International Journal of Nano Dimension
Volume:10 Issue: 1, Winter 2019

A biosensor can sense biological elements after interaction with the recognition element. The signal produced due to interaction of the analyte with its biochemical element is transduced by a transducer and detected by appropriate modes. The miniaturization of these biosensors at the nano level using nanostructures as a platform for sensing the analyte or its detection is called a nanobiosensor. Several biological elements can be detected like nucleic acids, enzymes, antibodies, microorganisms, toxins, cells etc. with high specificity. This mini review focuses on the different types of nanobiosensors based on the type of analyte and the type of transducer used for detection. The different types of fluorescence based design of biosensors are also discussed along with the metal enhanced fluorescence based nanobiosensors. The application of biosensors towards the diagnosis of various diseases, targeted drug delivery and imaging is also discussed.

The review article summarizes the applications of silver nanoparticles for diverse sectors. Over the decades, nanoparticles used as dignified metals such as silver exhibited distinctive characteristics basically correlated to chemical, physical and biological property of counterparts having bulkiness. Numerous studies reported that Nanoparticles of about 100nm diameter play a crucial role in widely spread industries due to unique properties including the dimension of small particle, high surface area and quantum confinement and they dispersed without agglomeration. Decade of discoveries clearly established that shape, size and distribution of Silver nanoparticles strongly affect the electromagnetic, optical and catalytic properties, which are often an assortment of changeable synthetic methods and reducing agents with stabilizers. Generation after generation the postulates come forth about properties of silver for the ancient Greeks cook from silver pots and the old adage ‘born with a silver spoon in his mouth’ thus show that eating with a silver spoon was well-known as uncontaminated. Impregnation of metals with silver nanoparticles is a practical way to exploit the microbe aggressive properties of silver at very low cost. The nanoparticles help in targeted delivery of drugs, enhancing bioavailability, sustaining drug or gene effect in target tissues, and enhancing the stability. Implementations of silver partials in medical science and biological science have been noticed from years ago; however alteration with nanotechnology is innovative potential. Over 23% of all nanotechnology based products, diagnostic and therapeutic applications implanted with silver nanoparticles (e.g. In arthritic disease and wound healing, etc.) and widely known for their antifungal, antibacterial, antiviral effect, employed in textile fabrics and added into cosmetic products as antiseptic to overcome skin problems. Thus, Silver nanoparticles (AgNPs) have been urbanized as an advanced artifact in the field of nanotechnology.

Characterization and the antibacterial potential of gold (AuNPs) and silver nanoparticle (SNPs) biosynthesized greenly using exopolysaccharides (EPS) and Culture Free Supernatant (CFS) of Wesiella confusa against some multidrug resistance (MDR) E. coli was investigated. The biosynthesized nanoparticles were characterized by UV-visible spectra, Fourier Transformed Infrared Spectroscopy and Scanning Electron Microscopy. The formation of AuNPs and SNPs were confirmed by changes in colour: Colour change from yellow to wine red and yellow to bluish purple, that indicate the formation of AuNPs from the EPS and CFS and colour change from colourless to brown that indicate the formation of SNPs from the EPS and CFS. Surface Plasmon Resonance (SRP) peaks were observed at 400nm. The particles were aggregate with size ranged from 0.5 – 2.6 µm and 0.08 - 1.00 µm for WCEPSAuNPs and WCCFSAuNPs and 0.2 -3.0 µm and 0.2 - 2.8 µm for WCEPSSNPs and WCCFSSNPs. The AuNPs and SNPs had antibacterial activity against the tested pathogens. The SNPs exhibited a broad spectrum of activity against the MDR E. coli strains tested pathogens. In conclusion EPS and CFS of Wesiella confusa were able to bio-reduced and bio-oxidized silver and gold for the biosynthesis of SNPs and AuNPs. The SNPs had broad spectra of activity against E. coli strains compared to the AuNPs.

Thickness stretching effect based on shear and normal deformation theory is used in this paper for magneto-electro-elastic vibration analysis of a three-layered curved nanobeam including a nano core and two piezo-magnetic layers. Size-dependency is included in derivation of governing equations of motion based Eringen's nonlocal elasticity theory. The initial curvature is accounted in calculation of external works due to pre-mechanical, electrical and magnetic loads. The analytical method is presented to study the effect of significant parameters on the vibration characteristics. The numerical results are presented in terms of initial electro-magneto-mechanical loads, size-dependency parameter, opening angle, two parameters of Pasternak's foundation and core thickness to face-sheet thickness ratio.

In this study, the reaction of 3-Picrylamino-1, 2, 4-Triazole (PATO) with B12N12 was investigated by density functional theory in the B3LYP/6-31G(d) level of theory. There were two possible isomers for reaction of PATO with B12N12 via carbon and nitrogen atoms of triazole ring to the Born atom of B12N12 (I and II-isomers). Thermodynamic parameters of these reactions including formation Enthalpy changes (ΔHf), Gibbs free energy alterations (ΔGf) and Heat capacity (Cv) were calculated in the temperature range of 300-400K. Variations of density and dipole moment values of PATO after interaction were studied. Also, the frontier orbital energies, HOMO-LUMO gap, chemical hardness (η), electrophilicity index (ω), charge transferred (∆Nmax) and chemical potential (μ) were computed.

In this paper, a novel catalyst (MgAl2O4@SiO2-PTA) was proposed for the green oxidation of aliphatic alcohols. The resultant composite was characterized by different techniques, such as X-ray diffraction (XRD), SEM, FT-IR, EDX and Brunauer-Emmett-Teller (BET) surface area analysis. The prepared nanocomposite was used as a catalyst for oxidation of aliphatic alcohols with hydrogen peroxide in water at 90 . Aliphatic alcohols were converted to aldehydes and ketones. Primary alcohols were converted to aldehydes but secondary alcohols were converted to ketones. Cyclohexanol is very active in this catalyst system but no product was detected in cyclohexanol oxidation without catalyst. It is noteworthy to highlight that the catalyst is environmentally friendly since it could be recovered by a simple filtration. The catalyst was reused for at least four successive times without any changes or loss of its high catalytic activity.

The main objective of this paper was to manipulate the Nano Fibrous Scaffold "NFS" surface roughness to achieve a new transdermal drug release profile. To assess the intrinsic mechanical properties of Nylon 6 or polycaprolactam, such as its proper resiliency, it was considered as the matrix. Cetirizine was used as a drug model and was loaded (1% w/v) to polymer solution (30%w/v) before spinning. Two polymeric meshes with different orifices in size and geometry were used to induce roughness on the surface of two collecting NFS during the electrospinning process. They were placed in line of conventional electrospinning, here after called “Mesh Electrospinning” and hereby, two roughened NFS were fabricated: Pentagonal templated nanofibrous scaffold (PeTNFS) and tetragonal nanofibrous scaffold (TeTNFS) beside ordinary NFS (ONFS). The kinetic of drug release was compared with known models and the release of cetirizine from these new drug delivery systems was done by UV–VIS spectroscopy and its in-vitro release profile was measured using Franz cell diffusion system. Release profiles from NFS were compared with a commercially available drug delivery system. To assess the simulation of NFS effect on the skin, NFS was placed on layer of dialysis film, and after three hours, the morphology was investigated using SEM. PeTNFS sample showed the greatest trend of drug release and it was about 20% more than un-roughened NFS. The best fit for drug release kinetic of NFS and TeTNFS samples were Higuchi model but it obeyed first order model for PeTNFS sample. The obtained NFS showed high potential for transdermal drug release.

Spinel MgAl2O4 nanopowders were synthesized by one-step solid state reactions using Al(NO3)3.9H2O and MgSO4 raw materials at stoichiometric 1 : 2, Mg : Al molar ratio at a constant reaction temperature of 1000 ºC for 8 h (S1), 10 h (S2) and 24 h (S3). The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. Structural analyses were performed by FullProf program making use of profile matching with constant scale factors. The results showed that the patterns had a cubic MgAl2O4 structure similar to the space group . Through textural analysis BJH (Barrette Joiner Halenda) and BET (Brunauer Emmett Teller) methods, the obtained materials were evaluated in terms of average pore size, specific surface area and average pore volume .The morphology of the obtained materials was studied by FESEM images. Ultraviolet–visible (UV-Vis) spectra showed that the nanostructured MgAl2O4 powders possessed strong light absorption properties in the ultraviolet-visible region. Direct optical band gap energies were calculated as 3.4, 2.9 and 3.1 eV for S1, S2 and S3, respectively. The photocatalytic performance of the synthesized nanomaterials was investigated for the degradation of pollutant Malachite Green (MG) in aqueous solutions under solar light. Optimum conditions (0.2 mL H2O2, 25 mg catalyst and 40 min catalytic reaction time for the removal of 80 mL of 100 ppm MG solution) were modeled and achieved by the design expert software for S1. The degradation yield in the condition was 100 % for S1.

In this research, geometrical structures of armchair single walled boron nitride nanotube (SWBNNT) and armchair single walled aluminum nitride nanotube (SWAlNNT) were optimized by Density Functional Theory (DFT) in the gas phase, both having the same length of 5 angstrom and n=9, m=9. B3LYP/6-31G* level of theory have been used to determine and compare electronic properties, natural charge and chemical shielding tensors of nanotubes. The chemical shielding tensors were calculated using GIAO method to obtain structural information and dynamic behavior for optimal boron nitride and aluminum nitride nanotube structures. Also, thermodynamic functions for the boron nitride nanotube (9, 9-5) and the aluminum nitride nanotube (9, 9-5) in the gas phase were carried out with using the B3LYP method and 6-31g* basis set. It is significant that all of NMR parameters and geometrical properties of both nanotubes were determined in 5 layers.

In this article a low power and low latency 4-2 compressor has been presented. By using modified truth table and Pass Transistor Logic (PTL) a novel structure has been proposed which outperforms previous designs from the frequency of operation view point. The proposed design method has reduced the total transistor count considerably which will lead to reduced power consumption and smaller active area in the final realized circuit. Comparison with previous works depicts that the proposed structure has the lowest number of transistor among them. The proposed design has been designed and simulated in Carbon Nanotube Field-Effect Transistor (CNTFET) technology having 32nm channel dimension. The comparison with the best reported recent designs demonstrates the superiority of the proposed work; these reported designs in literature were simulated here in the same settings and process to perform a fair comparison. In addition, the Complementary Metal-Oxide-Semiconductor (CMOS) 32nm standard process has also been employed to realize the proposed circuit and to do the comparison between CMOS and CNTFET technologies which illustrates the advantage of CNTFET over standard CMOS processes. The transistor level delay for the critical path of the proposed design is equal to 4 transistors which is equal to the best reported work in the literature; however in the proposed work here the total number of transistors is reduced to 58 which according to the authors knowledge is the lowest numb reported for a 4-2 compressor block in the papers.