Varun Saxena

Edible oil nanoemulsion: An organic nanoantibiotic as a potential biomolecule delivery vehicle

ABSTRACT Water-insoluble bioactive compounds typically require the formulation of lipophilic, antimicrobial delivery system to enhance their bio accessibility. Edible delivery system, in this contrast, plays an important role in food and medical industry. In the present study, an attempt has been made to increase the bioavailability of a model bioactive compound α-tocopherol as a food supplement through edible (coconut) oil nanoemulsion. A 9.5u2009mgu2009mL−1 of encapsulation capacity was obtained with almost 100% release of the loaded α-tocopherol within 24u2009h. The nanoemulsions were analyzed for various physical and chemical stability parameters, namely, solvent, ionic concentration, temperature, rotatory motion, and various gastrointestinal pH zones. The prepared nanoemulsions were found stable to these parameters. The synthesized nanoemulsions were also evaluated for their biocompatibility and antimicrobial activity. The result showed reasonable cell viability (biocompatibility) with apposite antimicrobial activity confirming the synthesized nanoemulsion as a potential delivery vehicle. Experimental release data were fitted by combining a diffusion-controlled (Higuchi model) and a kinetic-controlled (first-order kinetics) models. The contribution of kinetic-controlled release was found about 70% and that of diffusion-controlled release was found about 30%. The present study reveals plausible application of edible oil nanoemulsion in food, beverages, and health care industries. GRAPHICAL ABSTRACT

Nano-biocomposite scaffolds of chitosan, carboxymethyl cellulose and silver nanoparticle modified cellulose nanowhiskers for bone tissue engineering applications

In the present work, we aimed to synthesize highly efficient nano-composite polymeric scaffolds with controllable pore size and mechanical strength. We prepared nanocomposite (CCNWs-AgNPs) of silver nanoparticles (AgNPs) decorated on carboxylated CNWs (CCNWs) which serves dual functions of providing mechanical strength and antimicrobial activity. Scaffolds containing chitosan (CS) and carboxymethyl cellulose (CMC) with varying percent of nanocomposite were fabricated using freeze drying method. XRD and FESEM analysis of nanocomposite revealed highly crystalline structure with AgNPs (5.2u202fnmu202fdia) decorated on ~200u202fnm long CCNWs surface. FTIR analysis confirmed the interaction between CCNWs and AgNPs. Incorporation of nanocomposite during scaffolds preparation helped in achieving the desirable 80-90% porosity with pore diameter ranging between 150 and 500u202fμm and mechanical strength was also significantly improved matching with the mechanical strength of cancellous bone. The swelling capacity of scaffolds decreased after the incorporation of nanocomposite. In turn, scaffold degradation rate was tuned to support angiogenesis and vascularization. Scaffolds apart from exhibiting excellent antimicrobial activity, also supported MG63 cells adhesion and proliferation. Incorporation of CCNWs also resulted in improved biomineralization for bone growth. Overall, these studies confirmed excellent properties of fabricated scaffolds, making them self-sustained and potential antimicrobial scaffolds (without any loaded drug) to overcome bone related infections like osteomyelitis.

3D printing for cardiovascular tissue engineering: a review

Abstract Although the current medical treatments have been successful in reducing the coronary heart disease related mortality rate, however there still exist various challenges in cardiac tissue engineering due to the hierarchical property of native myocardium and branched structure of blood vessels. The regeneration of progenitor cells, replacement infarcted cardiac tissues and the tissue-engineered constructs are the demand of the current era. In this contrast, 3D printing of scaffold for cardiac tissue engineering plays a crucial role. 3D printing techniques are used to generate patient-specific foundation that mimics the milieu of biological tissue. Various studies are under investigation to regenerate the cardiac tissues. Lack of regeneration capacity is a major hunt in cardiac tissue engineering. This review will provide an overview of 3D bioprinting techniques for cardiovascular tissue engineering. First, it summarises the background about bioprinting (working principles) followed by various bioink materials for cardiac tissue engineering. Recent approaches for the 3D printing of cardiac scaffolds for the regeneration of cardiac tissues are discussed.

Surface Functionalization of Ti6Al4V via Self-assembled Monolayers for Improved Protein Adsorption and Fibroblast Adhesion

Although metallic biomaterials find numerous biomedical applications, their inherent low bioactivity and poor osteointegration had been a great challenge for decades. Surface modification via silanization can serve as an attractive method for improving the aforementioned properties of such substrates. However, its effect on protein adsorption/conformation and subsequent cell adhesion and spreading has rarely been investigated. This work reports the in-depth study of the effect of Ti6Al4V surface functionalization on protein adsorption and cell behavior. We prepared self-assembled monolayers (SAMs) of five different surfaces (amine, octyl, mixed [1:1 ratio of amine:octyl], hybrid, and COOH). Synthesized surfaces were characterized by Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy, contact angle goniometry, profilometry, and field emission scanning electron microscopy (FESEM). Quantification of adsorbed mass of bovine serum albumin (BSA) and fibronectin (FN) was determined on different surfaces along with secondary structure analysis. The adsorbed amount of BSA was found to increase with an increase in surface hydrophobicity with the maximum adsorption on the octyl surface while the reverse trend was detected for FN adsorption, having the maximum adsorbed mass on the COOH surface. The α-helix content of adsorbed BSA increased on amine and COOH surfaces while it decreased for other surfaces. Whereas increasing β-turn content of the adsorbed FN with the increase in the surface hydrophobicity was observed. In FN, RGD loops are located in the β-turn and consequently the increase in Δ adhered cells (%) was predominantly increased with the increasing Δ β-turn content (%). We found hybrid surfaces to be the most promising surface modifier due to maximum cell adhesion (%) and proliferation, larger nuclei area, and the least cell circularity. Bacterial density increased with the increasing hydrophobicity and was found maximum for the amine surface (θ = 63 ± 1°) which further decreased with the increasing hydrophobicity. Overall, modified surfaces (in particular hybrid surface) showed better protein adsorption and cell adhesion properties as compared to unmodified Ti6Al4V and can be potentially used for tissue engineering applications.

Recent advances in conventional and contemporary methods for remediation of heavy metal-contaminated soils

Remediation of heavy metal-contaminated soils has been drawing our attention toward it for quite some time now and a need for developing new methods toward reclamation has come up as the need of the hour. Conventional methods of heavy metal-contaminated soil remediation have been in use for decades and have shown great results, but they have their own setbacks. The chemical and physical techniques when used singularly generally generate by-products (toxic sludge or pollutants) and are not cost-effective, while the biological process is very slow and time-consuming. Hence to overcome them, an amalgamation of two or more techniques is being used. In view of the facts, new methods of biosorption, nanoremediation as well as microbial fuel cell techniques have been developed, which utilize the metabolic activities of microorganisms for bioremediation purpose. These are cost-effective and efficient methods of remediation, which are now becoming an integral part of all environmental and bioresource technology. In this contribution, we have highlighted various augmentations in physical, chemical, and biological methods for the remediation of heavy metal-contaminated soils, weighing up their pros and cons. Further, we have discussed the amalgamation of the above techniques such as physiochemical and physiobiological methods with recent literature for the removal of heavy metals from the contaminated soils. These combinations have showed synergetic effects with a many fold increase in removal efficiency of heavy metals along with economic feasibility.

Effect of Zn/ZnO integration with hydroxyapatite: a review

Abstract Hydroxyapatite (HAp) is one of the most studied ceramic for various biomedical applications such as bone tissue engineering, biologicals delivery systems and bioactive coatings. It owns extensive biocompatibility. However, lower mechanical properties for load bearing applications, lower antimicrobial activity and lower biological interaction rates are the major lags for biomedical applications of HAp. Various researchers have tried to integrate HAp with various metals and metal ions to overcome these holdups. In this review, we have described the crystal structure of both HAp and zinc oxide (ZnO) and have majorly focused on the zinc and ZnO integration with HAp. Zn/ZnO offer several physical and biological properties. We have evaluated the effect of zinc integration over physical state and mechanical properties of HAp with latest research examples. We have appraised the additional biological properties provided by the incorporation zinc into the HAp through recent examples of researchers with varying degree of successes.

Synthesis, characterization and in vitro analysis of α-Fe2O3-GdFeO3 biphasic materials as therapeutic agent for magnetic hyperthermia applications

The use of gadolinium orthoferrite for biomedical application like as contrast agents for magnetic resonance imaging (MRI) has been found to be very promising due to its fascinating properties. The present study focuses on the determination of the effect of the gadolinium concentration in the formation biphasic α-Fe2O3-GdFeO3 for hyperthermia applications. An in-situ sol-gel technique was adopted for the synthesis of biphasic orthoferrites with four different gadolinium concentrations. The XRD analysis confirmed the formation of gadolinium orthoferrites after heat treatment at 1000u202f°C, 1100u202f°C, and 1200u202f°C. The presence of α-Fe2O3 in trace amounts was observed in the materials with low gadolinium concentrations. VSM (Vibrating-sample magnetometer) analysis was performed to ensure the magnetic properties of the materials, which were found to be weakly ferromagnetic. The biocompatibility of the materials was investigated through MTT assay and no cytotoxic effect was observed. The assessment of heating ability of the materials was performed under an alternating magnetic field using an induction heating instrument and all the samples showed temperature rise in the range of hyperthermia temperature with a maximum temperature of 55.71u202f°C in 6u202fmin. The heating experiments at 44u202f°C in the absence of samples established the vulnerability of cancer cells as compared to normal cells.

Design and characterization of novel Al-doped ZnO nanoassembly as an effective nanoantibiotic

Nanoantibiotics are the new class of antibacterial agents that can be an alternative to the conventional antibiotics, which are expensive and require lengthy synthesis procedures. In view of such importance of nanoantibiotics, in the present study, we have systematically designed Al doped ZnO (AZO) via a co-precipitation method. ZnO nanoparticles own decent bactericidal activity against clinically isolated bacterial species, however, its bactericidal concentrations are compromised. To enhance the antibacterial efficiency of ZnO, different concentrations of Al was doped into ZnO lattice to design AZO nanorods, which were characterized using XRD, RAMAN, FESEM, DSC/TGA and Zetasizer. The XRD data confirmed a hexagonal wurtzite structure of AZO, while the bimetallic composition of the AZO was evaluated by RAMAN spectra and EDX. The average diameters of AZO nanorods were less than 100xa0nm. The zeta potential of ZnO was enhanced from 6.17u2009±u20090.5 to 22.7u2009±u20090.3xa0mV at 15% doping of Al. The biomedical value and commercial applicability of AZO nanorods were evaluated in terms of its biocompatibility using L929 mouse fibroblast and the antibacterial activity against Escherichia coli and Enterococcus hirae. The antibacterial activity was found to be significantly enhanced to ~u200919 times with MIC values of 14.33u2009±u20090.20 and 14.68u2009±u20090.20xa0µg/ml for AZO (15% doping) as compared to 254.88u2009±u20093.0 and 338.14u2009±u20099.0xa0µg/ml for ZnO against E. coli and E. hirae, respectively. The antibacterial mechanism was found to be electrostatic interaction between bacterial cell and AZO, followed by the intracellular accumulation of the Zn2+ ions. The release of Zn2+ ions from AZO was found to be kinetic controlled (diffusion limited). The synthesized nanorods showed excellent biocompatibility with more than 95u2009±u20093% of cell viability up to 6 days even at higher concentrations, indicating its promise for in vivo analysis. Hence, this study designates AZO as a plausible nanoantibiotic and unlocks its access for various other biomedical applications.