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.

&nbsp;

IIT Palakkad

A delta robot is a type of parallel robot that consists of three arms connected to universal joints at the base. Industries take advantage of these robots in packaging and pick and place operations due to its high accuracy and fastness. This three degrees of freedom robot is used in the process that automates the tea filter bags packing process through pick and place operation. Electrostatic gripper has been used as the end effectors. The tea filter bags are allowed to go through the conveyor and this delta configured robot is used for pick and place operation. This robot reduces the time complexity of the laborers and it also helps in increasing productivity by reducing the cost. Thus the tedious process becomes simpler through the delta configuration. Comparative analysis of the performance of robot with manual process is also shown in the results.

World University root node

Automation and performance analysis of tea filter bags packing process using delta configured robot

This review (with 163 refs) covers the recent developments of nanomaterial-based optical and electrochemical sensors for mycotoxins. The review starts with a brief discussion on occurrence, distribution, toxicity of mycotoxins and the legislations in monitoring their levels. It further outlines the research methods, various recognition matrices and the strategies involved in the development of highly sensitive and selective sensor systems. It also points out the salient features and importance of aptasensors in the detection of mycotoxins along with the different immobilization methods of aptamers. The review meticulously discusses the performance of different optical and electrochemical sensors fabricated using aptamers coupled with nanomaterials (CNT, graphene, metal nanoparticles and metal oxide nanoparticles). The review addresses the limitations in the current developments as well as the future challenges involved in the successful construction of aptasensors with the functionalized nanomaterials. [Figure not available: see fulltext.]. © 2019, Springer-Verlag GmbH Austria, part of Springer Nature.

Microchimica Acta

A review on recent developments in optical and electrochemical aptamer-based assays for mycotoxins using advanced nanomaterials

The 4-amino-1,8-naphthalimide-Tröger's base fluorophore, TBNap-TPy, adorned with phenyl-terpyridine moiety was synthesised and assessed for its aggregation-induced emission (AIE) behaviour. TBNap-TPy was further employed as a fluorescent sensor for the discriminative sensing of π-electron-deficient nitroaromatic; the TBNap-TPy displaying the largest fluorescence quenching with high selectivity for picric acid, a harmful environmental pollutant widely used in the dye industries. This journal is © The Royal Society of Chemistry.

Chemical Communications

Aggregation induced emission (AIE) active 4-amino-1,8-naphthalimide-Tröger's base for the selective sensing of chemical explosives in competitive aqueous media

The late-stage diversification (LSD) of structurally complex peptides has emerged as a powerful platform for molecular engineering and drug discovery. Besides traditional peptide modifications, such as native chemical ligations or cross-couplings with prefunctionalized substrates, during recent years, C―H activation has gained considerable momentum as a robust and step-economical strategy for late-stage peptide modifications, thus far predominantly for the formation of C―C bonds. Although C―N bond formations represent established strategies in medicinal chemistry and drug discovery, methods for direct amidations of tryptophan and tryptophan-containing peptides are rare and severely limited to the activated C2 position. In contrast, we herein disclose the first example of direct late-stage peptide C―H amidation reaction and the unprecedented late-stage peptide diversification on tryptophan C7 position in a highly site-selective manner. Moreover, this strategy sets the stage for sequential double C(7)―H/C(2)―H modifications, further improving the peptide structural complexity. © 2020 Elsevier Inc. Peptides represent biopolymers of key relevance to biochemistry, medicinal chemistry, natural product synthesis, and pharmaceutical industries, among others. Traditional peptide syntheses thus far largely relied on lengthy functional group interconversions. Resource-economic C–H activation has surfaced as a transformative platform for peptide modifications but continues to be restricted to tryptophan modifications at the C2-position. In sharp contrast, C7-selective peptide modifications have now been realized by versatile rhodium catalysis. The catalyzed C–H amidations occurred with outstanding levels of C7 site selectivity on highly functionalized peptides. These findings unravel the unique potential of biorthogonal late-stage diversification for the direct assembly of structurally complex peptides for biology, molecular syntheses, and drug discovery. © 2020 Elsevier Inc. Herein, we disclose the first late-stage peptide C–H nitrogenations through unprecedented rhodium(III)-catalyzed peptide C7 diversification. Thus, peptides were directly transformed through position-selective C7 amidations with easily accessible 1,4,2-dioxazol-5-ones. Structurally complex peptides featuring a wealth of functional groups underwent C7-C–H amidations to deliver selectively modified natural product and drug hybrids. © 2020 Elsevier Inc.

Fulltext

Chem

Peptide Late-Stage Diversifications by Rhodium-Catalyzed Tryptophan C7 Amidation

The catalytic generation of hypervalent iodine(III) reagents by anodic electrooxidation was orchestrated towards an unprecedented electrocatalytic C−H oxygenation of weakly coordinating aromatic amides and ketones. Thus, catalytic quantities of iodoarenes in concert with catalytic amounts of ruthenium(II) complexes set the stage for versatile C−H activations with ample scope and high functional group tolerance. Detailed mechanistic studies by experiment and computation substantiate the role of the iodoarene as the electrochemically relevant species towards C−H oxygenations with electricity as a sustainable oxidant and molecular hydrogen as the sole by-product. para-Selective C−H oxygenations likewise proved viable in the absence of directing groups. © 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Angewandte Chemie - International Edition

C−H Oxygenation Reactions Enabled by Dual Catalysis with Electrogenerated Hypervalent Iodine Species and Ruthenium Complexes

We disclose the unprecedented hybrid-ruthenium catalysis for distal meta-C−H activation. The hybrid-ruthenium catalyst was recyclable, as was proven by various heterogeneity tests, and fully characterized with various microscopic and spectroscopic techniques, highlighting the physical and chemical stability. Thereby, the hybrid-ruthenium catalysis proved broadly applicable for meta-C−H alkylations of among others purine-based nucleosides and natural product conjugates. Additionally, its versatility was further reflected by meta-C−H activations through visible-light irradiation, as well as para-selective C−H activations. © 2020 The Authors. Published by Wiley-VCH GmbH

Chemistry - A European Journal

Recyclable Ruthenium Catalyst for Distal meta-C−H Activation

Sensor technology, particularly disposable, field-deployable devices offer considerable promise for addressing major security demands, in general, and in particular the urgent needs for selective and rapid field detection of highly toxic G-type organophosphate (OP) nerve agents. Herein, we report on the first example of a disposable electrochemical biosensor chip for decentralized field detection of diisopropyl fluorophosphate (DFP), as the simulant compound of G-type nerve agents (e.g., Sarin and Soman), based on the integration of an all-solid-state fluoride potentiometric transducer with the enzyme organophosphorus acid anhydrolase (OPAA) in connection to a hand-held potentiometric analyzer. Such solid-contact fluoride ion-selective electrodes were realized by comparing different fluoride ionophores to select the bis(fluorodioctylstannyl)methane molecule, along with systematic optimization of the experimental parameters. This first solid-contact fluoride detection chip displayed a favorable analytical performance, with near-Nernstian behavior at neutral pH in different buffers, high selectivity against various anions along with excellent reproducibility. Combining such desirable merits of the new fluoride sensor with the selective biocatalytic hydrolysis via an immobilized OPAA, to break the P[sbnd]F bond of G-type neurotoxins and release detectable fluoride ions, thereby enabled an attractive analytical performance. Both the fluoride and the nerve-agent recognition layers have thus been systematically optimized. The resulting biosensor chip thus displays a fast, sensitive and selective response towards DFP (including efficient discrimination against OP pesticides), along with a wide dynamic range of 250–3000 μM. Key challenges towards developing the nerve-agent detection chip were carefully addressed, including the pH incompatibility of the enzymatic and detection processes. By providing effective discrimination against common OP pesticides and minimizing related false alarms, the resultant disposable potentiometric biochip platform is expected to provide an instantaneous reliable warning of chemical attack and exposure towards a timely countermeasure action, and hence, would dramatically advance the protection of our military personnel. © 2020 Elsevier B.V.

Sensors and Actuators, B: Chemical

OPAA/fluoride biosensor chip towards field detection of G-type nerve agents

This work provides a succinct insight into the recent developments in electrochemical quantification of vital biomedical markers using hybrid metallic composite nanostructures. After a brief introduction to the biomarkers, five types of crucial biomarkers, which require timely and periodical monitoring, are shortlisted, namely, cancer, cardiac, inflammatory, diabetic and renal biomarkers. This review emphasizes the usage and advantages of hybrid nanostructured materials as the recognition matrices toward the detection of vital biomarkers. Different transduction methods (fluorescence, electrophoresis, chemiluminescence, electrochemiluminescence, surface plasmon resonance, surface-enhanced Raman spectroscopy) reported for the biomarkers are discussed comprehensively to present an overview of the current research works. Recent advancements in the electrochemical (amperometric, voltammetric, and impedimetric) sensor systems constructed with metal nanoparticle-derived hybrid composite nanostructures toward the selective detection of chosen vital biomarkers are specifically analyzed. It describes the challenges involved and the strategies reported for the development of selective, sensitive, and disposable electrochemical biosensors with the details of fabrication, functionalization, and applications of hybrid metallic composite nanostructures. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Advanced Science

Recent Trends in Electrochemical Sensors for Vital Biomedical Markers Using Hybrid Nanostructured Materials

There are urgent needs for sensing devices capable of distinguishing between episodes of opioid overdose and nerve agent poisoning. This work presents a wearable microneedle sensor array for minimally invasive continuous electrochemical detection of opioid (OPi) and organophosphate (OP) nerve agents on a single patch platform. The new multimodal microneedle sensor array relies on unmodified and organophosphorus hydrolase (OPH) enzyme-modified carbon paste (CP) microneedle electrodes for square wave voltammetric (SWV) detection of the fentanyl and nerve agent targets, respectively. Such real-time simultaneous sensing provides distinct unique information, along with attractive analytical performance, including high sensitivity, selectivity, and stability, for real-time on-body OPi-OP analysis. The patch represents the first sensing device capable of continuously monitoring fentanyl down to the nanomolar level through a nanomaterial-based multilayered surface architecture. Applicability of the sensor array toward opioids screening is demonstrated for morphine and norfentanyl. Successful OPi-OP detection conducted in a skin-mimicking phantom gel demonstrates the suitability of the device for rapid on-body sensing. Such progress toward continuous minimally invasive transdermal analysis of drugs of abuse and nerve agents holds promise for rapid countermeasures for protecting soldiers, civilians, and healthcare personnel. Copyright © 2020 American Chemical Society.

Journal of the American Chemical Society

Continuous Opioid Monitoring along with Nerve Agents on a Wearable Microneedle Sensor Array

Reactions of a series of magnesium(I) compounds with ethylene, in the presence of an N-heterocyclic carbene (NHC), have been explored. Treating [{(MesNacnac)Mg}2] (MesNacnac=[HC(MeCNMes)2]−, Mes=mesityl) with an excess of ethylene in the presence of two equivalents of :C{(MeNCMe)2} (TMC) leads to the formal reductive coupling of ethylene and formation of the 1,2-dimagnesiobutane complex, [{(MesNacnac)(TMC)Mg}2(μ-C4H8)]. In contrast, when the reaction is repeated in the presence of three equivalents of TMC, a mixture of the β-diketiminato magnesium ethyl, [(MesNacnac)(TMC)MgEt] and the NHC coordinated magnesium diamide, [(MesNacnac-H)Mg(TMC)2], results. Four related products, [(ArNacnac)(TMC)MgEt] (Ar=2,6-dimethylphenyl (Xyl) or 2,6-diisopropylphenyl (Dip)) and [(ArNacnac-H)Mg(TMC)2] (Ar=Xyl or Dip), were similarly synthesised and crystallographically characterized. Computational studies have been employed to investigate the mechanisms of the two observed reaction types, which appear dependent on the substitution pattern of the magnesium(I) compound and the stoichiometric equivalents of TMC used in the reactions. © 2020 Wiley-VCH GmbH