Browsing by Author "Ajayaghosh, A"

Now showing 1 - 4 of 4
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    Cyclometalated Ir(III) complex as lysosome targeted photodynamic therapeutic agent for integrated imaging and therapy in cancer cells.
    (Chemistry - A European Journal, 2018-06) Sudheesh, KV; Jayaram, PS; Samanta, A; Kochan, S; Bejoymohandas, KS; Jayasree, RS; Ajayaghosh, A
    Organelle targeted photosensitizers (PSs) having luminescence properties are potential theranostic agents for simultaneous luminescence imaging and photodynamic therapy. Herein, we report a water soluble luminescent cyclometalated Ir(III) complex, Ir-Bp-Ly as lysosome targeted theranostic probe. Ir-Bp-Ly exhibits exceptional photophysical properties of good triplet state quantum yield (0.90), singlet oxygen generation quantum yield (0.71 at pH 4) and long lifetime (1.47 µs). Interestingly, Ir-Bp-Ly localized mostly in the lysosome because of the presence of morpholine units, suggesting its potential as a lyso-tracker. Ir-Bp-Ly displayed notable PDT effect in C6 glioma cells, as these PS efficiently generated ROS owing to the close proximity energy levels between triplet energy states of Ir-Bp-Ly and molecular oxygen (3O2). The mechanism of cell death was studied through caspase-3/7 and flow cytometry analysis that clearly established the apoptotic pathway.
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    Fluorescence Imaging Assisted Photo dynamic Therapy Using Photosensitizer-Linked Gold Quantum Clusters
    (ACS NANO, 2015) Nair, LV; Nazeer, SS; Jayasree, RS; Ajayaghosh, A
    Fluorescence imaging assisted photodynamic therapy (PDT) is a viable two-in-one clinical tool for cancer treatment and follow-up. While the surface plasmon effect of gold nanorods and nanoparticles has been effective for cancer therapy, their emission properties when compared to gold nanoclusters are weak for fluorescence imaging guided PDT. In order to address the above issues, we have synthesized a near-infrared-emitting gold quantum cluster capped with lipoic acid (L-AuC with (Au)(18)(L)(14)) based nanoplatform with excellent tumor reduction property by incorporating a tumor-targeting agent (folic acid) and a photosensitizer (protoporphyrin IX), for selective PDT. The synthesized quantum cluster based photosensitizer PFL-AuC showed 80% triplet quantum yield when compared to that of the photosensitizer alone (63%). PFL-AuC having 60 mu g (0.136 mM) of protoporphyrin IX was sufficient to kill 50% of the tumor cell population. Effective destruction of tumor cells was evident from the histopathology and fluorescence imaging, which confirm the in vivo PDT efficacy of PFL-AuC.
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    A Near-Infrared Fluorescent Nanosensor (AuC@Urease) for the Selective Detection of Blood Urea
    (Small, 2013-04) Nair, LV; Philips, DS; Jayasree, RS; Ajayaghosh, A
    The use of a nanosensor (AuC@Urease) based on an NIR-emitting gold cluster and urease enzyme selectively detects urea in whole blood. The detection is based on an enzyme-specific conversion of urea to ammonium ions which facilitates pH-induced aggregation of AuC, leading to fluorescence quenching. This method does not interfere with urease inactive analytes or the autofluorescence of blood as confirmed by comparable urea levels obtained by AuC@Urease and standard clinical methods within an error limit of ±3%
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    Real Time Imaging and Dynamics of Hippocampal Zn2+ under Epileptic Condition Using a Ratiometric Fluorescent Probe
    (Sci Rep. 2018, 2018-06) Santhakumar, H; Nair, RV; Philips, DS; Shenoy, SJ; Thekkuveettil, A; Ajayaghosh, A; Jayasree, RS