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S. Karpagam

Bio: S. Karpagam is an academic researcher from VIT University. The author has contributed to research in topics: Conjugated system & Polymer. The author has an hindex of 10, co-authored 32 publications receiving 252 citations.

Papers
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Journal ArticleDOI
TL;DR: The fluorescence intensity, detecting of multiple metal ions, solubility, photochemical stability and optoelectronic properties of these conjugated polymers, and how they can be regulated by different functional groups are discussed in detail.
Abstract: Over the past few years, significant progress has been made in the design of organic semi-conducting conjugated polymers that readily transport holes or electrons and can result in light emission. The conjugated backbone consist mainly of electron-donating (donor) and electron-withdrawing (acceptor) units as alternating groups in a conjugated oligomer or polymer that can be regulated by physical properties such as π conjugation length, monomer alteration, inter/intramolecular interactions and energy levels. Certainly, it is notable today that the highest occupied molecular orbital level of the producing material is localized predominantly on the electron-donating moiety and lowest unoccupied molecular orbital level on the electron-accepting moiety. Conjugated oligomers or polymers are used in many detecting fields due to their exceptional ability to sense toxic chemicals, metal ions and biomolecules. The conjugated polymers have unique delocalized π-electronic "molecular wires" that can expand the fluorescence intensity considerably. The fluorescence intensity of polymers can be quenched by particular quenching molecules. In this review, the fluorescence intensity, detecting of multiple metal ions, solubility, photochemical stability and optoelectronic properties of these conjugated polymers, and how they can be regulated by different functional groups, are discussed in detail.

30 citations

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TL;DR: From the in vitro release profile, the CNfib was competently showed rapid release of drug up to 97% than the thin film of CBF2 and CNF4 respectively in the initial period of 10min and the chitosan nanofiber has given significantly faster absorption rate.

29 citations

Journal ArticleDOI
K. Mahesh1, S. Karpagam1
TL;DR: In this paper, the effects of the thiophene and thiazole rings in the conjugated oligomer were systematically investigated for metal ion sensing applications, and the results showed that the effect of the rings on the detection limit of Cu 2+ and Fe 2+ was 1.04 and 0.988 M respectively.
Abstract: This paper reports the fluorescent and colorimetric sensing of Cu 2+ and Fe 2+ using thiophene-thiazole functionalized conjugated oligomers from water samples. Oligomers namely, oligo-4,5-bis-{2-[5-(2-thiophene-2-yl-vinyl)thiophene-2-yl]-vinyl}-thiazole ( OBTV-TZ ) and oligo-2,4,5-tris-{2-[5-(2-thiophene-2-yl-vinyl) thiophene-2-yl]-vinyl}-thiazole ( OTTV-TZ ) were synthesized through Wittig condensation and confirmed from FT-IR, 1 H NMR and LCMS analysis. The effects of the thiophene and thiazole rings in the oligomer towards metal ion sensing applications were systematically investigated. The color of both oligomers was changed from pale yellow to pale green and dark yellow by the addition of Cu 2+ and Fe 2+ ions respectively. Upon adding Cu 2+ and Fe 2+ , both sensors displayed a new absorption peak at around 207 nm which forms hyper and hypochromic effects. The detection limit (LOD) of Cu 2+ for OBTV-TZ and OTTV-TZ was 1.04 and 0.988 × 10 −5 M respectively. Both oligomers were successfully regained from the Fe 2+ coordinated system by adding of EDTA. A high selectivity of Cu 2+ and Fe 2+ using these oligomers in a competent environment of several other metal ions was successfully observed. The electrochemical studies revealed that HOMO and LUMO values of the oligomers increased after mixing with Cu 2+ and Fe 2+ . The LUMO value of the oligomer (OTTV-TZ) was sensed to −3.35 and −3.15 eV after incorporating Cu 2+ and Fe 2+ . Both oligomers exhibited wide pH response in absorbance (pH = 5–10) and fluorescence intensities (pH = 2–9).

26 citations

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TL;DR: The general aspects of Mycobacterium patho-genesis, disease treatment along with progressive updates in novel drug delivery carrier system are compiled to enhance therapeutic effects of drug and the high level of patient compliance.
Abstract: In spite of advances in tuberculosis (TB) chemotherapy, TB is still airborne deadly disorder as a major issue of health concern worldwide today. Extensive researches have been focused to develop novel drug delivery systems to shorten the lengthy therapy approaches, prevention of relapses, reducing dose-related toxicities and to rectify technologically related drawbacks of anti-tubercular drugs. Moreover, the rapid emergence of drug resistance, poor patient compliance due to negative therapeutic outcomes and intracellular survival of Mycobacterium highlighted to develop carrier with optimum effectiveness of the anti-tubercular drugs. This could be achieved by targeting and concentrating the drug on the infection reservoir of Mycobacterium. In this article, we briefly compiled the general aspects of Mycobacterium pathogenesis, disease treatment along with progressive updates in novel drug delivery carrier system to enhance therapeutic effects of drug and the high level of patient compliance. Recently developed several vaccines might be shortly available as reported by WHO.

26 citations

Journal ArticleDOI
TL;DR: In this article, a new series of donor-acceptor (P1-P3 ) conjugated polymers containing carbazole and quinoxaline units have been synthesized through multistep reactions.

21 citations


Cited by
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Journal ArticleDOI
TL;DR: This study provides a generalized nanozyme strategy to compensate both ferrotherapy and phototherapeutics for complete tumor regression and reports on the application of NIR-II hybrid semiconducting nanozymes for combined photothermal therapy and enhanced ferroTherapy with photoacoustic imaging and show application in vivo in tumour models.
Abstract: Despite its growing promise in cancer treatment, ferrotherapy has low therapeutic efficacy due to compromised Fenton catalytic efficiency in tumor milieu. We herein report a hybrid semiconducting nanozyme (HSN) with high photothermal conversion efficiency for photoacoustic (PA) imaging-guided second near-infrared photothermal ferrotherapy. HSN comprises an amphiphilic semiconducting polymer as photothermal converter, PA emitter and iron-chelating Fenton catalyst. Upon photoirradiation, HSN generates heat not only to induce cytotoxicity but also to enhance Fenton reaction. The increased ·OH generation promotes both ferroptosis and apoptosis, oxidizes HSN (42 nm) and transforms it into tiny segments (1.7 nm) with elevated intratumoral permeability. The non-invasive seamless synergism leads to amplified therapeutic effects including a deep ablation depth (9 mm), reduced expression of metastasis-related proteins and inhibition of metastasis from primary tumor to distant organs. Thereby, our study provides a generalized nanozyme strategy to compensate both ferrotherapy and phototherapeutics for complete tumor regression.

264 citations

Journal ArticleDOI
TL;DR: The concept of "aggregate science" is put forward to fill the gaps between molecules and aggregates and the structure-property relationships established for aggregates are expected to contribute to new materials and technological development.
Abstract: Molecular science entails the study of structures and properties of materials at the level of single molecules or small interacting complexes of molecules. Moving beyond single molecules and well-defined complexes, aggregates (i.e., irregular clusters of many molecules) serve as a particularly useful form of materials that often display modified or wholly new properties compared to their molecular components. Some unique structures and phenomena such as polymorphic aggregates, aggregation-induced symmetry breaking, and cluster excitons are only identified in aggregates, as a few examples of their exotic features. Here, by virtue of the flourishing research on aggregation-induced emission, the concept of "aggregate science" is put forward to fill the gaps between molecules and aggregates. Structures and properties on the aggregate scale are also systematically summarized. The structure-property relationships established for aggregates are expected to contribute to new materials and technological development. Ultimately, aggregate science may become an interdisciplinary research field and serves as a general platform for academic research.

212 citations

Journal ArticleDOI
TL;DR: A review of the major mechanisms behind the bactericidal actions of the silver and silver nanoparticles-based systems followed by comprehensive ideas related to their toxic potentials would open new robust possibilities to develop silver nanoparticle-based antimicrobial systems with desired properties for effective treatment of bacterial infections in humans.

166 citations

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TL;DR: This work reviews the various types of nanofibers from the latest available literature, based on their composition and drug-release properties, and classified them according to their mode of drug release.

118 citations

Journal ArticleDOI
TL;DR: The sustained release profile, enhanced drug activity, cytocompatibility, and significant wound healing activity affirm the potential applications of teicoplanin-loaded nanofibers in wound healing and local antibiotic delivery.

82 citations