The cellulose fibers functionalized with star-like zinc oxide nanoparticles with boosted antibacterial performance for hygienic products.

Bacterial infectious diseases are serious health problem which extends to economic and social complications. Moreover, bacterial antibiotic resistance, lack of suitable vaccine or emergence of new mutations is forcing the development of novel antimicrobial agents. The objective of this study is to synthesize and characterize star-like zinc oxide nanoparticles for the application of antibacterial activities in cellulose based hygiene products. ZnO NPs were in situ synthesized via precipitation method on the surface of cellulose fibers. Since bactericidal activity of nanoparticles in part depends on the concentration in the growth medium, various amount of ZnO was incorporated into cellulose matrix ranging from 1 to 3 wt%. Microscopic (TEM, SEM) and spectroscopic (FT-IR, XRD) methods were utilized to investigate the final products. The infrared absorption spectra analysis supported by theoretical finding that during the reaction, ZnO nanoparticles could be bonded with cellulose fibers via hydrogen bonding. The yield of functionalization was determined through thermogravimetric analysis. Collected data proved the successful functionalization of the cellulose fibers with nanoparticles. Static contact angle measurements were carried out showing absorptive character of as prepared fabrics. All the samples were tested for the antibacterial properties and the results were compared to the samples prepared from the pristine cellulose fibers. Moreover, mechanical tests were performed revealing that the addition of only 2 wt% of the nanofiller boosted tensile, tearing and bursting strength by a factor of 1.6, 1.4 and 2.2 in comparison to unfunctionalized paper sample, respectively. Fabricated fabric presenting high hydrophilicity and antibacterial properties have gained increased applications in fabric industry, including hygiene product industry and hence the result of this study would be a welcomed option.

Wet chemical development of CuO/GO nanocomposites: its augmented antimicrobial, antioxidant, and anticancerous activity.

This study employed a bottom-up technique to synthesize copper oxide (CuO) nanoparticles over hydrophilic graphene oxide (GO) nanosheets. The CuO/GO nanocomposite has been prepared using two selected precursors of copper nitrate and citric acid with an intermittent mixing of GO solutions. The synthesized Nanocomposites were characterized using different biophysical techniques like FT-IR, NMR, FE-SEM, and HR-TEM analyses. FT-IR analyses confirm the nanocomposites' successful formation, which is evident from the functional groups of C=C, C-O, and Cu-C stretching vibrations. Morphological analyses reveal the depositions of CuO nanoparticles over the planar rough GO sheets, which has been elucidated from the FE-SEM and HR-TEM analyses supported by respective EDAX analyses. The antimicrobial activities have been evident from the surface roughness and damages seen from the FE-SEM analyses. The CuO/GO sheets were tested against Gram-positive (e.g., Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa). It is evident that the intrinsic antibacterial activity of CuO/GO sheets, when combined in equal proportions, elicited a robust antibacterial activity when tested over Gram -ve representative bacteria Escherichia coli. The antioxidant behaviour of synthesized CuO/GO nanocomposite was evaluated by scavenging the free radicals of DPPH and ABTS. Moreover, the cytotoxic activity was also studied against epidermoid carcinoma cell line A-431. A brief mathematical formulation has been proposed in this study to uncover the possibilities of using the nanocomposites as potential drug candidates in theranostic applications in disease treatment and diagnosis. This study would help uncover the electronic properties that play in the nano-scaled system at the material-bio interface, which would aid in designing a sensitive nano-electromechanical device bearing both the therapeutic and diagnostic attributes heralding a new horizon in the health care systems.

Gelatin Reinforced with CNCs as Nanocomposite Matrix for Trichoderma harzianum KUEN 1585 Spores in Seed Coatings.

Increasing interest on sustainable agriculture has led to the development of new materials which can be used as seed coating agents. In this study, a new material was developed based on gelatin film reinforced with cellulose nanocrystals (CNC) which was further used as nanocomposite matrix for Trichoderma harzianum KUEN 1585 spores. The nanocomposite films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM), showing the formation of new hydrogen bonds between the components with a good compatibility between them. Measurements of water contact angles and tests of water vapor sorption and swelling degree revealed an improvement in the water vapor absorption properties of the films as a result of their reinforcement with CNC. Furthermore, by adding the Trichoderma harzianum KUEN 1585 spp. in the seed coating material, the germination percentage, speed of germination and roots length of the corn seeds improved. The polymeric coating did not inhibit the growth of T. harzianum KUEN 1585, with this material being a good candidate in modern agriculture.

Nanocomposite membrane and microbial community analysis for improved performance in microbial fuel cell.

To improve the performance of a microbial fuel cell (MFC), four variations of sulphonated silicon dioxide (S-SiO2) was incorporated into sulphonated poly ether ether ketone (SPEEK) membranes. S-SiO2 was characterized by scanning electron microscopy (SEM), fourier transform infra-red spectroscopy (FTIR) and X-ray diffraction (XRD) to confirm morphological, physical and chemical characteristics. The prepared membranes were incorporated into a fabricated tubular MFC of 300 mL holding capacity. Membrane characterizations such as water uptake, ion exchange capacity (IEC) and proton conductivity were determined. The highest maximum output of 154 ±â€¯1.5 mW m-2 is produced by SPEEK +7.5 wt% S-SiO2 with an IEC of 1.82 ±â€¯0.08 meq g-1 and an oxygen mass transfer coefficient of 1.42 × 10-6 cm s-1. Microbial community studies show the prevalence of novel microbial strains with the predominance of 3 distinct phyla, namely Betaproteobacteria, Gammaproteobacteria and Firmicutes. The results suggest that the prepared nanocomposite membrane proves to be an efficient and sustainable alternative for improving the performance of a MFC without abating the essential membrane characteristics.

Poly(piperizinamide) with copper ion composite membranes: Application for mitigation of Hexaconazole from water and combat microbial contamination.

Thin film Poly(piperazine-amide) composite membranes using sequential interfacial polymerization with tuning by Cu2+ have brought significant findings in it. The hydrophobicity is relatively enhanced for the copper containing membranes. The membrane in which copper solution is applied prior to piperizine (Memb-III) exhibits higher hydrophobicity where as membrane (Memb-II) in which copper solution is applied following piperizine, possesses higher roughness compared to other two. Filtration experiments in terms of salts, mono/disaccharides and hexaconazole indicate that modified membranes are of different behaviours according to their sequence of preparative methods. Memb-III has shown lower SO4=/Cl- selectivity compared to Memb-II (i.e. 3.92), though they are in different range. The unmodified membrane (Memb-I) exhibits SO4=/Cl- selectivity 3.23 is in the same scale of Memb-III (2.27). Memb-III exhibits higher hexaconazole separation (91.5%) compared to Memb-II (i.e. 53.9%). The flux decline follows the order: field water > tap water > deionized water. The copper incorporated membrane (Memb-II) has shown a low flux decline compared to Memb-III as well as Memb-I. The antibacterial properties towards E. Coli and Bacillus subtilis are well reflected. The copper containing membranes have promising antibacterial properties and follows the order Memb-II > Memb-III > Memb-I.

Green synthesis of silver nanoparticles combined to calcium glycerophosphate: antimicrobial and antibiofilm activities.

AIM: To synthesize, characterize and evaluate the antimicrobial and antibiofilm activities of novel nanocomposites containing silver nanoparticles (AgNPs) associated or not to ß-calcium glycerophosphate. MATERIALS & METHODS: These nanocomposites were produced through a 'green' route using extracts of different parts of pomegranate. Antimicrobial and antibiofilm properties against Candida albicans and Streptococcus mutans were determined by the minimum bactericidal/fungicidal concentration and biofilm density after treatments. RESULTS: All extracts used were successful in producing AgNPs. Composites made with peel extracts showed the highest antimicrobial and antibiofilm activity against both microorganisms tested and performed similarly or even better than chlorhexidine. CONCLUSION: AgNPs associated or not to calcium glycerophosphate produced by a 'green' process may be a promising novel antimicrobial agent against oral microorganisms.

The effect of carbon nanoparticles on biological properties of polyester nanocomposites.

The aim of present study was to determine the hemocompatibility, cellular response of endothelial cells and bacterial adhesion to a new polyester nanocomposite. The carbon nanoparticle nanocomposite was prepared via in situ polymerization of monomers to obtain material of hardness 55 Sh D similar to polyurethanes used in medical applications, for example, in heart-assisting devices. The carbon nanoparticle-containing polyester exhibits markedly reduced bacterial colonization, as compared to commercially available polyurethanes. Further the nanocomposite possesses markedly improved hemocompatibility, as determined by flow cytometry, and robust endothelialization. Possible explanations for these beneficial properties include surface nanoroughness of carbon nanoparticle-containing nanocomposites and presence of fatty acid sequences within polymer structure.

Pectin-non-starch nanofibers biocomposites as novel gastrointestinal-resistant prebiotics.

Incorporation of nanofibers of chitin (NC), lignocellulose (NLC) and bacterial cellulose (BNC) in pectin was studied to improve prebiotic activity and gastrointestinal resistance of the pectin-nanofibers biocomposites for protection of probiotics under simulated gastrointestinal conditions. The biocomposites were prepared using various compositions of pectin and nanofibers, which were designed using D-optimal mixture method. The incorporation of the nanofibers in pectin led to a slow degradation of the pectin-nanofibers biocomposites in contrast to their rapid swelling. AFM analysis indicated the homogenous distribution of interconnected nanofibers network structure in the pectin-nanofibers biocomposite. FTIR spectra demonstrated fabrication of the biocomposites based on the inter- and intra-molecular hydrogen bonding and ionic interaction of pectin-Ca2+. XRD patterns revealed the amorphous structures of the biocomposites as compared to the crystalline structures of the nanofibers. Among the compositions, the optimal compositions were as follows: 60% pectin+40% NC, 50% pectin+50% NLC and 60% pectin+40% BNC, where the prebiotic score, probiotic survival under simulated gastric and intestinal conditions were optimum. The optimal biocomposite pectin-NC exhibited the highest survival of the entrapped probiotic bacteria under simulated gastric (97.7%) and intestinal (95.8%) conditions when compared with the corresponding to free cells (76.2 and 73.4%).

Biological studies and electrical conductivity of paper sheet based on PANI/PS/Ag-NPs nanocomposite.

Polyaniline (PANI) with/without polystyrene (PS), was successfully manufactured in the occurrence of dispersed pulp fibers via the oxidative polymerization reaction of aniline monomer to produce conductive paper sheets containing PANI, PANI/PS composites. Additionally, sliver nitrate (Ag-NO3) was added by varied loadings to the oxidative polymerization of aniline monomer to provide sliver nanoparticles (Ag-NPs) emptied into the prepared paper sheets. The prepared paper sheets were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared spectroscopy (IR), the mechanical properties of the prepared paper sheets were evaluated. Moreover, the electrical conductivity and biological studies such as cellulases assay, Microorganism & culture condition and detection of the released of Ag-NPs were evaluated. Furthermore, the prepared paper sheets were displayed good antibacterial properties contrary to gram positive and gram negative bacteria. Consequently, the prepared paper sheet may be used as novel materials for packaging applications.

Preparation of the CNC/Ag/beeswax composites for enhancing antibacterial and water resistance properties of paper.

An effective method of preparing composites containing inorganic (Ag) and organic (beeswax) particles was established in this study. Ag nanoparticles were first immobilized on the cellulose nanocrystals (CNC) during the reduction of AgNO3 in the presence of CNC, then mixed with beeswax by high speed stirring. Scanning transmission electron microscopy (STEM) images indicated that Ag and beeswax particles were uniformly dispersed and stable in the network structure formed by CNC. Upon coating on a paper surface, a layer of beeswax film was evident based on scanning electron microscopy (SEM) images. The dynamic contact angle and antibacterial activity tests indicated that the contact angle of coated paper reached 113.06° and the growth inhibition of Escherichia coli increased to 99.96%, respectively, at a coating amount of 21.53 g/m(2). When applied onto paper surface by coating, the CNC/Ag/beeswax composites can impact paper with antibacterial property and improved water resistance.

[Study of oral microbial adhesion and biofilm formation on the surface of nano-fluorohydroxyapatite/polyetheretherketone composite].

OBJECTIVE: To develop novel polyetheretherketone (PEEK) based nanocomposites which possess the favorable antibacterial property, and to investigate the oral microbial adhesion and biofilm formation on the surfaces of PEEK, nano-fluorohydroxyapatite (n-FHA)-PEEK and nano-hydroxyaptite (n-HA)-PEEK. METHODS: The bacterial adhesion and biofilm formation on the surfaces of n-FHA-PEEK, n-HA-PEEK were investigated via microbial viability assay kit and laser scanning confocal microscope (LSCM), respectively, with pure PEEK as control group. RESULTS: No significantly statistical difference were found in the bacterial adhesion amounts on the surfaces of n-FHA-PEEK, n-HA-PEEK and PEEK at 1 h and 4 h. However, the number of bacteria on the n-FHA-PEEK surface decreased dramatically at 2 h (0.496 ± 0.008) compared with n-HA-PEEK groups (0.543 ± 0.015, P < 0.01). Although the biofilms formation on surfaces observed by LSCM had similar morphology and thickness at 3, 7, 14 d, that on the n-FHA-PEEK surface showed the highest dead-to-live bacteria ratio among the three materials at 14 d. CONCLUSIONS: The combination of n-HA, especially for the n-FHA could inhibit the bacteria adhesion and accelerate the bacterial death, eventually may have an influence on the structure of biofilms and reduce the risk of peri-implantitis. Therefore, n-FHA-PEEK nanocomposites presented a good prospect for clinical applications as dental implant materials.

Properties and characterization of bionanocomposite films prepared with various biopolymers and ZnO nanoparticles.

This study was aimed to develop biopolymer based antimicrobial films for active food packaging and to reduce environmental pollution caused by accumulation of synthetic packaging. The ZnO NPs were incorporated as antimicrobials into different biopolymers such as agar, carrageenan and CMC. Solvent casting method was performed to prepare active nanocomposite films. Methods such as FE-SEM, FT-IR and XRD were used to characterize resulting films. Physical, mechanical, thermal and antimicrobial properties were also examined. Remarkable surface morphological differences were observed between control and nanocomposite films. The crystallinity of ZnO was confirmed by XRD analysis. The addition of ZnO NPs increased color, UV barrier, moisture content, hydrophobicity, elongation and thermal stability of the films, while decreased WVP, tensile strength and elastic modulus. ZnO NPs impregnated films inhibited growth of L. monocytogenes and E. coli. So these newly prepared nanocomposite films can be used as active packaging film to extend shelf-life of food.

[New polymer materials for endoscopic equipment preventing biofilms formation].

Aim to study: The study of antimicrobial activity, hidrofobisity and physicochemical properties of nanostructured barrier layers on the surface of polyethyleneterephtalate and polytetrafluorethylene, formed by different methods of ion-plasma technique.

Silver-embedded modified hyperbranched epoxy/clay nanocomposites as antibacterial materials.

Silver-embedded modified hyperbranched epoxy/clay nanocomposites were prepared at different wt.% of octadecyl amine-modified montmorillonite at a constant silver concentration (1 wt.%). UV-visible, XRD and TEM studies confirmed the formation of silver nanoparticles. Compared to the system without silver and clay, the gloss from 70° to 94°, scratch hardness from 4 to 5.8 kg, impact strength from 60 to 90 cm, tensile strength from 8.5 to 15.5 MPa, adhesive strength from 5 to 7.1 × 10(9)N/m, flexibility from >6 to <4mm, and thermostability from 230 to 260 °C increased for the modified system. Resistance to aqueous 10% HCl, 0.5% NaOH, 10% NaCl also increased. The nanocomposites showed antibacterial activity in well diffusion assays against Staphylococcus aureus (ATCC11632), Bacillus subtilis (ATCC11774), Escherichia coli (MTCC40), Pseudomonas aeruginosa (MTCC7814) and Klebsiella pneumoniae (ATCC10031). The results showed that these nanocomposites have potential to be used as antimicrobial materials.

Multi-walled carbon nanotubes/epilson-polylysine nanocomposite with enhanced antibacterial activity.

AIMS: To develop a new nano-composite of multi-walled carbon nanotubes (MWNTs) with enhanced antimicrobial activity. METHODS AND RESULTS: A novel antimicrobial nanocomposite [MWNT-epilson-polylysine (MEPs)] was synthesized via covalent attachment of epilson-polylysine on MWNTs with hexamethylene diisocyanate (HDI) as the coupling agent. UV-visible spectra and Fourier transform infrared spectra (FT-IR) investigations indicate that MEPs is stable, with epilson-polylysine leaching effectively eliminated. When compared to MWNTs, the new nano-composite MEPs exhibits enhanced antimicrobial activities. In 20 mg l(-1) suspensions, significant increases of 72·1, 64·5 and 69% against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus can be observed. The deposited film of MEPs also shows improved antibacterial activities and excellent antiadhensive efficacies against Ps. aeruginosa and Staph. aureus. CONCLUSIONS: Epilson-polylysine functionalization of MWNTs with HDI as the bridge was found to be useful for improving the biocidal activity of MWNTs. SIGNIFICANCE AND IMPACT OF THE STUDY: The new nano-composite MEPs with improved antimicrobial activity will substantially facilitate the application of MWNTs as the antimicrobial material such as medical device, food, pharmaceutical process and package.