Stannous fluoride forms aggregates between outer and inner membranes leading to membrane rupture of Porphyromonas gingivalis and Prevotella pallens.

Objective: Stannous has been shown to bind to free lipopolysaccharides, thus preventing them from binding to TLR receptors. This study was undertaken to determine the histomorphological mechanism of stannous binding to anaerobic bacteria. Methods: Two bacteria associated with gingivitis and advanced periodontal disease, Porphyromonas gingivalis (P. gingivalis) and Prevotella pallens (P. pallens), were cultured in 25-1,000 µM of stannous fluoride and stannous chloride for 48 h. The growth rate was estimated using absorbance OD600. Bacterial cells were then fixed and processed for transmission electron microscopy (TEM) analysis. Results: Stannous fluoride inhibited proliferation of both P. gingivalis and P. pallens in a dose-dependent manner. There was a statistically significant suppression of the growth curve starting at 100 µM for P. pallens (P = 0.050) and 200 µM for P. gingivalis (P = 0.039). TEM analysis revealed a thick layer of polysaccharides (19.8 nm) in P. gingivalis. The outer and inner membranes were clearly visible with low electron densities in both bacteria. Stannous diffused into bacterial membranes and formed precipitates in the areas spanning outer and inner membranes and below inner membranes. Precipitates varied in size ranging from 46.4 to 84.5 nm in length, and 18.4 to 35.9 nm in width. The membranes were disintegrated in the region where stannous formed precipitates. Cytosolic contents were leaked out, and in several cases, small vesicles were formed. Stannous precipitates were more abundant in numbers and larger in size in bacteria treated with high concentrations (100-300 µM) than in low concentrations (25-50 µM) of stannous fluoride. Furthermore, most of the bacteria were disintegrated in the groups treated with 100-300 µM stannous fluoride. At low concentrations (25 µM), stannous fluoride formed complexes primarily around outer membranes, to which lipopolysaccharides are anchored. Stannous chloride results showed similar trends, but it was less potent than stannous fluoride. Conclusion: Stannous fluoride can penetrate bacteria, bind to the constituents of the membrane and form precipitates between outer and inner membranes and beneath inner membranes. These large precipitates damaged the integrity of membranes and allowed cytosolic contents to be leaked out. Stannous complexes formed at the outer membranes, even at low concentrations (25 µM).

Thiazolation of phenylthiosemicarbazone to access new thiazoles: anticancer activity and molecular docking.

Aim: Novel thiazole hybrids were synthesized via thiazolation of 4-phenylthiosemicarbazone (4). Materials & methods: The anticancer activity against the NCI 60 cancer cell line panel. Results: Methyl 2-(2-((1-(naphthalen-2-yl)ethylidene)hydrazineylidene)-4-oxo-3-phenylthiazolidin-5-ylidene)acetate (6a) showed significant anticancer activity at 10 µM with a mean growth inhibition (GI) of 51.18%. It showed the highest cytotoxic activity against the ovarian cancer OVCAR-4 with an IC50 of 1.569 ± 0.06 µM. Compound 6a inhibited PI3Kα with IC50 = 0.225 ± 0.01 µM. Moreover, compound 6a revealed a decrease of Akt and mTOR phosphorylation in OVCAR-4 cells. In addition, antibacterial activity showed that compounds 11 and 12 were the most active against Staphylococcus aureus. Conclusion: Compound 6a is a promising molecule that could be a lead candidate for further studies.

Novel naphthalene-azine-thiazole hybrids 5-12 were synthesized via late-stage thiazolation of the corresponding 4-phenylthiosemicarbazone 4. Compound 6a showed significant anticancer activity at single-dose screening and yielded excellent inhibitory activity with a mean GI of 51.18%. Compound 6a showed the highest cytotoxic activity against OVCAR-4 with an IC₅₀ of 1.569 ± 0.06 µM. Moreover, compound 6a exhibited an IC₅₀ of 31.89 ± 1.19 µM against normal ovarian cell line (OCE1) and a selectivity index of 19.1. Compound 6a inhibited PI3Kα with IC₅₀ = 0.225 ± 0.01 µM compared with alpelisib (IC₅₀ = 0.061 ± 0.003 µM). Moreover, compound 6a revealed a powerful decrease of Akt and mTOR phosphorylation in the OVCAR-4 cell line. The cell cycle analysis showed that compound 6a caused an arrest at the G2/M phase. The compound also increased the total apoptosis by 26.8-fold and raised the level of caspase-3 by 4.34 times in OVCAR-4. In addition, antibacterial activity was estimated against Gram-positive and Gram-negative bacterial strains. Compounds 11 and 12 were the most active derivatives, with MIC value of 256 µg/ml against Staphylococcus aureus. Molecular docking was done and showed that 6a interlocked and fitted well into the ATP binding site of PI3Kα kinase (Protein Data Bank ID: 4JPS) with a fitness value (-119.153 kcal/mol) and forms the key H-bonds with Val851 and Ser854 like the marketed PI3Kα inhibitor alpelisib. Consequently, 6a is the most promising molecule that could be a lead candidate for further studies.

Biosynthesis of silver nanoparticle from flower extract of Dillenia indica and its efficacy as antibacterial and antioxidant.

Dillenia indica is a medicinal tree of the Dilleniaceae and its flower extract was used for the synthesis of silver nanoparticle (AgNPs). The optimal conditions for AgNPs synthesis were as such: 2 mM AgNO3, pH 4.5 and 48-h reaction time. The characteristic band of AgNPs was observed at the wavelength of 435 nm by UV-visible spectroscopic study. Fourier-transform infrared (FTIR) analysis depicted the involvement of several functional groups of plant extracts in the synthesis of AgNPs. Nanoparticles were mostly spherical shaped and uniformly distributed, when observation was made by Transmission electron microscopy (TEM). Energy Dispersive X-Ray (EDX) showed absorption peak approximately at 3 keV thus confirmed the presence of silver metal in AgNP. X-ray diffraction (XRD) investigation and selected area electron diffraction (SAED) patterns showed the crystalline nature of the AgNPs. Dynamic light scattering (DLS) analysis exhibited average size of the nanoparticles as 50.17 nm with a polydispersity index (PDI) value of 0.298. The zeta potential of nanoparticles was observed as -24.9 mV. To assess antibacterial activity, both AgNPs alone or its combination with the antibiotic were tried against six pathogenic bacteria. The combination of AgNPs with antibiotic was maximum effective against Shigella boydii (16.07 ± 0.35) and Klebsiella pneumoniae (15.03 ± 0.20). AgNPs alone showed maximum inhibition for both Gram-positive bacteria: methicillin-resistant Staphylococcus aureus (19.97 ± 0.20 mm) and Enterococcus faecium (19.80 ± 0.15 mm). Maximum inhibition of Enterobactor cloacae and Pseudomonas aeruginosa was observed by antibiotic taken alone. Evaluation through 2,2-diphenyl-1-picrylhydrazyl (DPPH) and DNA nicking assays demonstrated the antioxidant capabilities of the nanoparticles.

Recent advances in the development of bacterial response regulators inhibitors as antibacterial and/or antibiotic adjuvant agent: A new approach to combat bacterial resistance.

The number of new antibacterial agents currently being discovered is insufficient to combat bacterial resistance. It is extremely challenging to find new antibiotics and to introduce them to the pharmaceutical market. Therefore, special attention must be given to find new strategies to combat bacterial resistance and prevent bacteria from developing resistance. Two-component system is a transduction system and the most prevalent mechanism employed by bacteria to respond to environmental changes. This signaling system consists of a membrane sensor histidine kinase that perceives environmental stimuli and a response regulator which acts as a transcription factor. The approach consisting of developing response regulators inhibitors with antibacterial activity or antibiotic adjuvant activity is a novel approach that has never been previously reviewed. In this review we report for the first time, the importance of targeting response regulators and summarizing all existing studies carried out from 2008 until now on response regulators inhibitors as antibacterial agents or / and antibiotic adjuvants. Moreover, we describe the antibacterial activity and/or antibiotic adjuvants activity against the studied bacterial strains and the mechanism of different response regulator inhibitors when it's possible.

Tailoring ZnS nanostructures through precipitation-cum-hydrothermal synthesis for enhanced wastewater purification and antibacterial treatment.

This study presents a novel blend of synthesis techniques for shape-controlled ZnS nanoparticles. Zinc sulfide (ZnS) nanoparticles with distinct morphologies cauliflower-like microstructures (∼4.5 µm) and uniform nanospheres (200-700 nm) were synthesized through an innovative blend of precipitation and hydrothermal techniques. Capping with polyvinylpyrrolidone (PVP) significantly decreased crystallite size (3.93 nm-2.36 nm), modulated the band gap (3.57 eV-3.71 eV), and dramatically influenced morphology, highlighting the novelty of shape-controlled synthesis and its impact on optoelectronic and functional properties. X-ray diffraction confirmed crystallinity and revealed the size-controlling influence of PVP. UV-vis spectroscopy suggested potential tuning of optical properties due to band gap widening upon PVP capping. Field-emission scanning electron microscopy (FESEM) unveiled distinct morphologies: cauliflower-like microstructures for ZnS and uniform nanospheres (200-700 nm) for PVP-ZnS. Both structures were composed of smaller spherical nanoparticles, demonstrating the role of PVP in promoting controlled growth and preventing agglomeration. High-resolution transmission electron microscope (HRTEM) images depicted that the majority of nanoparticles maintain a spherical shape, though slight deviations from perfect sphericity can be discerned. Fourier-transform infrared (FTIR) spectroscopy confirmed that successful PVP encapsulation is crucial for shaping nanospheres and minimizing aggregation through steric hindrance. Photocatalytic activity evaluation using methylene blue (MB) dye degradation revealed significantly faster degradation by PVP-ZnS under ultraviolet (UV) irradiation (within 60 min as compared to 120 min for ZnS), showcasing its superior performance. This improvement can be attributed to the smaller size, higher surface area, and potentially optimized band gap of PVP-ZnS. Additionally, PVP-ZnS exhibited promising antibacterial activity against S. aureus and P. aeruginosa, with increased activity at higher nanoparticle concentrations.

Chitosan extraction from Amanita phalloides: yield, crystallinity, degree of deacetylation, azo dye removal and antibacterial properties.

Chitosan, a biopolymer obtained from chitin, is known for its remarkable adsorption abilities for dyes, drugs, and fats, and its diverse array of antibacterial characteristics. This study explores the extraction and characterization of chitosan from the mycelium of Amanita phalloides. The moisture content, ash content, water binding capacity, fat binding capacity, and degree of deacetylation of the extracted chitosan were determined. The chitosan exhibited a high yield of 70%, crystallinity of 49.07%, a degree of deacetylation of 86%, and potent antimicrobial properties against both Gram-negative and Gram-positive bacteria. The study also examined the adsorption capabilities of chitosan to remove methylene blue (MB) dye by analysing specific factors like pH, reaction time, and MB concentration using the response surface model. The highest degree of MB dye removal was 91.6% at a pH of 6, a reaction time of around 60 min and an initial dye concentration of 16 ppm. This experimental design can be applied for chitosan adsorption of other organic compounds such as dyes, proteins, drugs, and fats.

Crystallographic structure, antibacterial effect, and catalytic activities of fig extract mediated silver nanoparticles.

Silver nanoparticles (Ag NPs) play a pivotal role in the current research landscape due to their extensive applications in engineering, biotechnology, and industry. The aim is to use fig (Ficus hispida Linn. f.) extract (FE) for eco-friendly Ag NPs synthesis, followed by detailed characterization, antibacterial testing, and investigation of bioelectricity generation. This study focuses on the crystallographic features and nanostructures of Ag NPs synthesized from FE. Locally sourced fig was boiled in deionized water, cooled, and doubly filtered. A color change in 45 mL 0.005 M AgNO3 and 5 mL FE after 40 min confirmed the bio-reduction of silver ions to Ag NPs. Acting as a reducing and capping agent, the fig extract ensures a green and sustainable process. Various analyses, including UV-vis absorption spectrophotometry (UV), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray spectroscopy (EDX) and Transmission electron microscopy (TEM) were employed to characterize the synthesized nanoparticles, and Gas chromatography-mass spectrometry (GC-MS) analysis of the fig extract revealed the presence of eleven chemicals. Notably, the Ag NPs exhibited a surface plasmon resonance (SPR) band at 418 nm, confirmed by UV analysis, while FTIR and XRD results highlighted the presence of active functional groups in FE and the crystalline nature of Ag NPs respectively. With an average particle size of 44.57 nm determined by FESEM and a crystalline size of 35.87 nm determined by XRD, the nanoparticles showed strong antibacterial activities against Staphylococcus epidermidis and Escherichia coli. Most importantly, fig fruit extract has been used as the bio-electrolyte solution to generate electricity for the first time in this report. The findings of this report can be the headway of nano-biotechnology in medicinal and device applications.

Assessment of the biological activity of Marrubium friwaldskyanum Boiss. (Lamiaceae).

Present scientific evidences about the biological activity and potential medical application of extracts derived from Marrubium friwaldskyanum Boiss. are limited. Therefore, our study was undertaken to define several main characteristics in this regard - in vitro cytotoxicity and antitumor properties, antibacterial activity and immunomodulatory potential. Extracts were obtained from different aerial parts of Marrubium friwaldskyanum - stems, leaves and flowers. The in vitro cytotoxicity and antitumor activity of the samples were evaluated by tetrazolium salt reduction tests and Neutral red uptake assays using four human cell lines (a normal fibroblastic and three adenocarcinoma cell lines/A549, HeLa, HT-29/) and by experiments with HT-29 tumor spheroids. Antibacterial activity toward Gram-negative (Escherichia coli) and Gram-positive (Bacillus cereus) species was assessed based on estimation of minimal inhibitory and minimal bactericidal concentrations as well as longitudinal studies on bacterial viability. Ex vivo assays with normal leukocytes were performed to define potential immunomodulatory activity of the extracts. Our results demonstrated selective antitumor activity of the extracts directed against colon adenocarcinoma HT-29 cells and cervical adenocarcinoma HeLa cell line. Metabolic activity of A549 lung adenocarcinoma cells was affected only by the sample derived from flowers. M. friwaldskyanum leaf and flower extracts showed the highest activity, which included reduction of HT-29 tumor spheroid growth and viability. The studied samples exhibited antibacterial activity against both bacterial species tested. Treatment with M. friwaldskyanum extracts affected specific leukocyte populations (HLA+, CD19+, CD11b+, CD25+ cells). These results demonstrate for the first time complex biological effects of extracts derived from M. friwaldskyanum and their potential to serve as a source of valuable compounds for the pharmaceutical industry.

Controversies in the management of community-acquired pneumonia in adults.

Community-acquired pneumonia (CAP) is a common infectious syndrome in Australia and a leading global cause of morbidity and mortality. It drives a significant amount of antimicrobial prescribing in Australia. Accurate assessment and stratification of CAP severity is important. However, adequate evaluation is challenging and controversy remains about the optimal method. Streptococcus pneumoniae is the most commonly identified bacterial pathogen causing CAP. As such, oral amoxicillin monotherapy is the mainstay of empirical therapy for low-severity CAP. The need to start empirical therapy for pathogens such as Mycoplasma pneumoniae and Legionella species in low-severity CAP remains controversial; evaluating the causative pathogen on clinical grounds alone is difficult. Oral antibiotics recommended for CAP (e.g. amoxicillin, doxycycline) have excellent bioavailability and may be used instead of intravenous therapy in some hospitalised patients. A duration of 5 days of antibiotic therapy is recommended in clinical practice guidelines for patients with uncomplicated CAP who meet stability criteria at follow-up.

Geese as reservoirs of human colon cancer-associated Streptococcus gallolyticus.

Recently, an increased number of reports have described pathogens of animal origin that cause a variety of infections and a rise in their transmission to humans. Streptococcus gallolyticus, a member of the Streptococcus bovis/Streptococcus equinus complex (SBSEC), is one of these pathogens and infects a wide range of hosts from mammals to poultry and has a broad functionality ranging from pathogenicity to food fermentation. As S. gallolyticus causes complications including bacteremia, infective endocarditis, and colorectal malignancy in humans, it is important to investigate its occurrence in various hosts, including geese, to prevent potential zoonotic transmissions. This study aimed to investigate the presence of S. gallolyticus in the droppings of clinically healthy and diarrheic geese, which were raised intensively and semi-intensively, by the in vitro culture method, characterize the isolates recovered by PCR and sequence-based molecular methods and determine their antibiotic susceptibility by the disk diffusion and gradient test methods. For this purpose, 150 samples of fresh goose droppings were used. Culture positivity for S. gallolyticus was determined as 8% (12/150). PCR analysis identified 54.55% (n = 6) of the isolates as S. gallolyticus subsp. gallolyticus and 45.45% (n = 5) as S. gallolyticus subsp. pasteurianus. Following the 16S rRNA sequence and ERIC-PCR analyses, S. gallolyticus subspecies exhibited identical cluster and band profiles that could be easily distinguished from each other and were clonally identified. High rates of susceptibility to florfenicol, penicillin, rifampicin, and vancomycin were detected among the isolates, regardless of the subspecies diversity. Both subspecies showed high levels of resistance to bacitracin, clindamycin, doxycycline, tetracycline, trimethoprim-sulfamethoxazole, and erythromycin and multiple MDR profiles, indicating their potential to become superbugs. This first report from Türkiye demonstrates the occurrence of the S. gallolyticus subspecies in geese. In view of the recent increase of geese production and the consumption of goose meat in Türkiye, the occurrence of S. gallolyticus in geese should not be ignored to prevent zoonotic transmission.

Films based on TEMPO-oxidized chitosan nanoparticles: Obtaining and potential application as wound dressings.

A series of novel films based on TEMPO-oxidized chitosan nanoparticles were prepared by casting method. Fourier transform infrared spectroscopy (FTIR) was employed to ascertain the chemical structure of TEMPO-oxidized chitosan. The surface morphology of the TEMPO-oxidized chitosan nanoparticles was analyzed by atomic force microscopy (AFM). The physicochemical (area density, thickness, iodine sorption, roughness), functional (moisture sorption, liquid absorption capacity, weight loss upon contact with the liquid, and water vapor transmission rate), antibacterial, and antioxidant properties of films based on TEMPO-oxidized chitosan nanoparticles were also investigated. The physicochemical properties of the films varied widely: area density ranged from 77.83 ± 0.06 to184.46 ± 0.05 mg/cm2, thickness varied between 80.5 ± 1.6 and 200.5 ± 1.6 µm, iodine sorption spanned from 333.7 ± 2.1 to166.4 ± 2.2 mg I2/g, and roughness ranged from 4.1 ± 0.2 to 5.6 ± 0.3 nm. Similarly, the functional properties also varied significantly: moisture sorption ranged from 4.76 ± 0.03 to 9.62 ± 0.11 %, liquid absorption capacity was between 129.04 ± 0.24 and 159.33 ± 0.73 % after 24 h, weight loss upon contact with the liquid varied between 31.06 ± 0.35 and 45.88 ± 0.58 % after 24 h and water vapor transmission rate ranged from 1220.10 ± 2.91to1407.77 ± 5.22 g/m2 day. Despite the wide variations in physicochemical and functional properties, all films showed maximum bacterial reduction of Staphylococcus aureus and Escherichia coli, although they exhibited low antioxidant activity. The results suggest that the films could be effectively utilized as antibacterial wound dressings.

Oleanane-type saponins from Lysimachia laxa Baudo and their anti-bacterial activities.

Seven new oleanane-type triterpene saponins, lysimaponins A-G, were isolated from aerial parts of Lysimachia laxa Baudo. Their chemical structures have been elucidated by analysis of spectroscopic and chemical methods. All compounds were evaluated for their anti-bacterial effects against Microcystis aeruginosa, Vibrio parahaemolyticus, V. harveyi, V. vulinificus, V. cholerae, and V. alginolyticus. All compounds showed potent anti-bacterial activities against the cyanobacteria M. aeruginosa with IC50 values ranging from 14.4 ± 1.2 to 35.3 ± 2.2 µg/mL. Compounds 1, 2, 4-7 inhibited V. parahaemolyticus with MIC values ranging from 64 to 256 µg/mL. The results suggested that saponins from L. laxa could be potential anti-cyanobacteria agents.

Antibacterial And Biofilm Removal Strategies Based On Micro/nanomotors In The Biomedical Field.

Bacterial infection, which can trigger varieties of diseases and tens of thousands of deaths each year, poses  serious threats to human health. Particularly, the new dilemma caused by biofilms is gradually becoming a severe and tough problem in the biomedical field. Thus, the strategies to address these problems are considered an urgent task at present. Micro/nanomotors (MNMs), also named micro/nanoscale robots, are mostly driven by chemical energy or external field, exhibiting strong diffusion and self-propulsion in the liquid media, which has the potential for antibacterial applications. In particular, when MNMs are assembled in swarms, they become robust and efficient for biofilm removal. However, there is a lack of comprehensive review discussing the progress in this aspect. Bearing it in mind and based on our own research experience in this regard, the studies on MNMs driven by different mechanisms orchestrated for antibacterial activity and biofilm removal are timely and concisely summarized and discussed in this work, aiming to show the advantages of MNMs brought to this field. In addition, an outlook was proposed, hoping to provide the fundamental guidance for future development in this area.

Advancements in inhibitors of crucial enzymes in the cysteine biosynthetic pathway: Serine acetyltransferase and O-acetylserine sulfhydrylase.

Infectious diseases have been jeopardized problem that threaten public health over a long period of time. The growing prevalence of drug-resistant pathogens and infectious cases have led to a decrease in the number of effective antibiotics, which highlights the urgent need for the development of new antibacterial agents. Serine acetyltransferase (SAT), also known as CysE in certain bacterial species, and O-acetylserine sulfhydrylase (OASS), also known as CysK in select bacteria, are indispensable enzymes within the cysteine biosynthesis pathway of various pathogenic microorganisms. These enzymes play a crucial role in the survival of these pathogens, making SAT and OASS promising targets for the development of novel anti-infective agents. In this comprehensive review, we present an introduction to the structure and function of SAT and OASS, along with an overview of existing inhibitors for SAT and OASS as potential antibacterial agents. Our primary focus is on elucidating the inhibitory activities, structure-activity relationships, and mechanisms of action of these inhibitors. Through this exploration, we aim to provide insights into promising strategies and prospects in the development of antibacterial agents that target these essential enzymes.

Fabrication of multifunctional cotton fabrics with quaternized N-halamine endowing the synergetic rechargeable antibacterial, wound healing and self-cleaning performances.

Cotton has attracted considerable attention due to its functional characteristics. The focus of research on cotton has shifted in recent years towards designing multi-functional and modified media for cotton fibers, which can be firmly combined with textiles, giving them reusability and extending their service life. This study constructed a synergistic antibacterial layer of quaternary ammonium compounds (QACs) and N-halamine (Hals) using an in-situ free radical copolymerization method in water, named QACs/Hals@cotton-Cl. The route significantly increases the number of antibacterial active centers. FTIR, XPS, and SEM were used to systematically analyze the product's chemical structure, surface morphology, and other characteristics. The modified fabric's antibacterial efficiency, wound healing, renewability, and durability were also evaluated. The chlorinated modified cotton fabric could completely eradicate S. aureus and E. coli within 10 min. Compared with pure cotton, it notably promoted the healing rate of infected wounds in mice. The modification method imparted excellent hydrophobicity to the cotton fabric, with a contact angle exceeding 130°, making it easy to remove surface stains. After 30 days of regular storage and 24 h of UV irradiation, the active chlorine concentration (Cl+%) only decreased by 25 % and 39 %, respectively, and the reduced Cl+% was effectively recharged via simple re-chlorination. The hydrophobicity and antimicrobial properties of QACs/Hals@cotton-Cl remained stable even after 20 cycles of friction. This simple synthesis technique provides a convenient approach for the scalable fabrication of multifunctional and rechargeable antibacterial textiles, with potential applications in medical devices and personal hygiene protection.

A poly (lactic-co-glycolic acid) /polyethylene glycol/doped hydroxyapatite/sodium alginate dressing with bidirectional biofluid transport for diabetic wound healing.

Diabetic wound healing poses a substantial challenge owing to bacterial infections, insufficient angiogenesis, and excessive exudates. Currently, most of the clinical dressings used for diabetic wounds are still conventional dressings such as gauze. In this study, a three-layer Janus dressing was developed via continuous electrostatic spinning. The top-layer was composed of polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate. The hydrophobic top-layer prevented the adhesion of foreign bacteria. The mid-layer was composed of polyethylene glycol, polylactic acid-glycolic acid and hydroxyapatite doped with silver ions and silicate facilitated exudate absorption and bioactive ion release. The modified sub-layer containing polylactic acid-glycolic acid, hydroxyapatite doped with silver ions and silicate and sodium alginate microspheres enabled both the transport of wound exudate from the wound bed to dressing and the backflow of bioactive silver ions and silicate to the wound bed, thereby reducing infection and stimulating angiogenesis. Through in vivo and in vivo experiments, the Janus dressing showed to have antimicrobial, angiogenic, and exudate-control properties that accelerate healing in diabetic wounds. As a novel dressing, the multifunctional, self-pumping Janus wound dressing with bi-directional biofluidic transport offers a new approach to diabetic wound healing.

"All-in-one" self-healing and injectable cationic guar gum hydrogel dressing functionalized by bioactive complexes composed of natural small molecules.

Reducing the risk of wound infection is an urgent issue health priority. Antibacterial polysaccharide-based hydrogels have attracted great attention for infectious wounds, attributed to their safe antimicrobial performance and natural non-toxicity and biodegradability advantages. In this study, the "all-in-one" self-adaptive and injectable cationic guar gum (CG)-based polysaccharide hydrogels (FA-TOB/CG) loaded with bioactive complexes were developed for infectious wound healing. The constructed antioxidant and antibacterial ferulic acid (FA)-tobramycin (TOB) bioactive complexes (FA-TOB) were used as the cross-linking agent and introduced into the CG matrix to construct the FA-TOB/CG hydrogel with a three-dimensional porous structure. The sterilization rates of FA-TOB/CG hydrogel against S. aureus and E. coli reached 98 % and 80 % respectively. In addition, the FA-TOB/CG also exhibits enhanced antioxidant performances (DPPH: > 40 %; ABTS: > 90 %; ·OH: > 50 %). More importantly, FA-TOB/CG hydrogel also showed the ability to sustain the release of FA and TOB. These superiorities of the FA-TOB/CG hydrogel enabled it to provide a moist wound environment and promote wound healing by eliminating bacteria, modulating the local inflammatory response, and accelerating collagen deposition and vascular regeneration. Thus, this study may enlarge a new sight for developing multifunctional dressings by incorporating bioactive complexes into polysaccharide hydrogels for infected wounds.

An injectable hydrogel based on sodium alginate and gelatin treats bacterial keratitis through multimodal antibacterial strategy.

Bacterial keratitis is among the most prevalent causes of blindness. Currently, the abuse of antibiotics in clinical settings not only lacks bactericidal effects but also readily induces bacterial resistance, making the clinical treatment of bacterial keratitis a significant challenge. In this study, we present an injectable hydrogel (GS-PNH-FF@CuS/MnS) containing self-assembled diphenylalanine dipeptide (FF) and CuS/MnS nanocomposites (CuS/MnS NCs) that destroy bacterial cell walls through a synergistic combination of mild photothermal therapy (PTT), chemodynamic therapy (CDT), ion release chemotherapy, and self-assembled dipeptide contact, thereby eliminating Pseudomonas aeruginosa. Under 808 nm laser irradiation, the bactericidal efficiency of GS-PNH-FF@CuS/MnS hydrogel against P. aeruginosa in vitro reach up to 96.97 %. Furthermore, GS-PNH-FF@CuS/MnS hydrogel is applied topically to kill bacteria, reduce inflammation, and promote wound healing. Hematoxylin-eosin (H&E) staining, Masson staining, immunohistochemistry and immunofluorescence staining are used to evaluate the therapeutic effect on infected rabbit cornea models in vivo. The GS-PNH-FF@CuS/MnS demonstrate good biocompatibility with human corneal epithelial cells and exhibit no obvious eyes side effects. In conclusion, the GS-PNH-FF@CuS/MnS hydrogel in this study provides an effective and safe treatment strategy for bacterial keratitis through a multimodal approach.

Cell Wall Binding Strategies Based on Cu3SbS3 Nanoparticles for Selective Bacterial Elimination and Promotion of Infected Wound Healing.

Utilizing nanomaterials as an alternative to antibiotics, with a focus on maintaining high biosafety, has emerged as a promising strategy to combat antibiotic resistance. Nevertheless, the challenge lies in the indiscriminate attack of nanomaterials on both bacterial and mammalian cells, which limits their practicality. Herein, Cu3SbS3 nanoparticles (NPs) capable of generating reactive oxygen species (ROS) are discovered to selectively adsorb and eliminate bacteria without causing obvious harm to mammalian cells, thanks to the interaction between O of N-acetylmuramic acid in bacterial cell walls and Cu of the NPs. Coupled with the short diffusion distance of ROS in the surrounding medium, a selective antibacterial effect is achieved. Additionally, the antibacterial mechanism is then identified: Cu3SbS3 NPs catalyze the generation of O2•-, which has subsequently been conversed by superoxide dismutase to H2O2. The latter is secondary catalyzed by the NPs to form •OH and 1O2, initiating an in situ attack on bacteria. This process depletes bacterial glutathione in conjunction with the disruption of the antioxidant defense system of bacteria. Notably, Cu3SbS3 NPs are demonstrated to efficiently impede biofilm formation; thus, a healing of MRSA-infected wounds was promoted. The bacterial cell wall-binding nanoantibacterial agents can be widely expanded through diversified design.

Maghamesin, a new prenylated flavanone from artocarpus heterophyllus lam. (moraceae).

The chemical investigation of the methanol root extract of Artocarpus heterophyllus Lam. led to the isolation of a new prenylated flavanone, 5,7,4'-trihydroxy-3'-(3-methylbuta-1,3-dienyl)-5'-(3-methylbut-2-enyl)flavanone, trivially named maghamesin (1), together with nine known compounds, 5-hydroxy-3',4',5',7-tetramethoxy-8-prenylflavanone (2), cycloheterophyllin (3), cyclomorusin (4), isobavachalcone (5), trans-isoferulic acid (6), 24-methylenecycloartan-3α-ol (7), stigmasterol (8), ß-sitosterol (9) and ß-sitosterol-3-O-ß-D-glucopyranoside (10). The structures of the isolates were elucidated by extensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-MS) and by comparison with previously reported data. The absolute configuration of 1 was deduced by comparison of its experimental CD with that of a reported similar compound. Compounds 1-3 and 6-7 were tested for their antibacterial and antifungal activities. Compound 1 displayed a significant antibacterial activity against Staphylococcus aureus with MIC value of 15.625 µg/mL. The others tested compounds showed moderate antibacterial and antifungal activities against several microorganisms with MIC values of either 31.25 or 62.5 µg/mL.