Anuj Kumar

Effect of crosslinking functionality on microstructure, mechanical properties, and in vitro cytocompatibility of cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds

Cellulose nanocrystals reinforced poly (vinyl alcohol)/sodium alginate hybrid scaffolds were fabricated by using freeze casting and freeze drying method. In this study, the effect of crosslinking agents such as calcium chloride, orthophosphoric acid, and borax on morphological, structural, thermal, mechanical, and cytocompatibility (cell adhesion and proliferation) properties was investigated. The results showed that the change in type of crosslinking agent significantly changed the properties of the hybrid scaffolds. Based on this study, borax-crosslinked hybrid scaffold showed good fibrous porous structure with high porosity (95.2%), highest water uptake capacity, good thermal stability, mechanical stability (storage modulus), and in vitro cell adhesion and proliferation with fibroblast (NIH3T3) cells. This primarily research study explores the way for further use of this crosslinking agent to design and fabricate scaffolds for tissue engineering applications.

Polysaccharide based bionanocomposite hydrogels reinforced with cellulose nanocrystals: Drug release and biocompatibility analyses

Cellulose nanocrystals (CNCs) reinforced, bionanocomposite (BNC) has shown great potential in tissue engineering and drug delivery applications due to the low toxicity, low density, and high aspect ratio. In this work, BNC hydrogels reinforced with CNCs were fabricated from xanthan (XG) solutions and chitosan (CS) in presence of green acidifying agent through electrostatic and hydrogen bonding interactions. As developed BNC hydrogels were characterized for complex formation, morphology, and mechanical behavior. The mechanical performance of BNC hydrogels was improved significantly as increased CNC content (from 2 to 10wt%). 5-Flurouracil as model chemotherapeutic agent was loaded into these BNC hydrogels for evaluating their drug release properties. The BNC hydrogels showed excellent cytocompatability and ability to release of chemotherapeutic agent that shows the suitability to be used in tissue engineering as well as drug delivery applications.

Application of xanthan gum as polysaccharide in tissue engineering: A review

Xanthan gum is a microbial high molecular weight exo-polysaccharide produced by Xanthomonas bacteria (a Gram-negative bacteria genus that exhibits several different species) and it has widely been used as an additive in various industrial and biomedical applications such as food and food packaging, cosmetics, water-based paints, toiletries, petroleum, oil-recovery, construction and building materials, and drug delivery. Recently, it has shown great potential in issue engineering applications and a variety of modification methods have been employed to modify xanthan gum as polysaccharide for this purpose. However, xanthan gum-based biomaterials need further modification for several targeted applications due to some disadvantages (e.g., processing and mechanical performance of xanthan gum), where modified xanthan gum will be well suited for tissue engineering products. In this review, the current scenario of the use of xanthan gum for various tissue engineering applications, including its origin, structure, properties, modification, and processing for the preparation of the hydrogels and/or the scaffolds is precisely reviewed.

pH and near-infrared active; chitosan-coated halloysite nanotubes loaded with curcumin-Au hybrid nanoparticles for cancer drug delivery

In this work, we propose biofriendly in-situ preparation method of Au NPs (hexagonal and rod-shape structures) in the lumen as well as the surface cage of biocompatible halloysite nanotubes (HNTs) using curcumin (CUR) as anticancer drug and subsequently coating with bio-adhesive chitosan (CS) as a polysaccharide. The formation of Au NPs and their interactions with CUR and CS exist in the HNTs has been characterized by FTIR, XRD, XPS, STEM techniques. Interestingly, Au NPs showed longitudinal plasmon resonance bands at 760 and 980 nm that indicate the near-infrared (NIR) responsive property of hybrid nanoparticles. Rod shape and hexagonal structures of Au NPs were produced as confirmed by TEM images. The loading efficiency of CUR was found as much as 12%. Importantly, more CUR release was achieved under acidic conditions (pH 5.5) than basic conditions (pH 7.4). The anticancer potential of HNT hybrid nanoparticles on MCF-7 cancer cells was studied and showed efficient anticancer activity under intracellular tumor cell environment (pH 5.5) than extracellular conditions (pH 7.4). Moreover, the developed HNT hybrid nanoparticles consisting of Au NPs (NIR responsive property) and pH-responsive CUR release could make it suitable for cancer cell-targeted drug delivery platform with NIR-imaging.

A novel use of cellulose based filter paper containing silver nanoparticles for its potential application as wound dressing agent

The frequent use of antibiotics against microbial infections may lead to the emergence of antibiotic resistant microbial strains. To overcome these microbial strains, we need to fabricate alternative materials which can handle them. It is for this reason, we have fabricated cellulose (CE) based filter paper (FP) composite scaffolds comprising of adsorbed chitosan (CS) and sliver (Ag) nanoparticles (NPs). The AgNPs are incorporated in the CS layer of the composite scaffold. Prior to evaluate the efficacy of the scaffolds against gram positive and gram negative bacterial strains, the scaffolds were characterized for the presence of the Ag NPs with field emission scanning electron microscope (FE-SEM), fourier transform infrared (FTIR) spectroscopy and x-ray diffractometer (XRD). These techniques confirmed the presence of Ag NPs in the composite scaffold. The biocompatibility of the scaffolds was assessed by subjecting pristine FP, CS adsorbed FP (CS-FP) and Ag loaded CS-FP (Ag-CS-FP) composite scaffolds to in vitro studies. From the data obtained, it was observed that NIH3T3 fibroblastic cells adhered and proliferated onto all the scaffolds. Furthermore, the scaffolds exhibited good antibacterial activity against both strains of bacteria. It is, therefore, concluded that these scaffolds could find potential application in biomedical field, particularly as a wound dressing agent.

Fabrication and Characterization of Multicomponent Polysaccharide/Nanohydroxyapatite Composite Scaffolds

ABSTRACT Carrageenan–hyaluronic acid/nanohydroxyapatite/microcrystalline cellulose composite scaffolds with various amounts of microcrystalline cellulose content (from 0 to 60 wt%) were prepared using freeze-drying method. The results showed highly porous (from 94.0 ± 1.09 to 85.0 ± 1.05%) composite scaffolds with high water-uptake capacity, average pore size ranging 200–650 µm, and improved mechanical properties (in dry and wet states). Additionally, cytocompatibility of composite scaffolds was evaluated by in vitro culture of osteoblast (MC3T3-E1) cells for 1 and 3 days of incubation and demonstrated good cell adhesion, infiltration, and proliferation. Thus, as-obtained composite scaffolds may have promising application in low-loading bone tissue engineering applications. GRAPHICAL ABSTRACT

Photo-mediated Biosynthesis of Silver Nanoparticles Using the Non-edible Accrescent Fruiting Calyx of Physalis peruviana L. Fruits and Investigation of its Radical Scavenging Potential and Cytotoxicity Activities

Silver nanoparticles (AgNPs) have been synthesized by various ways but the green technology methods using food waste materials has been accepted now a days for their cost effectiveness, environmental friendly and effective biomedical application. In the present study an attempt has been made to synthesize AgNPs by using the outer accrescent fruiting calyx of Physalis peruviana fruits, a food waste material under different light source condition, and to investigate their cytotoxic activity against the HepG2 cells as well as their antibacterial and radical scavenging potential. The surface morphology and elemental composition of the biosynthesized AgNPs were evaluated by scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray powder diffraction analysis. Fourier transform infrared spectroscopy of the sample extract and AgNPs was performed to determine the involvement of functional groups in the synthesis, capping, and stabilization process. The AgNPs showed promising cytotoxic activity against the HepG2 cells in a dose-dependent manner. The biosynthesized AgNPs also exhibited moderate antibacterial activity (8.14-10.22 mm inhibition zones) against two Gram-negative pathogenic bacteria with promising radical scavenging potential. Overall, the results highlight the effectiveness of the AgNPs for use in antibacterial wound dressing materials and other biomedical applications for the treatment of critical diseases such as cancer.

Mechanically viscoelastic nanoreinforced hybrid hydrogels composed of polyacrylamide, sodium carboxymethylcellulose, graphene oxide, and cellulose nanocrystals

Polyacrylamide-sodium carboxymethylcellulose (PMC) hybrid hydrogels reinforced with graphene oxide (GO) and/or cellulose nanocrystals (CNCs) were prepared via in situ free-radical polymerization. In this work, GO nanosheets were freshly synthesized by modified Hummers method alongwith the aqueous suspension of CNCs by acid-hydrolysis. In addition, the effect of GO content (1.5 wt%) and CNCs (from 2.5 wt% to 10.0 wt%) was investigated in these quaternary hydrogels. The results showed good pseudo-plastic behavior, self-healing ability, mechanical performance, and shape-recovery behavior of the hybrid hydrogels reinforced with GO and CNCs content. PMC-GO1.5/CNCs10.0 hybrid hydrogel showed 110.5 kPa as compressive strength and stiffness value of 887.7 N/m (at 30% strain). Moreover, the synergistic effect of both GO and CNCs as nanoreinforcements in hydrogels provides a new point of view for the preparation of hybrid hydrogels having exceptional structural and mechanical properties. As-obtained hybrid hydrogels may have potential application in tissue engineering for tunable mechanical properties.

The Multi Regulatory Role of Signal Transducer and Activator of Transcription Factor Brn-3a

In molecular biology and genetics, the transcription factor is a protein that binds to specific DNA sequences, thereby controlling the rate of transcription of genetic information from DNA to messenger RNA. Brn-3a is a POU-domain transcription factor that involve in the neurite outgrowth, induction of synaptic proteins, activation of the neurofilaments genes promoter, neuronal development, protects neuronal cells from apoptosis and plays a vital role in regulating different kinds of cancers. Brn-3a is an antiapoptotic transcription factor and the up-regulation of Brn-3a protects neuronal cells from undergoing apoptosis. Brn-3a specifically triggers the expression of Bcl-2 and Bcl- XL gene in neuronal cells. On the other hand, Brn-3a inhibits the pro-apoptotic factor like Bax. Brn-3a not only expresses in the neuronal cells but also its activity is detected in the cancer cells of non-neuronal nature. Brn-3a also modulates the activity of various others transcription factors, enzymes, receptors, ion channels, antiapoptotic proteins, adhesion molecules and cyclins. In this Review, we describe all the above factors in detail which are regulated by Brn-3a signaling in the neurology and the possible mechanisms underlying the many different functions of the Brn-3a complexes in neurological diseases. It also highlights the potential of Brn-3a as a novel target in heart development and cancer therapy.