Shakeel Ahmed Ansari

Potential applications of enzymes immobilized on/in nano materials: A review

Several new types of carriers and technologies have been implemented in the recent past to improve traditional enzyme immobilization which aimed to enhance enzyme loading, activity and stability to decrease the enzyme biocatalyst cost in industrial biotechnology. These include cross-linked enzyme aggregates, microwave-assisted immobilization, click chemistry technology, mesoporous supports and most recently nanoparticle-based immobilization of enzymes. The union of the specific physical, chemical, optical and electrical properties of nanoparticles with the specific recognition or catalytic properties of biomolecules has led to their appearance in myriad novel biotechnological applications. They have been applied time and again for immobilization of industrially important enzymes with improved characteristics. The high surface-to-volume ratio offered by nanoparticles resulted in the concentration of the immobilized entity being considerably higher than that afforded by experimental protocols based on immobilization on planar 2-D surfaces. Enzymes immobilized on nanoparticles showed a broader working pH and temperature range and higher thermal stability than the native enzymes. Compared with the conventional immobilization methods, nanoparticle based immobilization served three important features; (i) nano-enzyme particles are easy to synthesize in high solid content without using surfactants and toxic reagents, (ii) homogeneous and well defined core-shell nanoparticles with a thick enzyme shell can be obtained, and (iii) particle size can be conveniently tailored within utility limits. In addition, with the growing attention paid to cascade enzymatic reaction and in vitro synthetic biology, it is possible that co-immobilization of multi-enzymes could be achieved on these nanoparticles.

Immobilization of Aspergillus oryzae β galactosidase on zinc oxide nanoparticles via simple adsorption mechanism.

The present study demonstrates the immobilization of Aspergillus oryzae β galactosidase on native zinc oxide (ZnO) and zinc oxide nanoparticles (ZnO-NP) by simple adsorption mechanism. The binding of enzyme on ZnO-NP was confirmed by Fourier transform-infrared spectroscopy and atomic force microscopy. Native ZnO and ZnO-NP showed 60% and 85% immobilization yield, respectively. Soluble and immobilized enzyme preparations exhibited similar pH-optima at pH 4.5. ZnO-NP bound β galactosidase retained 73% activity at pH 7.0 while soluble and ZnO adsorbed enzyme lost 68% and 53% activity under similar experimental conditions, respectively. There was a marked broadening in temperature-activity profile for ZnO-NP adsorbed β galactosidase; it showed no difference in temperature-optima between 50°C and 60°C. Moreover, ZnO-NP adsorbed β galactosidase retained 53% activity after 1h incubation with 5% galactose while the native ZnO- and soluble β galactosidase exhibited 35% and 28% activity under similar exposure, respectively. Native ZnO and ZnO-NP adsorbed β galactosidase retained 61% and 75% of the initial activity after seventh repeated use, respectively. It was noticed that 54%, 63% and 71% milk lactose was hydrolyzed by soluble, ZnO adsorbed and ZnO-NP adsorbed β galactosidase in batch process after 9h while whey lactose was hydrolyzed to 61%, 68% and 81% under similar experimental conditions, respectively. In view of its easy production, improved stability against various denaturants and excellent reusability, ZnO-NP bound β galactosidase may find its applications in constructing enzyme-based analytical devices for clinical, environmental and food technology.

Designing and surface modification of zinc oxide nanoparticles for biomedical applications.

The present study aimed to work out a simple and high yield procedure for the immobilization of β galactosidase on bioaffinity support, concanavalin A (Con A) layered zinc oxide nanoparticles (ZnO-NP). Thermogravimetric analysis of bioaffinity support revealed 4% loss in weight at 600°C whereas its thermal decomposition was observed at 530°C by differential thermal analysis. No significant change was noticed in the band intensity of pUC19 plasmid after its treatment with Con A layered ZnO-NP. Comet assay further exhibited negligible change in tail length of comet after treating the lymphocytes by bioaffinity matrix. The bioaffinity matrix binds 89% of the enzyme activity. Atomic force microscopy analysis showed that the prepared matrix has an advantageous microenvironment and large surface area for binding significant amount of the enzyme. The functional groups present in native and parent compound were monitored by Fourier transform-infrared spectroscopy. Michaelis constant, K(m) was 2.38 and 5.88 mM for free and immobilized β galactosidase, respectively. V(max) for the soluble and immobilized enzyme was 0.520 mM/min and 0.460 mM/min, respectively. Concanavalin A layered ZnO-NP bound β galactosidase exhibited a shift in the temperature-optima and retained nearly 86% activity even after its 6th repeated use.

Immobilization of Aspergillus oryzae β galactosidase on concanavalin A-layered calcium alginate-cellulose beads and its application in lactose hydrolysis in continuous spiral bed reactors

Immobilization of Aspergillus oryzae β galactosidase on concanavalin A-layered calcium alginate-cellulose beads and its application in lactose hydrolysis in continuous spiral bed reactors In this study, Aspergillus oryzae β galactosidase was immobilized on concanavalin A layered calcium alginate-cellulose beads as a bioaffinity support. Immobilized enzyme showed a remarkable broadening in temperature-activity profiles as compared to the native enzyme and exhibited 65% activity in the presence of 5% galactose. Michaelis constant (Km) was 2.57 mM and 5.38 mM for the free and the immobilized β galactosidase, respectively. Crosslinked β galactosidase showed greater catalytic activity in the presence of Mg2+ and was more stable during storage at 4°C for 6 weeks. Immobilized enzyme hydrolyzed 67% lactose in milk in 8 h and 85% lactose in whey in 9 h in the stirred batch process at 50°C. The continuous hydrolysis of lactose by crosslinked β galactosidase in spiral bed reactor exhibited 93% and 88% hydrolysis of lactose at flow rate of 20 ml/h and 30 ml/h, after 1 month operation, respectively.

Current opinion in Alzheimerʼs disease therapy by nanotechnology-based approaches

Purpose of review Nanotechnology typically deals with the measuring and modeling of matter at nanometer scale by incorporating the fields of engineering and technology. The most prominent feature of these engineered materials involves their manipulation/modification for imparting new functional properties. The current review covers the most recent findings of Alzheimers disease (AD) therapeutics based on nanoscience and technology. Recent findings Current studies involve the application of nanotechnology in developing novel diagnostic and therapeutic tools for neurological disorders. Nanotechnology-based approaches can be exploited for limiting/reversing these diseases for promoting functional regeneration of damaged neurons. These strategies offer neuroprotection by facilitating the delivery of drugs and small molecules more effectively across the blood–brain barrier. Summary Nanotechnology based approaches show promise in improving AD therapeutics. Further replication work on synthesis and surface modification of nanoparticles, longer-term clinical trials, and attempts to increase their impact in treating AD are required.

Antibacterial activity of iron oxide nanoparticles synthesized by co-precipitation technology against Bacillus cereus and Klebsiella pneumoniae

Abstract The present study investigates the synthesis and characterization of iron oxide nanoparticles (Fe3O4-NPs) for their antibacterial potential against Bacillus cereus and Klebsiella pneumonia by modified disc diffusion and broth agar dilution methods. DLS and XRD results revealed the average size of synthesized Fe3O4-NPs as 24 nm while XPS measurement exhibited the spin-orbit peak of Fe 2p3/2 binding energy at 511 eV. Fe3O4-NPs inhibited the growth of K. pneumoniae and B. cereus in both liquid and soild agar media, and displayed 26 mm and 22 mm zone of inhibitions, respectively. MIC of Fe3O4-NPs was found to be 5 μg/mL against these strains. However, MBC for these strains was observed at 40 μg/mL concentration of Fe3O4-NPs for exhibiting 40–50% loss in viable bacterial cells and 80 μg/mL concentration of Fe3O4-NPs acted as bactericidal for causing 90–99% loss in viability. Hence, these nanoparticles can be explored for their additional antimicrobial and biomedical applications.

Investigating the antibacterial potential of agarose nanoparticles synthesized by nanoprecipitation technology

Abstract Herein, an effort was made to investigate the antibacterial potential of agarose nanoparticles (ANPs) and poly(quaternary ammonium) modified ANPs (mANPs) against Escherichia coli (gram-negative bacterium) and Staphylococcus aureus (gram positive bacterium) in liquid systems as well as on agar plates. ANPs were synthesized by nanoprecipitation technology and characterized by XRD, TEM, TGA, DTA and DLS. The particle size estimated was 30 nm while atomic force microscopy was used to observe the interaction of ligand on ANPs. Antimicrobial characterization was monitored by colony forming units (CFU) as a function of ANPs concentration on agar plates. It was observed that ANPs showed 15 × 109/ml CFU after 24 hours of incubation at 20 mM ANPs concentration while the modified ANPs exhibited 21 × 109/ml CFU under similar incubation conditions. Moreover, zone of inhibition (ZOI) was 2.9 and 3.8 cm, respectively for E. coli by ANPs at 0.2 and 0.4 mM, respectively while it was 3.2 and 3.8 cm respectively by modified ANPs under similar conditions. Similarly, ZOI for S. aureus by ANPs at 0.2 and 0.4 mM was observed at 3.1 and 4.0 cm, respectively, while these values were 3.5 and 4.1 cm, respectively for modified ANPs under similar incubation conditions.

UTILITY OF FUNCTIONALIZED AGAROSE NANOPARTICLES IN HYDROLYZING LACTOSE IN BATCH REACTORS FOR DAIRY INDUSTRIES

Shakeel Ahmed Ansaria,*, Syed Ismail Ahmadb, Mohammad Alam Jafria, Muhammad Imran Naseera and Rukhsana Satarc Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah-21589, Kingdom of Saudi Arabia Physics Division, Department of Basic Sciences, Ibn Sina National College for Medical Studies, Jeddah-21418, Kingdom of Saudi Arabia Department of Biochemistry, Ibn Sina National College for Medical Sciences, Jeddah-21418, Kingdom of Saudi Arabia