Department of Chemistry

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Zearalenone (ZEN) is an important non-steroidal estrogenic mycotoxin produced by fusarium fungi species. A number of methods based on enzyme-linked immune assays (ELISA) and chromatographic approaches are available for the detection of ZEN. In this research, ZEN conjugated by bovine serum albumin (BSA) was immobilized on the surface of the screen-printed carbon electrode (SPCE) followed by the subsequent addition of anti-zearalenone monoclonal antibody (ZEN-MAb), alkaline phosphatase (ALP)-labeled secondary antibody, and 1-napthyl phosphate (1-NP) as a substrate. This immunosensor had good specificity, selectivity, reproducibility, and sensitivity for ZEN (LOD of 0.25 ng mL−1) when employed for quantification based on differential pulse voltammetry (DPV). This immunosensor yielded good recovery values in the range of 89–97% against real matrices (i.e., beer and wine samples) after spiking. This novel immunosensing principle can be extensively applied for the development of advanced sensing techniques for various analytes. © 2018

World University root node

Journal of Electroanalytical Chemistry

A highly sensitive electrochemical immunosensor for zearalenone using screen-printed disposable electrodes

Aflatoxin B1 (AFB1) is the most toxic contaminant, causes carcinogenic, and immune toxic effects. There is an immense need to develop inexpensive, reliable biosensors for AFB1. The electrochemical aptasensor for detection of aflatoxin B1 has received much attention due to their trustworthy procedure. In this work, we have designed an electrochemical aptasensor by using methylene blue (MB) as a signalling fragment and polythiophene-3-carboxylic acid (PT3C) as the signal-enlarging platform. The (PT3C) was first screened onto the screen printed carbon electrode (SPCE) interface, and then the MB-tagged aptamer was immobilized on SPCE by using hexamethylenediamine (HMDA) as a spacer via carbodiimide amide-bonding chemistry. AFB1 has been chosen as model analyte to test the proposed aptasensing platform. A good dynamic range 2.5–30 ng L−1 was obtained for AFB1 with a limit of detection (LOD 1.6 ng L−1). The good reproducibility was recorded with RSD% of 3.21. The obtained straight-line equation was 3.6099 x + 19.073, R2 = 0.9977. For real-world sample applications, this aptasensor has been used in coffee samples. It displayed good recovery in the range 88.2–93.3%, thus showed the effectiveness of the proposed aptasensor for coffee samples. © 2019

Sensing and Bio-Sensing Research

An electrochemical aptasensor based on polythiophene-3-carboxylic acid assisted methylene blue for aflatoxin B1 detection

Continuous periodical monitoring of clopidogrel in physiological body fluids is indispensable in medical diagnosis of heart ailments and cardiovascular diseases. A highly sensitive electrochemical sensor has been fabricated with silver nanoparticles embedded chitosan-carbon nanotube hybrid composite (AgChit-CNT) as sensor interface for detection of the important anti-platelet drug, clopidogrel (CLP). Synthesized AgChit-CNT nanocomposite is examined by x-ray diffraction, Raman spectroscopy and field emission scanning electron microscopy for its chemical and structural characteristics. Crystalline silver nanoparticles of about 35 nm are well distributed in the composite and have formed continuous chain like linkages with CNTs all throughout. Electrochemical responses of the fabricated AgChit-CNT nanocomposite electrode for the determination of CLP have been examined by cyclic voltammetry and electrochemical impedance spectroscopy. The nanoAg patterned CNT nanocomposite interface acts as an excellent electron transfer mediator towards the oxidation of clopidogrel. Electrochemical determination of CLP was investigated by differential pulse voltammetry (DPV) and amperometric analysis under optimized conditions. The limit of detection by DPV and amperometry were 30 nM and 10 nM, respectively, and the time of the analysis is as low as 10 s. Practical applicability for determination in artificially prepared urine and pharmaceutical formulation has been examined with good recovery limits of 95.2 to 102.6%. © 2019

Materials Science and Engineering C

Silver nanoparticles impregnated chitosan layered carbon nanotube as sensor interface for electrochemical detection of clopidogrel in-vitro

Reactions of two N-heterocyclic silylenes with a boron azide have given the first N-boryl substituted silaimines, (HCNR)2SiN{B(DipNCH)2} (R = Dip or But, Dip = 2,6-diisopropylphenyl) which are either monomeric or dimeric in the solid state. The compounds shows divergent reactivity with CO2, in that the bulkier silaimine undergoes a [2+2] cycloaddition with CO2 to form (HCNDip)2Si{OC(O)N[B(DipNCH)2]} under mild conditions, while the smaller silaimine undergoes a bond metathesis reaction with CO2, affording the boron isocyanate, (HCNDip)2B(NCO) and a known oxo-bridged silicon(iv) system. Both silaimines add H2O across their SiN bonds to give the boryl-aminosilanols, (HCNR)2Si(OH)-(H)N{B(DipNCH)2}. The larger silaimine does not react with the bulky boron azide (HCNDip)2BN3, whereas the smaller system undergoes a [3+2] cycloaddition reaction with the azide to give spirocyclic borasilatetrazoline, (HCNBut)2Si{[(HCNDip)2B]NN}2. Overall, the reactivity of the prepared N-boryl substituted silaimines is similar to that reported for other silaimines. However, the steric differences between the two SiN bonded compounds plays a definitive role in the outcomes of their reactions with the small molecule substrates studied. © 2019 The Royal Society of Chemistry.

Dalton Transactions

Synthesis and reactivity of boryl substituted silaimines

Precise control over the monomer sequence of a polymer backbone, resulting in a sequence-defined polymer (SDP), is a crucial parameter for tuning the structures, properties, and functions. Examples of natural SDPs are the proteins and nucleic acids that possess the structural and functional complexity to support life. Highly sophisticated machinery has evolved in living organisms for the de novo synthesis of natural SDPs. However, gaining absolute control of the monomer sequence in a non-natural polymer is still challenging. In comparison to biopolymers, non-natural SDPs have an even wider scope of unlimited functional side-chains, as well as backbone diversity. Hence, SDP is a perfect platform for generating extensive structural complexity such as self-assembly into nanostructures, folding, the formation of stimuli-responsive sites, catalytic sites, and so on. In this review, the current status of the SDPs that have tremendous potential for future research and development are discussed. This review seeks to draw attention to the development of non-natural SDPs via innovative synthetic routes established recently. After synthesis and characterization, the next obvious step to move the field forward is to explore SDPs for their potential applications. Hence, this review is divided into two parts: (i) diversified synthetic strategies for SDPs, and (ii) applications of SDPs in materials and biomedical sciences. This field is progressing rapidly; there are immense possibilities for exploring different chemical reactions to develop novel classes of SDPs, and there are many potential application opportunities via pre-determined sequences in synthetic polymers. © The Royal Society of Chemistry.

Polymer Chemistry

Sequence-defined non-natural polymers: Synthesis and applications

Nearly 80% of the processes involved in the chemical production of bulk or fine chemicals employ heterogeneous catalysts that are typically solids. The heart of the heterogeneous catalyst is the surface active site which must be highly active, selective and stable during several hundred cycles of reaction. Although it is not always possible to determine the structure of an active site in a heterogeneous catalyst, the emphasis of modern day research has not only been to understand the structure of an active site but also synthesize and study them. The article will describe some of the challenges from this perspective with examples from the authors research. © 2019 Indian National Science Academy. All rights reserved.

Proceedings of the Indian National Science Academy

New opportunities in heterogeneous catalysis

Use of Iron oxyhydroxide (γ-FeO(OH)) as a robust catalyst for the synthesis of important intermediates like pseudoionones and their analogues through the C-C bond formation reactions like knoevenagel and aldol condensation is explored. These motifs are the building blocks for the construction of the sesquiterpenes as well as the diterpenes such as retinoic acid, Vitamin A etc. Iron oxyhydroxide (γ-FeO(OH)) was synthesized and well characterized using XRD, FT-IR, TEM, XPS and adsorption studies to establish the catalytic activity. A thorough investigation on the nature of basic sites and the role of water as a promoter was explored based on dye adsorption, in situ methanol dissociation and CO2 adsorption studies. The catalyst also showed a wide range of substrate scope with active methylene groups involving various functional groups such as cyanides, esters and acetophenones along with its stability and reproducibility. © 2019 Elsevier Inc.

Journal of Catalysis

Water-promoted surface basicity in FeO(OH) for the synthesis of pseudoionones (PS) and their analogues

Levodopa is the most effective medication for treating Parkinson's disease (PD). However, because dose optimization is currently based on patients' report of symptoms, which are difficult for patients to describe, the management of PD is challenging. We report on a microneedle sensing platform for continuous minimally invasive orthogonal electrochemical monitoring of levodopa (L-Dopa). The new multimodal microneedle sensing platform relies on parallel simultaneous independent enzymatic-amperometric and nonenzymatic voltammetric detection of L-Dopa using different microneedles on the same sensor array patch. Such real-time orthogonal L-Dopa sensing offers a built-in redundancy and enhances the information content of the microneedle sensor arrays. This is accomplished by rapid detection of L-Dopa using square-wave voltammetry and chronoamperometry at unmodified and tyrosinase-modified carbon-paste microneedle electrodes, respectively. The new wearable microneedle sensor device displays an attractive analytical performance with the enzymatic and nonenzymatic L-Dopa microneedle sensors offering different dimensions of information while displaying high sensitivity (with a low detection limit), high selectivity in the presence of potential interferences, and good stability in artificial interstitial fluid (ISF). The attractive analytical performance and potential wearable applications of the microneedle sensor array have been demonstrated in a skin-mimicking phantom gel as well as upon penetration through mice skin. The design and attractive analytical performance of the new orthogonal wearable microneedle sensor array hold considerable promise for reliable, continuous, minimally invasive monitoring of L-Dopa in the ISF toward optimizing the dosing regimen of the drug and effective management of Parkinson disease. © 2019 American Chemical Society.

ACS Sensors

Wearable Electrochemical Microneedle Sensor for Continuous Monitoring of Levodopa: Toward Parkinson Management

Complexity-increasing Domino reactions comprising C−H allenylation, a Diels–Alder reaction, and a retro-Diels–Alder reaction were realized by a versatile catalyst derived from earth-abundant, non-toxic manganese. The C−H activation/Diels–Alder/retro-Diels–Alder alkyne annulation sequence provided step-economical access to valuable indolone alkaloid derivatives through a facile organometallic C−H activation manifold with transformable pyridines. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Angewandte Chemie - International Edition

Manganese(I)-Catalyzed C−H Activation/Diels–Alder/retro-Diels–Alder Domino Alkyne Annulation featuring Transformable Pyridines

The widespread applications of substituted diketopyrrolopyrroles (DPPs) call for the development of efficient methods for their modular assembly. Herein, we present a π-expansion strategy for polyaromatic hydrocarbons (PAHs) by C−H activation in a sustainable fashion. Thus, twofold C−H/N-H activations were accomplished by versatile ruthenium(II)carboxylate catalysis, providing step-economical access to diversely decorated fluorogenic DPPs that was merged with late-stage palladium-catalyzed C−H arylation on the thus-assembled DPP motif. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH &amp; Co. KGaA.