ABSTRACT
Carbon monoxide (CO) is known for its multifaceted role in human physiology, and molecules that release CO in a controlled way have been proposed as therapeutic drugs. In this work, a light-responsive CO-releasing molecule (CORM-Dabsyl) showed a strong colourimetric response upon photochemical CO-release, owing to the tight conjugation of a Mn(i) tricarbonyl centre to a dabsyl chromophoric ligand (L). Whereas the complex was very stable in the dark in nitrogen-purged aqueous media, CO-release was effectively triggered using 405 nm irradiation. CORM-Dabsyl, L and the inactive product iCORM-Dabsyl have been investigated by DFT and TD-DFT calculations. Only mild toxicity of CORM-Dabsyl was observed against LX-2 and HepaRG® human cell lines (IC50 â¼ 30 µM). Finally, to develop a CO storage and release material that is readily applicable to therapeutic situations, CORM-Dabsyl was loaded on low-cost and easily disposable paper strips, from which the light triggered CO-release was conveniently visible with the naked eye.
ABSTRACT
Applicability of phototherapeutic CO-releasing molecules (photoCORMs) is limited because they are activated by harmful and poorly tissue-penetrating near-ultraviolet light. Here, a strategy is demonstrated to activate classical photoCORM Mn2(CO)10 using red light (635 nm). By mixing in solution a triplet photosensitizer (PS) with the photoCORM and shining red light, energy transfer occurs from triplet excited-state 3PS* to a photolabile triplet state of Mn2(CO)10, which, like under near-UV irradiation, led to complete release of carbonyls. Crucially, such "triplet-sensitized CO-release" occurred in solid-state materials: when PS and Mn2(CO)10 were embedded in electrospun nonwoven fabrics, CO was liberated upon irradiation with low-intensity red light (≤36 mW 635 nm).
Subject(s)
Carbon Monoxide/chemistry , Color , Light , Manganese Compounds/chemistry , Manganese Compounds/radiation effects , Polymers/chemistry , Carbon Monoxide/radiation effects , Energy Transfer/radiation effects , Polymers/radiation effects , Ultraviolet Rays/adverse effectsABSTRACT
A rhodamine conjugate (L) with a pseudo Stokes shift of 165 nm is used for probing changes in solution pH under physiological conditions. This reagent is found to be nontoxic, and the luminescence response could be used for imaging changes in endogenous pH induced by dexamethanose (DMT) in the endoplasmic reticulum.
Subject(s)
Fluorescent Dyes/chemistry , Lipids/analysis , Animals , Endoplasmic Reticulum/drug effects , HCT116 Cells , Humans , Hydrogen-Ion Concentration , Luminescence , Molecular Structure , Rhodamines/chemistryABSTRACT
A new coumarin-rhodamine conjugate is used as a specific probe for Pd(2+) ions and this could even delineate Pd(II) from Pd(0) or Pd(IV) in aqueous buffer medium (pH â¼ 7). Laser confocal microscopic studies reveal that efficient cellular internalization of this reagent helps in imaging the cellular uptake of Pd(2+) as low as 0.1 ppm in Hct 116 cells. This reagent could even be used for estimation of Pd(2+) in human urine samples.
Subject(s)
Coumarins/chemistry , Fluorescent Dyes/analysis , Fluorescent Dyes/chemistry , Lead/urine , Rhodamines/chemistry , Coumarins/metabolism , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/metabolism , HCT116 Cells , Humans , Rhodamines/metabolismABSTRACT
A new molecular probe that demonstrates a distinct TBET process, induced by the Hg(II)-η(2)-arene π-interaction, in pure aqueous medium with a large pseudo-Stokes shift of 200 nm.
Subject(s)
Fluorescent Dyes/chemistry , Mercury/analysis , Biological Transport , Buffers , Cell Survival/drug effects , Colonic Neoplasms , Energy Transfer , Fluorescent Dyes/pharmacology , HCT116 Cells , Humans , Hydrogen/chemistry , Mercury/chemistry , Mercury/metabolismABSTRACT
A new Cu(II)-complex is used as a "Turn-On" luminescence probe for specific detection of endogenous Cys in live Hct116 cells and Cys present in human blood plasma without any interference from other amino acids, especially GSH and Hcy. Difference in the mechanistic pathway for Cys and His recognition is discussed.
Subject(s)
Coordination Complexes/chemistry , Copper/chemistry , Cysteine/analysis , Cysteine/blood , Fluorescent Dyes/chemistry , Histidine/analysis , Histidine/blood , Colorectal Neoplasms/chemistry , Fluorescence , HCT116 Cells , Humans , Luminescent MeasurementsABSTRACT
A new and simple chemodosimetric probe L1 is utilized for the selective detection of biothiols in the presence of other relevant amino acids under physiological conditions (pH = 7.4). This eventually led to a turn-off luminescence response due to an effective photoinduced electron transfer based signaling mechanism. A comparison of the results of the fluorescence kinetic analysis and (1)H NMR studies of the reaction between thiol and L1 or the analogous compound L2 revealed the role of intramolecular hydrogen bonding in activating the imine functionality towards nucleophilic addition. Such an example is not common in contemporary literature. Conventional MTT assay studies revealed that this probe (L1) has low cytotoxicity. Results of the cell imaging studies revealed that this probe was cell membrane permeable and could detect the intracellular distribution of biothiols within living HeLa cells. Furthermore, our studies with human blood plasma demonstrated the possibility of using this reagent for the quantitative optical detection of total biothiols in biological fluid. Such an example for the detection of biothiols in real biological samples is rare in the contemporary literature. These results clearly demonstrate the possibility of using this reagent in medicinal biology and diagnostic applications.
Subject(s)
Drug Design , Fluorescent Dyes/chemistry , Sulfhydryl Compounds/blood , Cell Survival/drug effects , Dose-Response Relationship, Drug , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/pharmacology , HeLa Cells , Humans , Hydrogen Bonding , Kinetics , Microscopy, Fluorescence , Molecular Structure , Structure-Activity RelationshipABSTRACT
A new "turn-on" luminescence probe for imaging the uptake of 0.2 ppm inorganic CN(-) in live HeLa cells as well as for probing the CN(-) generation through an enzymatic process in a virtual aqueous medium at appropriate pH.
Subject(s)
Cyanides/chemistry , Fluorescent Dyes/chemistry , Copper/chemistry , Enzyme Assays , HeLa Cells , Humans , Hydrogen-Ion Concentration , Microscopy, Confocal , Water/chemistryABSTRACT
A new rhodamine-based receptor, derivatized with an additional fluorophore (quinoline), was synthesized for selective recognition of Hg(2+) and Cr(3+) in an acetonitrile/HEPES buffer medium of pH 7.3. This reagent could be used as a dual probe and allowed detection of these two ions by monitoring changes in absorption and the fluorescence spectral pattern. In both instances, the extent of the changes was significant enough to allow visual detection. More importantly, the receptor molecule could be used as an imaging reagent for detection of Hg(2+) and Cr(3+) uptake in live human cancer cells (MCF7) using laser confocal microscopic studies. Unlike Hg(ClO(4))(2) or Hg(NO(3))(2) salts, HgCl(2) or HgI(2) failed to induce any visually detectable change in color or fluorescence upon interaction with L(1) under identical experimental conditions. Presumably, the higher covalent nature of Hg(II) in HgCl(2) or HgI(2) accounts for its lower acidity and its inability to open up the spirolactam ring of the reagent L(1). The issue has been addressed on the basis of the single-crystal X-ray structures of L(1)·HgX(2) (X(-) = Cl(-) or I(-)) and results from other spectral studies.