Anti-microbial surfaces: An approach for deposition of ZnO nanoparticles on PVA-Gelatin composite film by screen printing technique.

Initially micro-organisms get exposed to the surfaces, this demands development of anti-microbial surfaces to inhibit their proliferation. Therefore, herein, we attempt screen printing technique for development of PVA-GE/ZnO nanocomposite (PG/ZnO) films. The synthesis of PG/ZnO nanocomposite includes two steps as: (i) Coating of Zinc Oxide nanoparticles (ZnO NPs) by poly ethylene glycol in order to be compatible with organic counterparts. (ii) Deposition of coated nanoparticles on the PG film surface. The results suggest the enhancement in anti-microbial activity of PG/ZnO nanocomposite over pure ZnO NPs against both Gram positive Bacillus subtilis and Gram negative Escherichia coli from zone of inhibition. The uniformity in deposition is further confirmed by scanning electron microscopy (SEM) images. The phase identification of ZnO NPs and formation of PG/ZnO nanocomposite has been confirmed by X-ray diffraction (XRD) analysis and UV-vis spectroscopy (UV-vis). The Attenuated total reflection Spectroscopy (ATR) analysis indicates the ester bond between PVA and gelatin molecules. The thermal stability of nanocomposite is studied by thermogravimetric analysis (TGA) revealing increase in crystallinity due to ZnO NPs which could be utilized to inhibit the growth of micro-organisms. The tensile strength is found to be higher and percent elongation is double of PG/ZnO nanocomposite than PG composite film.

Canna edulis Leaf Extract-Mediated Preparation of Stabilized Silver Nanoparticles: Characterization, Antimicrobial Activity, and Toxicity Studies.

A novel approach to synthesize silver nanoparticles (AgNPs) using leaf extract of Canna edulis Ker-Gawl. (CELE) under ambient conditions is reported here. The as-prepared AgNPs were analyzed by UV-visible spectroscopy, transmission emission microscopy, X-ray diffraction, Fourier transform-infrared spectroscopy, energy-dispersive analysis of X-ray spectroscopy, zeta potential, and dynamic light scattering. The AgNPs showed excellent antimicrobial activity against various pathogens, including bacteria and various fungi. The biocompatibility of the AgNPs was analyzed in the L929 cell line using NRU and MTT assays. Acridine orange/ethidium bromide staining was used to determine whether the AgNPs had necrotic or apoptotic effects on L929 cells. The concentration of AgNPs required for 50% inhibition of growth of mammalian cells is far more than that required for inhibition of pathogenic microorganisms. Thus, CELE is a candidate for the eco-friendly, clean, cost-effective, and nontoxic synthesis of AgNPs.

Synthesis and characterization of chitosan-TiO2:Cu nanocomposite and their enhanced antimicrobial activity with visible light.

In the present investigation, novel strategy for the preparation of hybrid nanocomposite containing organic polymer (Chitosan) and inorganic (TiO2:Cu) nanoparticles (NPs) has been developed and demonstrated its biomedical application. The sol-gel and ultra-sonication method assisted for the preparation of uniformly distributed Chitosan-TiO2:Cu (CS-CT) nanocomposite. The structural properties of prepared CS-CT nanocomposite were studied by XRD and FTIR techniques. The XPS was used to estimate elemental composition of the nanocomposite. Thermal properties were studied using TGA. TEM and SEM analysis showed the non-spherical nature of NPs with the average mean diameter 16nm. The optical properties were analyzed with UV-vis diffuse reflectance spectroscopy to confirm optical absorption in the visible region of light. Where CS-CT showed 200% enhanced light mediated photocatalytic antimicrobial activity against microorganism (Escherichia coli and Staphylococcus aureus) as compared with control. The antimicrobial activity of CS-CT nanocomposite in presence of light is found to be enhanced than that of its components, this is due to synergistic effect of organic and inorganic material complimenting each other's activity. The OH radicals release studied by PL spectroscopy on the surface of nanocomposite was used to examine antibacterial activity. Cytotoxicity assessment of CS-CT on human fibroblast cells was performed by MTT assay.

In vitro hyperthermia with improved colloidal stability and enhanced SAR of magnetic core/shell nanostructures.

Magnetic core/shell nanostructures of Fe3O4 nanoparticles coated with oleic acid and betaine-HCl were studied for their possible use in magnetic fluid hyperthermia (MFH). Their colloidal stability and heat induction ability were studied in different media viz. phosphate buffer solution (PBS), saline solution and glucose solution with different physiological conditions and in human serum. The results showed enhanced colloidal stability in these media owing to their high zeta potential values. Heat induction studies showed that specific absorption rates (SAR) of core/shells were 82-94W/g at different pH of PBS and concentrations of NaCl and glucose. Interestingly, core/shells showed 78.45±3.90W/g SAR in human serum. The cytotoxicity of core/shells done on L929 and HeLa cell lines using 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide and trypan blue dye exclusion assays showed >89% and >80% cell viability for 24 and 48h respectively. Core/shell structures were also found to be very efficient for in vitro MFH on cancer cell line. About 95% cell death was occurred in 90min after hyperthermia treatment. The mechanism of cell death was found to be elevated ROS generation in cells after exposure to core/shells in external magnetic field. This study showed that these core/shells have a great potential to be used in in vivo MFH.

Synthesis and characterization of chitosan-alginate scaffolds for seeding human umbilical cord derived mesenchymal stem cells.

BACKGROUND: Chitosan and alginate are two natural and accessible polymers that are known to be biocompatible, biodegradable and possesses good antimicrobial activity. When combined, they exhibit desirable characteristics and can be created into a scaffold for cell culture. OBJECTIVE: In this study interaction of chitosan-alginate scaffolds with mesenchymal stem cells are studied. METHODS: Mesenchymal stem cells were derived from human umbilical cord tissues, characterized by flow cytometry and other growth parameters studied as well. Proliferation and viability of cultured cells were studied by MTT Assay and Trypan Blue dye exclusion assay. RESULTS: Besides chitosan-alginate scaffold was prepared by freeze-drying method and characterized by FTIR, SEM and Rheological properties. The obtained 3D porous structure allowed very efficient seeding of hUMSCs that are able to inhabit the whole volume of the scaffold, showing good adhesion and proliferation. These materials showed desirable rheological properties for facile injection as tissue scaffolds. CONCLUSION: The results of this study demonstrated that chitosan-alginate scaffold may be promising biomaterial in the field of tissue engineering, which is currently under a great deal of examination for the development and/or restoration of tissue and organs. It combines the stem cell therapy and biomaterials.

Intracellular synthesis of silver nanoparticle by actinobacteria and its antimicrobial activity.

Intracellular synthesis of silver nanoparticles (AgNPs) using Rhodococcus spp. is demonstrated. The synthesized nanoparticles were characterized by UV-Vis spectroscopy, X-ray diffraction, energy dispersive spectroscopy, Fourier trans-form infrared spectroscopy, and transmission electron microscopy. Transmission electron microscopy study of microorganisms' revealed synthesis of nanoparticle was occurring inside the cell, in the cytoplasm. AgNPs ranged from 5 to 50 nm. Formed nanoparticles were stable in the colloidal solution due to presence of proteins on the surface. AgNPs showed excellent bactericidal and bacteriostatic activity against pathogenic microorganisms.

Structured superparamagnetic nanoparticles for high performance mediator of magnetic fluid hyperthermia: synthesis, colloidal stability and biocompatibility evaluation.

Core-shell structures with magnetic core and metal/polymer shell provide a new opportunity for constructing highly efficient mediator for magnetic fluid hyperthermia. Herein, a facile method is described for the synthesis of superparamagnetic LSMO@Pluronic F127 core-shell nanoparticles. Initially, the surface of the LSMO nanoparticles is functionalized with oleic acid and the polymeric shell formation is achieved through hydrophobic interactions with oleic acid. Each step is optimized to get good dispersion and less aggregation. This methodology results into core-shell formation, of average diameter less than 40 nm, which was stable under physiological conditions. After making a core-shell formulation, a significant increase of specific absorption rate (up to 300%) has been achieved with variation of the magnetization (<20%). Furthermore, this high heating capacity can be maintained in various simulated physiological conditions. The observed specific absorption rate is almost higher than Fe3O4. MTT assay is used to evaluate the toxicity of bare and core-shell MNPs. The mechanism of cell death by necrosis and apoptosis is studied with sequential staining of acridine orange and ethidium bromide using fluorescence and confocal microscopy. The present work reports a facile method for the synthesis of core-shell structure which significantly improves SAR and biocompatibility of bare LSMO MNPs, indicating potential application for hyperthermia.

Magnetic hyperthermia with magnetic nanoparticles: a status review.

Recent advances in development of potential magnetic nanoparticles for magnetic fluid hyperthermia are summarized. This review covers relation between various size dependent physical properties and their applications subject to modification in synthesis methods. Brief discussion on different heating mechanism of magnetic nanoparticles is provided. This review covers recent progress of various magnetic nanoparticles including core shell type for in vitro, in vivo and pre-clinical trials. The highlight of this review is to build up a bridge between synthesis, surface modification and in vivo- pre-clinical in magnetic fluid hyperthermia.

Green synthesis of silver nanoparticles by microorganism using organic pollutant: its antimicrobial and catalytic application.

A novel approach for the green synthesis of silver nanoparticles (AgNPs) from aqueous solution of AgNO3 using culture supernatant of phenol degraded broth is reported in this work. The synthesis was observed within 10 h, and AgNPs showed characteristic surface plasmon resonance around 410 nm. Spherical nanoparticles of size less than 30 nm were observed in transmission electron microscopy. X-ray diffraction pattern corresponding to 111, 200, 220, and 311 revealed the crystalline nature of the as-formed nanoparticles. It was found that the colloidal solution of AgNP suspensions exhibited excellent stability over a wide range of ionic strength, pH, and temperature. The effect of pH and ionic strength indicated that stabilization is due to electrostatic repulsion arising from the negative charge of the conjugate proteins. The AgNPs showed highly potent antimicrobial activity against Gram-positive, Gram-negative, and fungal microorganisms. The as-prepared AgNPs showed excellent catalytic activity in reduction of 4-nitrophenol to 4-aminophenol by NaBH4. By manufacturing magnetic alginate beads, the reusability of the AgNPs for the catalytic reaction has been demonstrated.

Enhanced colloidal stability of polymer coated La0.7Sr0.3MnO3 nanoparticles in physiological media for hyperthermia application.

Surface of La(0.7)Sr(0.3)MnO3 (LSMO) magnetic nanoparticles (MNPs) is functionalized with polymer (dextran) and their colloidal stability in various mediums is carried out. The influence of the surface functionalization of LSMO MNPs on their colloidal stability in physiological media is studied and correlated with their hyperthermia properties. Many studies have concerned the colloidal stability of MNPs coated with polymer, but their long-term stability when such complexes are exposed to physiological media is still not well understood. After zeta potential study, it is found that the dextran coating on MNPs improves the colloidal stability in water as well as in physiological media like PBS. The specific absorption rates (SAR) of these MNPs are found to be in 50-85 W/g in different concentrations of glucose and NaCl; and there values are suitable for hyperthermia treatment of cancer cells under AC magnetic field. After incorporation of MNPs up to 0.2-1mg/mL in 2 × 10(5)cells/mL (L929), the apoptosis and necrosis studies are carried out by acridine orange and ethidium bromide (AO and EB) staining and followed by visualization of microstructures under a fluorescence microscope. It is found that there are no morphological changes (i.e. no signs of cell rounding, bubble formation on the membrane and nuclear fragmentation) suggesting biocompatibility of dextran coated LSMO nanoparticles up to these concentrations.

A novel microbial synthesis of catalytically active Ag-alginate biohydrogel and its antimicrobial activity.

The green synthesis of supported noble metal nanoparticles is now the most exciting field for various catalytic applications as well as biomedical applications. In this paper we report a novel synthesis method of a polymer consisting of silver nanoparticles (AgNPs) using immobilized microorganisms in alginate beads. Microorganisms present in the polymer reduce aqueous AgNO3 to AgNPs which get trapped in the polymer to form Ag-Alginate (Ag-Alg) biohydrogel. The formed biohydrogel was characterized by UV-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) analysis. TEM analysis showed that less than 15 nm AgNPs formed in the polymer. The Ag-Alg biohydrogel exhibited efficient heterogeneous catalytic activity in the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH4 in aqueous solution with durable reusability. Also this biohydrogel showed excellent antimicrobial activity against pathogenic bacteria (antibiotic resistant) and fungi. The described synthesis method of Ag-Alg biohydrogel can be considered robust, cost effective and eco-friendly. The formed highly catalytic active biohydrogel can be used as catalyst in industries and drinking water purification.

Natural radioactivity study in soil samples of South Konkan, Maharashtra, India.

This study assesses the level of natural radioactivity due to radionuclides, ²³8U, ²³²Th and 4°K, in 50 soil samples collected from South Konkan, Maharashtra, India. The mean activity concentrations of ²³8U, ²³²Th and 4°K are 44.97 ± 1.22 Bq kg⁻¹, 59.70 ± 2.17 Bq kg⁻¹ and 217.51 ± 8.75 Bq kg⁻¹, respectively, measured from all the soil samples studied. The good correlation between activity concentration of U-238 and Th-232; U-238 and K-40 as well as between activity concentration of Th-232 and K-40 was observed. The average calculated absorbed dose rate in air (68.08 nGy h⁻¹) was found to be higher than the world average of 57 nGy h⁻¹ (UNSCEAR 2000). Radium equivalent activity for all the villages was found to be lower than the worldwide value. The values of external hazard index and internal hazard index determined from all the soil samples were found to be within recommended limit. The calculated average annual effective dose was found to be 0.42 mSv y⁻¹, and it is lower than the worldwide value of 0.46 mSv y⁻¹.The annual effective dose values calculated from present study were comparable with previous studies carried out in other countries and in India. The data established from the study can be useful as baseline information on natural radioactivity in South Konkan, Maharashtra, India.

Functionalization of La(0.7)Sr(0.3)MnO3 nanoparticles with polymer: studies on enhanced hyperthermia and biocompatibility properties for biomedical applications.

Now-a-days surface functionalized La(0.7)Sr(0.3)MnO(3) (LSMO) nanoparticles by different biocompatible polymers are attracted considerable interest in various biomedical applications in general and magnetic fluid hyperthermia treatment of cancer in particular. In this paper La(0.7)Sr(0.3)MnO(3) nanoparticles are synthesized and functionalized with polymer (dextran, with mean particle size ~25 nm). Magnetic measurements of both coated and uncoated particles reveal the superparamagnetic nature at room temperature. The resulting coated particles form a stable suspension in an aqueous environment at physiological pH and possess a narrow hydrodynamic size distribution. In vitro cytotoxicity of the MNPs has been assessed under Trypan blue dye exclusion and MTT assay on HeLa and L929 cell lines. The results demonstrate that dextran functionalized nanoparticles have no significant effect on cell viability within the tested concentrations (0.2-1 mg/mL) as compared to bare LSMO. Magnetic fluid hyperthermia studies have been done in detail; the influence of an applied alternating current (AC) magnetic field on heat generation is presented in brief. Dextran functionalized LSMO has the higher Specific absorption rate (SAR) value than the bare LSMO. After functionalization with dextran the SAR values of LSMO nanoparticles increased from 25 to 51 W/g. The study shows that the rise in temperatures by these nanoparticles could be safely controlled around Curie temperature (T(c)).

Induction heating studies of dextran coated MgFe2O4 nanoparticles for magnetic hyperthermia.

MgFe(2)O(4) nanoparticles with sizes around 20 nm have been prepared by a combustion method and functionalized with dextran for their possible applications in magnetic particle hyperthermia. The induction heating study of these nanoparticles at different magnetic field amplitudes, from 6.7 kA m(-1) to 26.7 kA m(-1), showed self-heating temperature rise up to 50.25 °C and 73.32 °C (at 5 mg mL(-1) and 10 mg mL(-1) concentrations in water respectively) which was primarily thought to be due to hysteresis losses activated by an AC magnetic field. The dextran coated nanoparticles showed a maximum specific absorption rate (SAR) of about 85.57 W g(-1) at 26.7 kA m(-1) (265 kHz). Dextran coated nanoparticles at concentrations below 1.8 mg mL(-1) exhibit good viability above 86% on mice fibroblast L929 cells. The results suggest that combustion synthesized MgFe(2)O(4) nanoparticles coated with dextran can be used as potential heating agents in magnetic particle hyperthermia. Uncoated and dextran coated samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TG-DTA) and zeta potential-DLS studies.

Polyvinyl alcohol: an efficient fuel for synthesis of superparamagnetic LSMO nanoparticles for biomedical application.

La(0.7)Sr(0.3)MnO(3) (LSMO) nanoparticles have been prepared using glycine and polyvinyl alcohol (PVA) as fuels. Their crystal structure, particle morphology and compositions are characterized using X-ray diffraction, transmission electron microscopy, field-emission electron microscopy and energy dispersive analysis of X-ray. They show a pseudo-cubic perovskite structure. The spherical particle sizes of 30 and 20 nm have been obtained from samples prepared by glycine and PVA respectively. The field cooled (FC) and zero field cooled (ZFC) magnetizations have been recorded from 5 to 375 K at 500 Oe and superparamagnetic blocking temperatures (T(B)) of 75 and 30 K are obtained from samples prepared by glycine and PVA respectively. Particle size distribution is observed from dynamic light scattering measurements. Dispersion stability of the particles in water is studied by measuring the Zeta potential with varying the pH of the medium from 1 to 12. Under induction heating experiments, a hyperthermia temperature (42-43 °C) is achieved by both the samples (3-6 mg mL(-1)) at magnetic fields of 167-335 Oe and at a frequency of 267 kHz. The bio-compatibility of the LSMO nanoparticles is studied on the L929 and HeLa cell lines by MTT assay for up to 48 h. The present work reveals the importance of synthesis technique and fuel choice on structural, morphological, magnetic, hyperthermia and biocompatible properties of LSMO and predicts the suitability for biomedical applications.