Intrinsic Antibacterial Properties Research Articles

Polyhexamethylene biguanide chemically modified cotton with desirable hemostatic, inflammation-reducing, intrinsic antibacterial property for infected wound healing

Medical cotton dressing is cheap and widely used in diversified fields, but in the application of promoting wound healing, the continuous research of multifunctional medical cotton dressing is still of great significance. Here, we developed a fresh type of antibacterial cotton dressing through a succinct strategy based on chemically anchoring polyhexamethylene biguanide (PHMB). Intriguingly, after PHMB modification, the cotton dressing exhibited outstanding antibacterial performance which could maintain >99.99% antibacterial rate after several treatments, including washing 50 times, repeated use 10 times, UV irradiation for 7 days, cationic dyes dying, and conditioned under 90 °C water bath for 2 h. In addition, the water contact angle of cotton dressing increased dramatically from 0° to 111°, which could facilitate bacterial adhesion, thus further enhance the antibacterial efficiency, and easily remove the bacterial debris. Apart from that, the developed cotton dressing showed good cytocompatibility, promoted blood clotting and expression of platelets, and promoted the wound healing process in the infection intervened skin wound model. Taken together, this antibacterial cotton dressing with desirable blood clotting, sustained protection against bacterial infection and bacterial removal features shows the potential to be a candidate for infected skin wound healing.

Mechanically robust, creep-resistant, intrinsic antibacterial and reprocessable dynamic polyurethane networks based on azine moieties

The azine moieties provide outstanding creep-resistant, mechanical, exchangeable and intrinsic antibacterial properties.

Green biosynthesis of hydroxyapatite-silver nanoparticle nanocomposite using aqueous Indian curry leaf (Murraya koengii) extract and its biological properties

Implant-associated disease triggered by bacterial colonization would hinder the osseointegration of bone implant at the implantation site and further jeopardize the outcome of bone regeneration. Thus, the use of implant material with intrinsic antibacterial property can be promising to address the shortcoming associated with bacterial infection. In the present study, we aimed to develop an antibacterial implant material based on a combination of hydroxyapatite (HAp) and silver nanoparticle (AgNPs) via a green biosynthetic route. In this work, aqueous extract of Indian curry leaf (Murraya koengii) was employed as a bio-reducing and stabilizing agent for the in-situ fabrication of HAp-AgNPs nanocomposite. According to XRD, EDX, TEM, XPS and FTIR results, AgNPs had been successfully synthesized and deposited to the surface of HAp, where the amount and size of decorated AgNPs were found to rely on the concentration of AgNO3 precursor used. Antibacterial examinations in vitro showed that HAp-AgNPs nanocomposites displayed an effective antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria when AgNO3 precursor concentration used >1 mM. Furthermore, HAp-AgNPs-5 and HAp-AgNPs-7 nanocomposites also exhibit improved bioactivity in comparison with pristine HAp, being able of developing more bone-like apatite after 4 weeks of soaking in Hank's balanced salt solution. These findings significantly demonstrate the feasibility of HAp-AgNPs nanocomposite to be applied as antibacterial implant material for orthopedic application.

Injectable, Intrinsically Antibacterial Conductive Hydrogels with Self-Healing and pH Stimulus Responsiveness for Epidermal Sensors and Wound Healing.

Torealize intelligent and personalized medicine, it is a huge challenge to develop a hydrogel dressing that can be used as a sensor to monitor human health in real-time while promoting wound healing. Herein, an injectable, self-healing, and conductive chitosan-based (CPT) hydrogel with pH responsiveness and intrinsic antibacterial properties was fabricated via a Schiff base linkage and a hydrogen bond. Due to the introduction of Schiff base bonds, the injectable CPT hydrogel exhibits various excellent properties, such as pH responsiveness to sol-gel transition, self-healing properties, and broad-spectrum antibacterial properties even without additional antibacterial agents. In vitro experiments verify the excellent biocompatibility of the as-prepared hydrogel. An in vivo experiment in a mouse full-thickness skin-wound model was performed to confirm the outstanding effect on wound healing. Meanwhile, as epidermal sensors, the conductive hydrogel that perceives various human activities in real-time could provide the real-time analysis of the patient's healthcare information. Based on these excellent properties, the CPT hydrogel, as a biological dressing with a sensing function, lays a solid foundation for the further realization of personalized medicine.

Dual-Functional Nano-Functionalized Titanium Scaffolds to Inhibit Bacterial Growth and Enhance Osteointegration.

Implantable biomaterials play a key role for the success of orthopedic surgery procedures. However, infections remain one of the most damaging post-operative complications that lead to the implant failure. Recently, several approaches have been proposed to avoid or manage implant-associated infections. Among these, an appropriate surface functionalization to confer intrinsic antibacterial properties preserving the osteo-integration ability represents an appealing strategy for the development of innovative implant materials. Titanium and its alloys are the most used materials for manufacturing of both articular and bone skull prostheses as well as dental implants. However, to date there is still a significant clinical need to improve their bioactivity, osseointegration and antibacterial activity. In this study, titanium biomimetic scaffolds are prepared by nano-functionalization with TiO2 (Ti_TiO2) and γFe2O3 (Ti_γFe2O3). Both cytocompatibility and antibacterial activity have been evaluated. Data show that both nano-functionalized scaffolds exhibit a good antibacterial activity towards Staphylococcus aureus, reducing colony number to 99.4% (Ti_TiO2) and 99.9% (Ti_γFe2O3), respectively. In addition, an increase of both human adipose-derived mesenchymal stem cells (hADSCs) cell proliferation (up to 4.3-fold for Ti_TiO2 and 3.7-fold for Ti_γFe2O3) and differentiation has been observed. These data suggest that these nano-functionalized titanium substrates represent promising prototypes for new antimicrobial and osteoconductive biomaterials to be used in the orthopedic field to reconstruct significant bone defect.

Novel Diabetic Foot Wound Dressing Based on Multifunctional Hydrogels with Extensive Temperature-Tolerant, Durable, Adhesive, and Intrinsic Antibacterial Properties.

Diabetic foot ulcers (DFUs) are hard-healing chronic wounds and susceptible to bacterial infection. Conventional hydrogel dressings easily lose water at high temperature or freeze at low temperature, making them unsuitable for long-term use or in extreme environments. Herein, a temperature-tolerant (-20 to 60 °C) antibacterial hydrogel dressing is fabricated by the assembly of polyacrylamide, gelatin, and ε-polylysine. Owing to the water/glycerin (Gly) binary solvent system, the resultant hydrogel (G-PAGL) displayed good heat resistance and antifreezing properties. Within the wide temperature range (-20 to 60 °C), all the desirable features of the hydrogel, including superstretchability (>1400%), enduring water retention, adhesiveness, and persistent antibacterial property, are quite stable. Remarkably, the hydrogel wound dressing displayed lasting and broad antibacterial activity against Gram-positive and Gram-negative bacteria. Satisfactorily, the double-network (DN) G-PAGL hydrogel dressing could effectively promote the healing of DFUs by accelerating collagen deposition, promoting angiogenesis, and inhibiting bacterial breed. As far as we know, this is the first time that the extensive temperature-tolerant DN hydrogel with antibacterial ability is developed to use as DFU wound dressing. The G-PAGL hydrogel provides more choices for DFU wound dressings that could be used in extreme environments.

ANTIBACTERIAL ACTIVITY OF SOME NANO-ANTIMICROBIAL POLY(AMIDOAMINE) (PAMAM) DENDRIMERIC PRODUCTS

"Dendrimers are synthetic, branched macromolecules. Compared to linear polymers, dendrimers hold multiple advantages as potential carrier molecules: high capacity to incorporate pharmacologically active substances, chemical stability of micelles under physiological conditions, increased bioavailability of active substances covalently or noncovalently bound to dendrimers, due to increased dendrimers capacity to cross biological barriers. The carrier potential of dendrimers has been evaluated in combination with different antibiotics, as an alternative way to address the increasing resistance of Gram-positive and Gram-negative bacteria. This paper presents a study on the intrinsic antibacterial properties of the following poly(amidoamino) (PAMAM) ethylenediamine core dendrimers: PAMAM generation 3.5, PAMAM generation 4.0 and PAMAM-OH generation 4.0. The following bacterial strains were used: Staphylococcus aureus ATCC 29213, Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 15442, Enterococcus faecalis ATCC 51299 and a multi-drug resistant (MDR) Acinetobacter baumannii clinical isolate. The dendrimers’ concentrations used in the experiment were established within the range of admissibility obtained following cytotoxicity testing on human cell cultures. The dendrimers’ antibacterial activity varied depending on the concentration and the bacterial species. The antibacterial efficacy was quantified by calculating the percentage and logarithmic reduction of the number of viable microorganisms. The logarithmic reduction varied between 0.06 and 1.10, corresponding to percentage reductions between 13% and 92%. The strongest antibacterial activity of all dendrimers used in this study was registered for the D3.5 dendrimer (50 μg/mL) against Acinetobacter baumannii and Pseudomonas aeruginosa ATCC 15442 reference strain. For A. baumannii, a logarithmic reduction of bacterial activity of 1.10 log10 (percentage reduction in the number of CFU of 92%) was registered, while for P. aeruginosa ATCC 15442 the logarithmic reduction was 0.75 log10 (percentage reduction of 82%)."

Rationally designed protein cross-linked hydrogel for bone regeneration via synergistic release of magnesium and zinc ions

The development of recombinant protein cross-linked injectable hydrogels with good mechanical strength and effective drug loading capacity for bone regeneration is extremely attractive and rarely reported. Here, we report the fabrication of a smart hydrogel delivery system by incorporating a rationally designed T4 lysozyme mutant (T4M) to mediate the localized delivery and synergistic release of Mg2+ and Zn2+ for bone repair. Apart from its intrinsic antibacterial properties, T4M bears abundant free amine groups on its surface to function as effective covalent crosslinkers to strengthen the hydrogel network as well as exhibits specific binding affinity to multivalent cations such as Zn2+. Moreover, the integrin receptor-binding Arg-Gly-Asp (RGD) sequence was introduced onto the C-terminus of T4 lysozyme to improve its cellular affinity and further facilitate rapid tissue regeneration. The final composite hydrogel displays excellent injectability, improved mechanical properties, antibacterial activity, and unique bioactivities. The effective loading of Mg2+/Zn2+ in the hydrogels could mediate the sequential and sustained release of Mg2+ and Zn2+, thereby resulting in synergistic enhancement on bone regeneration through modulation of the MAPK signaling pathway. We believe that the strategy proposed in this paper opens up a new route for developing protein cross-linked smart delivery systems for tissue regeneration.

Eco-friendly and intrinsic nanogels for durable flame retardant and antibacterial properties

Fire hazard and public health security have become the main potential problems affecting human safety and health. Eco-friendly, healthy, and multi-function materials represent an inevitable tendency. In this research, nanogels of intrinsic flame retardance and antibacterial properties were prepared via Michael addition reaction. The resultant nanogels possessed regular, robust spherical morphologies and size-controllable properties, exhibited stable thermal performance and strong ability to kill bacteria. The antibacterial efficacy reached to more than 99.9% for both Staphylococcus aureus and Escherichia coli when being exposed in nanogel suspension at the concentration of 120 μg/mL. Moreover, anti-infection experiments were explored by in vivo wound model confirmed that the nanogels had capability to prevent infection, and the healing efficiency reached 97.7% after 14 days’ treatment. By grafting on the cotton fibers and fabrics, the nanogels displayed excellent flame retardancy protection of the matrix. The peak of heat release rate (pHRR) reduced by 41.2% compared with raw cotton fabric and the total heat release (THR) declined by 24.4%. In addition, the usage of nanogels could reduce the grafting ratio and improve the functionality, which effectively saved resource and decreased the damage of matrix. The durability test demonstrated the nanogels were ideal candidate for nanoscale materials with durable flame retardant and antimicrobial.

Wearable and self-powered sensors made by triboelectric nanogenerators assembled from antibacterial bromobutyl rubber

Energy, information, and materials are the three main factors required for the survival and development of modern humankind, with energy being the cornerstone of all development. In recent years, self-powered devices have received widespread attention. As a new generation device, Triboelectric nanogenerators (TENGs) assembled from flexible materials possess the characteristics of flexible design, low-cost, stable output performance, etc., and can be widely used in wearable and self-powered medical detection sensors of human body. In this paper, flexible bromobutyl rubber (BIIR) and PET were used as friction materials, and assembled into arched vertical contact-separation triboelectric nanogenerators following various film formation and surface roughening treatments. The treatment and assembly methods of the friction materials were studied in order to obtain the best power generating effects. In addition, due to the biocompatibility and intrinsic antibacterial property of BIIR films, the fabricated triboelectric nanogenerator was also applied to wearable self-powered sensor equipment, proving its potential in the fields of identification and gait analysis. The manuscript described the triboelectric nanogenerators assembled by bromobutyl rubber (BIIR) and PET, which has intrinsic antibacterial performance and high force detection sensitivity. It can be used in wearable and self-powered sensors. • Ÿ Intrinsic antibacterial BIIR films were prepared by electrospinning and assembled into wearable and self - powered TENG. • Ÿ The BIIR-based TENGs is capable of energy-harvesting and signal recognition for identification and gait analysis. • The BIIR-based TENGs are easy to prepare and have the potential for large-scale industrial production.

Establishment of a Method to Allow Microbial Limit Testing of Iodine-containing Preparations

Background: Contamination of pharmaceuticals with microorganisms may lead to deleterious effects on the therapeutic properties of the drug, and may potentially cause injuries to intended recipients. Iodine can inhibit and kill microorganisms in pharmaceutical preparations. The risk of microbial contamination of cellular products can be reduced when cultured in the presence of iodine. This however, may impact the sensitivity of microbiological tests. Iodine-containing Preparations does not guarantee sterility but may just reduce the proliferation rate of microorganisms, microbiological testing of medicinal products remains obligatory. Thus, an appropriate method to test for microbial contamination of iodine-containing products has to be validated. Objective: To establish a method that would allow microbial limit testing of four iodine-containing preparations (concentrated iodine tincture, compound iodine oral solution, iodine tincture, and iodine glycerin). Methods: To specifically determine the degree of contamination in the four in-house iodine preparations, sodium thiosulfate was used to reduce the iodine molecules to iodide ions, thereby eliminating the intrinsic antibacterial property of the preparations. Then, the suitability of this method was evaluated according to the regulations for non-sterile microbial limit tests. Results: The neutralization method effectively eliminated the interference of the antibacterial iodine component, rendering the control bacteria detectable. The recovery ratio of the test strains met the required standards. Conclusion: The neutralization method with sodium thiosulfate as the iodine neutralizer is suitable for microbial limit testing of concentrated iodine tincture, compound iodine oral solution, iodine tincture, and iodine glycerin, with the results being accurate and reliable.

Visible-Light-Responsive Antibacterial Property of Boron-Doped Titania Films

Pure titanium dioxide TiO2 photocatalytic substrates exhibit antibacterial activity only when they are irradiated with ultraviolet light, which comprises high-energy wavelengths that damage all life. Impurity doping of TiO2-related materials enables visible light to stimulate photocatalytic activity, which enhances opportunities for TiO2 to be used as a disinfectant in living environments. Boron-doped TiO2 displays visible-light-responsive bactericidal properties. However, because boron-derived compounds also exert notable antibacterial effects, most reports did not clearly demonstrate the extent to which the bactericidal property of boron-doped TiO2 is contributed by visible-light-stimulated photocatalysis. In addition, TiO2 thin films have considerable potential for applications in equipment that requires sterilization; however, the antibacterial properties of boron-doped TiO2 thin films have been examined by only a few studies. We found that boron-doped TiO2 thin films displayed visible-light-driven antibacterial properties. Moreover, because boron compounds may have intrinsic antibacterial properties, using control groups maintained in the dark, we clearly demonstrated that visible light stimulated the photocatalysis of boron-doped TiO2 thin films but not the residue boron compounds display antibacterial property. The bactericidal effects induced by visible light are equally potent for the elimination of the model organism Escherichia coli and human pathogens, such as Acinetobacter baumannii, Staphylococcus aureus, and Streptococcus pyogenes. The antibacterial applications of boron-doped TiO2 thin films are described, and relevant perspectives discussed.

Metal doped calcium silicate biomaterial for skin tissue regeneration in vitro.

This study spots light on combined Wound healing process conjoining blood coagulation, inflammation reduction, proliferation and remodeling of the cells. The objective is to overcome the drawbacks of conventional clinically applied wound dressings such as poor rigidity, porosity, mechanical potency and bactericidal activity. As nosocomial infection is a very common condition at the wound site, bio-adhesive materials with intrinsic antibacterial properties are used in clinical applications. Considering the provenability of Wollastonite [Calcium silicate (CaSiO3)] to regenerate the soft tissues by inducing vascularization and regeneration of fibroblast cells And the antibacterial potentiality of zinc in clinical applications, the present study focuses on synthesis of Zn-Ws particles and evaluation of its antimicrobial and wound healing potentialities towards skin tissue engineering applications. The compositional characterization by EDAS and FT-IR spectral analysis have substantiated the presence of major elements and corresponding band stretching associated with the synthesized particles whereas the particles morphology by SEM images have shown the size of the Ws and Zn-Ws to be 370 nm and 530 nm respectively. From the in vitro studies, skin regenerative potential of Zn-Ws was determined on promoting fibroblast cell (NIH3T3) proliferation by providing better adhesiveness, biocompatibility and cytocompatibility. The antibacterial property of Zn-Ws evaluation by minimum inhibitory concentration (MIC) and zone of inhibition (ZOI) methods against clinical isolates of Gram +Ve and Gram -Ve bacterial strains have confirmed that the addition of Zn has diminished the bacterial growth and also helped in degrading the bacterial biofilms. Thus it is summed up that the process of wound healing is expected to occur with reduced risk of post-injury infections by the presence of zinc-doping on wollastonite for skin tissue application.

Antibacterial Zwitterionic Polyelectrolyte Hydrogel Adhesives with Adhesion Strength Mediated by Electrostatic Mismatch.

Biotissue adhesives and antibacterial materials have great potential applications in wound dressing, implantable devices, and bioelectronics. In this study, stretchable tissue adhesive hydrogels with intrinsic antibacterial properties have been demonstrated by copolymerizing zwitterionic monomers with ionic monomers. The hydrogels are stretchable to about 900% strain and show a modulus of 4-9 kPa. The zwitterionic moieties provide strong dipole-dipole interaction, electrostatic interaction, and hydrogen bonding with the skin surface, and thus show adhesion strength values of 1-4 kPa to skin. Meanwhile, the copolymerized cationic or anionic monomers break the intrinsic electrostatic stoichiometry of the zwitterionic units and thus mediate the electrostatic interactions and the adhesion strength with the surface. The stretchable hydrogels form a robust and compliant (due to low modulus and stretchability) adhesive to skin, rubber, glass, and plastics, and could be repeatedly peeled-off and readhered to the skin. Moreover, the abundant quaternary ammonium (QA) groups in the zwitterionic moieties and the added QA groups endow it outstanding antibacterial properties (>99%). These stretchable tissue adhesive antibacterial hydrogels are promising for wound dressings and implantable devices.

Biodegradable and Drug-Eluting Inorganic Composites Based on Mesoporous Zinc Oxide for Urinary Stent Applications.

Conventional technologies for ureteral stent fabrication suffer from major inconveniences such as the development of encrustations and bacteria biofilm formation. These drawbacks typically lead to the failure of the device, significant patient discomfort and an additional surgery to remove and replace the stent in the worst cases. This work focuses on the preparation of a new nanocomposite material able to show drug elution properties, biodegradation and eventually potential antibacterial activity. Poly(2-hydroxyethyl methacrylate) or the crosslinked poly(2-hydroxyethyl methacrylate)-co-poly(acrylic acid) hydrogels were prepared by the radical polymerization method and combined with a biodegradable and antibacterial filling agent, i.e., flower-like Zinc Oxide (ZnO) micropowders obtained via the hydrothermal route. The physico-chemical analyses revealed the correct incorporation of ZnO within the hydrogel matrix and its highly mesoporous structure and surface area, ideal for drug incorporation. Two different anti-inflammatory drugs (Ibuprofen and Diclofenac) were loaded within each composite and the release profile was monitored up to two weeks in artificial urine (AU) and even at different pH values in AU to simulate pathological conditions. The addition of mesoporous ZnO micropowders to the hydrogel did not negatively affect the drug loading properties of the hydrogel and it was successfully allowed to mitigate undesirable burst-release effects. Furthermore, the sustained release of the drugs over time was observed at neutral pH, with kinetic constants (k) as low as 0.05 h−1. By exploiting the pH-tunable swelling properties of the hydrogel, an even more sustained release was achieved in acidic and alkaline conditions especially at short release times, with a further reduction of burst effects (k ≈ 0.01–0.02 h−1). The nanocomposite system herein proposed represents a new material formulation for preparing innovative drug eluting stents with intrinsic antibacterial properties.

Eugenyl Methacrylate Microsponges Loaded with Eugenol Incorporated In Situ Gel for Treatment of Periodontitis

The study was aimed to formulate eugenol-loaded polymeric microsponges using eugenyl methacrylate (Eg-MA) incorporated in situ gelling system for the treatment of periodontitis. Eg-MA monomer was first synthesized by reacting eugenol with methacryloyl chloride, which acted as a monomer and cross-linking agent for preparing microsponges of Eg-MA using suspension polymerization method. The formation of Eg-MA monomer was confirmed by FTIR. A 32 Box–Behnken design was applied to optimize Eg-MA polymeric microsponges which were characterized by SEM and antimicrobial activity. An optimized batch of polymeric microsponges was incorporated into in situ gelling system which was evaluated on the basis of pH, viscosity, gelling temperature, and mucoadhesion on the goat buccal mucosa. Ligature-induced experimental periodontitis (EPD) was induced in rats to assess the efficacy of the formulation. SEM revealed the spherical shape of Eg-MA microsponges with antibacterial activity against Streptococcus mutans and potential to load eugenol with a drug content of 96.38 ± 0.09%. The study of the eugenol-loaded microsponges in situ gel showed sustained release of the drug up to 24 h with a mucoadhesive strength of 31 ± 0.13 N. Treatment with eugenol-loaded Eg-MA polymeric microsponges decreased tooth mobility and gingival inflammation in rats. The histological studies of the periodontium also confirmed decrease in the infiltration of inflammatory cells and alveolar bone destruction (p < 0.05) in EPD rats. Thus, a novel formulation using Eg-MA with intrinsic antibacterial property was used to formulate eugenol-loaded polymeric microsponges in situ gel for the management of periodontitis.

Antimicrobial Mechanisms and Effectiveness of Graphene and Graphene-Functionalized Biomaterials. A Scope Review.

Bacterial infections represent nowadays the major reason of biomaterials implant failure, however, most of the available implantable materials do not hold antimicrobial properties, thus requiring antibiotic therapy once the infection occurs. The fast raising of antibiotic-resistant pathogens is making this approach as not more effective, leading to the only solution of device removal and causing devastating consequences for patients. Accordingly, there is a large research about alternative strategies based on the employment of materials holding intrinsic antibacterial properties in order to prevent infections. Between these new strategies, new technologies involving the use of carbon-based materials such as carbon nanotubes, fullerene, graphene and diamond-like carbon shown very promising results. In particular, graphene- and graphene-derived materials (GMs) demonstrated a broad range antibacterial activity toward bacteria, fungi and viruses. These antibacterial activities are attributed mainly to the direct physicochemical interaction between GMs and bacteria that cause a deadly deterioration of cellular components, principally proteins, lipids, and nucleic acids. In fact, GMs hold a high affinity to the membrane proteoglycans where they accumulate leading to membrane damages; similarly, after internalization they can interact with bacteria RNA/DNA hydrogen groups interrupting the replicative stage. Moreover, GMs can indirectly determine bacterial death by activating the inflammatory cascade due to active species generation after entering in the physiological environment. On the opposite, despite these bacteria-targeted activities, GMs have been successfully employed as pro-regenerative materials to favor tissue healing for different tissue engineering purposes. Taken into account these GMs biological properties, this review aims at explaining the antibacterial mechanisms underlying graphene as a promising material applicable in biomedical devices.

Click erreakzioa erabiliz aktibitate biologikoa erakusten duten sistema polimerikoen garapena

Azken urteetan, inplante kirurgikoak oso erabiliak bilakatu dira kaltetutako hezurrak, lotai- luak edota giharrak ordezkatzeko. Hala ere, haien erabilera dela eta, ezinbestekoa da antibiotikoen tratamendua jasotzea, inplanteetan aurki daitezkeen bakterio eta beste mikroorganismoei aurre egiteko. orokorrean, bakterioak inplanteen gainazaletan adsorbatzen dira, biofilm bat eratuz, zeinak eragiten baitu antibiotikoei erresistentzia handiagoa izatea eta baita ostalarien defentsaren babespena handitzea ere. Horren ondorioz, desiragarria da propietate antibakteriano intrintsekoa duen inplantea diseinatzea. Hala ere, batzuetan zaila da aurkitzea konposatu antibakterianoa eransteko estrategia egokia, gainazalarekin lotzeko burututako erreakzioan aktibitatea bermatzeko behar den egitura alda daitekeelako. Antibiotikoa gainazal polimeriko batean atxikitzeko ezaguna den «click» erreakzioa metodologia egokienetariko bat izan daiteke. Beraz, esan dezakegu metodologia aproposena izan daitekeela, izan ere prozedura bidez molekula organiko konplexuak materialen gainazalean lotzen dira kobalenteki. Gainera antibiotikoak biokonjugatzeko erreakzioa aurrera burutu daiteke inguru-tenperaturan, baldintza fisiologikoetan eta ura disolbatzaile gisa erabiliz etekin kuantitatiboak (ia % 100) lortuz.

Uncovering the Mechanical, Thermal, and Chemical Characteristics of Biodegradable Mushroom Leather with Intrinsic Antifungal and Antibacterial Properties.

The growing demand for a sustainable leather industry with a low environmental impact has prompted the development of alternative vegetable-based materials. In this study, a biodegradable mushroom-based leather derived from the fruiting body of Phellinus ellipsoideus is investigated. The biodegradable leather proves to be thermally stable up to 250 °C. The mechanically robust macrostructure combines a tensile strength of 1.2 MPa and ductility (101% strain at break) attributed to the natural balance of chitin (0.3) and proteins (0.7) constituting the mycelium fibers. The chitin-protein system results in an intrinsic scratch-resistant structure with exciting damping properties in a low frequency range. Enhanced damping capabilities within 5-20 Hz (tan δ: 0.1-0.20) are attributed to the macrostuctural alignment of the mycelium under cyclic tension. Whereas, increasing frequencies >20 Hz induce micromolecular interactions between chitin and proteins within the fibers. Exposure of the bioleather to acidic (pH 4, 5) and basic (pH 8, 9) media demonstrated the selective dissolution of proteins (basic) and chitin (acid) components within the mycelium, opening an opportunity for tunable mechanical response. Reducing the protein content induced an increase in stiffness and strength (pH 8 and 9), while reducing its chitin component showed variable ductility (pH 4 and 5). Owing to the entirely natural composition of the mushroom leather, intrinsic antifungal and antibacterial properties found in the mycelium resist fungal invasion and bacterial growth. Thus, this study displays the unique morphology-property relationship of a biodegradable mushroom leather, proving its potential as a fully sustainable and environmentally friendly alternative.

Antibacterial potential of essential oils of Zataria multiflora and Mentha piperita, micro- and nano-formulated forms

Plant-derived essential oils (EOs) shave many usages in health and medicine, such as antibacterial agents. The aim of this study was the improvement of antibacterial activities of two EOs using nanotechnology. Antibacterial activity was investigated on four important human pathogenic bacteria using the 96-well plate microdilution method, a quantitative approach. Eleven formulations were prepared using each of the EOs. Eventually, the best nanoformulation with the smallest particle size and polydispersive indices (PDI and SPAN) was selected using each EO for further investigations. Moreover, two microemulsions with similar ingredients and the same portion in comparison with two selected nanoemulsions were also prepared. Antibacterial activity of each EO was compared with its micro- and nano-emulsions. The antibacterial efficacy of Zataria multiflora EO (ZMEO) was significantly better than Mentha piperita EO (MPEO). Besides, the antibacterial activity of nanoemulsion of ZMEO with a particle size of 129 ± 12 nm was significantly better than no- and micro-formulated forms of ZMEO. Interestingly, the efficiency of MPEO nanoemulsion (160 ± 25 nm) was also significantly better than MPEO and its micro-formulated form. Regardless of the intrinsic antibacterial property of two examined EOs, by formulating to nanoemulsion, their efficiencies were improved. Nanoemulsion of ZMEO introduced as an inexpensive, potent and green antibacterial agent.