Geometric Transformation of Modified Multiwalled Carbon Nanotubes-Based Heterometallic Nanostructured Material: A Model for the Electrochemical Discrimination of Insecticides.

Multifunctional carbon-based materials exhibit a large number of unprecedented active sites via an electron transfer process and act as a desired platform for exploring high-performance electroactive material. Herein, we exemplify the holistic design of a heterometallic nanostructured material (MWCNTs@KR-6/Mn/Sn/Pb) formed by the integration of metals (Mn2+, Sn2+, and Pb2+) and a dipodal ligand (KR-6) at the surface of multiwalled carbon nanotubes (MWCNTs). First, MWCNTs@KR-6 was readily synthesized via a noncovalent approach, which was further sequentially doped by Mn2+, Sn2+, and Pb2+ to give MWCNTs@KR-6/Mn/Sn/Pb. The designed material showed excellent electrochemical activity for the discrimination of insecticides belonging to structurally different classes. In contrast to that of the individual building components, both the stability and electrochemical activity of heterometallic nanostructured material were remarkably enhanced, resulting in a magnificent electrochemical performance of the developed material. Hence, the current work reports a comprehensive synthetic approach for MWCNTs@KR-6/Mn/Sn/Pb synthesis by synergizing unique properties of the heterometallic complex with MWCNTs. This work also offers a new insight into the design of multifunctional carbon-based materials for discrimination of different analytes on the basis of their redox potential.

A compact and highly collimated atomic/molecular beam source.

We describe the design, characterization, and application of a simple, highly collimated, and compact atomic/molecular beam source. This source is based on a segmented capillary design, constructed using a syringe needle. Angular width measurements and free molecular flow simulations show that the segmented structure effectively suppresses atoms traveling in off-axis directions, resulting in a narrow beam of Helium atoms having a width of 7 mrad (full width half maximum). We demonstrate an application of this source by using it for monitoring real-time changes in surface coverage on a clean Cu(110) surface exposed to oxygen by measuring the specular reflectivity of the Helium beam generated using this source.

Studies on Structural Changes of Modified MWCNTs: Material for Electrochemical Monitoring of Antiviral Drug in Human Serum Samples.

The development of a universal approach for precisely tuning the electrochemical characteristics of conducting carbon nanotubes for tracking harmful agents in the human body with high selectivity and sensitivity remains a challenge. Herein, we describe a simplistic, versatile, and general approach to the construction of functionalized electrochemical material. The design of electrochemical material consists of (i) modification of multiwalled carbon nanotubes (MWCNT) with dipodal naphthyl-based dipodal urea (KR-1) through non-covalent functionalization (KR-1@MWCNT) which enhances the dispersibility of MWCNT and hence conductivity, (ii) complexation of KR-1@MWCNT with Hg2+ accelerate the electron transfer in the material which amplify the detection response of functionalized material (i. e., Hg/KR-1@MWCNT) towards various thymidine analogues. Further, the application of functionalized electrochemical material (Hg/KR-1@MWCNT) achieves real-time electrochemical monitoring of harmful antiviral drug 5-iodo-2'-iododeoxyuridine (IUdR) levels in human serum for the first time.

A high-performance Calix@ZnO based bifunctional nanomaterial for selective detection and degradation of toxic azinphos methyl in environmental samples.

One of the key tenets of sustainable agriculture and food safety is the removal of toxic pesticides from the environment. However, developing reliable, affordable, and efficient methods for detecting and degrading pesticides into non-toxic degradable products remains an immediate matter of concern. Herein, we attempt to develop a strategy for the detection as well as degradation of highly toxic phosphorodithioate pesticide, Azinphos methyl (AZM), using hybrid zinc oxide nanoparticles (ZnO NPs). Considering the non-selectivity of bare ZnO and receptor R1, we have fabricated the heterocalixarene-based Calix (R1) over zinc oxide (ZnO) surface in situ via the sol-gel process. The synthesized heterocaliaxrene-modified ZnO (R1@ZnO) NPs show an excellent affinity for the selective and sensitive detection of AZM with a tremendously low limit of detection (68 mg L-1) and no interference from other pesticides. Degradation of AZM was fully supported by fluorescence spectroscopy, scanning electron microscopy (SEM), 1H NMR titrations, FTIR spectroscopy, cyclic voltammetry, and mass spectroscopy, which unequivocally confirmed the formation of non-toxic products. According to our findings, R1@ZnO NPs are sustainable nanomaterials that can be employed for environmental remediation since they operate in an aqueous medium.

Gold nanoparticles capped DHPMs for meliorate detection of antiretroviral drug: Azidothymidine.

Anti-human immunodeficiency (HIV)-drug azidothymidine interferes with the reverse transcriptase enzyme, which results in reduced activity of HIV thereby inhibiting the growth of the virus. Owing to the side effects of high doses and short half-life of this antiviral drug azidothymidine (AZT): a fast and convenient method for its detection would be helpful for HIV patients getting treated with AZT. Referring to this, we synthesized a Biginelli based receptor R1 and evaluated its sensing properties towards AZT with different techniques (UV-Visible, circular dichroism (CD), cyclic voltammetry (CV) by preparing its organic nanoparticles (ONPs) and gold-coated ONPs (AuNP@ONP). The formation of AuNP@ONP was confirmed by UV-Visible spectroscopy, cyclic voltammetry, and HRTEM. It was observed that both the probes selectively sense AZT among various thymidine analogs but AuNP@ONP showed better response on CV, Differential pulse voltammetry (DPV) and, linear sweep voltammetry (LSV) with a detection limit of 6 nM. Proton NMR (1H NMR) reveals that the azide group present at the 3' position is responsible for the selective response of AZT with probes. Quantitative determination by the probes in the pharmaceutical sample gives the recovery percentage above 97%. Hence, economic, affordable, ready-to-use chemosensor for AZT (in an aqueous medium) with low detection limit having satisfactory utility for HIV supplements have been developed.