Immobilization of α-amylase on GO-magnetite nanoparticles for the production of high maltose containing syrup.

Robust amylases with stability and catalysis at multitude of extremities are the need of an hour. Enzyme immobilization may prove beneficial at commercial scale to achieve such attributes. In the present study, a commercially available amylase was immobilized on graphene oxide (GO) - magnetite (Fe3O4) nanoparticles through covalent bonding. The structural and morphological characterizations were conducted by XRD, SEM and TEM. Further, FTIR and TGA confirmed the interaction between amylase, GO and nanoparticles. The variables, such as concentrations of GO (1.3 mg), Fe3O4 (58 µg), and amylase (4.5 mg) were optimized by the response surface methodology using central composite design. High loading capacity of 77.58 µg amylase over 1 µg GO-magnetite nanoparticles was achieved under optimum conditions. Biochemically, the pH optimum remained unaltered, i.e., pH 7, whereas, the alkalitolerance was increased by ~20% in relative activities upon immobilization. The half-life of soluble amylase was 13 h, which enhanced to 20 h upon immobilization in 20 mM phosphate buffer, pH 7 at 50 °C. Besides, the thermodynamic parameters supported the stability trends. The immobilized amylase could be used for 11 subsequent cycles. The mentioned attributes and the dextrose equivalent values during the production of high maltose containing syrup highlighted its commercialization.

Enhancement in recovery of drugs with high protein binding efficiency from human plasma using magnetic nanoparticles.

In this paper, we propose an alternate method for bioanalytical extraction of drugs from human plasma samples using bare magnetic nanoparticles. The magnetic nanoparticles (MNPs) were used for deproteination of biological samples that further assist in extraction of plasma bound drugs for bioanalytical studies. The method uses basic solvents (ethanol, methanol, etc.) rather than the expensive and toxic solvents. The MNPs provide several advantages like avoiding the use of centrifuge machine, and making extraction time effective. The average time involved for the sample preparation is around 30-40min. The developed method was examined for seven different drugs having moderate (40-70%) to high (>80%) plasma protein binding efficiency. The present study focuses on the principle of magnetic nanoparticle based extraction of drug that binds with the plasma protein. In calcitriol (protein binding efficiency >99%), it was observed that the drug extraction efficiency could be enhanced by 16% using the present method. However, we assume that still there is a scope for improving the extraction efficiency by optimizing proper solvent for the specific drug. The use of magnetic nanoparticles makes the extraction cost effective and quick with improved efficiency.

Experimental evidence of zero forward scattering by magnetic spheres.

Magnetically induced diffraction patterns by micron sized magnetic spheres dispersed in a ferrofluid disappear at a certain critical magnetic field. This critical field is found to depend on the concentration of the ferrofluid and on the volume of the magnetic spheres. We attribute this effect to the zero forward scattering by magnetic spheres as predicted by Kerker, Wang, and Giles [J. Opt. Soc. Am. 73, 765 (1983)]. We suggest that such a dispersion can be used to study the optical analogues of localization of electrons in condensed matter, the Hall effect, and the anisotropic diffusion, etc. The combination of the micron sized magnetic spheres and the ferrofluid will also be useful to design magnetically tunable photonic devices.