Tan Mei Chee
Email Address
msetmc@nus.edu.sg
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Publication NIR-sensitive nanoparticle(2009-10-13) CHOW, GAN MOOG; TAN, MEI CHEE; REN, LEI; YING, JACKIE YI-RU; SINGAPORE-MIT ALLIANCE; CHEMISTRY; MATERIALS SCIENCE AND ENGINEERING; NATIONAL UNIVERSITY OF SINGAPOREIt is provided a Near Infrared Sensitive (NIR-sensitive) nanoparticle complex comprising a NIR-sensitive nanoparticle and surfactant(s) adsorbed on the nanoparticle, wherein the surfactant is at least one surfactant selected from: ##STR00001## wherein X=1-9; Y=0-9; n=0-9; Z=1-9; W=0-9; m=0-9; each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4, if present, is H, substituted or unsubstituted C.sub.1-C.sub.6 alkyl, substituted or unsubstituted C.sub.1-C.sub.6 aryl, HS, COOH, NH.sub.2 or OH; R.sup.5 is COOH, NH.sub.2 or OH; with the proviso that n+m is <10; (b) an amino acid having the structure in (a), wherein X=1; Y=2; Z=1; W=1; R.sup.1, R.sup.2 and R.sup.4 are not present; R.sup.3 is NH.sub.2; and R.sup.5 is COOH; or (c) a peptide, wherein the peptide comprise at least one amino acid (b). Further, it is provided a NIR-sensitive nanoparticle complex(es) having biomolecule(s), for example drug(s), loaded on the surfactant(s).Publication NIR sensitive Au-Au 2S nanoparticles as the potential optically-activated drug delivery systems(2008) Ren, L.; Wang, Z.-Y.; Liu, W.; Qiao, Y.-P.; Zhang, Q.-Q.; Tan, M.-C.; Chow, G.-M.; MATERIALS SCIENCE AND ENGINEERINGPublication Biocompatibility of near-IR sensitive Au-based nanoparticles as the potential drug delivery carriers(2007) Zhang, B.; Huang, X.-L.; Ren, L.; Zhang, Q.-Q.; Tan, M.-C.; Chow, G.-M.; MATERIALS SCIENCE AND ENGINEERINGWe successfully synthesized near infrared (NIR) sensitive Au(shell)-Au 2S(core) nanoparticles, where Au2S dielectric core was encapsulated by a thin gold shell. The cytotoxicity in vitro and biodistribution in vivo of Au-Au2S nanoparticles was studied by using NIH3T3 cells and KM mice, respectively. The quantitative analysis of Au in each tissue of mice was done by using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Au-Au2S nanoparticles (< 300 μg/ml) showed good biocompatibility. Au-Au2S nanoparticles were preferentially taken up by the liver and spleen, and ultimately eliminated mostly in the feces.Publication In vivo toxic studies and biodistribution of near infrared sensitive Au-Au2S nanoparticles as potential drug delivery carriers(2008-07) Huang, X.-L.; Zhang, B.; Ren, L.; Ye, S.-F.; Sun, L.-P.; Zhang, Q.-Q.; Tan, M.-C.; Chow, G.-M.; MATERIALS SCIENCE AND ENGINEERINGNear infrared (NIR) sensitive Au-Au2S nanoparticles are intensively being developed for biomedical applications including drug and gene delivery. Although all possible clinical applications will require compatibility of Au-Au2S nanoparticles with the biological milieu, their in vivo capabilities and limitations have not yet been explored. Au-Au2S nanoparticles and cisplatin-loaded Au-Au2S nanoparticles were successfully synthesized by the reduction of tetrachloroauric acid (HAuCl 4) using sodium sulfide (Na2S), and cisplatin was loaded onto NIR sensitive Au-Au2S nanoparticles via an MUA (11-mercaptoundecanoic acid) layer. In this work, acute systemic toxicity in vivo, blood biochemistry assay, and tissue distribution in mice were carried out to further investigate the biocompatibility and biodistribution of these nanoparticles. The results from these studies demonstrated that both of nanoparticles (Publication A detailed understanding of the enhanced hypothermic productivity of interferon-γ by Chinese-hamster ovary cells(2005-06) Fox, S.R.; Tan, H.K.; Tan, M.C.; Wong, S.C.N.C.; Yap, M.G.S.; Wang, D.I.C.; MATERIALS SCIENCE AND ENGINEERING; CHEMICAL & BIOMOLECULAR ENGINEERINGCulturing CHO (Chinese-hamster ovary) cells at low temperature leads to growth arrest in the G0/G1 phase of the cell cycle and, in many cases, causes an increase in the specific productivity of recombinant protein. Controlled proliferation is often used to increase CHO specific productivity, and thus there is speculation that the enhanced productivity at low temperature is due to G0/G1-phase growth arrest. However, we show that the positive effect of low temperature on recombinant protein production is due to elevated mRNA levels and not due to growth arrest and that a cell line can still exhibit growth-associated productivity at low temperatures. Using a CHO cell producing recombinant human IFN-γ (interferon-γ), we show that productivity increases as the percentage of cells in the S phase of the cell cycle increases, at both 32 and 37 °C. The increased productivity is due to higher recombinant IFN-γ mRNA levels. We also show that, for a given cell-cycle distribution, specific productivity increases as the temperature is lowered from 37 to 32 °C. Thus specific productivity is maximized when cells are actively growing (high percentage of S-phase cells) and also exposed to low temperature. These findings have important implications for cell-culture optimization and cell-line engineering, providing evidence that a CHO cell line capable of actively growing at low temperature would provide improved total protein production relative to the current growth strategies, namely 37 °C active growth or low-temperature growth arrest. © 2005 Portland Press Ltd.Publication Cisplatin-loaded Au-Au2S nanoparticles for potential cancer therapy: Cytotoxicity, in vitro carcinogenicity, and cellular uptake(2008-06-01) Ren, L.; Huang, X.-L.; Zhang, B.; Sun, L.-P.; Zhang, Q.-Q.; Tan, M.-C.; Chow, G.-M.; MATERIALS SCIENCE AND ENGINEERINGCisplatin is one of the most effective cytotoxic agents against cancers. Its usage, however, is limited because of severe resistance and systemic toxicity. A formulation of cisplatin-loaded Au-Au2S nanoparticles (NPs) with near-IR (NIR) sensitivity is reported to partly overcome this limitation in this paper. NIR sensitive Au-Au2S NPs were successfully synthesized by the reduction of tetrachloroauric acid (HAuCl4) using sodium sulfide (Na2S), and cisplatin was loaded onto Au-Au 2S NPs via a MUA (11-mercaptoundecanoic acid) layer. To further investigate the biological safety of cisplatin-loaded Au-Au2S NPs, three different cell lines were used to investigate the acute cytotoxicity and the long-term potential carcinogenicity in vitro. Cisplatin-loaded Au-Au 2S NPs were also tested for limited hemocompatibility in vitro. Our in vitro short and long-term data provided preliminary evidence suggesting that cisplatin-loaded Au-Au2S NPs with NIR sensitivity are nontoxic below the maximum recommended dosage. © 2007 Wiley Periodicals, Inc.Publication NIR-sensitive nanoparticle(2006-05-11) CHOW, GAN MOOG; TAN, MEI CHEE; REN, LEI; YING, JACKIE YI-RU; SINGAPORE-MIT ALLIANCE; MATERIALS SCIENCE AND ENGINEERING; CHEMICAL & BIOMOLECULAR ENGINEERINGIt is provided a Near Infrared Sensitive (NIR-sensitive) nanoparticle complex comprising a NIR-sensitive nanoparticle and surfactant(s) adsorbed on the nanoparticle, wherein the surfactant is at least one surfactant selected from: wherein X=1-9; Y=0-9; n=0-9; Z=1-9; W=0-9; m=0-9; each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4, if present, is H, substituted or unsubstituted C.sub.1-C.sub.6 alkyl, substituted or unsubstituted C.sub.1-C.sub.6 aryl, HS, COOH, NH.sub.2 or OH; R.sup.5 is COOH, NH.sub.2 or OH; with the proviso that n+m is <10; (b) an amino acid having the structure in (a), wherein X=1; Y=2; Z=1; W=1; R.sup.1, R.sup.2 and R.sup.4 are not present; R.sup.3 is NH.sub.2; and R.sup.5 is COOH; or (c) a peptide, wherein the peptide comprise at least one amino acid (b). Further, it is provided a NIR-sensitive nanoparticle complex(es) having biomolecule(s), for example drug(s), loaded on the surfactant(s).