Biocidal Property Research Articles

Cationized orthogonal triad as a photosensitizer with enhanced synergistic antimicrobial activity

Single-molecule-based synergistic phototherapy holds great potential for antimicrobial treatment. Herein, we report an orthogonal molecular cationization strategy to improve the reactive oxygen species (ROS) and hyperthermia generation of heptamethine cyanine (Cy7) for photodynamic and photothermal treatments of bacterial infections. Cationic pyridine (Py) is introduced at the meso‑position of the asymmetric Cy7 with intramolecular charge transfer (ICT) to construct an atypical electron-transfer triad, which reduces ΔES1-S0, circumvents rapid charge recombination, and simultaneously enhances intersystem crossing (ISC) based on spin-orbit charge-transfer ISC (SOCT-ISC) mechanism. This unique molecular construction produces anti-Stokes luminescence (ASL) because the rotatable CN bond enriched in high vibrational-rotational energy levels improves hot-band absorption (HBA) efficiency. The obtained triad exhibits higher singlet oxygen quantum yield and photothermal conversion efficiency compared to indocyanine green (ICG) under irradiation above 800 nm. Cationization with Py enables the triad to target bacteria via intense electrostatic attractions, as well as biocidal property against a broad spectrum of bacteria in the dark. Moreover, the triad under irradiation can enhance biofilm eradication performance in vitro and statistically improve healing efficacy of MRSA-infected wound in mice. Thus, this work provides a simple but effective strategy to design small-molecule photosensitizers for synergistic phototherapy of bacterial infections. Statement of SignificanceWe developed an orthogonal molecular cationization strategy to enhance the reactive oxygen species and thermal effects of heptamethine cyanine (Cy7) for photodynamic and photothermal treatments of bacterial infections. Specifically, cationic pyridine (Py) was introduced at the meso‑position of the asymmetric Cy7 to construct an atypical electron-transfer triad, which reduced ΔES1-S0, circumvented rapid charge recombination, and simultaneously enhanced intersystem crossing (ISC). This triad, with a rotatable CN bond, produced anti-Stokes luminescence due to hot-band absorption. The triad enhanced antimicrobial performance and statistically improved the healing efficacy of MRSA-infected wounds in mice. This site-specific cationization strategy may provide insights into the design of small molecule-based photosensitizers for synergistic phototherapy of bacterial infections.

Structurally Heterogeneous Amphiphilic Conetworks of Poly(vinyl imidazole) Derivatives with Potent Antimicrobial Properties and Cytocompatibility.

We report the construction of amphiphilic conetwork (APCN)-based surfaces with potent antimicrobial activity and biofilm inhibition ability. The construction strategy is based on the separation of lipophilic alkyl groups (>C6) from the cationic network to obtain good antibacterial properties. The reaction of partially alkylated poly(vinyl imidazole) with the activated halide compounds followed by coating a glass or poly(dimethylsiloxane) (PDMS) sheet leads to the formation of the APCN surface. The dangling alkyl chains, crosslinking junctions, and unreacted vinyl imidazole groups are heterogeneously distributed in the APCNs. The swelling, mechanical property, and phase morphology of the APCN films have been evaluated. Bacterial cell disrupting potency of the APCN coatings increases with increasing alkyl chain length from C6 to C18 with somewhat more of an effect on Escherichia coli as compared to Bacillus subtilis bacteria. The minimum inhibitory amount of the APCNs on glass and a hydrophobic PDMS surface is in the range of 0.02-0.04 mg/cm2 depending on the chain length of the alkyl and the degree of quaternization. The effect of the type of crosslinker for the construction of the conetwork on the antimicrobial property has been evaluated to elucidate the exclusive design of the APCNs. The APCN-based coatings provide potent biocidal activity without much negatively affecting the hemocompatibility and cytocompatibility. These APCNs provide a good model system for comparative evaluation of the biocidal property and structural effect on the biocidal activity.

Enhancing the antibacterial property of chitosan through synergistic alkylation and chlorination

Chitosan exhibits moderate antimicrobial properties. Here, we enhanced the antimicrobial properties of chitosan through alkylation and chlorination and evaluated the effect of alkylation on chitosan's hydrophobicity, bacterial attachment, chlorination, biocidal property, and stability. First, chitosan films were prepared through casting and were then immersed in a hexanal solution of different concentrations. The aldehyde groups of hexanal reacted with the amino group in chitosan through a Schiff base reaction. Next, the hexanal-modified chitosan films were soaked in 10 % bleach to form N-halamine. The results demonstrated that the surface became more hydrophobic, and chitosan films with increased hexanal-grafting concentrations exhibited less bacterial attachment. However, the degree of chlorination decreased as the degree of alkylation increased, further reducing the diameter of the zone of inhibition. Nevertheless, all chlorinated samples could kill ~5 log of Staphylococcus aureus and Escherichia coli within 30 min. Unlike previous results for chlorinated chitosan, in this study, alkylation before chlorination enhanced antibacterial properties and bactericidal ability and decelerated the degradation of chlorinated samples. The results of a systematic evaluation indicated that a hexanal-grafting concentration of approximately 80 mM maintains the equilibrium of the various properties of chitosan. Alkylated and chlorinated chitosan has considerable potential application as mask filter layers.

A Sustainable and Antimicrobial Food Packaging Film for Potential Application in Fresh Produce Packaging.

N-halamines are a group of compounds containing one or more nitrogen-halogen covalent bond(s). This high-energy halide bond provides a strong oxidative state so that it is able to inactivate microorganisms effectively. In this study, a sustainable film was developed based on polylactic acid (PLA) with incorporated N-halamine compound 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC), as a promising antimicrobial food packaging material. Results showed that the incorporation of MC prevented the crystallization of PLA and improved the physical properties of the films. In addition, both the moisture barrier and the oxygen permeability were improved with the presence of MC. Importantly, the antimicrobial film was able to inactivate inoculated microorganisms by a factor of seven log cycles in as little as 5 min of contact. Films that contained higher levels of MC further enhanced the antimicrobial efficacy. Fresh strawberries packed with the fabricated films maintained the quality for up to 5 days. Due to the ease of fabrication and the effective biocidal property, these films have a wide range of potential applications in the field of food packaging to extend the shelf life of fresh produce.

Synthesis, spectroscopic characterization, molecular docking, as well as in vitro cytotoxicity of calcium-sulfasalazine complex

With the growing resistance of the bacterial strains resistant against antibiotics like sulfasalazine (SSZ) drug which has been of a great concern recently, bioactive metal complexation with an antibacterial agent “sulfasalazine” could be a potential solution in order to enhance the biocidal property of the drug. Herein, Calcium (II) sulfasalazine complex was experimentally synthesized and characterized by using infrared (IR) and UV–vis spectroscopic techniques. The complex was modeled using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations in order to analyze its electronic and optical properties and thermodynamic parameters in gas and PCM (ethanol) environments and compare these results with those of the experimental results where relevant. Cell toxicity assay (MTT) indicated that the half-maximal inhibitory concentrations (IC50) of SSZ and its combination with Ca were has no significant toxicity at concentrations below 650 µM in HDF cell lines.

Hierarchical membrane integration of shear stress-resistant nanoparticles and biomimetic micropatterns for ultrahigh and durable biofouling resistance

• Anti-biofouling pattern and biocidal nanoparticles were hierarchically integrated onto membranes. • Langmuir-Schaefer technique and nonsolvent-induced phase separation were rationally combined. • Silver nanoparticle integration is highly resistant to hydrodynamic shear stress (30 cm/s). • The resultant membrane enhanced biofouling resistance by 100% compared to the pristine counterpart. Herein, we report a rational strategy for fabricating dual-functional microfiltration (MF) membranes hierarchically integrated with micropatterns and Ag nanoparticles (NPs) for ultrahigh and durable fouling resistance. To harness hydrodynamic force and chemical oxidation for an enhanced anti-biofouling ability, a monolayer of Ag NPs was transferred onto negative patterns of polyurethane acrylate molds via the Langmuir-Schaefer technique. Then, they were integrated onto the biomimetic micropattern of porous polyacrylonitrile (PAN) membranes through nonsolvent-induced phase separation. Without the use of chemical linkers, our method achieved a stable and partial embedment of Ag NPs onto the porous PAN network and exhibited a negligible loss of Ag NPs even after exposure to high shear stress. Compared with the same micropatterned MF membranes without Ag NPs and the bare MF membranes, the resultant MF membrane significantly suppressed the decrease in water flux for the microbial solution by over 40% and 100%, respectively, owing to the dual anti-bacterial activities of the biocidal property of Ag NPs and the hydrodynamic repulsion of the micropatterns. Our hierarchical fabrication method can be applied to various biocidal NPs for ultrahigh biofouling-resistant porous membranes.

Hive‐Inspired Multifunctional Wood‐Nanotechnology‐Derived Membranes with a Double‐Layer Conductive Network Structure for Flexible Electronics

AbstractNext‐generation flexible electronics must achieve multifunctionality, environmental friendliness and antibacterial activity. Accordingly, organisms in nature are interconnected. Inspired by the honeycomb multilayer porous structure, a wood‐nanotechnology‐derived flexible membrane circuit is created to meet the abovementioned requirements. The flexible wood (FW) matrix is made of natural balsa wood that underwent a simple top‐down chemical treatment. The multiwalled carbon nanotube (MWCNT) acts as a “bridge” between the FW matrix with a porous array structure and the active material (silver nanoparticles (Ag NPs) and poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS). Due to the three‐dimensional porous microstructure and highly conductive surface inherited by the wood‐nanotechnology‐derived flexible membrane (FW/MWCNT/Ag/PEDOT:PSS), it shows a high area capacitance (266.7 mF cm−2 at 20 mV s−1) and a good long‐term cycling stability 84.3% capacitance retention after 5000 cycles at 5 mA cm−2 when used as a supercapacitor electrode. In addition, it shows an excellent specific electromagnetic shielding efficiency (up to 970 dB cm2 g−1), proving its application potential in the field of electromagnetic shielding. Because of the biocidal property of Ag NPs, the FW/MWCNT/Ag/PEDOT:PSS shows a remarkable antibacterial effect on Escherichia coli and Staphylococcus aureus. This strategy provides a new opportunity for researchers to design biomass‐based integrated electronic materials.

Decay resistance of wood treated with copper oxide nanoparticles synthesised using leaf extracts of Lantana camara L. and Nerium oleander L.

ABSTRACT Owing to the expensive and toxic nature of physical and chemical methods employed in the synthesis of commercially available metal nanoparticles used in wood protection, researchers are in search of non-toxic methods for nanoparticle synthesis. The present study involves biological synthesis of copper oxide nanoparticles using leaf extracts of Lantana camara L. and Nerium oleander L. The synthesised copper oxide nanoparticles were characterised using Scanning Electron Microscopy coupled with EDAX. The efficacy of formulations, containing leaf extracts and copper oxide nanoparticles, is screened against wood decay fungi Trametes hirsuta (White-rot) and Oligoporus placenta (brown-rot). Similarly, the efficacies of CuSO4. 5H2O (0.5%), CuO (0.5%) nanoparticle and CuO (0.5%) were also tested. Results indicated that the formulation of Lantana camara leaf extract and CuO nanoparticles effectively protected the treated rubberwood from the attack of both white-rot and brown-rot, whereas the formulation of Nerium oleander leaf extract and CuO nanoparticles protected from brown-rot attack only. Since test chemicals and leaf extracts alone were not effective against decay fungi, the protective effect of the formulation can be attributed to the synergistic effect of the intrinsic property of leaf extracts and the biocidal property of copper oxide nanoparticles resulting in an effective wood protectant.

Green Synthesis of Silver Nanoparticles Using Exopolysaccharides Produced by Bacillus anthracis PFAB2 and Its Biocidal Property

Nowadays when control of environmental toxicity is a matter of concern, the focus of the researchers is to find an eco-friendly process. Considering the hazards associated with chemical synthesis of nanoparticles, green synthesis approaches have gained considerable attention for their sustainable nature in nanomedicine and nanobiotechnology. Here, exopolysaccharide (EPS) synthesized by a geothermal spring origin B. anthracis PFAB2 is used for green synthesis of silver nanoparticles (AgNPs). Elemental analysis of EPS-coated AgNPs exhibited solid peaks of silver (39.66%) along with oxygen and carbon. TEM analysis confirmed the hexagonal shape of the AgNPs. Polydispersity index (PDI) reinforced the moderately monodisperse nature of the nanoparticles. High negative zeta potential indicated longer shelf life, good colloidal nature and high dispersive nature of the AgNPs. The B. anthracis PFAB2 EPS-coated AgNPs demonstrated prospective biocidal characters for both gram positive and gram negative bacteria along with some potentially hazardous fungi compared with the conventional antimicrobials. The results can be much expedient in the future for treatment of microorganisms that are otherwise resistant to traditional antibiotics or antifungal drugs.

Pentaerythritol p-hydroxybenzoate ester-based zinc metal alkoxides as multifunctional antimicrobial thermal stabilizer for PVC

There is a wide demand for PVC products with microbiocidal property. For this purpose, additional antimicrobial agents have to be added. In this work, we synthesized pentaerythritol p-hydroxybenzoate ester-based zinc metal alkoxides (PHE-Zn) additive as highly efficient antibacterial agent, thermal stabilizer, plasticizer and lubricant for PVC. PHE-Zn was characterized by Fourier-transform infrared spectrometer (FT-IR), X-ray photoelectron spectroscopy (XPS), and elemental analysis. The results confirm the formation of R-O-Zn bonds and the molecular structure of PHE-Zn. The property enhancement of PVC by PHE-Zn were investigated by conductivity, oven aging, and torque rheological tests. PHE-Zn not only contributes to excellent initial whiteness and significant long-term thermal stability (without color change up to 90 min), but also improves plasticization and lubrication of PVC. In addition, using E. coli (E. coli) and Staphylococcus aureus (S. aureus) as typical microorganisms, the antibacterial properties of PHE-Zn stabilized PVC were tested. PVC with 4 phr PHE-Zn displayed high killing rates against E. coli and S. aureus (97.92% and 91.84%, respectively). Further experiments showed that PHE-Zn was a contact-active antibacterial agent. Moreover, the mechanisms for the enhanced thermal stability and biocidal property of PHE-Zn on PVC was explored.

Production of compost with biopesticide property from toxic weed Lantana: Quantification of alkaloids in compost and bacterial pathogen suppression

Toxic weed Lantana camara foliage was composted with cow dung in 2:1 and 1:1 ratio (v/v) and changes in physicochemical characteristics, and faecal coliform bacterial population (Escherichia coli and Salmonella) was estimated for 35 d. Results showed a significant increase in total N (1.48-1.69-folds), Paval (6.87–9.19-folds), and total K (1.08−1.23-folds) content, while a decrease in C/N ratio (1.87–2.13-folds) and total organic carbon (1.12−1.46-folds) after composting process. Germination index (GI) results (> 70 %) suggested the non-toxic property of Lantana compost against tested rapeseed mustard seeds. E. coli and Salmonella population reduced to the safe limit after 35 d composting. Compost extract (sterilized and non-sterilized) (from 2:1 setup) showed about 0.88 – 1.08-, 0.88 – 0.96-, 0.83 – 0.94-, and 0.79–1.08-folds higher inhibition in Xanthomonas citrus, Xanthomonas campestris, Erwinia carotovora, and Pseudomonas aerogenosa, respectively, indicating strong pathogen-inhibiting substances in Lantanacompost. GC–MS analysis of compost extract indicated the presence of isomers of several compounds of biocidal property – hexadecane (9-hexyl and 9-octyl); 2-tridecyl ester; eicosane; tetradecane, heptacosane (1-chloro- and 9-hexyl); heptadecane, octadecane, 3-ethyl-5-(2-ethylbutyl)-, heptacosane, tetradecane, 2,6,10-trimethyl-, etc.). Result revealed that Lantana compost could be used as biomanure with biopesticide properties for sustainable organic farming system.

Bio-mediated synthesis of ZnO nanostructures from Thymus Schimperi leaves extract and its antibacterial and photocatalytic activities

In this work, zinc oxide nanostructures were synthesized from thymus schimperi leaves extract and ZnSO4.7H2O precursor, and antibacterial and photocatalytic activities were studied. The as-synthesized nanostructures were characterized by UV-Vis spectrophotometer, powder X-ray diffraction, Fourier transform infrared spectrophotometer and scanning electron microscopy. Powder X-ray diffraction patterns revealed that the as-synthesized zinc oxide was hexagonal wurtzite structure with no peaks from other phases or impurity. The maximum UV-Vis spectrum peak at about 255 nm also supports the evidence for the formation of zinc oxide nanostructures. The presence of functional groups on the surface of the nanostructures from the Fourier transform infrared spectrum exhibited that the phytochemicals play a key role in the formation of the nanostructures. The appearance of peak at 595cm-1 in the spectrum further corroborates the presence of zinc oxide in the sample. Scanning electron micrographs depict that there was mesh like nanostructures on the surface, which are likely to be convenient for catalytic application. The synthesized nanostructures inhibited the growth of both gram-positive and gram-negative bacteria, showing its biocidal property. Moreover, Congo red, which is one of the carcinogenic textile dyes, has been photodegraded by 83.33% at a pH of 6.5 due to the as-synthesized zinc oxide nanostructures indicating its potential application for waste water treatment.

Zinc oxide‑selenium heterojunction composite: Synthesis, characterization and photo-induced antibacterial activity under visible light irradiation

The designing of new antibacterial agents with high and long-lasting activities are urgently needed in order to cope with the fast-emerging bacterial resistance. Zinc oxide nanoparticles (ZnO) have shown a significant promise as broad-spectrum antibacterial agents, and are efficient material in compromising bacterial membrane stability that leads to an increased cell permeability to nano-products. However, further engineering is required to improve their biological activities and to minimize their toxicity to healthy cells. In an attempt to resolve this issue, two semiconductor materials, ZnO and selenium (Se), were fabricated into a unique structural composite by a newly developed facile green method, and the designed composite was applied as an antibacterial nanomedicine. The developed methodology involves the initial preparation of ZnO, followed by its fabrication with Se at different temperatures (70 °C to 95 °C). Our experimental data showed that well defined interpenetrated crystalline Se network on ZnO (ZnO-Se) can be obtained at 80 °C for 180 min. The as-prepared ZnO-Se showed promising results in inhibiting the challenged bacterial strains under light irradiation (visible light) as compared to free ZnO. The enhanced biocidal property of ZnO-Se could be ascribed to its improved light-harvesting ability for sustainable induction of reactive oxygen species (ROS) and an active contact killing mechanism. Thus, ZnO-Se composite with a novel architecture could be a promising material in the treatment of bacterial infections by a mutual antibacterial synergy from the incorporated elements. Interestingly, the ZnO-Se has the ability to scavenge the overproduction of hydroxyl radicals, thus protecting the healthy cells from oxidative damage.

Cytocompatible, thermostable hydrogel with utility to release drug over skin

Hydrogel has wide applicability in biomedical applications and other industrial applications due to its strong biocompatibility. A natural polymer is eco-friendly, nontoxic, and biocompatible. There are vast varieties of natural polymers whose combination can form excellent hydrogels. Pectin and carboxymethyl cellulose (CMC) are some such kinds of polymers. Plasticizer has wide applicability to enhance properties of polymers mix. Glycerol has been widely used as a plasticizer in many hydrogels but it does not render thermostability whereas, PEG is known to render thermostability. Thermostable hydrogel provides easy sterilization by using heat and pressure such as an autoclave. Small molecular size plasticizer is known to provide more space among the polymer mix and affect the porosity and water uptake capability. PEG 400 has wide applications in pharmaceutical industries and it is one of the small molecular size plasticizers. Other than this, copper ions are known to render skin regenerative property with biocidal property help in the wound healing treatment. Thus, a hydrogel was fabricated using pectin and CMC with PEG 400 as the plasticizer and copper ion as cross-linker (PCPEG2). The resulted hydrogel not only showed high thermal stability but also has high porosity, a high degree of swelling, pH sensitivity and good cytocompatibility and good drug release efficiency. The hydrogel was characterized by using FTIR, XRD, DSC, TGA/DTG/DTA, and XPS which showed good fabrication of hydrogel with high thermal stability. Thus, a novel hydrogel of pectin/CMC with PEG 400 was fabricated with enhancing properties applicable in biomedical applications and other industrial applications.

Characterization of Exopolysaccharide Produced by Pseudomonas sp. PFAB4 for Synthesis of EPS-Coated AgNPs with Antimicrobial Properties

Thermal ecosystems like hot springs are exclusive habitat of thermotolerant microorganisms that produce exopolysaccharides (EPS). In this study, EPS produced by a hot spring origin Pseudomonas species is structurally elucidated.The EPS is highly thermostable (Td 289.98 °C), has low molecular weight (1510 Da) and is rhamnoglucose type consisting α-(1 → 3) linked to L-Rhap and α-(1 → 6) linked to d-Glc substituted with O-acetyl groups. Irregular EPS sheets with smooth surface were observed that signify the compact structure of the biopolymer; a characteristic plasticized film-like feature. Intra- and inter-molecular aggregation of EPS units are observed in atomic force microscopy. The EPS showed good rheological property at neutral pH. EPS-mediated green synthesis of silver nanoparticles (AgNP) was performed using co-precipitation method. Size of individual AgNPs had a Z-average of 93.6 nm and 0.437 polydispersity index. The EPS-coated AgNPs were moderately monodisperse. These AgNPs also exhibited biocidal property preferentially against gram negative bacteria and some fungi. Incorporating EPS to the metal nanoparticles confers them biocompatibility. Green synthesis of silver nanoparticles has gained considerable attention for its eco-friendliness in nano-medicine and nano-biotechnology. Keeping in context, the results of our study will support a new polysaccharide-mediated green synthesis approach of metal nanoparticles that shows profound antimicrobial property.

A new approach to wood protection: Preliminary study of biologically synthesized copper oxide nanoparticle formulation as an environmental friendly wood protectant against decay fungi and termites

Nanoparticles have addressed many challenges in science and technology and wood science research is one such field that has benefitted from application of metal nanoparticles. The metal nanoparticles that are commercially available for wood protection are synthesised by physical and chemical methods which produces toxic by-products and are expensive. The current study deals with a new approach for utilization of metal nanoparticle for wood protection in an ecofriendly and cost effective way. Metal nanoparticles were synthesised using plant extracts that are known to have wood preservative properties. The synergistic effects of the intrinsic property of plant extracts along with the biocidal property of metal nanoparticles were utilized. Copper oxide nanoparticles were synthesised using leaf extracts of Neem (Azadirachta indica), Pongamia (Pongamia pinnata), Lantana (Lantana camara) and extract of orange peel (Citrus reticulata). The effectiveness of the synthesised plant extract and copper oxide nanoparticle formulation is tested against wood decay fungi using agar mixed with the test substance. Graveyard test is employed to assess the effect of the copper oxide nanoparticle formulation against termites. Preliminary results are promising and studies are progressing to develop a stable and environmentally benign wood preservative formulation of metal nanoparticles and plant extracts.

Aryl fluorosulfate analogues as potent antimicrobial agents: SAR, cytotoxicity and docking studies

A series of aryl fluorosulfate analogues (1–37) were synthesized and tested for in vitro antibacterial and antifungal studies, and validated by docking studies. The compounds 9, 12, 14, 19, 25, 26, 35, 36 and 37 exhibited superior antibacterial potency against tested bacterial strains, while compounds 2, 4, 5, 15, 35, 36 and 37 were found to have better antifungal activity against tested fungal strains, compared to standard antibiotic gentamicin and ketoconazole respectively. Among all the synthesized 37 analogs, compounds 25, 26, 35, 36 and 37 displayed excellent anti-biofilm property against Staphylococcus aureus. The structure–activity relationship (SAR) revealed that the antimicrobial activity depends upon the presence of –OSO2F group and slender effect of different substituent’s on the phenyl rings. The electron donating (OCH3) groups in analogs increase the antibacterial activity, and interestingly the electron withdrawing (Cl, NO2, F and Br) groups increase the antifungal activity (except compound 35, 36 and 37). The mechanism of potent compounds showed membrane damage on bacteria confirmed by SEM. Compounds 35, 36 and 37 exhibited highest glide g-scores in molecular docking studies and validated the biocidal property.

Synthesis of novel benzodioxane midst piperazine moiety decorated chitosan silver nanoparticle against biohazard pathogens and as potential anti-inflammatory candidate: A molecular docking studies

Nanoparticles (NPs) are currently being investigated along with the use of biodegradable polymer containing active agents in many areas of medicine for targeted applications. The present study was aimed to synthesize novel compound Benzodioxane midst piperazine (BP) and characterization of a BP decorated chitosan silver nanoparticles (BP*C@AgNPs) and shown effective against hazardous pathogens, and also having anti-inflammatory property. It was further evaluated for molecular docking proofs, and toxicity. The BP*C@AgNPs had spherical shape with size of 36.6nm with wide biocidal activity against hazardous Gram-positive and Gram-negative bacteria with excellent inhibition at 100μg/mL for S. aureus (10.08±0.05mm ZOI), and E. coli (10.03±0.04mm ZOI) compared to antibiotic Streptomycin. The anti-inflammatory activity exhibited IC50 value of 71.61±1.05μg/mL for BP*C@AgNPs compared to indomethacin (IC50=40.15±1.21μg/mL). Also, the docking study of BP showed excellent score for COX1 and DNA gyrase. This in silico study confirmed the achieved efficacy of BP, with less toxicity against normal PMBCs in vitro and in vivo studies. This study concludes that, the novel synthesized BP*C@AgNPs had excellent biocidal property and as anti-inflammatory candidate revealed by docking studies, it confirms BP*C@AgNPs for first-class therapeutic applications in the area of medicinal nanotechnology for the coming days.

Control of multi-drug-resistant pathogens with non-thermal-plasma-treated alginate wound dressing.

Non-thermal dielectric-barrier discharge plasma (non-thermal plasma) is being investigated for use in wound healing. Alginate gel, already in clinical use, is non-toxic but has no meaningful antimicrobial property. This study reports that a non-thermal-plasma-treated alginate wound dressing has strong antimicrobial properties. Alginate gel was treated with non-thermal plasma in room air and inoculated with bacterial pathogens. At 15 min after this, bacterial cell viability was determined by colony assay or 2,3-bis-(2-methoxy-4- nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay. The anti-biofilm efficacy of the non-thermal-plasma-treated alginate gel was investigated and the treated gel was tested against vascular endothelial cells for a cytotoxic effect. The proliferation and migration of bacterial cells before and after exposure to the treated gel were investigated with an in vitro wound testing assay. Scanning electron microscopy was used to observe changes in the gel surface associated with exposure to bacterial pathogens. The treated gel was tested against Acinetobacter baumannii, Escherichia coli, Staphylococcus aureus, S. epidermidis, Candida albicans, and C. glabrata as representative pathogens (at 10(6)-10(9) colony-forming units [CFU]/mL), and the thickness of a plasma-treated gel dressing and distance between a glass dielectric-barrier discharge plasma probe and the gel surface were kept constant. Non-thermal-plasma-treated alginate gel exhibited a strong biocidal property and inactivated all of the pathogens included in the study at counts of 10(8) CFU/mL and within 15 sec of treatment. The treated gel inactivated 10(9) CFU/mL of the organisms within 1 min, and 3 min of exposure to the treated gel inactivated pathogens embedded in biofilms. The plasma-treated gel showed no significant cytotoxicity, and endothelial cells exposed to the treated gel proliferated and migrated well across a wound area over a period of time. Dressings made with the treated gel retained their biocidal effects for about a month. Scanning electron microscopy showed no damage to the surfaces of treated gels, but damage to the bacterial pathogens on plasma exposure. A non-thermal-plasma-treated alginate gel dressing has the clinical potential to decontaminate wounds, prevent surgical site infection, and promote wound healing.

Improvement of antibiofouling performance of a reverse osmosis membrane through biocide release and adhesion resistance

To improve antibiofouling properties, a commercial reverse osmosis (RO) membrane was modified by surface deposition of a polyelectrolyte multilayers (PEMs) embedded with silver nanoparticles. The modified membrane was further coated with an amphiphilic polyzwitterion, a 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer with 2-aminoethyl methacrylate (AEMA). Thus, the modified surface layer consisted of PEMs embedded with silver nanoparticles and polyzwitterion as a top layer. Embedding of silver nanoparticles and polyzwitterion coating were confirmed by transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The effectiveness of biocide release from the modified membranes was evaluated with Pseudomonas putida (P. putida) and Escherichia coli (E. coli) and the anti-adhesion property was studied using P. putida. The silver nanoparticles embedded within PEMs showed biocidal property because of silver ion release, and polyzwitterion at the top layer showed high anti-adhesion properties because of the high hydrophilicity of surface. Thus, the membrane modified by PEMs embedded with silver nanoparticles and polyzwitterion as a top layer showed a high antibiofouling properties, attributed to the combined effect of biocide release and adhesion resistance.