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).
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.
Although carbon monoxide (CO) delivery materials (CORMAs) have been generated, remote-controlled delivery with light-activated CORMAs at a local site has not been achieved. In this work, a fiber optic-based CO delivery system is described in which the photoactive and water insoluble CO releasing molecule (CORM) manganese(i) tricarbonyl [(OC)3Mn(μ3-SR)]4 (R = nPr, 1) has been non-covalently embedded into poly(l-lactide-co-d/l-lactide) and poly(methyl methacrylate) non-woven fabrics via the electrospinning technique. SEM images of the hybrid materials show a porous fiber morphology for both polymer supports. The polylactide non-woven fabric was attached to a fiber optical device. In combination with a laser irradiation source, remote-controlled and light-triggered CO release at 405 nm excitation wavelength was achieved. The device enabled a high flexibility of the spatially and timely defined application of CO with the biocompatible hybrid fabric in aqueous media. The rates of liberated CO were adjusted with the light intensity of the laser. CO release was confirmed via ATR-IR spectroscopy, a portable electrochemical CO sensor and a heterogeneous myoglobin assay.
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.
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