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SYNTHESIS AND CHARACTERIZATION OF NOVEL EXCITED STATE INTRAMOLECULAR PROTON TRANSFER (ESIPT) CYANINE DYES WITH NEAR INFRARED (NIR) EMISSION FOR BIOLOGICAL APPLICATIONS

Dahal, Dipendra, Dahal
http://rave.ohiolink.edu/etdc/view?acc_num=akron1567644552737644

Abstract Details

2019, Doctor of Philosophy, University of Akron, Chemistry.
Fluorescence molecular probes have become one of the most popular tools in many aspects of chemistry and biology. Many fluorescence probes have been developed for the detection of different cations, anions, and some essential small molecules in the live cells. Some of the probes are useful for visualization of the cell organelles, which could be powerful tools to aid the study in cellular activities. Near-infrared (NIR) emitting probes are desirable for biological applications as they offer deep tissue penetration and reduce the autofluorescence and background noise. Toward this direction, several new NIR emitting fluorescence probes have been developed via combining excited-state intramolecular mechanism (ESIPT) with cyanine, and other different architectures. In chapter II, a cyanine dye 2.1 (λem~700 nm) with a large Stokes’ shift (Δλ ≈ 234 nm) is synthesized by coupling 2-(2’-hydroxyphenyl)benzothiazole (HBT) with a benzothiazolium-derived unit. The phenolic proton, which controls ESIPT, also acts as a switch to respond to an acidic environment (pH=4-6). Staining the normal human lung fibroblast cells (NHLF) reveals that 2.1 is selectively staining lysosome without “alkalinizing effect.” Chapter III demonstrates the synthesis of NIR-emitting dyes 3.1 and 3.2 with large Stokes’ shifts (Δλ ≈ 231 - 246 nm), whose structures consist of a hemicyanine unit (benzothiazolium and indolium respectively) and an ESIPT unit [2-(benzo[d]oxazol-2-yl)-4-methylphenol (HBO)]. Compound 3.1 (Ф ≈ 0.28 – 0.35 in CH2Cl2) exhibited excellent selectivity for staining intracellular lysosomes. However, probe 3.2 (Ф ≈ 0.27, in CH2Cl2) has excellent selectivity towards mitochondria. Chapter IV includes a near infrared-emitting pyridinium cyanine with a large Stokes shift (Δλ ≈ 230 nm) which has been synthesized by coupling pyridinium cyanine with ESIPT unit HBT. The developed new probe 4.1a exhibits a significantly higher fluorescence quantum yield (Фfl≈0.34 in Dichloromethane) than commercial FM-143 dye (Фfl≈0.03 in DCM). In addition, the probe exhibits excellent selectivity for imaging plasma membrane of prokaryotic cells, indicating its potential for imaging plasma membrane of prokaryotic (E. coli) cells. In chapter V, mitochondria staining near-infrared (NIR) emitting cyanine dye 5.1 is synthesized which exhibits larger Stokes’ shifts (Δλ ≈ 161 nm) due to internal charge transfer (ICT). A highly acidic proton (pKa = 4.0) of Probe 5.1 in a meta-phenylene linkage has a synergistic impact on its photophysical properties. Accumulation via depending upon mitochondrial potential gradient showing promising application for detection of mitochondrial dysfunction. Chapter VI introduces the synthesis of a fluorescence probe for Ca2+ ions by combining cyanine with a popular Ca2+ chelating ligand derivative of BAPTA to detect Ca2+ ions. Weak fluorescence of free BT-Ca becomes intense when it binds with Ca2+ ions with about ⁓5 folds increase in the fluorescence amplitude.
Yi Pang, Ph. D. (Advisor)
Wiley Youngs, Ph. D. (Committee Member)
Chrys Wesdemiotis, Ph. D. (Committee Member)
Sailaja Paruchuri, Ph. D. (Committee Member)
Qin Liu, Ph. D. (Committee Member)
295 p.
Analytical Chemistry; Chemistry; Organic Chemistry
Near-Infrared emission, Hemicyanine, and Cyanine dyes, Excited states intramolecular proton transfer, Internal charge transfer, MItochondria, Lysosomes, Plasma membrane, Absorbance, Fluorescence, fluorescence crosstalk confocal imaging

Recommended Citations

Citations

  • Dahal, Dahal, D. (2019). SYNTHESIS AND CHARACTERIZATION OF NOVEL EXCITED STATE INTRAMOLECULAR PROTON TRANSFER (ESIPT) CYANINE DYES WITH NEAR INFRARED (NIR) EMISSION FOR BIOLOGICAL APPLICATIONS [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1567644552737644

    APA Style (7th edition)

  • Dahal, Dahal, Dipendra. SYNTHESIS AND CHARACTERIZATION OF NOVEL EXCITED STATE INTRAMOLECULAR PROTON TRANSFER (ESIPT) CYANINE DYES WITH NEAR INFRARED (NIR) EMISSION FOR BIOLOGICAL APPLICATIONS. 2019. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1567644552737644.

    MLA Style (8th edition)

  • Dahal, Dahal, Dipendra. "SYNTHESIS AND CHARACTERIZATION OF NOVEL EXCITED STATE INTRAMOLECULAR PROTON TRANSFER (ESIPT) CYANINE DYES WITH NEAR INFRARED (NIR) EMISSION FOR BIOLOGICAL APPLICATIONS." Doctoral dissertation, University of Akron, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1567644552737644

    Chicago Manual of Style (17th edition)

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© 2019, some rights reserved.Creative Commons License SYNTHESIS AND CHARACTERIZATION OF NOVEL EXCITED STATE INTRAMOLECULAR PROTON TRANSFER (ESIPT) CYANINE DYES WITH NEAR INFRARED (NIR) EMISSION FOR BIOLOGICAL APPLICATIONS by Dipendra Dahal Dahal is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Akron and OhioLINK.