Samina Akbar

Facile Production of Ordered 3D Platinum Nanowire Networks with “Single Diamond” Bicontinuous Cubic Morphology

Direct electrochemical templating is carried out using a thin layer of a self-assembled diamond phase (QIID) of phytantriol to create a platinum film with a novel nanostructure. Small-angle X-ray scattering shows that the nanostructured platinum films are asymmetrically templated and exhibit “single diamond” morphology with Fd3m symmetry.

Electrochemical determination of folic acid: A short review

Folic acid (FA) is an electroactive compound of biological origin. It helps our body to produce and maintain healthy cells. It can significantly reduce the occurrence of neural tube defects and also prevents change in DNA structure. FA deficiency can lead to various health risks. Therefore, a sensitive, specific, and reproducible way of FA detection is essential. A number of analytical methods are in practice for the quantification of FA. However, electroanalytical methods are attracting much attention because of their advantage over conventional methods, as they are fast, simple, sensitive, and cost effective. Moreover, modification of electrodes offers control over size and morphology which allows miniaturization for applicability in portable electrochemical devices.

Phytantriol based smart nano-carriers for drug delivery applications

ABSTRACT From the last couple of decades, lyotropic liquid crystals have garnered enormous attentions in medical and pharmaceutical sciences. Non‐toxic, chemically stable, and biocompatible properties of these liquid crystal systems are contributing to their applications for drug delivery. Among a large variety of liquid crystal phases, inverse bicontinuous cubic and inverse hexagonal mesophases have been extensively investigated for their ability to encapsulate and controlled release of bioactive molecules of various sizes and polarity. The concept of changing the drug release rate in situ by simply changing the mesophase structure is much more fascinating. The encapsulation of bioactive compounds in mesophase systems of desirable features in sub‐micron sized particles such as hexosomes and cubosomes, at ambient and high temperature is bringing innovation in the development of new drug applications. This review article outlines unique structural features of cubosomes and hexosomes, their methods of productions, factors affecting their formations and their potential utilization as smart nano‐carriers for biopharmaceuticals in drug delivery applications. Graphical abstract Model representation of inverse hexagonal (HII) and inverse bicontinuous cubic (QIID) liquid crystalline phases. Figure. No Caption available.

Experimental evidence for proposed transformation pathway from the inverse hexagonal to inverse diamond cubic phase from oriented lipid samples

A macroscopically oriented inverse hexagonal phase (HII) of the lipid phytantriol in water is converted to an oriented inverse double diamond bicontinuous cubic phase (QII(D)). The initial HII phase is uniaxially oriented about the long axis of a capillary with the cylinders parallel to the capillary axis. The HII phase is converted by cooling to a QII(D) phase which is also highly oriented, where the cylindrical axis of the former phase has been converted to a ⟨110⟩ axis in the latter, as demonstrated by small-angle X-ray scattering. This epitaxial relationship allows us to discriminate between two competing proposed geometric pathways to convert HII to QII(D). Our findings also suggest a new route to highly oriented cubic phase coatings, with applications as nanomaterial templates.

Synthesis and characterization of pure and nanosized hydroxyapatite bioceramics

Abstract Synthetic nanosized hydroxyapatite (HA) particles (<120 nm) were prepared using a co-precipitation technique by adopting two different routes – one from an aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate at pH 10 and the other by using calcium hydroxide and phosphoric acid as precursors at pH 8.5 and reaction temperature of 50°C. The lattice parameters of HA nanopowder were analogous to reference [Joint Committee on Powdered Diffraction Standards (JCPDS)] pattern no. 09-432. No decomposition of HA into other phases was observed even after heating at 1000°C in air for 1 h. This observation revealed the high-temperature stability of the HA nanopowder obtained using co-precipitation route. The effects of preliminary Ca/P molar ratio, precipitation, pH and temperature on the evolution of phase and crystallinity of the nanopowder were systematically examined and optimized. The product was evaluated by techniques such as X-ray-diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and Raman spectroscopy analyses. The chemical structural analysis of the as-prepared HA sample was performed using X-ray photoelectron spectroscopy (XPS). After heat treatment at 1000°C for 1 h and ageing for 15 h, the product was obtained as a phase-pure, highly crystalline HA nanorods.

Platinum as an electrocatalyst: effect of morphological aspects of Pt/Pt-based materials

ABSTRACT Platinum and platinum-based materials with high catalytic performance, and chemical and mechanical stability are vital to electronic devices, biomedical science, optics, petroleum, and automotive industries. Because of the limited supply and high cost of platinum, it is highly desirable to develop new effective methodologies which can decrease the platinum loading by increasing its electrocatalytic properties. Depending upon their size, shape, and morphology, platinum materials have shown significant improvement in the surface catalysed chemical transformation pathways in fuel cell technology. Much research is now focused on the manufacturing and engineering of platinum and platinum-based materials which proffer enhanced catalytic efficiency, and offer chemical and mechanical robustness.

Ultrathin Uniform Platinum Nanowires via a Facile Route Using an Inverse Hexagonal Surfactant Phase Template

We present an attractive method for the fabrication of long, straight, highly crystalline, ultrathin platinum nanowires. The fabrication is simply achieved using an inverse hexagonal (HII) lyotropic liquid crystal phase of the commercial surfactant phytantriol as a template. A platinum precursor dissolved within the cylindrical aqueous channels of the liquid crystal phase is chemically reduced by galvanic displacement using stainless steel. We demonstrate the production of nanowires using the HII phase in the phytantriol/water system which we obtain either by heating to 55 °C or at room temperature by the addition of a hydrophobic liquid, 9- cis-tricosene, to relieve packing frustration. The two sets of conditions produced high aspect nanowires with diameters of 2.5 and 1.7 nm, respectively, at least hundreds of nanometers in length, matching the size of the aqueous channels in which they grow. This versatile approach can be extended to produce highly uniform nanowires from a range of metals.