Construction of Antibacterial N‐Halamine Polymer Nanomaterials Capable of Bacterial Membrane Disruption for Efficient Anti‐Infective Wound Therapy

The increasing occurrence of bacterial infection at the wound sites is a serious global problem, demanding the rapid development of new antibacterial materials for wound dressing to avoid the abuse of antibiotics and thereby antibiotic resistance. In this work, the authors first report on antibacterial N‐halamine polymer nanomaterials based on a strategic copolymerization of 3‐allyl‐5,5‐dimethylhydantoin (ADMH) and methyl methacrylate (MMA), which exhibits in vitro and in vivo antimicrobial efficacy against pathogenic bacteria including Staphylococcus aureus and Escherichia coli. Particularly, when a biological evaluation is run for wound therapy, the N‐halamine polymer nanomaterials exhibit a powerful antibacterial efficiency and wound healing ability after a series of histological examination of mouse wound. After the evaluation of biological and chemical surroundings, the proposed four‐stage mechanism suggests that, with unique antibacterial N? Cl bonds, the N‐halamine polymer nanomaterials can disrupt the bacterial membrane, as a result causing intracellular content leaked out and thereby cell death. Based on the synergistic action of antibacterial and wound therapy, the N‐halamine polymer nanomaterials are expected to be promising as wound dressing materials in medical healing and biomaterials.     

Porous Microstructured Surfaces with pH‐Triggered Antibacterial Properties

New antibacterial films are designed with the capability to reversibly regulate their killing and repelling functions in response to variations in environmental pH. These systems consist of porous polystyrene surfaces as the main components and a copolymer bearing pH‐sensitive thiazole and triazole groups as the minor components. These pH‐sensitive groups, located on the surfaces, can be partially protonated at acidic pH levels, increasing the positive charge density of the surfaces and their antibacterial activity. Similarly, their bacterial adhesion and killing efficiencies in response to changes in pH are evaluated by analyzing the bacterial viability of Staphylococcus aureus bacteria on the surfaces under acidic and neutral pH values. It is demonstrated that after only 1 h of incubation with the bacterial suspension in acidic conditions, the surfaces killed the bacteria, while at pH = 7.4, some of the adhered bacteria are removed. Furthermore, the surface topography exerts an important role by intensifying this response.     

Design,Synthesis and Molecular Modeling of Nonsteroidal Anti‐inflammatory Drugs Tagged Substituted 1,2,3‐Triazole Derivatives and Evaluation of Their Biological Activities

A novel series of 1,4‐disubstituted‐1,2,3‐triazole derivatives 3a – l and 5a – i were one‐pot synthesized via CuAAC‐alkyne click chemistry and evaluated for their antibacterial activity against four organisms and screened for their anticancer activity against human colon cancer cell line HT‐29 and human lung cancer cell line HTB‐29. These hybrid molecules structure elucidation has been performed by IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral analysis. Synthesized nonsteroidal anti‐inflammatory drugs‐triazoles evaluated for their antibacterial activities against bacterial microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia. Final compounds 3i , 3c , and 5b showed magnificent broad spectrum activity against P. aeruginosa, K. pneumonia, E. coli, and S. aureus with zone of inhibition values of 20, 15, 17, and 16 mm, respectively. Among the series of compound, 3j showed the best antibacterial activity against all the strains. Further, the compounds 3i and 5a were more cytotoxic than cisplatin against all tested two human cancer cell lines, with 50.8%, and 52.3% and 73.4% and 75.3% of growth, respectively. The synthesized compounds were tested for kinase inhibitory activity against glycogen synthase kinase‐3 protein kinases, in addition, for cytotoxic activity against two different human cancer cell lines.     

Dual‐Functional Dextran‐PEG Hydrogel as an Antimicrobial Biomedical Material

Microbial infections continually present a major worldwide public healthcare threat, particularly in instances of impaired wound healing and biomedical implant fouling. The development of new materials with the desired antimicrobial property to avoid and treat wound infection is urgently needed in wound care management. This study reports a novel dual‐functional biodegradable dextran‐poly(ethylene glycol) (PEG) hydrogel covalently conjugated with antibacterial Polymyxin B and Vancomycin (Vanco). The hydrogel is designed as a specialized wound dressing that eradicates existing bacteria and inhibits further bacteria growth, while, ameliorating the side effects of antibiotics and accelerating tissue repair and regeneration. The hydrogel exhibits potent antibacterial activities against both gram‐negative bacteria Escherichia coli (E. coli) and gram‐positive bacteria Staphylococcus aureus (S. aureus) with no observable toxicity to mouse fibroblast cell line NIH 3T3. These results demonstrate the immense potential of dextran‐PEG hydrogel as a wound dressing healthcare material in efficiently controlling bacteria growth in complex biological systems.     

Hybrid 4‐Aminoquinoline‐1,3,5‐triazine Derivatives: Design,Synthesis, Characterization,and Antibacterial Evaluation

A series of novel 4‐aminoquinoline 1,3,5‐triazine derivatives were synthesized and characterized by FTIR, ¹H‐NMR, ¹³C‐NMR, MS, and elemental analysis. The antibacterial activities of synthesized compounds were tested against three Gram‐positive bacteria, namely Bacillus subtilis (NCIM‐2063), Bacillus cereus (NCIM‐2156), and Staphylococcus aureus (NCIM‐2079), and four Gram‐negative bacteria, namely Proteus vulgaris (NCIM‐2027), Proteus mirabilis (NCIM‐2241), Escherichia coli (NCIM‐2065), and Pseudomonas aeruginosa (NCIM‐2036), using ciprofloxacin as reference standard drug. Results showed compound 9a and 9e as potent antibacterial agents against all bacterial strains except Bacillus cereus (NCIM‐2156). Copyright © 2014 HeteroCorporation     

Polydopamine‐Mediated Immobilization of Alginate Lyase to Prevent P. aeruginosa Adhesion

Given alginate's contribution to Pseudomonas aeruginosa virulence, it has long been considered a promising target for interventional therapies, which have been performed by using the enzyme alginate lyase. In this work, instead of treating pre‐established mucoid biofilms, alginate lyase is immobilized onto a surface as a preventive measure against P. aeruginosa adhesion. A polydopamine dip‐coating strategy is employed for functionalization of polycarbonate surfaces. Enzyme immobilization is confirmed by surface characterization. Surfaces functionalized with alginate lyase exhibit anti‐adhesive properties, inhibiting the attachment of the mucoid strain. Moreover, surfaces modified with this enzyme also inhibit the adhesion of the tested non‐mucoid strain. Unexpectedly, treatment with heat‐inactivated enzyme also inhibits the attachment of mucoid and non‐mucoid P. aeruginosa strains. These findings suggest that the antibacterial performance of alginate lyase functional coatings is catalysis‐independent, highlighting the importance of further studies to better understand its mechanism of action against P. aeruginosa strains.

     

Impact of polymeric films and hydrogels: Physical characteristics on bacterial growth

Hydrogels find diverse applications in manipulating bacteria, and serving purposes like elevation, maintenance, and elimination. Several factors of hydrogel have been studied in the benefits of antibacterial activity. Factors such as hydrogel stiffness and roughness gain significance in surface coating, influencing bacterial behavior. However, the intricate interplay of hydrogel stiffness, roughness, polymer types, and bacterial species necessitates further exploration. The choice of polymer is dictated by the specific objectives, particularly in antibacterial scenarios where polymers with positive charge, hydrophilicity, and acidity prove effective. These properties induce robust electrostatic and hydrophobic/hydrophilic interactions, along with pH-induced cell membrane damage, collectively contributing to hindered bacterial adhesion and growth. Additionally, extracellular polymeric substances (EPS) emerge as pivotal influencers in bacterial adhesion and proliferation. EPS production alters bacterial surfaces, fostering connections between bacteria and facilitating biofilm formation. The hydrophobic nature of EPS further complicates bacterial interactions with surface materials, emphasizing the nuanced interplay of hydrophilic and hydrophobic forces in bacterial adhesion. Herein, this work article has reviewed the related study of each physical property related to antibacterial property on the surface of the hydrogel. Moreover, this work also illustrates applications of the antibacterial properties of hydrogel for medical and surface treatment, including wound healing, food packaging, and surface coating. Additionally, the bacteria growing on hydrogel for engineered living materials, have been updated in various applications.     

Design,Synthesis and Computational Studies of Novel Carbazole N‐phenylacetamide Hybrids as Potent Antibacterial,Anti‐inflammatory,and Antioxidant Agents

The present study deals with the synthesis of N‐phenylacetamide‐functionalized carbazole derivatives and their antibacterial, anti‐inflammatory, and antioxidant assays. In vitro antibacterial studies of synthesized compounds shows prominent activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. In addition, in silico molecular docking studies corroborated that the methyl substituent ( 3g ), ( 3h ), and ( 3i ) showed promising activity with lower ∆G (kcal/mol) values. This study envisages that these compounds can serve as a new leading template in the chemotherapy of various bacterial ailments.     

Non‐Woven Fibrous Materials with Antibacterial Properties Prepared by Tailored Attachment of Quaternized Chitosan to Electrospun Mats from Maleic Anhydride Copolymer

In order to impart antibacterial properties to microfibrous electrospun materials from styrene/maleic anhydride copolymers, quaternized chitosan derivatives (QCh) containing alkyl substituents of different chain lengths are covalently attached to the mats. A complete inhibition of the growth of bacteria, S. aureus (Gram‐positive) and E. coli (Gram‐negative), for a contact time of 30–120 min or a decrease of the bacterial titer by 2–3 log units is observed depending on the quaternization degree, the chain length of the alkyl substituent, and the molar mass of QCh. The modified mats are also effective in suppressing the adhesion of pathogenic S. aureus bacteria.

     

Defect‐Rich Adhesive Nanozymes as Efficient Antibiotics for Enhanced Bacterial Inhibition

Nanozymes have emerged as a new generation of antibiotics with exciting broad‐spectrum antimicrobial properties and negligible biotoxicities. However, their antibacterial efficacies are unsatisfactory due to their inability to trap bacteria and their low catalytic activity. Herein, we report nanozymes with rough surfaces and defect‐rich active edges. The rough surface increases bacterial adhesion and the defect‐rich edges exhibit higher intrinsic peroxidase‐like activity compared to pristine nanozymes due to their lower adsorption energies of H₂O₂ and desorption energy of OH*, as well as the larger exothermic process for the whole reaction. This was demonstrated using drug‐resistant Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus in vitro and in vivo. This strategy can be used to engineer nanozymes with enhanced antibacterial function and will pave a new way for the development of alternative antibiotics.     

Specific Adhesion of 3T3‐L1 Fibroblast onto Uridine‐Containing Polystyrene

A hydrophobic 96‐well multiplate was incubated with aqueous poly(uridine 5′‐p‐styrenesulfonate) (PUSS). Analysis of the PUSS‐coated surface indicated that the surface incubated at higher polymer concentration (50 mg·mL^–1) was hydrophilic while the surface incubated at lower polymer concentration (1 mg·mL^–1) was hydrophobic. Adhesion of 3T3‐L1, which has GalTase on the cell membrane, on the hydrophobic PUSS‐coated surface was greater than on the non‐coated surface. 3T3‐L1 adhesion on the hydrophilic PUSS‐coated surface was even greater. On the other hand, the adhesion of HeLa cells, which did not show GalTase on the cell membrane, on the hydrophilic surface was quite weak. It may well be said that the 3T3‐L1 adhesion on the hydrophilic PUSS‐coated surface was GalTase‐mediated.     

Enhanced antifouling and anticoagulant properties of grafted biomolecule polyethersulfone membranes

Polyethersulfone (PES) has been widely used in membrane technology and used to purify water in water treatments application or as a dialyzer to purify blood in hemodialysis. In this work, PES was chemically modified by separately grafting two biomolecules, 4‐aminobenzenesulfonamide (ABS), and 4‐amino‐N‐(5‐methylisoxazol‐3‐yl)benzenesulfonamide (AMBS), on PES backbone, and these modified membranes were blended to unmodified PES, in 1:1 ratio, in order to obtain PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes. The first aim of this study is to measure the anticoagulant properties of the modified membrane by measuring the activated partial thromboplastin time (APTT) and prothrombin time (PT). The second aim of the study is to evaluate the antifouling properties of the modified PES membranes by examining its antimicrobial activity against two Gram‐negative bacteria, which are Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli); two Gram‐positive bacteria, which are Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus); and a fungus, which is Candida albicans (C. albicans). The results showed that grafting of ABS and AMBS improved overall the hydrophilicity properties of the modified PES membranes. PES‐b‐PES‐ABS membranes showed better anticoagulant properties with 13 seconds for PT and 38 seconds for APPT, in comparison with the control sample (pure plasma), which showed 12 seconds for PT and 30 seconds for APPT. For antimicrobial tests, both PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes did not show any antibacterial activity, but when zinc oxide (ZnO) nanoparticles were added to the modified PES membranes in concentrations between 3% to 5% w/w, PES‐b‐PES‐ABS‐ZnO (M‐4 and M‐5), and PES‐b‐PES‐AMBS‐ZnO (M‐8 and M‐9) nanocomposite membranes showed antibacterial activity against P. aeruginosa and S. aureus.     

Organoiodine(III) Mediated Synthesis of Novel Symmetrical Bis([1,2,4]triazolo)[3,4‐a:4′,3′‐c]phthalazines as Antibacterial and Antifungal Agents

A series of new symmetrical 3,6‐bis(aryl)bis([1,2,4]triazolo)[3,4‐a:4′,3′‐c]phthalazines 9a‐l has been conveniently synthesized by oxidative cyclization of 1,4‐bis(substituted benzalhydrazino)phthalazines 8a‐l promoted by iodobenzene diacetate under mild conditions (12 examples, up to 93% yield). All the 12 compounds were tested in vitro for their antibacterial activity against two Gram‐positive bacteria, namely, Staphylococcus aureus, Bacillus subtilis and two Gram‐negative bacteria, namely, Escherichia coli and Pseudomonas aeruginosa. All the synthesized compounds were also tested for their antifungal action against two fungi, Aspergillus niger and Aspergillus flavus.     

Microwave Assisted Green Synthesis of Pyrazole, 1, 2, 3‐ Triazole Based Novel Benzohydrazones and Their Antibacterial Activities

A series of novel pyrazole, triazole based benzohydrazones ( 7a‐l ) were synthesized via conventional and microwave methods in the presence of acetic acid catalyst. Microwave method provided green and economical approach towards the synthesis of novel Schiff bases ( 7a‐l ). Some intermediates and all the final compounds were characterized by NMR, mass, and elemental analysis. The compounds were screened for their in vitro antibacterial activity against Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive bacteria (Staphylococcus aureus and Bacillus cereus). Compounds 7e and 7g showed good antibacterial activity.     

N‐Phenyl‐substituted carbene precursors and their silver complexes: synthesis,characterization and antimicrobial activities

A series of unsymmetrically substituted N‐heterocyclic carbene (NHC) precursors ( 1a , 1b , 1c , 1d , 1e ) were synthesized from the reaction of N‐phenylbenzimidazole with various alkyl halides. These compounds were used to synthesize NHC–silver(I) complexes ( 2a , 2b , 2c , 2d , 2e ). The five new 1‐phenyl‐3‐alkylbenzimidazolium salts ( 1a , 1b , 1c , 1d , 1e ) and their NHC–silver complexes ( 2a , 2b , 2c , 2d , 2e ) were characterized by the ¹H NMR, ¹³C NMR and FT‐IR spectroscopic methods and elemental analysis techniques. Also, the two NHC–silver complexes 2b and 2c were characterized by single‐crystal X‐ray crystallography, which confirmed the linear C―Ag―Cl arrangements. The antibacterial activities of the NHC precursor and NHC–silver complexes were tested against three Gram‐positive bacterial strains (Bacillus subtilis, Listeria monocytogenes and Staphylococcus aureus) and three Gram‐negative bacterial strains (Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa) using the microdilution broth method. The NHC–silver complexes showed higher antibacterial activity than the NHC precursors. In addition, silver complexes 2a , 2b , 2c , 2d showed high antibacterial activity against the Gram‐positive bacteria L. monocytogenes and S. aureus compared to the standard, tetracycline. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of New Triazole and Oxadiazole Derivatives of Quinazolin‐4(3H)‐one and Their Antimicrobial Activity

A series of new triazole derivatives of quinazolin‐4(3H)‐one and new oxadiazole derivatives of quinazolin‐4(3H)‐one were synthesized. The newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR and mass spectral data. All the newly synthesized compounds were screened for antibacterial activity against Staphylococcus aureus, Bacillus subtilis (gram‐positive bacteria), Escherichia coli, Pseudomonas aeruginosa (gram‐negative bacteria), and antifungal activity was carried out against Candida albicans and Aspergillus niger.     

Biofunctional properties of polyester fibers grafted with chitosan and collagen

Poly(ethylene terephthalate) (PET) fiber was treated with ⁶⁰Co-γ-ray and grafted with acrylic acid (AA). The resulting fibers were further grafted with chitosan (CS) via esterification. Afterward collagen (COL) was immobilized onto CS-grafting fibers. The antibacterial activity of CS against Staphylococus aureus, Escherichia coli, and Pseudomonas aeruginosa was preserved after COL-immobilization. After immobilizing COL, the L929 fibroblasts cell proliferation was promoted than CS-grafting PET fiber. The results indicate that by grafting with CS and immobilizing with COL, PET fibers exhibited both antibacterial activity against four pathological bacteria and improvement in the proliferation of fibroblast. Copyright © 2007 John Wiley & Sons, Ltd.     

3D‐Printed Titanium Cage with PVA‐Vancomycin Coating Prevents Surgical Site Infections (SSIs)

Many coating materials have been studied to prevent surgical site infections (SSIs). However, antibacterial coating on surfaces show weak adhesion using the traditional titanium (Ti) cage, resulting in low efficacy for preventing SSIs after spinal surgery. Herein, a 3D‐printed Ti cage combined with a drug‐releasing system is developed for in situ drug release and bacteria killing, leading to prevention of SSIs in vitro and in vivo. First, a 3D‐printed Ti cage is designed and prepared by the Electron Beam Melting (EBM) method. Second, polyvinyl alcohol (PVA) containing hydrophilic vancomycin hydrochloride (VH) is scattered across the surface of 3D‐printed porous Ti (Ti‐VH@PVA) cages. Ti‐VH@PVA cages show an efficient drug‐releasing profile and excellent bactericidal effect for three common bacteria after more than seven days in vitro. In addition, Ti‐VH@PVA cages exhibit reliable inhibition of inflammation associated with Staphylococcus aureus and effective bone regeneration capacity in a rabbit model of SSIs. The results indicate that Ti‐VH@PVA cages have potential advantages for preventing SSIs after spinal surgery.     

A Synergistic Capture Strategy for Enhanced Detection and Elimination of Bacteria

Despite the advanced detection and sterilization techniques available today, the sensitive diagnosis and complete elimination of bacterial infections remain a significant challenge. A strategy is reported for efficient bacterial capture (ca. 90 %) based on the synergistic effect of the nanotopography and surface chemistry of the substrate on bacterial attachment and adhesion. The outstanding bacterial‐capture capability of the functionalized nanostructured substrate enables rapid and highly sensitive bacterial detection down to trace concentrations of pathogenic bacteria (10 colony‐forming units mL^?1). In addition, this synergistic biocapture substrate can be used for efficient bacterial elimination and shows great potential for clinical antibacterial applications.     

Synthesis and Evaluation of Antimicrobial Activity of Some New Hetaryl‐Azoles Derivatives Obtained from 2‐Aryl‐4‐methylthiazol‐5‐carbohydrazides and Isonicotinic Acid Hydrazide

A series of new 1,3,4‐oxadiazole/thiadiazole and 1,2,4‐triazole derivatives have been synthesized starting from 2‐aryl‐4‐methylthiazol‐5‐carbohydrazides and isonicotinic acid hydrazide. All the newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR, and mass spectrometry. The synthesized compounds were screened for their antibacterial and antifungal activity, assessed as growth inhibition diameter. Some of them showed good antibacterial activity against gram positive Staphylococcus aureus, while the antibacterial activity against Listeria monocytogenes, Escherichia coli, and Salmonella typhymurium and antifungal activity against Candida albicans was modest. None of the tested compounds showed inhibitory activity against gram positive bacteria Enterococcus faecalis and Bacillus cereus and against gram negative bacteria Pseudomonas aeruginosa.