Ultra-Sensitive Immuno-Sensing Platform Based on Gold-Coated Interdigitated Electrodes for the Detection of Parathion

Pesticides are unavoidable in agriculture to protect crops from pests and insects. Organophosphates (OPs) are a class of pesticides that are more harmful because of the irreversible inhibition reaction with acetylcholinesterase enzyme, thereby posing serious health hazards in human beings. In the present work, a sensitive and selective immuno-sensing platform is developed using gold inter-digitized electrodes (Au-IDEs) as substrates, integrated with a microfluidic platform having the microfluidic well capacity of 10 µL. Au-IDE having digit width of 10 µm and gap length of 5 µm was used in this study. The surface morphological analysis by field-effect scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) revealed the direct information regarding the modification of Au-IDEs with anti-parathion (Anti-PT) antibodies. In SEM analysis, it was seen that the Au-IDE surface was smooth in contrast to the Anti-PT modified surface, which is supported by the AFM studies showing the surface roughness of ~2.02 nm for Au-IDE surface and ~15.86 nm for Anti-PT modified surface. Further, Fourier transform infra-red (FTIR) spectroscopic analysis confirms the immobilization of Anti-PT by the bond vibrations upon the successive modification of Au-IDE with –OH groups, amine groups after modifying with APTES, and the amide bond formation after incubation in Anti-PT antibody. Electrochemical impedance spectroscopy (EIS) was carried out for the electrochemical characterization and for testing the sensing performances of the fabricated electrode. The developed immuno-sensor provided a linear range of detection from 0.5 pg/L–1 µg/L, with a limit of detection (LoD) of 0.66 ng/L and sensitivity of 4.1 MΩ/ngL−1/cm2. The sensor response was also examined with real samples (pomegranate juice) with good accuracy, exhibiting a shelf life of 25 days. The miniaturized sensing platform, along with its better sensing performance, has huge potential to be integrated into portable electronics, leading to suitable field applications of pesticide screening devices

INFLUENCE OF FORMULATION PARAMETERS ON DISSOLUTION RATE ENHANCEMENT OF ACYCLOVIR USING LIQUISOLID FORMULATION

Objective: The objective of this research work is to explore the use of liquisolid technique in enhancement of acyclovir dissolution rate. This current study was planned to assess the impact of different formulation variables, such as non-volatile liquid type and concentrations of acyclovir on its dissolution rates profile. Method: Acyclovir liquisolid tablets were prepared with Tween 60 (liquid vehicle), Microcrystalline cellulose PH 102 (acted as a carrier to turn liquid medication into free-flowing powder) and Syloid XDP (coating material). In vitro, drug dissolution rate of liquisolid formulations of acyclovir was performed and compared with pure acyclovir drug using USP dissolution apparatus (Type II) for 60 min at a paddle speed of 50 rpm and filled with 900 mL of distilled water. Results: The dissolution study showed that 94.1% of the drug was released in 60 min of ratio 10 while only 66% of the pure drug acyclovir was released in 60 min. Hence, present work concluded that the acyclovir dissolution rate profile has been improved with the formation of liquisolid formulations. Conclusion: From the present study, it may be ratified that the drug dissolution rate of acyclovir has been improved with the utilization of liquisolid formulations approach.Â

Magnetic properties of microwave-plasma (thermal) chemical vapour deposited Co-filled (Fe-filled) multiwall carbon nanotubes: comparative study for magnetic device applications

'Co-filled' and 'Fe-filled' multiwall carbon nanotubes (MWCNTs) were grown using microwave-plasma chemical vapour deposition (MPCVD) and thermal chemical vapour deposition (TCVD) methods respectively, and their structural and magnetic properties were studied for magnetic device applications. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show the average tube length approximate to 80-500 mu with outer (inner) diameter approximate to 20-50 (approximate to 10-20) nm for MWCNTs prepared by both methods. The diffraction peaks of both x-ray diffraction patterns show the interlayer distance, d(002) approximate to 3.36 , which is comparable to the graphite structure (d(002) = 3.35 ). The graphitic crystallite sizes (L-a) of MPCVD (TCVD) synthesized MWCNTs are approximate to 24.78 nm (approximate to 22.13 nm) as obtained from the intensity ratio of (I-D/I-G) D-peak, the disordered structure of graphite and G-peak, the C-C bond in graphitic structure of Raman spectra. The magnetization of 'Fe-filled' TCVD grown MWCNTs is much higher than 'Co-filled' MPCVD grown MWCNTs due to the formation of higher content of Fe-C and/or Fe-oxides in the MWCNT structures. The higher magnetic coercivity approximate to 2900 Oe and formation of isolated single-domain Fenanoparticles in 'Fe-filled' TCVD grown MWCNTs, as found from SEM / TEM micrographs, makes the ferromagnetic MWCNTs a promising material for the high-density magnetic recording media

Synthesis, properties and applications of titania nanostructures

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Development of MoSe2 Nano-Urchins as a Sensing Platform for a Selective Bio-Capturing of Escherichia coli Shiga Toxin DNA

The present study was aimed to develop “fluorine doped” tin oxide glass electrode with a MoSe2 nano-urchin based electrochemical biosensor for detection of Escherichia coli Shiga toxin DNA. The study comprises two conductive electrodes, and the working electrodes were drop deposited using MoSe2 nano-urchin, and DNA sequences specific to Shiga toxin Escherichia coli. Morphological characterizations were performed using Fourier transforms infrared spectrophotometer; X-ray diffraction technique and scanning electron microscopy. All measurements were done using methylene blue as an electrochemical indicator. The proposed electrochemical geno-sensor showed good linear detection range of 1 fM–100 µM with a low detection limit of 1 fM where the current response increased linearly with Escherichia coli Shiga toxin dsDNA concentration with R2 = 0.99. Additionally, the real sample was spiked with the dsDNA that shows insignificant interference. The results revealed that the developed sensing platform significantly improved the sensitivity and can provide a promising platform for effective detection of biomolecules using minute samples due to its stability and sensitivity

Microbial exopolysaccharide composites with inorganic materials and their biomedical applications: A review

Microbial exopolysaccharides (EPS) are high molecular weight carbohydrate-based materials produced and secreted in response to external environmental stress to protect microbial cells. These molecules also contain non-carbohydrate moieties including acetate, pyruvate, phosphate, and succinate along with sugar molecules. EPS has been incorporated into industrial operations as a gelling, emulsifying, and stabilizing agent to increase viscosity. Besides, these molecules have also shown high biocompatibility, immunomodulatory, antitumor, anti-microbial, and anti-viral activity which suggest their possible applications in healthcare. However, these molecules are facing some commercial shortcomings due to low stability, bioactivity, and poor mechanical and tensile strength in comparison to the required standard. Hence use of composites of EPS with other polymers and moieties has been suggested for higher performance. Especially in the context of inorganic moieties like silver, gold nanomaterials, clay, salts, and minerals will add bioactivity and functional sites for the attachment of drug molecules and other compounds. The current review summarizes the higher physical and chemical characteristics of EPS composites with inorganic materials and their immense potential in the biomedical sector