A5077397613- Advanced biosensing and bioanalysis techniques
- DNA and Nucleic Acid Chemistry
- Luminescence and Fluorescent Materials
- Molecular Sensors and Ion Detection
- Conducting polymers and applications
- Nanoplatforms for cancer theranostics
- Metal complexes synthesis and properties
- Nanocluster Synthesis and Applications
- Photochromic and Fluorescence Chemistry
- Molecular Junctions and Nanostructures
- Organic Light-Emitting Diodes Research
- Photochemistry and Electron Transfer Studies
- Organic Electronics and Photovoltaics
- Synthesis and Biological Evaluation
- DNA Repair Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Gold and Silver Nanoparticles Synthesis and Applications
- Perovskite Materials and Applications
- Photodynamic Therapy Research Studies
- Radical Photochemical Reactions
- Transition Metal Oxide Nanomaterials
- Fullerene Chemistry and Applications
- SARS-CoV-2 detection and testing
- Polydiacetylene-based materials and applications
- Supramolecular Self-Assembly in Materials
National Institute for Interdisciplinary Science and Technology
2015-2024
Academy of Scientific and Innovative Research
2015-2024
Nirma (India)
2022
University of Notre Dame
2022
NOAA Chemical Sciences Laboratory
2015-2019
National Institute of Technology Calicut
2014
Georgia Institute of Technology
2004-2013
Kannur University
2012
Indian Institute of Technology Indore
2008
Council of Scientific and Industrial Research
2001-2006
All organisms store the information necessary to maintain life in their DNA. Any process that damages DNA, causing a loss or corruption of information, jeopardizes viability organism. One-electron oxidation is such process. In this Account, we address three central features one-electron DNA: (i) migration radical cation away from site its formation; (ii) electronic and structural factors determine nucleobases at which irreversible reactions most readily occur; (iii) mechanism reaction for...
Abstract Four new N ‐ethylcarbazole‐linked aza‐boron‐dipyrromethene (aza‐BODIPY) dyes ( 8 a , b and 9 ) were synthesized characterized. The presence of the ‐ethylcarbazole moiety shifts their absorption fluorescence spectra to near‐infrared region, λ ≈650–730 nm, electromagnetic spectrum. These possess strong molar absorptivity in range 3–4×10 4 m −1 cm with low quantum yields. triplet excited state singlet oxygen generation these enhanced upon iodination at core position. core‐iodinated...
Photodynamic therapy (PDT) emerged as a promising cancer therapeutic technique due to the prospect of triggering and controlling drug action with light, which will reduce detrimental side effects traditional chemotherapy. In recent years, in PDT design, progressive approaches such use nanocarriers targeted delivery systems have been achieved improve bioavailability efficacy therapy. Herein, we report synthesis, photophysical, photobiological properties graphene oxide quantum dot (GQD)–BODIPY...
Thymine−Hg(II)−thymine base pairs have been incorporated in an oligonucleotide duplex to study their effect on DNA-mediated charge transport. The introduction of a formally charged Hg atom inside the DNA core does not significantly alter hopping and trapping properties, as discussed this paper. Hg(II) replaces protons normally found thymines within complex acts like "big proton" terms its role
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTTransmissive-to-Black Electrochromic Devices Based on Cross-Linkable Tetraphenylethene-Diphenylamine DerivativesSilja Abraham†, Sreejith Mangalath†‡, Deepika Sasikumar†, and Joshy Joseph*†‡View Author Information† Photosciences Photonics Section, Chemical Sciences Technology Division, CSIR-National Institute for Interdisciplinary Science Technology, Thiruvananthapuram 695019, Kerala, India‡ Academy of Scientific Innovative Research (AcSIR),...
In this paper, we demonstrate the design and fabrication of an AlGaN/GaN High Electron Mobility Transistor (HEMT) as a bio sensing platform. Bio-compatible functionalization process with thioglycolic acid antibody-antigen immobilization EDC-NHS chemistry is optimized, HEMT biosensor validated using recombinant C3G (RAPGEF1) protein indigenously developed mouse monoclonal antibody (clone 3F6mAb). The designed its extended source-drain pads inter-digital gate increases sensitivity device to...
A series of acridinium derivatives 1−6, wherein steric factors have been varied systematically through substitution at the 9 position acridine ring, synthesized and their DNA interactions investigated by various biophysical techniques. The unsubstituted methylacridinium 1 2 o-tolylacridinium derivative 6 exhibited high fluorescence quantum yields (Φf ≅ 1) lifetimes (τ = 35, 34, 25 ns, respectively), when compared with arylacridinium 3−5. showed binding affinity (K 7.3−7.7 × 105 M-1), to 3-5...
Multicolor electrochromic systems based on heat cross-linkable arylamine-substituted fluorene derivatives, FD and FDOMe, are reported. These derivatives with pendant vinyl groups have been synthesized by the Buchwald-Hartwig amination reaction were well-characterized using various analytical spectroscopic techniques such as NMR, ESI-MS, single-crystal X-ray diffraction analysis. FDOMe exhibited thermally activated cross-linking above their melting temperatures, which was confirmed through...
Photodynamic therapy (PDT) has emerged as an efficient and noninvasive treatment approach utilizing laser-triggered photosensitizers for combating cancer. Within this rapidly advancing field, iridium-based with their dual functionality both imaging probes PDT agents exhibit a potential precise targeted therapeutic interventions. However, most reported classes of Ir(III)-based comprise mononuclear iridium(III), very few examples dinuclear systems. Exploring the full systems applications...
One-electron oxidation of A/T-rich DNA leads to mutations at thymine. Experimental investigation containing methyl-deuterated thymine reveals a large isotope effect establishing that cleavage this carbon-hydrogen bond is involved in the rate-determining step reaction. First-principles quantum calculations reveal radical cation (electron hole) generated by oxidation, initially located on adenines, localizes as proton lost from methyl group, demonstrating role proton-coupled electron transfer...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPuromycin. Synthetic Studies. XIV. Use of the N-Phthalyl Blocking Group for Synthesis AminonucleosidesB. R. Baker, J. P. Joseph, and E. SchaubCite this: Am. Chem. Soc. 1955, 77, 22, 5905–5910Publication Date (Print):November 1, 1955Publication History Published online1 May 2002Published inissue 1 November 1955https://doi.org/10.1021/ja01627a038RIGHTS & PERMISSIONSArticle Views207Altmetric-Citations21LEARN ABOUT THESE METRICSArticle Views are...
Abstract A new series of photoactivated DNA oxidizing agents in which an acridine moiety is covalently linked to viologen by alkylidene spacer was synthesized, and their photophysical properties interactions with DNA, including cleaving properties, were investigated. The fluorescence quantum yields the viologen‐linked acridines found be lower than that model compound 9‐methylacridine (MA). changes free energy for electron transfer reactions favorable, quenching observed these systems...
With the objective of developing efficient DNA oxidizing agents, a new series viologen-linked pyrene conjugates with general formula PYLnV2+, having different number methylene spacer units (Ln) was synthesized, and their interactions nucleosides have been investigated through photophysical biophysical techniques. The derivatives PYL1V2+ (n = 1), PYL7V2+ 7), PYL12V2+ 12) exhibited characteristic fluorescence emission chromophore centered around 380 nm but significantly reduced yields when...
Novel bifunctional conjugates 1−3, with varying polymethylene spacer groups, were synthesized, and their DNA interactions have been investigated by various biophysical techniques. The absorption spectra of these systems showed bands in the regions 300−375 375−475 nm, corresponding to acridine acridinium chromophores, respectively. When compared 1 (Φf = 0.25), derivatives 2 3 exhibited quantitative fluorescence yields 0.91 0.98) long lifetimes (τ 38.9 33.2 ns). significant quenching observed...
The one-electron oxidation of a series DNA oligonucleotides was examined. Each oligomer contains covalently linked anthraquinone (AQ) group. Irradiation the AQ group with near-UV light results in that generates radical cation (electron "hole"). migrates through by hopping mechanism and is trapped reaction water or molecular oxygen, which chemical at particular nucleobases. This revealed as strand cleavage when irradiated oligonucleotide treated piperidine. specific oligomers examined reveal...
We report a series of four efficient photosensitizers (PSs) based on Bodipy core for photodynamic therapy (PDT). In the absence hydrophilic functional groups, these PSs have been encapsulated in liposomes and examined photocytotoxicity against human ovarian carcinoma cell line (SK-OV-3). The IC50 values obtained are as low 0.350 μM, which compete with classical photosensitizer chlorine E6 (IC50 = 0.39 μM) under similar experimental conditions.
The feature article is a review of the reaction thymine in one-electron oxidation duplex DNA. Oxidation DNA causes chemical reactions that result remote damage (mutation) to nucleobase. Normally this occurs at guanine, but oligonucleotides lack guanines, or when contains thymine-thymine mispair, primarily notwithstanding its high potential. Selective substitution uracil for TT sequences indicates operation tandem mechanism adjacent thymines. Analysis products suggests proton-coupled electron...
The preparation of a supramolecular nanocomposite containing BODIPY, tryptophan and gold nanoparticles capable photosensitized generation singlet oxygen is reported.
Thymine−thymine mispairs are barriers to long-distance radical cation migration and high reactivity sites in duplex DNA oligomers. A oligomer was prepared that contains only A/T base pairs, arranged into a regularly repeating series of TT steps, covalently linked anthraquinone photosensitizer. Its UV irradiation causes the one-electron oxidation introducing reacts predominantly at steps as revealed by subsequent strand cleavage. When remote GG step is introduced oligomer, there little...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPUROMYCIN. SYNTHETIC STUDIES. IV. GLUCOSYL DERIVATIVES OF 6-DIMETHYLAMINOPURINEB. R. BAKER, J. P. JOSEPH, E. SCHAUB, and H. WILLIAMSCite this: Org. Chem. 1954, 19, 11, 1780–1785Publication Date (Print):November 1, 1954Publication History Published online1 May 2002Published inissue 1 November 1954https://pubs.acs.org/doi/10.1021/jo01376a011https://doi.org/10.1021/jo01376a011research-articleACS PublicationsRequest reuse permissionsArticle...
Triphenylamine derivatives are promising organic electrochromic (EC) materials due to their easy synthesis, low oxidation potentials, high charge-carrier mobilities, electrochemical stability, coloration efficiency, and tunability of EC properties via substitution. Further, the cross-linking strategy provides an added advantage small-molecule-based devices in terms better-quality films with enhanced properties. Herein, we discuss two carbazole–diphenylamine derivatives, C-Sty2 C-Sty3, three...