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296 results on '"Shieh, Yeong-Tarng"'

18. A CO 2 -Responsive Imidazole-Functionalized Fluorescent Material Mediates Cancer Chemotherapy.

Author

Ngan, Vo Thuy Thien, Chiou, Po-Yen, Ilhami, Fasih Bintang, Bayle, Enyew Alemayehu, Shieh, Yeong-Tarng, Chuang, Wei-Tsung, Chen, Jem-Kun, Lai, Juin-Yih, and Cheng, Chih-Chia

Subjects
CANCER chemotherapy, CARBON dioxide, ERYTHROCYTES, ANTINEOPLASTIC agents, LIGHT absorption
Abstract

We present a breakthrough in the synthesis and development of functional gas-responsive materials as highly potent anticancer agents suitable for applications in cancer treatment. Herein, we successfully synthesised a stimuli-responsive multifunctional material (I-R6G) consisting of a carbon dioxide (CO2)-sensitive imidazole moiety and spirolactam-containing conjugated rhodamine 6G (R6G) molecule. The resulting I-R6G is highly hydrophobic and non- or weakly fluorescent. Simple CO2 bubbling treatment induces hydrophobic I-R6G to completely dissolve in water and subsequently form self-assembled nanoparticles, which exhibit unique optical absorption and fluorescence behaviours in water and extremely low haemolytic ability against sheep red blood cells. Reversibility testing indicated that I-R6G undergoes reversible CO2/nitrogen (N2)-dependent stimulation in water, as its structural and physical properties can be reversibly and stably switched by alternating cycles of CO2 and N2 bubbling. Importantly, in vitro cellular assays clearly demonstrated that the CO2-protonated imidazole moiety promotes rapid internalisation of CO2-treated I-R6G into cancer cells, which subsequently induces massive levels of necrotic cell death. In contrast, CO2-treated I-R6G was not internalised and did not affect the viability of normal cells. Therefore, this newly created system may provide an innovative and efficient route to remarkably improve the selectivity, safety and efficacy of cancer treatment. [ABSTRACT FROM AUTHOR]

Published
2023
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37. Preparation of pH-responsive poly(methyl methacrylate) nanoparticles with CO2-triggered aggregation.

Author

Hong, Wei-Xiang, Shevtsov, Vladislav Y., and Shieh, Yeong-Tarng

Subjects
METHACRYLIC acid, METHYL methacrylate, ADDITION polymerization, EMULSION polymerization, CARBOXYLIC acids, RANDOM copolymers, NANOPARTICLES
Abstract

Healthcare industry is one of the major consumers of surface-modified polymer nanoparticles (NPs). If an incorporation of the stimuli-responsive polymers to such NPs is achieved, it can potentially broaden the range of their applications tremendously. In this work, an emulsifying ability of poly(methacrylic acid) (PMAA) and a series of its random methyl methacrylate (MMA) copolymers (PMAA-co-PMMA) prepared by free-radical polymerization was studied. It was found that these random copolymers and PMAA homopolymer could act as the surfactants (at certain pH values) in aqueous emulsion polymerization of MMA, which produces spherical PMMA NPs with carboxylic groups on the particles' surface. With the help of 1H NMR analysis it was determined that the PMMA NPs synthesized in this manner had 9.6 wt% PMAA (or PMAA-co-PMMA) coating, and due to that, the aqueous dispersions of these NPs exhibited pH-responsiveness. Although all the dispersions prepared were pH-responsive, only PMAA15-co-PMMA85/PMMA latex was found to be CO2-responsive: this sample could undergo CO2-triggered aggregation and N2-triggered redispersion. This newly developed method of preparation of smart NPs functionalized with carboxylic acid groups is uncomplicated and provides an environmentally friendly way of adjusting the dispersions' properties using gases only, avoiding the necessity of acids and bases addition. [ABSTRACT FROM AUTHOR]

Published
2022
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