabrics show excellent leveling properties and adjustable chromaticity. Importantly, the mussel‐inspired coating strategies are universally applicable, so the dyeing technology can be applied to various fabrics. Consequently, the environmentally friendly dyeing process based on low‐cost catecholamine polymers as a dye will have a broad application prospect in the printing and dyeing industry. Moreover, the antibacterial tests showed that dyed cotton cloth, mulberry silk, and polyester fabrics all have favorable antibacterial properties, especially dyed mulberry silk fabrics have a greater than 90% bacterial reduction rate for both Escherichia coli and Staphylococcus aureus.