Nanofibrous scaffold engineering using electrospinning

Scaffold plays a critical role in tissue engineering where it provides necessary structural support for the cells to accommodate and to guide their growth in the three dimensional space into a specific tissue. Therefore, engineering scaffolds favorable for cell/tissue growth is of great importance and a pre-requisite for scaffold-based tissue engineering. Electrospinning is a versatile method that has been recently adapted in engineering nano-fibrous scaffolds that mimic the structural features of biological extracellular matrix (ECM). It offers many advantages over conventional scaffold methodologies, for example, capable of producing ultra-fine fibers with high porosity, high spatial orientation, high aspect ratio, and high surface area, which are highly required for the initial cell attachment, tissue formation, and continued function. Considering these astonishing merits, this article emphasis on nano-fibrous scaffold engineering by electrospinning.     

Characterization of new hybridoma clones producing monoclonal antibodies reactive against both live and heat-killed Listeria monocytogenes

ABSTRACT:  The objective of this study is to develop high affinity monoclonal antibody (MAb) probes recognizing all major serotypes of Listeria monocytogenes cells. From 500 candidate hybridoma clones, 2 new monoclonal antibody-producing hybridomas were selected and evaluated. MAbs 22D10 and 24F6 reacted strongly with live cells of most serotypes of L. monocytogenes except 4c and 4e and with some L. innocua strains; MAb 22D10 reacted strongly with both live and heat-killed cells (100 °C for 20 min) of Listeria . Both MAbs 22D10 and 24F6 did not show any cross-reactions with the other non- Listeria G(+) bacteria tested in ELISA. The mixture of EM-7G1 and 22D10 or 24F6 reacted with all 13 major serotypes of live L. monocytogenes except serotype 4c, while none of these 3 MAbs when tested alone did so. MAb 22D10 mixed with 7G1 reacted with all heat-killed L. monocytogenes serotypes except 4c and 4e. In Western blots, MAbs 22D10 and 24F6 reacted with 1 major protein band of 66 kDa in extracts from L. monocytogenes , but with 2 major protein bands of 66 kDa and 76 kDa in extracts from L. innocua . These results suggest that MAbs 22D10 and 24F6 have high affinity for 11 of 13 serotypes of L. monocytogenes , both live and heat-killed cells. MAbs 22D10 and 24F6—in combination with species-specific MAb EM-7G1—should be useful candidates for use in an ELISA sandwich assays for detecting L. monocytogenes in RTE meat and poultry products.     

Rheological behavior of syrups containing sugar substitutes

The rheological properties of syrups prepared using bulk sweeteners such as sorbitol and bulking agents like maltodextrin and polydextrose along with aspartame were studied. The apparent viscosity, consistency index, yield stress, and flow behavior index were determined from the shear stress versus shear rate data. The Herschel–Bulkley model was found to adequately describe the flow behavior of the syrups. The activation energy for all the syrups at different concentrations was determined from the Arrhenius equation. The yield stress, flow behavior index, and consistency index were dependent on the temperature and concentration of the syrups. The apparent viscosity increased from 8.8 to 129 mPa·s for sugar and sorbitol syrups, respectively, over the concentration range from 35 to 65%. In general, the rheological characteristic of sorbitol syrup was similar to that of sugar syrup, while syrups made with polydextrose and its mixture with maltodextrin were significantly different from those of sugar syrup.     

A TRIBAND SWASTIKA SHAPED PATCH ANTENNA WITH REDUCED MUTUAL COUPLING FOR WIRELESS MIMO SYSTEMS

A novel compact Swastika shaped patch antenna is designed in the present work,which can be used for Multiple Input Multiple Output (MIMO) systems.The proposed two element MIMO system resonates at a tri...     

A General Strategy toward Carbon Cloth‐Based Hierarchical Films Constructed by Porous Nanosheets for Superior Photocatalytic Activity

Herein, the controlled synthesis of 3D hierarchical films on carbon cloth (CC) in a high yield through a hydrothermal process and their high photocatalytic properties are reported. As representative examples, the obtained ZnIn₂S₄/CdIn₂S₄ composites are composed of porous nanosheets. During the hydrothermal process, l ‐cysteine plays an important dual role as a coordinating agent and sulfur source, which is in favor of adjusting stoichiometry of the final product and forming the nanoporous structure. This facile method can be extended to synthesize other sulfides and oxides on CC substrates, such as CoIn₂S₄, MnIn₂S₄, FeIn₂S₄, SnS₂, and Bi₂WO₆. When evaluated the photocatalytic activity, the optimized ZnIn₂S₄/CdIn₂S₄(20%)‐CC with an easily recycling feature shows higher photocatalytic degradation activity for methylene blue (MB) than ZnIn₂S₄‐CC, CdIn₂S₄‐CC, and ZnIn₂S₄/CdIn₂S₄(20%) powder. More importantly, ZnIn₂S₄/CdIn₂S₄(20%)‐CC also exhibits superior H₂ production activity. The enhanced photocatalytic activity is attributed to the unique porous sheet‐like structure and the formation of heterojunction. Our results could provide a promising way to develop high‐performance photocatalytic films, which makes it possible to be used in real devices.     

Silver nanoparticle incorporated poly(l‐lactide‐co‐glycolide) nanofibers: Evaluation of their biocompatibility and antibacterial properties

The objective of this work is the fabrication of poly(l ‐lactide‐co‐glycolide) or PLGA (with LA/GA ratios of 50/50 and 75/25) nanofibers containing silver nanoparticles (AgNPs) by the method of electrospinning. The incorporation of AgNPs in PLGA was carried out in three different concentrations (1, 3, 6 w/w %).The electrospun nanofibers were evaluated for their morphology by scanning electron microscopy and their fiber diameters ranged between 487 and 781 nm. Integration of AgNPs within the fibers was verified by spectroscopy studies, while the mechanical properties of the developed fibers were found comparable to the mechanical properties of the human skin. Proliferation of human dermal fibroblasts (HDF) demonstrated minimal cytotoxicity on fibers containing 1 wt % and 3 wt % of AgNPs, while 6 wt % of AgNPs inhibited cell proliferation. Antimicrobial activity was studied using three different strains of Gram‐positive and Gram‐negative bacteria. Results of the HDF proliferation and antimicrobial studies showed that the electrospun PLGA75/25 containing 3 wt % AgNP can function as a suitable substrate for wound dressing, compared to the other scaffolds of this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42686.     

Process optimisation of<Emphasis Type="Italic"> Gulab jamun</Emphasis>, an Indian traditional sweet,using sugar substitutes

Models capable of predicting the product quality of Gulab jamun using sugar and a sugar substitute have been developed using response surface methodology (RSM) and applied to determine the optimum processing conditions. Box–Behnken design was used considering three independent variables, namely concentration (°B) of syrup, its temperature and time of soaking, each at three different levels. The dependent variable or response measured for each treatment was a sensory score for overall quality, which is taken as a combination of the sensory impact of colour, appearance, texture, mouthfeel, taste and aroma. According to RSM, the optimum score for overall quality attained for Gulab jamun prepared with sugar was 7.7, obtained at processing conditions of 51°B syrup, 54 °C and 4 h soaking, whereas for the Gulab jamun prepared with the sugar substitute, sorbitol, a maximum overall quality score of 8.0 was obtained at processing conditions of 54°B syrup, 65 °C and 3 h soaking. These processing conditions were found to correlate with those of experimental conditions.     

Smart Vitamin Micelles as Cancer Nanomedicines for Enhanced Intracellular Delivery of Doxorubicin

Chemotherapy is one of the most effective treatments for cancer. However, intracellular delivery of many anticancer drugs is hindered by their hydrophobicity and low molecular weight. Here, we describe highly biocompatible and biodegradable amphiphilic vitamin conjugates comprising hydrophobic vitamin E and hydrophilic vitamin B labeled with dual pH and glutathione-responsive degradable linkages. Vitamin-based micelles (vitamicelles), formed by self-assembly in aqueous solutions, were optimized based on their stability after encapsulation of doxorubicin (DOX). The resulting vitamicelles have great potential as vehicles for anticancer drugs because they show excellent biocompatibility (>94% after 48 h of incubation) and rapid biodegradability (>90% after 2.5 h). Compared with free DOX, DOX-loaded vitamicelles showed a markedly enhanced anticancer effect as they released the drug rapidly and inhibited drug efflux out of cells efficiently. By exploiting these advantages, this study not only provides a promising strategy for circumventing existing challenges regarding the delivery of anticancer drugs but also extends the utility of current DOX-induced chemotherapy.     

Surface Engineering Strategies to Enhance the In Situ Performance of Medical Devices Including Atomic Scale Engineering

Decades of intense scientific research investigations clearly suggest that only a subset of a large number of metals, ceramics, polymers, composites, and nanomaterials are suitable as biomaterials for a growing number of biomedical devices and biomedical uses. However, biomaterials are prone to microbial infection due to Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), hepatitis, tuberculosis, human immunodeficiency virus (HIV), and many more. Hence, a range of surface engineering strategies are devised in order to achieve desired biocompatibility and antimicrobial performance in situ. Surface engineering strategies are a group of techniques that alter or modify the surface properties of the material in order to obtain a product with desired functionalities. There are two categories of surface engineering methods: conventional surface engineering methods (such as coating, bioactive coating, plasma spray coating, hydrothermal, lithography, shot peening, and electrophoretic deposition) and emerging surface engineering methods (laser treatment, robot laser treatment, electrospinning, electrospray, additive manufacturing, and radio frequency magnetron sputtering technique). Atomic-scale engineering, such as chemical vapor deposition, atomic layer etching, plasma immersion ion deposition, and atomic layer deposition, is a subsection of emerging technology that has demonstrated improved control and flexibility at finer length scales than compared to the conventional methods. With the advancements in technologies and the demand for even better control of biomaterial surfaces, research efforts in recent years are aimed at the atomic scale and molecular scale while incorporating functional agents in order to elicit optimal in situ performance. The functional agents include synthetic materials (monolithic ZnO, quaternary ammonium salts, silver nano-clusters, titanium dioxide, and graphene) and natural materials (chitosan, totarol, botanical extracts, and nisin). This review highlights the various strategies of surface engineering of biomaterial including their functional mechanism, applications, and shortcomings. Additionally, this review article emphasizes atomic scale engineering of biomaterials for fabricating antimicrobial biomaterials and explores their challenges.