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Lee J.H.,Seoul National University of Science and Technology | Roh J.H.,Korea Electronics Technology Institute | Shin K.S.,Korea Electronics Technology Institute | Lee D.S.,Korea Electronics Technology Institute | And 4 more authors.
17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 | Year: 2013

In this study, Si-NWs with the length of 200 jim, width of 200 nm, and height of 50 nm were fabricated using basic MEMS processes such as photolithography, RIE and KOH etching. They had high sensitivity and showed the FET characteristics due to high surface-to-volume ratio. Also, high affinity aptamers for prostate specific antigen (PSA) were immobilized on Si-NW using sol-gel method and then the real-time measurement of electrical signal of free-PSA and total-PSA which was guideline of prostate cancer was carried out according to PSA concentration. Copyright © (2013) by the Chemical and Biological Microsystems Society All rights reserved. Source

Kim T.K.,PCL Inc. | Jeong O.C.,Inje University
15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011 | Year: 2011

This paper presents the pneumatically-driven tensile stimulator for investigating the effect of mechanical strain on the intracellular calcium expression in MG-63 cells (human osteoblast-like bone cell line). An optically transparent micro tensile stimulator array consisting of the deformable diaphragms and the micro fluidic channels was fabricated with a polydimethylsiloxane (PDMS) and a glass substrate. A strain gradient generated by the three-dimensional dome-shape deformation of the circular diaphragm was applied to live cells seeded on the deformable diaphragm of the pneumatic stimulator. During operation, intracellular calcium responses were measured using a laser-scanning microscope. Our new finding from temporal responses of fluorescence intensities was that the period of measured calcium expressions of cells under different strain regions were matched well with the applied signal waveform of the external compressed air, and variations of the calcium expression might be also highly correlated with the magnitude of the strain. The release/uptake of intracellular calcium in the endoplasmic reticulum may be activated and more sensitive to applied strain. Copyright © (2011) by the Chemical and Biological Microsystems Society. Source

Chang C.I.,Sungkyunkwan University | Chang C.I.,Harvard University | Kim H.A.,PCL Inc. | Dua P.,Sungkyunkwan University | And 4 more authors.
Nucleic Acid Therapeutics | Year: 2011

Since the discovery of double-stranded (ds) RNA-mediated RNA interference (RNAi) phenomenon in Caenorhabditis elegans, specific gene silencing based upon RNAi mechanism has become a novel biomedical tool that has extended our understanding of cell biology and opened the door to an innovative class of therapeutic agents. To silence genes in mammalian cells, short dsRNA referred to as small interfering RNA (siRNA) is used as an RNAi trigger to avoid nonspecific interferon responses induced by long dsRNAs. An early structure-activity relationship study performed in Drosophila melanogaster embryonic extract suggested the existence of strict siRNA structural design rules to achieve optimal gene silencing. These rules include the presence of a 3′ overhang, a fixed duplex length, and structural symmetry, which defined the structure of a classical siRNA. However, several recent studies performed in mammalian cells have hinted that the gene silencing siRNA structure could be much more flexible than that originally proposed. Moreover, many of the nonclassical siRNA structural variants reported improved features over the classical siRNAs, including increased potency, reduced nonspecific responses, and enhanced cellular delivery. In this review, we summarize the recent progress in the development of gene silencing siRNA structural variants and discuss these in light of the flexibility of the RNAi machinery in mammalian cells. © 2011, Mary Ann Liebert, Inc. Source

Ahn J.-Y.,Cornell University | Ahn J.-Y.,Dongguk University | Jo M.,Dongguk University | Jo M.,PCL Inc. | And 3 more authors.
Oligonucleotides | Year: 2011

RNA and DNA aptamers that bind to target molecules with high specificity and affinity have been a focus of diagnostics and therapeutic research. These aptamers are obtained by SELEX often requiring many rounds of selection and amplification. Recently, we have shown the efficient binding and elution of RNA aptamers against target proteins using a microfluidic chip that incorporates 5 sol-gel binding droplets within which specific target proteins are imbedded. Here, we demonstrate that our microfluidic chip in a SELEX experiment greatly improved selection efficiency of RNA aptamers to TATA-binding protein, reducing the number of selection cycles needed to produce high affinity aptamers by about 80%. Many aptamers were identical or homologous to those isolated previously by conventional filter-binding SELEX. The microfluidic chip SELEX is readily scalable using a sol-gel microarray-based target multiplexing. Additionally, we show that sol-gel embedded protein arrays can be used as a high-throughput assay for quantifying binding affinities of aptamers. © 2011 Mary Ann Liebert, Inc. Source

A method of preparing a protein chip by gelation of a sol composition. In the method, a mixture of specific silicate monomers, such as SolB

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