Browsing by Author "Wu, Shu Pao"

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    An isophorone-derived AIE-active probe for peroxynitrite detection and bioimaging applications
    (Royal Society of Chemistry, 2025-07-11) Lalitha, Raguraman; Vivek, Vishnu Halnor; Lu, Yueh-Hsun; Wu, Shu Pao; Velmathi, Sivan
    Compounds exhibiting aggregation-induced emission (AIE) are remarkable due to their characteristic restriction of intramolecular rotation, making them highly versatile for a wide range of applications. Herein, an isophorone based probe (IHP) was developed for the detection of peroxynitrite (ONOO−) using the C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 N as the reactive group. Photophysical investigations were conducted to explore the aggregation behaviour of IHP in two different solvent systems: DMSO:PBS and DMSO. In DMSO, only the monomeric form of the dye was observed, showing no unusual behaviour. However, in DMSO : PBS (1 : 1), multiple emitting species were detected, indicating the coexistence of dye aggregates and monomers. The fluorescence spectra exhibited wavelength-dependent changes, with the aggregates displaying a red-shift compared to the monomers, indicating J-aggregation. The AIE properties of IHP resulted in red emission, with a fluorescence response towards ONOO− through oxidative cleavage of the C N bond to an aldehyde accompanied by the shift in emission maximum. Under physiological conditions, the probe exhibited good selectivity and high sensitivity to ONOO−, low detection limit of 1.1 μM and rapid recognition within 200 seconds. Furthermore, the probe was effectively used to image exogenous and endogenous peroxynitrite in living cells. © 2025 The Royal Society of Chemistry.
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    New spirooxindole pyrrolidine/pyrrolizidine analogs: design, synthesis, and evaluation as an anticancer agent
    (Royal Society of Chemistry, 2025-05-19) Nivetha, Narayanasamy; Venkatesan, Janarthanan; Murugan, Dhanashree; Rangasamy, Loganathan; Wu, Shu Pao; Velmathi, Sivan
    A novel series of mesitylene-based spirooxindoles were synthesized via the multicomponent [3 + 2] cycloaddition reaction in a greener medium. Spectroscopic techniques such as 1H and 13C NMR and HRMS analysis were carried out for the structural elucidation of all the spirooxindole derivatives. The in vitro cytotoxicity properties of spirooxindole analogs 4/5(a-g) against the human lung (A549) cancer cell line exhibited encouraging outcomes. Of the fourteen synthesized spirooxindole analogs, seven compounds (4a, 4b, 4e, 4g, 5c, 5e, and 5f) showed greater potency towards the A549 lung cancer cell line. The cytotoxicity of the spirooxindole analogs was also investigated against a non-cancerous mouse embryonic fibroblast NIH-3T3 cell line. Compounds 5e and 5f, which exhibited better cytotoxic effect against the cancerous A549 cells (3.48 and 1.2 μM), appeared to be non-cytotoxic against the non-cancerous mouse embryonic fibroblast. Studies using Hoechst and acridine orange/ethidium bromide staining also demonstrated the apoptotic effect of the potent compounds, which decreased cell proliferation. © 2025 The Royal Society of Chemistry.