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Park S.,Dankook University | Song B.,Dankook University | Kong H.Y.,Institute of Nanosensor and Biotechnology | Byun J.,Institute of Nanosensor and Biotechnology | Hwang C.-S.,Dankook University
Bulletin of the Korean Chemical Society | Year: 2014

In this study, water-dispersible ZnS:Mn nanocrystals were synthesized by capping the surface with conventional and simple structured amino acid ligands: L-Glycine and L-Alanine. The ZnS:Mn-Gly and ZnS:Mn-Ala nanocrystal powders were characterized by XRD, HR-TEM, EDXS, ICP-AES, and FT-IR spectroscopy. The optical properties were measured by UV-Visible and photoluminescence (PL) spectroscopy. The PL spectra for the ZnS:Mn-Gly and ZnS:Mn-Ala showed broad emission peaks at 599 nm and 607 nm with PL efficiencies of 6.5% and 7.8%, respectively. The measured average particle size from the HR-TEM images were 6.4 ± 0.8 nm (ZnS:Mn-Gly) and 4.1 ± 0.5 nm (ZnS:Mn-Ala), which were also supported by Debye-Scherrer calculations. In addition, the degree of aggregation of the nanocrystals in aqueous solutions were measured by a hydrodynamic light scattering method, which showed formation of sub-micrometer size aggregates for both ZnS:Mn-Gly (273 ± 94 nm) and ZnS:Mn-Ala (233 ± 34 nm) in water due to the intermolecular attraction between the capping amino acids molecules. Finally, the cytotoxic effects of ZnS:Mn-Gly and ZnS:Mn-Ala nanocrsystals over the growth of wild type E. coli were investigated. As a result, no toxicity was shown for the ZnS:Mn-Gly nanocrystal in the colloidal concentration region from 1 μg/mL to 1000 μg/mL, while ZnS:Mn- Ala showed significant toxicity at 100 μg/mL. Source

Kim M.Y.,Institute of Nanosensor and Biotechnology | Kim M.Y.,Dankook University | Jeong S.,Institute of Nanosensor and Biotechnology | Jeong S.,Dankook University
Nucleic Acid Therapeutics | Year: 2011

The ErbB family (also referred to as HER/neu or HER) of receptor tyrosine kinases plays major roles in the formation and progression of human tumors. Amplification and/or overexpression of ErbB2 have been reported in numerous cancers, including breast, ovarian, stomach, bladder, salivary, and lung cancers. As ErbB2 has been used as a target for the treatment of advanced cancer, RNA aptamers for the extracellular domain of the ErbB2 were selected from a RNA library consisting of 2′-fluorine-modified RNA transcripts. After 15 cycles of selection, high-affinity RNA aptamer was isolated. Binding patterns of the selected RNA aptamer clones were evaluated to choose RNA aptamers that were specific to the extracellular domain of ErbB2 protein. RNA aptamer 15-8 was the best candidate and its minimal version (mini-aptamer) was chemically synthesized. Surface plasmon resonance measurement showed that the mini-aptamer specifically bound to the ErbB2 protein with high affinity and specificity. To evaluate its potential as an ErbB2-targeting molecule in breast cancer cells, specific recognition of the mini-aptamer was confirmed with various breast cancer cell lines. We propose that the selected RNA aptamer is a potential cancer imaging agent by targeting malignant cells overexpressing the ErbB2 receptor. © 2011, Mary Ann Liebert, Inc. Source

Lee C.H.,Institute of Nanosensor and Biotechnology | Lee S.-H.,Konkuk University | Kim J.H.,Institute of Nanosensor and Biotechnology | Noh Y.-H.,University of California at San Francisco | And 2 more authors.
Molecular Therapy - Nucleic Acids | Year: 2015

Hepatitis C virus (HCV) is the major cause of progressive liver disease such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Previously, we reported that a 29 nucleotide-long 2'-F pyrimidine modified RNA aptamer against the HCV nonstructural protein 5B efficiently inhibited HCV replication and suppressed HCV infectious virus particle formation in a cell culture system. In this study, we modified this aptamer through conjugation of cholesterol for in vivo availability. This cholesterol-conjugated aptamer (chol-aptamer) efficiently entered the cell and inhibited HCV RNA replication, without any alteration in gene expression profiling including innate immune response-related genes. Moreover, systemic administration of the chol-aptamer was well tolerated without any abnormalities in mice. To evaluate the pharmacokinetics of the chol-aptamer in vivo, dose proportionality, bioavailability, and pharmacokinetic parameters were evaluated by noncompartmental analyses in normal BALB/c mice. Population analysis was performed using nonlinear mixed effects modeling. Moreover, the pharmacokinetics of two different routes (intravenous, IV, versus intraperitoneal, IP) were compared. Cholesterol conjugation showed dose proportionality, extended the time that the aptamer was in the plasma, and enhanced aptamer exposure to the body. Noticeably, the IV route was more suitable than the IP route due to the chol-aptamer remaining in the plasma for a longer period of time. Source

Won Y.-S.,Institute of Nanosensor and Biotechnology | Jeong J.-S.,Dong - A University | Kim S.J.,Institute of Nanosensor and Biotechnology | Ju M.H.,Dong - A University | Lee S.-W.,Institute of Nanosensor and Biotechnology
Cancer Letters | Year: 2015

We previously generated a group I intron-based ribozyme that can reprogram human telomerase reverse transcriptase (hTERT) RNA to stimulate transgene activity in cancer cells expressing the target RNA via an accurate and specific trans-splicing reaction. One of the major concerns of the hTERT RNA targeting anti-cancer approach is the potential side effects to hTERT(+) hematopoietic stem cell-derived blood cells. Thus, here we modified the ribozyme by inserting target sites against microRNA-181a, which is a blood cell-specific microRNA, downstream of its 3' exon. The specificity of transgene induction and anticancer activity in hTERT(+) cancer cells improved significantly with the modified ribozyme, resulting in selective targeting of hTERT(+) cancer cells, but not hematopoietic cells even if they are hTERT-positive. Importantly, the trans-splicing reaction of the microRNA-regulated ribozyme worked equally well in a nude mouse model of hepatocarcinoma-derived intrasplenic carcinomatosis, inducing highly specific expression of a therapeutic transgene and efficiently regressing hTERT-positive liver tumors with minimal liver toxicity when systemically delivered with an adenoviral vector encoding the ribozyme. These results suggest that a combined approach of microRNA regulation with targeted RNA replacement is more useful for effective anti-cancer treatment. © 2014 Elsevier Ireland Ltd. Source

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