Biomedical Perspective of Electrochemical Nanobiosensor

Electrochemical biosensor holds great promise in the biomedical area due to its enhanced specificity, sensitivity, label-free nature and cost effectiveness for rapid point-of-care detection of diseases at bedside. In this review, we are focusing on the working principle of electrochemical biosensor and how it can be employed in detecting biomarkers of fatal diseases like cancer, AIDS, hepatitis and cardiovascular diseases. Recent advances in the development of implantable biosensors and exploration of nanomaterials in fabrication of electrodes with increasing the sensitivity of biosensor for quick and easy detection of biomolecules have been elucidated in detail. Electrochemical-based detection of heavy metal ions which cause harmful effect on human health has been discussed. Key challenges associated with the electrochemical sensor and its future perspectives are also addressed.

Structural,optical and antimicrobial properties of pure and Agdoped ZnO nanostructures

In the present work,zinc oxide(ZnO)and silver(Ag)doped ZnO nanostructures are synthesized using a hydrothermal method.Structural quality of the products is attested using X-ray diffraction,which confirms the hexagonal wurtzite struc-ture of pure ZnO and Ag-doped ZnO nanostructures.XRD further confirms the crystallite orientation along the c-axis,(101)plane.The field emission scanning electron microscope study reveals the change in shape of the synthesized ZnO particles from hexagonal nanoparticles to needle-shaped nanostructures for 3 wt%Ag-doped ZnO.The optical band gaps and lattice strain of nanostructures is increased significantly with the increase of doping concentration of Ag in ZnO nanostructure.The anti-microbial activity of synthesized nanostructures has been evaluated against the gram-positive human pathogenic bacteria,Staphylococcus aureus via an agarose gel diffusion test.The maximum value of zone of inhibition(22 mm)is achieved for 3 wt%Ag-doped ZnO nanostructure and it clearly demonstrates the remarkable antibacterial activity.

Influence of heat treatment on the structural and optical properties of SrGd_2O_4:Eu^(3+) phosphor

Novel red emitting Eu3＋ doped SrGd2O4 phosphors were synthesized by homogeneous precipitation method followed by a subsequent combustion process at various temperatures. A systematic study on the consequent structural evolution and optical properties were investigated as a function of various processing temperatures. With the enhancement of processing temperature, SrGd2O4 phosphor showed a gradual transformation from a mixed phase to monophasic nature, with minimized volatile imptwities. The microscopic images exhibited homogeneous aggregates of varying shapes and sizes with an average length of about 0.5-5μl. Eu3＋ doped SrGd2O4 phosphors prepared at low temperatures, showed miserably low values of red emission upon UV excitation owing to the presence of volatile impurities. The SrGd2O4：Eu3＋ phosphors prepared at relatively high temperature exhibited strong red-orange emissions due to homogeneously occupied Eu3＋ ions in the host lattice. The dominant red to orange （R/O） emission intensity ratios and CIE parameters of EU3＋ ions substantiated the site occupation of higher asymmetry sites of Gd3＋ ions and the strong covalent nature. Dexter theory and critical distance calculation suggested that the dipole-dipole interaction could be responsible for the concentration quenching of Eu3＋ （4 mol.%） doped SrGd2O4 phosphors. Elevated physical and chemical durability and stable photoluminescence made these phosphors suitable for white LEDs and other display applications.

Natural additives as active components in edible films and coatings

The incorporation of natural active components into edible films and coatings adds value to them by modifying the film characteristics in terms of physical,functional as well as bioactive properties.Till date,a wide variety of natural additives(glucosides,polysaccharides,phytosterols,phenolic acids,esters,carotenoids,tannins,alkaloids,anthocyanins,flavonoids,terpenoids,caffeic acid,other organic acids)have been used which are extracted from plants,herbs,spices,seeds,fruits,vegetables etc.The additives developed using active components from natural sources have overcome the adverse effects caused by synthetic additives on human health.These active coatings minimize the surface proliferation of pathogenic microorganisms and prevent food deterioration.The biopolymeric base of edible films/coatings incorporated with the natural active component can be formed of chitosan,hydroxypropyl methylcellulose,sodium benzoate,gelatin,pectin etc.From an economical perspective,the recent trend has also shifted towards the utilization of biowaste and bio residues obtained from the food industry for the extraction of natural active components and their application which will help in meeting the increased demand for healthy foods,well-being,achieving sustainable development goal of zero hunger as well as aid in cutting down the high cost.Thus,more research is required in the exploration,extraction and successful utilization of natural active components in edible films/coatings which will prove to be beneficial for researchers,industrialists and consumers.This review encompasses several aspects related to different types of active components used as natural additives,the interaction of additives with films/coatings,their pharmacological properties,extraction techniques,safety recommendations and applications.