Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 85
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Food Sci Technol ; 58(3): 834-843, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33678866

RESUMO

Use of nano minerals in farm animal nutrition offers considerable advantages over inorganic or organic mineral sources. But, the conventional chemical synthesis of nano minerals suffers from disadvantage of possible environmental accumulation and pollution due to the non-biodegradable materials and chemicals. This study investigated the effects of green nano-zinc (GNZ) and market nano-zinc (MNZ) with respect to the inorganic zinc (IZ) on meat quality, antioxidant status, mineral deposition, and bone development in broiler chicken. Following a 3 × 3 factorial design, nine dietary treatments were formulated by employing three levels (40, 60, and 80 ppm) and three sources (inorganic, green nano, and market nano) of zinc viz. IZ-40, GNZ-40, MNZ-40, IZ-60, GNZ-60, MNZ-60, IZ-80, GNZ-80, MNZ-80. Six replicates of broiler chicken were assigned to each treatment with eight birds in each. The birds fed 80 ppm Zinc of either GNZ or MNZ source resulted in significantly higher serum SOD, glutathione peroxidase, catalase, zinc, calcium, and phosphorus levels; increased bone dimensions, weight, total ash, phosphorus, and zinc content along with higher liver and muscle zinc concentration. The meat of chicken fed 80 ppm zinc of MNZ source followed by GNZ source has shown significantly better antioxidant (DPPH and ABTS values) status and lower lipid peroxidation (free fatty acid and TBARS values). The 80 ppm zinc of either MNZ or GNZ source resulted in significantly lower fat and cholesterol content of chicken meat compared to lower Zn levels and IZ source. This study indicated that 80 ppm dietary zinc of either MNZ or GNZ source improved the antioxidant status, and reduced the meat cholesterol, fat content, and lipid peroxidation of chicken meat along with increased bone dimensions and mineralization.

2.
J Anim Physiol Anim Nutr (Berl) ; 103(6): 1800-1809, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31483533

RESUMO

This study was conducted to evaluate the effects of dietary soapnut (Sapindus mukorossi) shell powder (SSP), a cheap source of saponins, on growth performance, immunity, serum biochemistry and gut health of broiler chickens. The experimental design was 4×2, employing four saponin levels (0, 100, 150 and 200 mg/kg diet), each provided for two time durations (0-42 day and 21-42 day) resulting into eight dietary treatments. Results revealed no significant effect of dietary saponins on body weight gain, feed intake and feed conversion ratio of birds. The abdominal fat percentage, heterophil to lymphocyte ratio, serum cholesterol and triglyceride levels, faecal total plate count, coliform count and E. coli count decreased (p < .05) progressively with increasing saponin levels and lower values were observed at 150 mg and 200 mg saponin levels. Significant improvement of cell-mediated and humoral immune response was observed in birds fed 150 mg and 200 mg saponin compared to control. The serum glucose concentration was significantly (p < .05) higher in control group compared to other groups. No significant effects of dietary saponin were observed on carcass characteristics, faecal Lactobacillus count, intestinal histomorphometry and cost economics of broiler chicken production. Thus, dietary saponins at 150 mg/kg diet as SSP for three weeks (21-42 days) was optimum for better immunity and welfare of birds without adverse effects on the growth performance.


Assuntos
Ração Animal/análise , Galinhas/sangue , Dieta/veterinária , Intestinos/efeitos dos fármacos , Sapindus/química , Saponinas/farmacologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Galinhas/crescimento & desenvolvimento , Galinhas/imunologia , Saponinas/administração & dosagem , Saponinas/química
3.
ACS Omega ; 4(2): 3745-3754, 2019 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-31459587

RESUMO

The present study aimed to improve the adsorption characteristics of the pristine layered double hydroxide (LDH) by physicochemical modification using polyethylene glycol (PEG400), a nontoxic hydrophilic polymer. With this objective, LDH was synthesized and modified with different concentrations of PEG400. The PEG-modified LDHs (LDH/PEGs) were characterized using X-ray diffraction, thermogravimetric analysis, Brunauer-Emmett-Teller surface area and porosity measurement, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and zeta potential measurements. The adsorption properties of the pristine LDH (PLDH) and the LDH/PEGs were studied for the removal of Acid Orange II from water, and the results were compared. The PLDH treated with 15% PEG solution showed ∼30% increase in adsorption capacity as compared to the PLDH. The adsorption isotherm data were analyzed using Langmuir, Freundlich, and Temkin isotherm models. The values of thermodynamic parameters such as ΔS and ΔH showed the spontaneous and endothermic nature of the adsorption process. The adsorption kinetics data for both PLDH and the LDH/PEG adsorbents presented a good fit to the pseudo-second-order kinetic model.

4.
Sci Rep ; 9(1): 5581, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30944362

RESUMO

Flax (Linum usitatissimum) is a cool season crop commercially cultivated for seed oil and stem fibre production. A comprehensive characterization of the heat shock factor (HSF) candidate genes in flax can accelerate genetic improvement and adaptive breeding for high temperature stress tolerance. We report the genome-wide identification of 34 putative HSF genes from the flax genome, which we mapped on 14 of the 15 chromosomes. Through comparative homology analysis, we classified these genes into three broad groups, and sub-groups. The arrangement of HSF-specific protein motifs, DNA-binding domain (DBD) and hydrophobic heptad repeat (HR-A/B), and exon-intron boundaries substantiated the phylogenetic separation of these genes. Orthologous relationships and evolutionary analysis revealed that the co-evolution of the LusHSF genes was due to recent genome duplication events. Digital and RT-qPCR analyses provided significant evidence of the differential expression of the LusHSF genes in various tissues, at various developmental stages, and in response to high-temperature stress. The co-localization of diverse cis-acting elements in the promoters of the LusHSF genes further emphasized their regulatory roles in the abiotic stress response. We further confirmed DNA-binding sites on the LusHSF proteins and designed guide RNA sequences for gene editing with minimal off-target effects. These results will hasten functional investigations of LusHSFs or assist in devising genome engineering strategies to develop high-temperature stress tolerant flax cultivars.


Assuntos
Adaptação Biológica/genética , Linho/genética , Genoma de Planta/genética , Proteínas de Choque Térmico/genética , Resposta ao Choque Térmico/genética , Proteínas de Plantas/genética , Estresse Fisiológico/genética , Evolução Molecular , Éxons/genética , Duplicação Gênica/genética , Edição de Genes/métodos , Regulação da Expressão Gênica de Plantas/genética , Genômica/métodos , Íntrons/genética , Família Multigênica/genética , Filogenia , Temperatura
5.
Vet World ; 11(11): 1592-1596, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30587894

RESUMO

AIM: The aim of this study was to investigate the effect of feeding rice based distillers dried grains with solubles (rDDGS) and gluten meal on nutrient transporter genes and immunity in broiler chickens. MATERIALS AND METHODS: A 2×3 factorial design resulted in six experimental diets, namely T1 (no rDDGS/rice gluten meal [RGM]/enzyme), T2 (no rDDGS/RGM, with multienzymes), T3 (12.5% rDDGS, 15% RGM, no enzyme), T4 (12.5% rDDGS, 15% RGM, with protease enzyme), T5 (10% rDDGS, 12.5% RGM, no enzyme), and T6 (10% rDDGS, 12.5% RGM, with protease enzyme). Each treatment was allocated five replicates of chicks, with eight birds in each. Nutrient transporter genes such as Mucin (MUC 2), excitatory amino acid transporter 3 (EAAT3), and peptide transporter (PepT1) and immunity were estimated using standard procedures. RESULTS: Feeding rDDGS and RGM combination improved humoral immunity, while cell-mediated immunity did not show any significant (p>0.05) effect on broiler chickens. MUC and PepT1 genes showed significantly (p<0.01) decreased relative fold expression in 12.5% rDDGS +15% RGM combination, while EAAT3 gene showed significantly (p<0.01) decreased relative fold expression in both rDDGS and RGM combination levels. CONCLUSION: Thus, it may be concluded that feeding rDDGS and RGM combination improved humoral immunity but had an adverse effect on nutrient transporter gene in broiler chickens.

6.
ACS Omega ; 3(5): 5155-5164, 2018 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31458730

RESUMO

Physicochemical studies on aqueous mixtures of ionic liquids (ILs) and reverse pluronics are limited. Self-aggregation dynamics and microstructure of a surface-active IL (SAIL), 1-butyl-3-methylimidazolium octylsulfate [C4mim] [C8OSO3], in the presence of a reverse pluronic, PO8EO22PO8 (known as 10R5), were studied using isothermal titration calorimetry (ITC), high-resolution nuclear magnetic resonance (NMR), and small-angle neutron scattering (SANS) methods. Also, cryo-/freeze-fracture transmission electron microscopy was employed to determine the microstructures of SAIL/10R5 mixtures. The ITC and NMR results revealed facilitation of SAIL aggregation in the presence of 10R5 forming mixed aggregates as well as free SAIL micelles. 2H spin relaxation rate data pointed out the onset of slow dynamics of the aqueous SAIL/10R5 mixture with an increase in either the former or the latter. Globular morphologies of the mixed species as well as their individual components were corroborated from the measurements. The preferential location of interaction of the SAIL with the 10R5 was identified from 13C NMR chemical shift findings to be in the interfacial region of the assembled SAIL. The formed species were mixed interacted aggregates but not mixed micelles that arise from mixed surfactants. The physicochemical information acquired herein would enrich the literature on the 10R5/SAIL mixed microheterogeneous systems having importance in the making of useful green drug carrier systems and templates for the synthesis of nanomaterials.

7.
ACS Omega ; 3(9): 11486-11496, 2018 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31459250

RESUMO

A novel porous polymer-inorganic hybrid biocomposite with various functional groups (hide substance/chitosan/hydroxyapatite) has been synthesized in simple, economic, and scalable process utilizing leather industry solid waste and seafood industry waste composed with hydroxyapatite. Physicochemical characterization of the material reveals formation of composites with homogenous distribution of the constituents in the material matrix. The composite is hard and porous (with 0.1632 cm3/g slit-shaped mesopores and micropores) having particle sizes 40-80 µm and a Brunauer-Emmett-Teller surface area of 55.54 m2/g. The material is polycrystalline in nature with a fair amount of amorphous substance and less hydrophilic in character than constituent polymers. The dye removal efficiency of the material has been tested with two model dyes, namely, methylene blue (MB) (cationic/basic dye) and sunset yellow (SY) (anionic/acid dye). Optimum adsorptions of 3.8 mg MB (pH 12, RT ≈ 27 °C) and 168 mg of SY (pH 3, RT ≈ 27 °C) have been found per gram of the composite material. Langmuir isotherm and pseudo second order rate models have been found to be the best-fit models to explain the equilibrium isotherm and kinetics of the adsorption process for both the dyes. However, higher and faster adsorption of SY in comparison with MB indicated higher binding efficiency of the material toward the acidic dye. Desorption of dyes from the dye-adsorbed material was studied using a suitable eluent of appropriate pH and recycling for five times showed without loss of efficiency. The prepared composite showed very high dye removal efficiency toward four different commercially used dyes (496 mg/g of Orange-NR, 477 mg/g of Red-VLN, 488 mg/g of Blue-113 dye, and 274 mg/g of Green-PbS dye) from their individual and cocktail solutions. It was also efficient to decolorize dye-bearing tannery exhaust bath. Hence, waste materials generated during industrial processes could be efficiently used for the decontamination of colored wastewater produced by various industries.

8.
ACS Omega ; 3(9): 11710-11717, 2018 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31459267

RESUMO

Diketopyrrolopyrrole (DPP)-based polymers are often considered as the most promising donor moiety in traditional bulk heterojunction solar cell devices. In this paper, we report the synthesis, characterization of various DPP-based copolymers with different molecular weights, and polydispersity where other aromatic repeating units (phenyl or thiophene based) are connected by alternate double bonds or triple bonds. Some of the copolymers were used for device fabrication and the crucial parameters such as fill factor (FF) and open circuit voltage (V oc) were calculated. The density functional theory was used to optimize the geometries and deduce highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of all the polymers and theoretically predict their optical and electronic properties. Optical properties of all the polymers, electrochemical properties, and band gaps were also obtained experimentally and compared with the theoretically predicted values.

9.
Disabil Rehabil Assist Technol ; 11(5): 407-12, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27054411

RESUMO

PURPOSE: In the Indian scenario, the Jaipur foot is a low-cost breakthrough that enabled the disabled person to adapt to the Indian environment. The aim of this study is to modify the present foot in terms of ankle support design and method of fabrication, foot moulds profile and the inner core material in order to improve the performance and durability. METHOD: The optimized design of ankle support and flat foot profile moulds suitable for both left and right foot were developed through CAD/CAM and prosthetic feet were fabricated using ethylene vinyl acetate (EVA) foam as an appropriate alternative core material for microcellular rubber (MCR). The developed prosthetic feet were tested for rigidity by load-deflection analysis in universal testing machine. RESULT: EVA foot had shown better rigidity than conventional MCR foot, which will help in weight transfer during walking and increase the durability. The CAD modeled ankle support and single block EVA had made the manufacturing process easy and reduced the weight of foot and improved Gait to the person fitted with it due to improved flat foot profile. CONCLUSION: The new artificial foot had proven to be efficacious technically as well as functionally, which is clearly borne out from the extremely positive feedback given by the amputees. Implications of Rehabilitation Persons with below knee amputation are usually provided with transtibial prosthesis, which allows for easier ambulation and helps them to get back to their normal life. Transtibial prosthesis is an artificial limb that replaces a lower limb that is amputated below the knee. In our study, a new prosthetic foot with a modified ankle support and flat foot profile using better inner-core material than the conventional Jaipur foot was developed and the process was also optimized for mass production. The developed prosthetic foot can be fitted with both above and below knee exoskeleton type of prosthesis.


Assuntos
Amputação Cirúrgica/reabilitação , Amputados/reabilitação , Membros Artificiais , , Desenho de Prótese/métodos , Tornozelo , Fenômenos Biomecânicos , Marcha , Humanos , Índia , Polivinil , Borracha , Caminhada
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 153: 465-70, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26363731

RESUMO

Synthesis and fluorescence turn-on behavior of a naphthalimide based probe is described. Selective interactions of trivalent cations Fe(3+), Al(3+) or Cr(3+) with probe 1 inhibit the PET operating in the probe, and thereby, permit the detection of these trivalent cations present in aqueous samples and live cells. Failure of other trivalent cations (Eu(3+), Gd(3+) and Nb(3+)) to inhibit the PET process in 1 demonstrates the role of chelating ring size vis-à-vis ionic radius in the selective recognition of specific metal ions.


Assuntos
Alumínio/química , Cromo/química , Ferro/química , Sondas Moleculares/química , Naftalimidas/química , Cátions , Células Cultivadas , Cristalografia por Raios X , Elétrons , Humanos , Luz , Conformação Molecular , Soluções , Espectrometria de Fluorescência , Fatores de Tempo
11.
Sci Rep ; 5: 15977, 2015 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-26527296

RESUMO

Serum albumin can be transformed to a stimuli (pH and redox) responsive hydrogel using the reduction process followed by oxidative refolding. The preparation of albumin hydrogel involves a range of concentrations (75, 150, 300, 450, 600 and 750 µM) and pH (2.0-10.0) values and the gelation begins at a concentration of 150 µM and 4.5-8.0 pH value. The hydrogel shows maximum swelling at alkali pH (pH > 9.0). The increase in albumin concentration increases hydrogel stability, rheological property, compressive strength, proteolytic resistance and rate of in vivo biodegradation. Based on the observed physical and biological properties of albumin hydrogel, 450 µM was determined to be an optimum concentration for further experiments. In addition, the hemo- and cytocompatibility analyses revealed the biocompatibility nature of albumin hydrogel. The experiments on in vitro drug (Tetracycline) delivery were carried out under non reducing and reducing conditions that resulted in the sustained and fast release of the drug, respectively. The methodology used in the preparation of albumin hydrogel may lead to the development of autogenic tissue constructs. In addition, the methodology can have various applications in tissue engineering and drug delivery.


Assuntos
Materiais Biocompatíveis/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Soroalbumina Bovina/química , Albumina Sérica/química , Animais , Materiais Biocompatíveis/farmacologia , Bovinos , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Feminino , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Microscopia Eletrônica de Varredura , Células NIH 3T3 , Oxirredução , Ratos Wistar , Tetraciclina/administração & dosagem , Tetraciclina/farmacocinética
12.
J Nanosci Nanotechnol ; 15(5): 3879-86, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26505018

RESUMO

Nanomaterials decorated with polypyrrole were synthesized using two types of oxidants by chemical oxidative polymerization method. The interaction and influence of the addition of single-walled carbon nanotubes (SWCNTs) and titanium dioxide (TiO2) nanoparticles in polypyrrole (PPy) were studied using Fourier transform infrared spectroscopy and Raman spectroscopy. Thermal stability has been observed by using thermogravimetric analysis. Electrochemical properties were calculated by using Cyclic Voltammetry to study comparative analysis between samples. Particle size measurements and morphology were determined by Field emission transmission electron microscopy. All the nanocomposites exhibit better thermal and electrochemical properties than native polymer. The size of the polypyrrole particles were in the range of 50 nm to 60 nm.


Assuntos
Nanocompostos/química , Nanotubos de Carbono/química , Polímeros/química , Pirróis/química , Titânio/química , Microscopia Eletrônica , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
13.
Soft Matter ; 11(41): 8126-40, 2015 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-26338226

RESUMO

In recent years, several fluorenylmethoxycarbonyl (Fmoc)-functionalized amino acids and peptides have been used to construct hydrogels, which find a wide range of applications. Although several hydrogels have been prepared from mono Fmoc-functionalized amino acids, herein, we demonstrate the importance of an additional Fmoc-moiety in the hydrogelation of double Fmoc-functionalized L-lysine [Fmoc(Nα)-L-lysine(NεFmoc)-OH, (Fmoc-K(Fmoc))] as a low molecular weight gelator (LMWG). Unlike other Fmoc-functionalized amino acid gelators, Fmoc-K(Fmoc) exhibits pH-controlled ambidextrous gelation (hydrogelation at different pH values as well as organogelation), which is significant among the gelators. Distinct fibrous morphologies were observed for Fmoc-K(Fmoc) hydrogels formed at different pH values, which are different from organogels in which Fmoc-K(Fmoc) showed bundles of long fibers. In both hydrogels and organogels, the self-assembly of Fmoc-K(Fmoc) was driven by aromatic π-π stacking and hydrogen bonding interactions, as evidenced from spectroscopic analyses. Characterization of Fmoc-K(Fmoc) gels using several biophysical methods indicates that Fmoc-K(Fmoc) has several advantages and significant importance as a LMWG. The advantages of Fmoc-K(Fmoc) include pH-controlled ambidextrous gelation, pH stimulus response, high thermal stability (∼100 °C) even at low minimum hydrogelation concentration (0.1 wt%), thixotropic property, high kinetic and mechanical stability, dye removal properties, cell viability to the selected cell type, and as a drug carrier. While single Fmoc-functionalized L-lysine amino acids failed to exhibit gelation under similar experimental conditions, the pH-controlled ambidextrous gelation of Fmoc-K(Fmoc) demonstrates the benefit of a second Fmoc moiety in inducing gelation in a LMWG. We thus strongly believe that the current findings provide a lead to construct or design various new synthetic Fmoc-based LMW organic gelators for several potential applications.


Assuntos
Aminoácidos/química , Fluorenos/química , Hidrogéis/química , Lisina/química , Aminoácidos/farmacologia , Compostos Azo/química , Bacillus subtilis/efeitos dos fármacos , Dicroísmo Circular , Elasticidade , Escherichia coli/efeitos dos fármacos , Fluorenos/farmacologia , Concentração de Íons de Hidrogênio , Cinética , Microscopia de Força Atômica , Peso Molecular , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Viscosidade
14.
Chem Soc Rev ; 44(10): 3212-43, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-25839067

RESUMO

Polymer functionalized surfaces are important components of various sensors, solar cells and molecular electronic devices. In this context, the use of self-assembled monolayer (SAM) formation and subsequent reactions on the surface have attracted a lot of interest due to its stability, reliability and excellent control over orientation of functional groups. The chemical reactions to be employed on a SAM must ensure an effective functional group conversion while the reaction conditions must be mild enough to retain the structural integrity. This synthetic constraint has no universal solution; specific strategies such as "graft from", "graft to", "graft through" or "direct" immobilization approaches are employed depending on the nature of the substrate, polymer and its area of applications. We have reviewed current developments in the methodology of immobilization of a polymer in the first part of the article. Special emphasis has been given to the merits and demerits of certain methods. Another issue concerns the utility - demonstrated or perceived - of conjugated or non-conjugated macromolecules anchored on a functionally decorated SAM in the areas of material science and biotechnology. In the last part of the review article, we looked at the collective research efforts towards SAM-based polymer devices and identified major pointers of progress (236 references).


Assuntos
Biotecnologia/métodos , Substâncias Macromoleculares , Polimerização , Propriedades de Superfície
15.
J Mech Behav Biomed Mater ; 52: 131-138, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25922091

RESUMO

The success of a tissue engineering scaffold depends on a fine balance being achieved between the physicochemical and biological properties. This study attempts to understand the influence of silica concentration on the functional properties of collagen-silica (CS) composite scaffolds for soft tissue engineering applications. Increasing the ratio of silica to collagen (0.25, 0.5, 0.75, 1.0, 1.25, 1.5 and 2.0 w/w) gave a marked advantage in terms of improving the water uptake and compressive modulus of the CS scaffolds, while also enhancing the biological stability and the turnover time. With increase in silica concentration the water uptake and compressive modulus increased concurrently, whereas it was not so for surface porous architecture and biocompatibility which are crucial for cell adhesion and infiltration. Silica:collagen ratio of ≤1 exhibits favourable surface biocompatibility, and any further increase in silica concentration has a detrimental effect.


Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Colágeno Tipo I/química , Dióxido de Silício/química , Alicerces Teciduais/química , Células 3T3 , Animais , Bovinos , Estabilidade de Medicamentos , Fenômenos Mecânicos , Camundongos , Porosidade , Relação Estrutura-Atividade , Engenharia Tecidual , Água/química
16.
Soft Matter ; 11(21): 4154-7, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-25820320

RESUMO

While biomacromolecules such as proteins are shown to form fibrous spherulites, which are generally "semicrystalline" in nature, here we show that a simple, low molecular weight compound such as fluorenylmethoxycarbonyl-functionalized phenolic amino acid (Fmoc-l-tyrosine) can form "fibrous" spherulites with highly "cross-linked" microfibrils using the supramolecular self-assembly process.


Assuntos
Aminoácidos/química , Fluorenos/química , Tirosina/química , Dicroísmo Circular , Peso Molecular , Proteínas/química , Espectroscopia de Infravermelho com Transformada de Fourier
17.
J Hazard Mater ; 290: 117-26, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25746571

RESUMO

The biosynthesis of nano-silica silver nanocomposite (NSAgNC) and it is as antibacterial effect on gram-negative bacteria viz.Escherichia coli and Pseudomonas aeruginosa has been investigated for disinfection of water. The as-synthesized NSAgNC exhibited antibacterial activity in a dose dependent manner and ∼ 99.9% of E. coli and P. aeruginosa were killed at a concentration of 1.5 mg/mL of NSAgNC (5.1 wt% Ag) within 5h. The NSAgNC showed similar antibacterial activities both in oxic and anoxic conditions. The results further demonstrated that NSAgNC exhibited reactive oxygen species (ROS) independent "particle specific" antibacterial activity through multiple steps in absence of leached out Ag(+) ions. The initial binding of NSAgNC on the cell wall caused loss of cell membrane integrity and leakage of cytoplasmic materials. Inhibition of respiratory chain dehydrogenase by NSAgNC caused metabolic inactivation of the cells and affecting the cell viability. Genomic and proteomic studies further demonstrated the fragmentations of both plasmid and genomic DNA and down regulation of protein expression in NSAgNC treated cells, which leading to the cell death. Thus the biosynthesized NSAgNC has great potential as disinfectant for water purification while minimizing the toxic effects.


Assuntos
Antibacterianos/farmacologia , Desinfecção/métodos , Nanocompostos/química , Dióxido de Silício/química , Compostos de Prata/farmacologia , Antibacterianos/química , Carga Bacteriana , Fragmentação do DNA , DNA Bacteriano/genética , Escherichia coli/efeitos dos fármacos , Hipóxia , Plasmídeos/genética , Proteômica , Pseudomonas aeruginosa/efeitos dos fármacos , Espécies Reativas de Oxigênio , Compostos de Prata/química
18.
J Mater Chem B ; 3(7): 1230-1244, 2015 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32264474

RESUMO

Imparting functional properties on a biomaterial for high end applications is always a challenging task. In the present study, an attempt was made to construct an injectable hydrogel through bioconjugation of dihydroxy phenolic acids to a gelatin backbone. Bioconjugating caffeic acid with gelatin followed by oxidation with mild oxidation agents provided a hydrogel with all the requisite properties (biocompatibility, controlled biodegradability, and antioxidant, antimicrobial and wound healing ability). Bioconjugation was performed using EDC/NHS and the resultant gel named as caffeic acid bioconjugated gel (CBG gel). The physicochemical, rheological, swelling, in vitro (biocompatibility, biodegradability, antimicrobial properties, antioxidant properties and drug release properties) and in vivo (biocompatibility, biodegradability and wound healing properties) studies on the CBG gel were carried out using standard protocols. The bioconjugation was confirmed by 1H NMR and UV-Vis analysis. Rheological analysis of the CBG gel revealed that the storage modulus was greater than the loss modulus at all the frequencies and suggested the elastic nature of the gel. About 50% weight gain within 12 hours during swelling studies and 50% weight loss within 12 hours during evaporation suggested the suitability of the CBG gel as a drug carrier. The drug release studies implied that there was an initial burst and later the release was sustained. The CBG gel promotes cell migration and demonstrates radical scavenging behavior. When subcutaneously injected into the animal, as in situ CBG gel, the gel was highly biocompatible and did not cause any necrosis. The crosstalk with adjacent tissue cells was smooth and the gel completely degraded within 24 days. The wound healing efficacy on full-thickness wounds suggested that the CBG gel accelerated healing and imparted high strength on the healed skin at an appreciable level. With all these additional functional properties, the CBG gel could be useful for biomedical applications.

19.
Mater Sci Eng C Mater Biol Appl ; 43: 164-71, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25175201

RESUMO

The effect of Gallic acid (GA) in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-hydroxysuccinimide (NHS) on collagen scaffold is investigated. The thermal mechanical analyzer (TMA), differential scanning calorimetric (DSC), and thermogravimetric analysis (TGA) including tensile strength (TS, 180 ± 3 MPa), denaturation temperature (Td, 80.03°C), % elongation (% E, 180 ± 9) and weight loss (31.76%), indicate that the modification improves the structural integrity and stability of the collagen scaffold. The GA-EDC/NHS treatment inhibits the action of collagenase against collagen degradation compared to GA and EDC/NHS. It is concluded from docking studies that GA binds with collagen like peptide (CLP) and collagenase through multiple H-bonds and hydrophobic interactions leading to low binding energy -5.1 and -5.3 Kcal/mol, respectively. The hydrophobic core of the GA molecules, probably incorporates itself into the hydrophobic areas of the collagen groups, whereas OH and COOH moieties of GA establish multiple H-bonds with neighboring collagen molecules and carboxamide bond, thereby improving the swelling and water uptake properties, biocompatibility and cell adhesion properties. This results in improving stability of the scaffold, which prevents the free access of the collagenase to reactive sites in the triple helical collagen chains.


Assuntos
Colágeno/química , Ácido Gálico/química , Alicerces Teciduais , Animais , Varredura Diferencial de Calorimetria , Bovinos , Clostridium histolyticum/enzimologia , Colagenases/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Células NIH 3T3 , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
20.
Phys Chem Chem Phys ; 16(37): 20175-83, 2014 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-25138771

RESUMO

The present investigation attempts at fabricating collagen-based scaffolds impregnated with sago starch capped silver nanoparticles (AgNPs), useful for biomedical applications, and aims at studying their physicochemical aspects. AgNPs synthesized through a chemical reduction method, capped using different concentrations of sago starch, are incorporated into collagen derived from fish scales, and lyophilized to form scaffolds. FT-IR spectra confirm and validate the interaction of sago starch capped AgNPs with collagen in the scaffolds. TGA and DSC results indicate enhanced thermal stability of collagen scaffolds impregnated with sago capped AgNPs compared to collagen alone. All the collagen scaffolds containing sago starch capped AgNPs show high tensile strength values for their use as wound dressing materials. Moreover, lower minimum inhibitory concentration values are obtained for the above capped AgNP collagen scaffolds, which indicate higher antibacterial activities compared to uncapped AgNPs tested against both gram positive and negative bacterial strains. The novelty is that the developed scaffolds are biodegradable and in vitro studies reveal them as biocompatible and suitable for tissue regeneration applications.


Assuntos
Materiais Biocompatíveis/química , Colágeno/química , Nanopartículas Metálicas/química , Prata/química , Amido/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Varredura Diferencial de Calorimetria , Sobrevivência Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Nanopartículas Metálicas/toxicidade , Camundongos , Testes de Sensibilidade Microbiana , Células NIH 3T3 , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Resistência à Tração , Termogravimetria
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...