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Kim S.,Kyungpook National University | Lee J.,Gwangju Institute of Science and Technology | Lee S.J.,BIO-NEMS | Lee H.J.,Kyungpook National University
Talanta | Year: 2010

This paper describes an ultra-sensitive surface-based detection method using nanoparticle-enhanced surface plasmon resonance (SPR) for the detection of immunoglobulin E (IgE) proteins, which could potentially be used for the diagnosis of allergic diseases. Two different probes, anti-IgE and IgE specific aptamers, which can specifically interact with IgE at different epitopes were first investigated for their specific interaction with IgE using SPR. Langmuir adsorption coefficient (Kads) values were measured as 2.0(±0.22) × 108 M-1 and 2.2(±0.20) × 108 M-1 for IgE interactions with anti-IgE and IgE specific aptamers, respectively. The SPR detection limit of the simple adsorption of IgE onto either anti-IgE or IgE specific aptamers was found to be about 1 nM. In order to improve the SPR detection signal for IgE, two different approaches utilizing surface formed sandwich complexes with biofunctionalized gold nanoparticles (Au-Nps) were designed and their detection performance were compared; the complexes were created via the adsorption of IgE onto (i) surface immobilized anti-IgE followed by the adsorption of IgE specific aptamer coated gold nanoparticles and (ii) IgE specific aptamer surface with the subsequent adsorption of anti-IgE coated gold nanoparticles. Both detection schemes were able to directly measure IgE at femtomolar concentrations. © 2010 Elsevier B.V. All rights reserved.

Zheng S.,KAIST | Kim D.-K.,KAIST | Park T.J.,KAIST | Lee S.J.,BIO-NEMS | And 2 more authors.
Talanta | Year: 2010

A simple biosensing strategy for the diagnosis of patients with hepatitis B virus (HBV) was developed. This study can be divided into two themes, both of which utilized gold-binding polypeptide (GBP) fusion proteins: HBV surface antigen PreS2 (HBsAg) detection with GBP-fused single chain antibody (GBP-ScFv) and anti-HBsAg detection with GBP-HBsAg. These GBP-fusion proteins can directly bind onto the gold surface via the high binding affinity between the GBP and the gold surface, while at the same time, orient the recognition sites toward the sample for target binding. This one-step immobilization strategy, which greatly simplifies a fabrication process as well as maintaining biological activity of the recognition elements, can be applied to optical analytical methods, such as surface plasmon resonance (SPR) and localized surface plasmon resonance (LSPR). © 2010 Elsevier B.V. All rights reserved.

Lee K.G.,KAIST | Wi R.,KAIST | Park T.J.,Institute for the BioCentury | Yoon S.H.,Korea Minting and Security Printing Corporation | And 3 more authors.
Chemical Communications | Year: 2010

Fluorescent silica nanoparticles deposited with highly monodisperse gold nanoparticles (1-2 nm) were synthesized via the W/O method and intensive ultrasound irradiation. A large surface area of gold-doped fluorescent silica nanoparticle serves as a platform to immobilize a specific binding protein for biomolecules interaction in bioimaging applications. © 2010 The Royal Society of Chemistry.

Bae N.-H.,National NanoFab Center | Bae N.-H.,Hanbat National University | Han S.,Korea Institute of Machinery and Materials | Lee K.E.,Korea Institute of Machinery and Materials | And 2 more authors.
Current Applied Physics | Year: 2011

A micro thermoelectric device consists of bonding layer, electrodes and thermoelectric thin films. At interfaces between metallic electrodes, solder materials and thermoelectric thin films in a micro thermoelectric device, diffusion occurs and degrades its performance and reliability. Ni layer is used as the diffusion barrier in a commercial device using bulk thermoelectric materials, but few studies have been conducted to examine the diffusion phenomenon in a micro thermoelectric device using thermoelectric thin films. In this study, n-type Bi2Te3 and p-type Bi 0.5Sb1.5Te3 thin films were deposited by RF magnetron sputtering. Sn was considered as solder materials, and Au, Ag, Ni, Ta, TiN and TiW were used as diffusion barriers. According as increasing anneal temperature, we analyzed the diffusion characteristics at interfaces between solder materials and thermoelectric thin films. The cross section of interfaces was investigated using FE-SEM (field emission scanning electron microscope), and FE-TEM (field emission transmission electron microscope). © 2011 Elsevier B.V. All rights reserved.

Park J.H.,BIO-NEMS | Shim J.,Yeungnam University | Lee D.-Y.,Yeungnam University
Sensors | Year: 2010

A compact vertical scanner for an atomic force microscope (AFM) is developed. The vertical scanner is designed to have no interference with the optical microscope for viewing the cantilever. The theoretical stiffness and resonance of the scanner are derived and verified via finite element analysis. An optimal design process that maximizes the resonance frequency is performed. To evaluate the scanner's performance, experiments are performed to evaluate the travel range, resonance frequency, and feedback noise level. In addition, an AFM image using the proposed vertical scanner is generated. © 2010 by the authors.

Zhou H.,Pusan National University | Lee J.,Pusan National University | Park T.J.,Center for Nanobio Integration and Convergence Engineering | Lee S.J.,BIO-NEMS | Park J.Y.,South Korean National Fisheries Research and Development Institute
Sensors and Actuators, B: Chemical | Year: 2012

Quantitative detection of biomolecules (e.g. DNA and proteins) has become increasingly important in a variety of fields, including medical diagnostics, food safety, and anti-bioterrorism. We report a simple, sensitive, and inexpensive quantitative approach for DNA detection based on the optical properties of gold nanoparticles and gold-coated magnetic nanoparticle hybrids. We employed a simple one-step reaction to synthesize gold-coated iron oxide nanoparticles (Fe 3O 4-Au NP). Fe 3O 4 nanoparticles were used as the central core for preparation of Fe 3O 4-Au in an aqueous state without precipitation and aggregation of nanoparticles. Citrate-coated Fe 3O 4 nanoparticles were prepared and subsequently coated with Au layers through reduction of HAuCl 4 by citrate on the surface Fe 3O 4. The resulting Fe 3O 4-Au nanoparticles showed good paramagnetic properties and were coated with thin layers of gold atoms (∼10 nm) having an average diameter of ca. 20 nm. These magnetic nanoparticles were well-dispersed in water and stable at physiological pH without precipitation. Nucleic acid-functionalized Fe 3O 4-Au nanoparticles were then hybridized with complementary target DNA molecules. This resulted in nucleic acid-functionalized gold nanoparticles. To achieve high sensitivity, Fe 3O 4-Au nanoparticles were employed for the collection of gold nanoprobes that hybridized with complementary target DNA molecules. The Au-Fe 3O 4-Au nanocomplex remains in solution at a concentration proportional to the concentration of the target DNA and its optical properties allow it to be easily quantified using UV/Vis absorption spectroscopy. The limit of detection for this method was as low as 0.1 fM. This selectable detection system is easy to operate, inexpensive, and versatile, making it a candidate for future use in predicting the seafood safety risks through detection of different DNA sequences and any related genetic mutations. © 2012 Elsevier B.V. All rights reserved.

Freedman K.J.,Drexel University | Jurgens M.,Uppsala University | Prabhu A.,Drexel University | Ahn C.W.,BIO-NEMS | And 3 more authors.
Analytical Chemistry | Year: 2011

Single-molecule experimental techniques have recently shown to be of significant interest for use in numerous applications in both the research laboratory and industrial settings. Although many single-molecule techniques exist, the nanopore platform is perhaps one of the more popular techniques due to its ability to act as a molecular sensor of biological macromolecules. For example, nanopores offer a unique, new method for probing various properties of proteins and can contribute to elucidating key biophysical information in conjunction with existing techniques. In the present study, various forms of bovine serum albumin (BSA) are detected including thermally refolded BSA, urea-denatured BSA, and multiple forms of BSA detected at elevated electric field strengths (with and without urea). We also provide excluded volume measurements for each of these states that normally are difficult to obtain due to unknown and unstable protein conformations. © 2011 American Chemical Society.

Bio-Nems | Date: 2013-08-16

A method and system for classifying a target nucleic acid includes exposing, in a test system, one or more capture probes to the target nucleic acid. The one or more capture probes is attached to a surface. A first hybridization condition is established in the test system. A first degree of hybridization of the one or more capture probes with the target nucleic acid under the first hybridization condition is determined. A second hybridization condition in the test system is established. A second degree of hybridization of the one or more capture probes with the target nucleic acid under the second hybridization condition is determined and the target nucleic acid is classified by comparing the first and the second degrees of hybridization.

Methods in molecular biology (Clifton, N.J.) | Year: 2010

In this chapter, we discuss in detail the fabrication of carbon nanotube biosensors that use a single-walled carbon nanotube field-effect transistor (SWNT-FET) as a transducer, and aptamers as molecular recognition elements. We use a patterned growth technique to grow SWNTs on Si/SiO(2) substrates, and standard microfabrication procedures are then employed to fabricate sensing devices.

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