Electrospun salicylic acid/polyurethane composite nanofibers for biomedical applications

Salicylic acid (SA)/polyurethane (PU) composite nanofiber mats were fabricated by introducing SA in PU solution during the electrospinning process. Cell viability assays showed that the as-prepared composite nanofibers had a good biocompatibility. Further, the composite mats showed good antibacterial performance against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus bacteria. Easy fabrication, good mechanical properties, good biocompatibility as well as the antibacterial activity of PU nanofibers containing SA indicated their significant promise for a variety of potential medical applications such as tissue engineering, wound healing, and drug delivery system.     

N-dodecylated chitosan/graphene oxide composite cryogel for hemostasis and antibacterial treatment

Uncontrolled massive bleeding remains a global issue, which requires an exigent response for safe and efficient hemostat. However, most of hemostats without antimicrobial property could trigger serious bacterial infection problem. Herein, a composite cryogel was synthesized by double bond N-dodecylated chitosan (DCSG) and graphene oxide (GO). The cryogel (DCSG/GO) with macroporous structure exhibited high-fluid adsorption ability, excellent mechanical property, and fluid-triggered shape recovery performance. Moreover, the in vitro blood coagulation experiments proved that DCSG/GO_5% possessed better coagulation efficiency than medical gelatin sponge. And the DCSG/GO_5% cryogel exhibited more erythrocyte and platelets activation. Besides, the cryogel had excellent near-infrared (NIR)-assisted photothermal antibacterial activity against both Escherichia coli and Staphylococcus aureus and killed 99% of them after 20 min NIR irradiation. In addition, the vitro hemolysis and cytotoxicity results proved the well biocompatibility of cryogel. Therefore, the biocompatible DCSG/GO cryogel has great potential application prospect in clinical hemorrhage control and anti-infection treatment.     

In Vitro Biocompatibility and Antibacterial Activity of Electrospun Ag Doped HAp/PHBV Composite Nanofibers

The authors report herein in vitro antibacterial property and osteoblast biocompatibility of electrospun Ag doped HAp/PHBV (Ag-HAp/PHBV) composite nanofibers as an osteoconductive and antibacterial material for bone tissue engineering applications. Ag-HAp powders were synthesized and stable composite suspensions of Ag-HAp/PHBV were prepared with the aid of a cationic surfactant DTAB for the electrospinning process. Continuous and uniform composite nanofibers were generated within a diameter range of 400–900 nm. Obtained nanocomposite scaffolds provide a favorable environment for bone mineralization, SaOS-2 osteoblastic cell attachment and growth as well as they present antibacterial activity against E. coli and S. aureus bacteria without any noticeable cytotoxic effect.     

Research of antibacterial activity on silver containing yttria-stabilized–zirconia bioceramic

An antibacterial bioceramic, silver containing yttria-stabilized zirconia (YSZ), was fabricated by sintering for dental prosthesis applications. The biocompatibility, hemocompatibility and antibacterial ability of the silver containing YSZ were evaluated. The addition of silver did not cause tetragonal phase to transform into monoclinic phase and the silver containing YSZ maintained an excellent mechanical property. Furthermore, the sintered silver containing YSZ showed no toxicity and possessed a good antibacterial ability against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) cell.     

Highly antibacterial and toughened polystyrene composites with silver nanoparticles modified tetrapod‐like zinc oxide whiskers

In this work, high‐performance multifunctional composites were obtained by melt blending silver deposited tetrapod‐like zinc oxide whiskers (Ag‐ZnOw) with polystyrene (PS). The chemical, spectroscopic, antibacterial, mechanical, and morphological properties of the PS/Ag‐ZnOw composites were carefully investigated and discussed. The obtained PS/Ag‐ZnOw composites characterized remarkable antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Moreover, it is found that impact strength of the composite increase with increasing nanofiller concentration (up to 0.25 wt %). Morphological characterization of the impact fractured surface of composites revealed that toughening was achieved through uniform filler distribution in the polymer matrix, and anchoring effect was imparted by the tetrapod‐like shape of ZnO whiskers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40900.     

Preparation,Characterization, and Surface Functionality of Polyester Bioplastic-based Green Composites Containing Powdered Curcumin Products

The structural and thermal properties, antibacterial activity, and biocompatibility of composite materials containing polylactide and curcumin powder were evaluated. Glycidyl methacrylate-grafted polylactide and curcumin powder were used to enhance the desired characteristics of these composites. The water resistance of glycidyl methacrylate-grafted polylactide/curcumin powder composites was greater than that of the polylactide/curcumin powder composites. A biocompatibility evaluation with tail skin fibroblasts indicated that both materials were nontoxic for biomedical material applications. Moreover, curcumin powder enhanced the Escherichia coli(BCRC10239) andStaphylococcus aureus (BCRC107801) antibacterial activities of the membranes. Membranes of glycidyl methacrylate-grafted polylactide- or polylactide-containing curcumin powder had better antibacterial activity.     

Facile preparation and good performance of nano-Ag/metallocene polyethylene antibacterial coatings

Metallocene polyethylene/nano-silver coatings were prepared by a facile air-spray method on polymer films. Different from the prevailing strategy to endow polyethylene with antibacterial performance, we used metallocene polyethylene sol and nano-silver as a precursor to deposit coatings on polymers at a relatively low operating temperature. Antibacterial coatings with excellent mechanical properties, water resistance, and low silver release were achieved. The composite coatings were examined in terms of surface characteristics, mechanical properties, and antibacterial activity against two representative bacterial strains including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The composite coatings exhibited favorable microstructure, good mechanical properties, and suitable crystallinity. The antimicrobial tests indicated that the fabricated composite coatings showed promising antibacterial activity against E. coli and S. aureus. Furthermore, Ag ions released by the composite coating after 30 days were under 1.2 ppb. These results indicated a promising prospect of the composite coating for wide antibacterial applications.     

Poly(2‐hydroxyethyl methacrylate)/boric acid composite hydrogel as soft contact lens material: Thermal,optical, rheological,and enhanced antibacterial properties

The present work proposes to fabricate a composite hydrogel material that well characterized, transparent, biocompatible, and self‐antibacterial as potential soft contact lens material. For this purpose, poly(2‐hydroxyethyl methacrylate) (PHEMA)/boric acid (BA) composite hydrogels were successfully prepared by chemical crosslinking with BA through in situ polymerization using different BA ratios between 1 and 10% w/w. Afterward, the compositions, thermal stability, transparence, oxygen permeability, water uptake capacity, swelling ratio as well as morphological and rheological properties, in vitro degradability, in vitro cytotoxicity, and antibacterial properties of the all prepared materials were analyzed using a series of different techniques. The thermal stability, hydrophilicity, water uptake, oxygen permeability gradually increased depending ratio of BA, which is desirable for biomaterial. While the transparence and refractive index decreased, the composite hydrogels, except for BA content of 10 wt %, maintained enough transparency to be used for contact lens. In addition, PHEMA/BA composite hydrogels exhibited good cytocompatibility (PHEMA‐1%BA and PHEMA‐3%BA) and excellent antibacterial activity against Gram‐positive (Staphylococcus aureus and Enterococcus faecium) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrated that the obtained PHEMA/BA composite hydrogels could be considered as self‐antibacterial contact lens and a potential composite biomaterial for other applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46575.     

Preparation and properties of antibacterial,biocompatible core–shell fibers produced by coaxial electrospinning

Coaxial electrospinning is a method for producing fibrous mats with optional features, such as antibacterial properties, controllable release, and hydrophobicity based on shell materials. Because these features are important in biomedical applications, in this study, biocompatible hydrophobic polymer (polycaprolactone) and hydrophilic polymer [poly(vinyl alcohol)] with silver nanoparticles loaded in the core solution were coaxially electrospun. The effect of silver addition on the conductivity and viscosity of the solutions, chemical structure of the fiber mats, mechanical properties, porosity, hydrophobicity, water vapor transmission rate (WVTR), silver release, and antibacterial properties were investigated. Fibers with silver exhibited less porosity and a lower WVTR and a greater contact angle than the fibers without silver. Furthermore, the core–shell fibers reduced the burst release of silver and successfully prevented the growth of Escherichia coli and Staphylococcus aureus bacteria. Therefore, it seems that these fibers are suitable for providing electrospun mats with long‐term antibacterial properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44979.     

Biocompatible surface modification of poly(ethylene terephthalate) focused on pathogenic bacteria: Promising prospects in biomedical applications

Poly(ethylene terephthalate)—PET, is one of the most common polyesters, widely used in biomedical applications ranging from catheters to stents, vascular grafts, heart valves, sutures, and scaffolds. PET surface modification is necessary to impart desired properties for biomedical applications, making the polymer biocompatible, noncytotoxic and antibacterial that can preferably resist biofilm formation caused by pathogenic bacteria. A novel approach to anticorrosive wet chemical surface modification of PET by insertion of alkyl and hydroxyl groups was achieved by using Grignard reagents and confirmed by several different characterization methods including Fourier transform infrared spectroscopy (FTIR), water contact angle (WCA) measurement, free surface energy (FSE) measurement, scanning electron microscopy (SEM), and atomic force microscopy (AFM). High antibacterial efficiency against four different types of biofilm active, pathogenic bacterial strains namely: Staphylococcus aureus, Escherichia coli, methicillin‐resistant S. aureus (MRSA), and Pseudomonas aeruginosa was established on the modified PET surface. Biocompatibility higher than 84% of the modified samples has been proved. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44990.     

Electrospun Sandwich‐Structure Composite Membranes for Wound Dressing Scaffolds with High Antioxidant and Antibacterial Activity

In this study, the sandwich‐structured composite (SSC) membranes with well‐antibacterial and antioxidant properties, which have the promising application as wound dressing, are successfully fabricated by combining an electrospinning process. The SSC membranes are composed of three layers, including the bottom polyvinylidene fluoride fibrous layer, the middle curcumin/polylactic acid (PLA) microsphere layer, and the top enrofloxacin/PLA fibrous layer, respectively. The obtained SSC membranes are characterized in terms of morphology, component, and mechanical property using scanning electronic microscope, X‐ray diffractometer, Fourier transform infrared spectroscopy, and universal electronic testing machine, respectively. Moreover, in vitro drug release, antioxidant activity, antimicrobial activity, and biocompatibility of the SSC membranes are also evaluated. The results showed that the obtained composite membranes indeed possess the sandwich structure, where the middle microsphere layer is located between two fibrous surface layers. It is found that the drug‐loaded SSC membranes show excellent antioxidant activity against ^?OH and DPPH free radicals and antibacterial activity against Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Candida albicans. The combination of electrospinning and electrospraying opens up a new way to fabricate a variety of composite membranes with a sandwich structure, which have promising potential application as wound dressing scaffolds.     

Synthesis of antibacterial polypropylene film with surface immobilized polyvinylpyrrolidone‐iodine complex

A novel antibacterial material with surface immobilized polyvinylpyrrolidone‐iodine complex was synthesized facilely by a two‐step approach. First, N‐vinylpyrrolidone (NVP) was photografted onto polymeric substrates, and subsequently the surface‐grafted polyvinylpyrrolidone (PVP) underwent complexation of iodine. In the UV‐induced photografting process, PVP was efficiently grafted onto the polypropylene (PP) film surface by a unique film interlayer photopolymerization (FIP) technique; the grafting yield (Y_g) could be controlled by varying the irradiation time or the monomer concentration. Further, we demonstrated that the grafted PVP chains could readily perform the complexation reaction with iodine as the homopolymer PVP does, which was characterized by UV–vis spectroscopy. The antibacterial activity of the modified polymer against Escherichia coli, Staphylococcus aureus, and Candida albicans was investigated. The results show that the modified PP film with surface‐immobilized PVP‐I complex has a desirable antibacterial property, with broad spectrum and high efficiency. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2026–2031, 2005     

Preparation,characterization, electrical and antibacterial properties of sericin/poly(vinyl alcohol)/poly(vinyl pyrrolidone) composites

In this study, we focused on the fabrication of poly(vinyl alcohol) (PVA)/poly(vinyl pyrrolidone) (PVP)/sericin composites via a simple solution‐blending method. The composites were characterized by Fourier transform infrared (FTIR) spectroscopy, UV spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis (TGA), and measurements of the conductivity, tensile strength, and antibacterial activity against Staphylococcus aureus. The results of FTIR and UV spectroscopy implied the occurrence of hydrogen bonding between sericin and the PVA/PVP blend. The structure and morphology, studied by XRD and SEM, revealed that the sericin particles were well dispersed and arranged in an orderly fashion in the blend. The glass‐transition temperature (T_g) of the composite was higher than that of the pure blend, and the T_g value shifted toward higher temperatures when the volume fraction of sericin increased. TGA indicated that sericin retarded the thermal degradation; this depended on the filler concentration. The mechanical and electrical properties, such as the tensile strength, alternating‐current electrical conductivity, dielectric constant, and dielectric loss of the composites, were higher than those of the pure blend, and these properties were enhanced when the concentration of sericin was increased up to 10 wt % filler content, whereas the elongation at break of the composite decreased with the addition of sericin particles. The antibacterial properties of the composite showed that sericin had a significant inhibitory effect against S. aureus. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43535.     

Physical and antibacterial properties of polyvinyl alcohol films reinforced with quaternized cellulose

Hydroxypropyltrimethylammonium chloride cellulose (CM) was homogeneously synthesized in a NaOH/urea aqueous solution. CM was blended in a polyvinyl alcohol (PVA) matrix to produce composite films via co‐regeneration from the alkaline solution. The PVA film and the blend films were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction measurements and scanning electron microscopy. The mechanical properties, water swelling ratio, hydrophobicity, light transmission, and antibacterial activity against Staphylococcus aureus and Escherichia coli were also evaluated. The results showed that CM could interact with PVA by hydrogen bonding and exhibit an obvious reinforcement effect. The addition of CM improved the surface roughness, hydrophobicity and water swelling ratio, especially, the antibacterial activity. However, compared with neat PVA film, the elasticity and optical transmission decreased. The increased tensile strength, powerful antibacterial activity, and medium light transmission indicate that the biocompatible blend film will become an exceptional alternative in functional bio‐material field. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43552.     

Photosensitive antibacterial and cytotoxicity performances of a TiO2/carboxymethyl chitosan/poly(vinyl alcohol) nanocomposite hydrogel by in situ radiation construction

Nano‐TiO₂/carboxymethyl chitosan (CMCS)/poly(vinyl alcohol) (PVA) ternary nanocomposite hydrogels were prepared by freezing–thawing cycles and electron‐beam radiation with PVA, CMCS, and nano‐TiO₂ as raw materials. The presence of nano‐TiO₂ nanoparticles in the composite hydrogels was confirmed by thermogravimetry, Fourier transform infrared spectroscopy, and X‐ray powder diffraction. Field emission scanning electron microscopy images also illustrated that the TiO₂/CMCS/PVA hydrogel exhibited a porous and relatively regular three‐dimensional network structure; at the same time, there was the presence of embedded nano‐TiO₂ throughout the hydrogel matrix. In addition, the nano‐TiO₂/CMCS/PVA composite hydrogels displayed significant antibacterial activity with Escherichia coli and Staphylococcus aureus as bacterial models. The antibacterial activity was demonstrated by the antibacterial circle method, plate count method, and cell density method. Also, with the Alamar Blue assay, the cytotoxicity of the composite hydrogel materials to L929 cells was studied. The results suggest that these materials had no obvious cytotoxicity. Thus, we may have developed a novel, good biocompatibility hydrogel with inherent photosensitive antibacterial activity with great potential for applications in the fields of cosmetics, medical dressings, and environmental protection. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44150.     

Study of antibacterial properties of polypropylene filled with surfactant‐coated silver nanoparticles

Medical applications require, in most cases, antibacterial protection. The use of silver (Ag) gives important antibacterial properties since silver is highly toxic for bacteria. In this research work, we have used silver nanoparticles (Ag NPs) with different surfactants, polyvinyl pyrrolidone (PVP) and oleic acid (OA) to facilitate dispersion. PP‐Ag NPs compounds were prepared by melt mixing, and the effects of the processing conditions on nanoparticles' dispersion were investigated by transmission electron microscopy (TEM). The antibacterial efficiency of PP‐Ag NPs compounds against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8379 was evaluated. Results show that good dispersion is obtained with rotating speeds in the 350–500 rpm range. TEM analysis reveals balanced dispersion and presence of some Ag NPs aggregates. Regarding antimicrobial properties, the use of PVP as surfactant leads to “significant” antimicrobial activity of 1.5 against Staphylococcus aureus and Escherichia coli; on other hand, the use of oleic acid (OA) as surfactant leads to strong protection against Staphylococcus aureus (antimicrobial activity between 2.5 and 3.3) but the overall protection against Escherichia coli is very low (lower than 1). Results show that the use of surfactants for Ag NPs has important effects on antibacterial properties of polypropylene filled with coated Ag NPs. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Preparation and characterization of antimicrobial films based on nanocrystalline cellulose

Nanocrystalline cellulose (NCC) has great potential in applications in medical and food packaging due to its abundance, high specific surface area, biodegradability, biocompatibility, and reproducibility. N-Halamine is one of the most effective antibacterial agents, with broad-spectrum efficacy against microorganisms, good stability, and reproducibility. Due to the nanosize effect and high specific surface area of NCC, N-halamine-modified NCC is potentially an excellent biocidal compound. In this paper, an N-halamine precursor 1-hydroxymethyl-5,5-dimethylhydantoin (HDH) was used to modify NCC with cyanuric chloride (cych) as the bonding agent. After chlorination, the produced NCC-cych-HDH-Cl became antibacterial. The synthesized NCC-cych-HDH-Cl was added to a chitosan (CS) and polyvinyl alcohol (PVA) solution to prepare antibacterial films. The optimum mixing ratio of PVA and CS in the PVA/CS films and concentration of NCC-cych-HDH-Cl were investigated. The surface morphologies and mechanical properties of the antibacterial films were characterized with scanning electron microscopy, transmission electron microscopy, and mechanical strength tests. The results indicated that the film with 90/10 PVA/CS and 7.0% loading of NCC-cych-HDH-Cl exhibited excellent tensile strength. The antibacterial film with 5.91 × 10¹⁷ atoms/cm² of active chlorine displayed an excellent antibacterial property against Staphylococcus aureus (ATCC 6538) and Escherichia coli O157:H7 (ATCC 43895). © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47101.     

Multifunctional ZnO/TiO2 nanoarray composite coating with antibacterial activity,cytocompatibility and piezoelectricity

Metal oxides with nanostructures such as zinc oxide (ZnO), titanium dioxide (TiO₂) have been used in biomedical fields for their multifunctional properties. In this study, ZnO/TiO₂ nanoarray (nZnO/TiO₂) coatings were prepared via hydrothermal synthesis followed by low temperature liquid phase method. The particle size of the composites were no more than 100 nm in diameter, assembled into nanoarray on the Ti substrate. In vitro antibacterial experiments showed that the maximum bacteriostatic rate could reach 99% against Staphylococcus aureus and 90% against Escherichia coli, respectively. Moreover, the nZnO/TiO₂ coatings were of cytocompatibility and biocompatibility, promoting the proliferation of MC3T3-E1 and the expression of alkaline phosphatase (ALP). The piezoelectric properties of nZnO/TiO₂ coatings were preliminarily investigated. The smaller the size of the composite particle was, the better the antibacterial property, biocompatibility and piezoelectric properties were. Under the stimulation of the periodic loading, the growth of MC3T3-E1 was promoted, so the secretion of ALP was. The nZnO/TiO₂ composite coating with antibacterial activity, osteogenesis and intellectual stimulation would be a promising smart coating for orthopedic implants.     

Preparation and antibacterial effects of PVA‐PVP hydrogels containing silver nanoparticles

The poly(vinyl alcohol)/poly(N‐vinyl pyrrolidone) (PVA–PVP) hydrogels containing silver nanoparticles were prepared by repeated freezing–thawing treatment. The silver content in the solid composition was in the range of 0.1–1.0 wt %, the silver particle size was from 20 to 100 nm, and the weight ratio of PVA to PVP was 70 : 30. The influence of silver nanoparticles on the properties of PVA–PVP matrix was investigated by differential scanning calorimeter, infrared spectroscopy and UV–vis spectroscopy, using PVA–PVP films containing silver particles as a model. The morphology of freeze‐dried PVA–PVP hydrogel matrix and dispersion of the silver nanoparticles in the matrix was examined by scanning electron microscopy. It was found that a three‐dimensional structure was formed during the process of freezing–thawing treatment and no serious aggregation of the silver nanoparticles occurred. Water absorption properties, release of silver ions from the hydrogels and the antibacterial effects of the hydrogels against Escherichia coli and Staphylococcus aureus were examined too. It was proved that the nanosilver‐containing hydrogels had an excellent antibacterial ability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 125–133, 2007     

Electrospun polylactic acid nanofiber membranes containing Capparis spinosa L. extracts for potential wound dressing applications

Capparis spinosa L. (CSL) is a medicinal plant with high antibacterial activity against a variety of pathogens and antioxidation properties. In this paper, for the first time, nanofiber membranes of polylactic acid (PLA) containing 0, 4, 7,and 10 wt% CSL ethyl acetate extract were fabricated by electrospinning. Scanning electron microscopy showed that the fiber diameter decreased after adding CSL to the PLA nanofibers. Fourier transform infrared spectroscopy confirmed that CSL was successfully incorporated in the matrix. The water contact angle test proved that the addition of CSL improved the hydrophilic properties of the material. Moreover, the addition of CSL improved the oxidation resistance of the composite fiber membrane. A burst drug release from the composite nanofibers occurred within the first 12 hr, followed by slow release over a prolonged period of time. As the concentration of CSL increased, the inhibition ability of nanofibers against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) gradually increased. In summary, due to their good mechanical, antioxidant, and antibacterial properties, CSL/PLA nanofiber membranes may possess potential applications as wound dressing materials.