Nanostructured SnO 2 encapsulated guar-gum hybrid nanocomposites for electrocatalytic determination of hydrazine

Electro-optical behaviour of CuFe2 O4 @rGO nanocomposite for nonenzymatic detection of uric acid via the electrochemical method

Uric acid (UA) is a blood and urine component obtained as a metabolic by-product of purine nucleotides. Abnormalities in UA metabolism cause crystal deposition as monosodium urate and lead to various diseases such as gout, hyperuricemia, Lesch-Nyhan syndrome, etc. Monitoring these diseases requires a rapid, sensitive, selective, and portable detection approach. Therefore, this study demonstrates the hydrothermal synthesis of CuFe2 O4 /reduced graphene oxide (rGO) nanocomposite for selective detection of UA. After the nanocomposite synthesis, characterization was performed by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, UV-visible spectrometry, atomic force spectroscopy, scanning electron microscopy, and electrochemical analysis. Furthermore, from the electrochemical analysis using cyclic voltammetry (CV), kinetic studies were carried out by varying the scan rate to obtain the diffusion coefficient, surface concentration, and rate of charge transfer to achieve a calibration curve that indicates the quasi reversible nature of the fabricated electrode with a linear regression coefficient of oxidation (R2 : 0.9992) and reduction (R2 : 0.9971) peaks. Moreover, the fabricated nonenzymatic amperometric sensor to detect UA with a linearity (R2 : 0.9989) of 1-400 μM was highly sensitive (2.75 × 10-4  mAμM-1  cm-2 ) and had a lower limit of detection (0.01231 μM) at pH 7.5 in phosphate-buffered saline solution. Therefore, the CuFe2 O4 /rGO/ITO-based nonenzymatic sensor could detect interfering agents and spiked real bovine serum samples with higher sensitivity and selectivity for UA detection.

Seed gum-based delivery systems and their application in encapsulation of bioactive molecules

Now-a-days, the food/pharma realm faces with great challenges for the application of bioactive molecules when applying them in free form due to their instability in vitro/in vivo. For promoting the biological and functional properties of bioactive molecules, efficient delivery systems have played a pivotal role offering a controlled delivery and improved bioavailability/solubility of bioactives. Among different carbohydrate-based delivery systems, seed gum-based vehicles (SGVs) have shown great promise, facilitating the delivery of a high concentration of bioactive at the site of action, a controlled payload release, and less bioactive loss. SGVs are potent structures to promote the bioavailability, beneficial properties, and in vitro/in vivo stability of bioactive components. Here, we offer a comprehensive overview of seed gum-based nano- and microdevices as delivery systems for bioactive molecules. We have a focus on structural/functional attributes and health-promoting benefits of seed gums, but also strategies involving modification of these biopolymers are included. Diverse SGVs (nano/microparticles, functional films, hydrogels/nanogels, particles for Pickering nanoemulsions, multilayer carriers, emulsions, and complexes/conjugates) are reviewed and important parameters for bioactive delivery are highlighted (e.g. bioactive-loading capacity, control of bioactive release, (bio)stability, and so on). Future challenges for these biopolymer-based carriers have also been discussed. HighlightsSeed gum-based polymers are promising materials to design different bioactive delivery systems.Seed gum-based delivery systems are particles, fibers, complexes, conjugates, hydrogels, etc.Seed gum-based vehicles are potent structures to promote the bioavailability, beneficial properties, and in vitro/in vivo stability of bioactive components.

Preparation, antibacterial activity, and electrocatalytic detection of hydrazine based on biogenic CuFeO2/PANI nanocomposites synthesized using Aloe barbadensis miller

This study reports the synthesis of B-CuFeO2 nanocomposites (NCs) and B-CuFeO2/PANI NCs from Aloe vera gel extract and their utility for label-free detection of hydrazine and their antibacterial efficiency.

Guar (Cyamopsis tetragonoloba L.) plant gum: From biological applications to advanced nanomedicine

Natural polymers are an efficient class of eco-friendly and biodegradable polymers, because they are readily available, come from natural sources, inexpensive and can be chemically modified with the correct reagents. Guar gum (GG) is a natural polymer with great potential to be used in pharmaceutical formulations due to its unique composition and lack of toxicity. GG can be designed to suit the needs of the biological and medical engineering sectors. In the development of innovative drug delivery systems, GG is commonly utilized as a rate-controlling excipient. In this review, different properties of GG including chemical composition, extraction methods and its usefulness in diabetes, cholesterol lowering, weight control, tablet formulations as well as its food application were discussed. The other purpose of this study is to evaluate potential use of GG and its derivatives for advanced nanomedicine such as drug delivery, tissue engineering and nanosensing. It should be noted that some applicable patents in medical area have also been included in the rest of this survey to extend knowledge about guar gum and its polymeric nature.

Photocatalysis, photoinduced enhanced anti-bacterial functions and development of a selective m-tolyl hydrazine sensor based on mixed Ag·NiMn2O4 nanomaterials

In this work, a tri-metal based nanocomposite was synthesized and characterized. A detailed investigation of the photocatalytic dye degradation efficiency of the nanocomposite under visible light showed promising results in a wide pH range, both acidic and basic medium. Studies on anti-bacterial activity against seven pathogenic bacteria, including both Gram positive and Gram negative species, were conducted in the presence and absence of light and compared with the standard antibiotic gentamicin. The minimum inhibitory concentration (MIC) values of Ag·NiMn2O4 against multidrug-resistant (MDR) pathogens ranged from 0.008 to 0.65 μg μL-1, while the minimum bactericidal concentration (MBC) was found to be 0.0016 μg μL-1. The nanomaterial, Ag·NiMn2O4 was deposited onto the surface of a glassy carbon electrode (GCE; 0.0316 cm2) as a thin film to fabricate the chemical sensor probe. The proposed sensor showed linear current (vs. concentration) response to m-THyd (m-tolyl hydrazine) from 1.0 pM to 0.01 mM, which is denoted as the linear dynamic range (LDR). The estimated sensitivity and detection limit of the m-THyd sensor were found to be 47.275 μA μM-1 cm-2 and 0.97 ± 0.05 pM, respectively. As a potential sensor, it is reliable due to its good reproducibility, rapid response, higher sensitivity, working stability for long duration and efficiency in the analysis of real environmental samples.

Chemistry, Structures, and Advanced Applications of Nanocomposites from Biorenewable Resources

Researchers have recently focused on the advancement of new materials from biorenewable and sustainable sources because of great concerns about the environment, waste accumulation and destruction, and the inevitable depletion of fossil resources. Biorenewable materials have been extensively used as a matrix or reinforcement in many applications. In the development of innovative methods and materials, composites offer important advantages because of their excellent properties such as ease of fabrication, higher mechanical properties, high thermal stability, and many more. Especially, nanocomposites (obtained by using biorenewable sources) have significant advantages when compared to conventional composites. Nanocomposites have been utilized in many applications including food, biomedical, electroanalysis, energy storage, wastewater treatment, automotive, etc. This comprehensive review provides chemistry, structures, advanced applications, and recent developments about nanocomposites obtained from biorenewable sources.

Amperometric determination of hydrazine using a CuS-ordered mesoporous carbon electrode

An electrocatalytic sensor for hydrazine using copper sulfide-ordered mesoporous carbon (CuS-OMC) is described. A facile solvothermal synthetic strategy was adopted for CuS-OMC and the ordered mesoporous carbon was obtained through nanocasting method. The synthesized CuS-OMC was characterized using microscopic and spectrochemical techniques. CuS-OMC was immobilized on GCE and evaluated for its electrochemical sensing of hydrazine using cyclic voltammetry and amperometry. CuS-OMC modified GCE exhibited better hydrazine sensing at an optimized pH 7.4 in terms of oxidation potential and current compared with that of GCE, CuS, and OMC. The observed sensing performance of CuS-OMC was attributed to the presence of Cu (I/II) in CuS dispersed in OMC which acts as an electrocatalytic center for the sensing of hydrazine. Amperometry under optimized experimental condition with an applied potential of 270 mV was employed to obtain a linear calibration plot in the range 0.25 to 40 μM (R² = 0.9908) with a detection limit of 0.10 μM with a sensitivity of 0.915 (± 0.02) μA cm^-2 μM^-1. Real sample analyses were carried out by spiking of hydrazine in different water samples and the recoveries were in the range of 97 ± 2.1% (n = 3). Graphical abstract.

Guar gum and its composites as potential materials for diverse applications: A review

Naturally occurring polymers are currently of prime importance among which polysaccharides occupies superior position due to their easy availability, eco- friendly and non-toxic nature. Guar gum, one of the naturally occurring polymer, is a galactomannan acquired by ground endosperm of Cyamopsis tetragonolobus or Cyamopsis psoraloides. It belongs to the family leguminosae. Presence of large number of hydroxyl groups increases its H- bonding ability when dissolved in water that enhance the viscosity and gelling properties of the guar gum solution. Based upon these properties, guar gum is used in several industries such as textile, food, petrochemical, mining and paper for varied applications. It is used as suspending, emulsifying, gelling and stabilising agent in the conventional dosage forms. Last few decades have marked the increase in development of various composites of guar gum that have intrinsic utilization in various fields. Immobilization of guar gum with the others not only enhances its properties but also enriches its utilization in numerous fields for diverse applications such as water purification, drug delivery, pharmaceutical, cosmetic and food industries, etc. Guar gum derivatives are found to have therapeutic importance in certain physiological disorders also. In this review article, we have summarized various possible composites of guar gum and their most probable applications in different fields.

Electrochemical Detection of Hydrazine Using Poly(dopamine)-Modified Electrodes

We have developed a simple and selective method for the electrochemical detection of hydrazine (HZ) using poly(dopamine) (pDA)-modified indium tin oxide (ITO) electrodes. Modification with pDA was easily achieved by submerging the ITO electrode in a DA solution for 30 min. The electrocatalytic oxidation of HZ on the pDA-modified ITO electrode was measured by cyclic voltammetry. In buffer solution, the concentration range for linear HZ detection was 100 µM–10 mM, and the detection limit was 1 µM. The proposed method was finally used to determine HZ in tap water to simulate the analysis of real samples. This method showed good recovery (94%–115%) and was not affected by the other species present in the tap water samples.

Ultrasensitive and selective hydrazine sensor development based on Sn/ZnO nanoparticles

Fabrication of highly sensitive (∼5.0108 μA cm⁻² μM⁻¹) and selective hydrazine chemical sensor based on wet-chemically prepared Sn/ZnO nanoparticles deposited glassy carbon electrodes with a detection limit as low as 18.95 ± 0.02 pM (at an S/N of 3).

Investigation of bioactivity, biocompatibility and thermal behavior of sol-gel silica glass containing a high PEG percentage

SiO2/PEG organic-inorganic hybrid materials, which contain 60 or 70 weight percentage of PEG, were synthesized by the sol-gel technique. The materials were characterized and subjected to various tests to assess their application in the biomedical field. The evaluation of their morphology by scanning electron microscopy (SEM) confirms the homogeneity of the samples on the nanometer scale. Fourier transform infrared spectroscopy (FT-IR) indicated that the two components of the hybrids (SiO2 and PEG) are linked by hydrogen bonds. This feature makes them class I hybrids. Simultaneous thermogravimetry/differential thermal analysis (TG/DTA) was used to investigate their thermal behavior and to establish the best temperatures for their pre-treatment. The fundamental properties that a material must have to be used in the biomedical field are biocompatibility and bioactivity. The formation of a hydroxyapatite layer was observed on the hybrid surface by SEM/EDX and FTIR after soaking in simulated body fluid. This indicates that the materials are able to bond to bone tissue. Moreover, the biocompatibility of SiO2/PEG hybrids was assessed by performing WST-8 cytotoxicity tests on fibroblast cell NIH 3T3 after 24h of exposure. The cytotoxicity tests highlight that the cell viability is affected by the polymer percentage. The results showed that the synthesized materials were bioactive and biocompatible. Therefore, the results obtained are encouraging for the use of the obtained hybrids in dental or orthopedic applications.