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A testing method is disclosed. The testing method includes: providing a mixture solution of a gelling agent and a microbe to a gelling device; solidifying the mixture solution to form a solid thin film in which the microbe is immobilized; supplying a bioactive agent to the solid thin film and allowing the bioactive agent to diffuse into the solid thin film; and imaging the individual responses of the single microbial cells to the bioactive agent, and determining the minimum inhibitory concentration (MIC) of the bioactive agent based on the analysis of the images to obtain AST results.


Choi J.,Seoul National University | Choi J.,Korea University | Jung Y.-G.,QuantaMatrix Inc. | Kim E.K.,Seoul National University | And 7 more authors.
17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013 | Year: 2013

The rise in antimicrobial resistance has become a serious global health problem. For proper treatment of antimicrobial resistive bacteria and suppress the antimicrobial resistance, rapid antibiotic susceptibility test (AST) for clinical application is urgently needed. However, currently available AST platforms need 9 hours in average to obtain the susceptibility result. In this research, we develop a rapid AST based on the morphological determination in single cell resolution. For single cell tracking, we use the agarose as fixing agent in the microfluidic channel which is integrated with 96 well plate for user friendly and high throughput test for clinical application. Copyright © (2013) by the Chemical and Biological Microsystems Society All rights reserved. All rights reserved.


Jang J.,Seoul National University | Jang J.,Seoul Semiconductor | Han S.,Seoul National University | Han S.,Seoul Semiconductor | And 7 more authors.
Microelectronic Engineering | Year: 2014

We introduce a conformal phosphor coating technique for white light-emitting diodes (LEDs) using image-processing-based maskless lithography (IP-ML). The use of IP-ML allows real-time recognition of LEDs, which enables the generation of photo-patterning masks on a spatial light modulator by means of image processing, making the process suitable for a chip-level conformal phosphor coating with contact openings. This automated photolithographic chip array coating process enables phosphor coating onto chips with a consistent thickness, and the chips treated using this method show a narrow color distribution in which the chromaticity is controllable by varying phosphor thickness and concentration. © 2014 Elsevier B.V. All rights reserved.


Choi J.,Korea Basic Science Institute | Choi J.,Seoul National University | Yoo J.,QuantaMatrix Inc. | Lee M.,QuantaMatrix Inc. | And 14 more authors.
Science Translational Medicine | Year: 2014

A rapid antibiotic susceptibility test (AST) is desperately needed in clinical settings for fast and appropriate antibiotic administration. Traditional ASTs, which rely on cell culture, are not suitable for urgent cases of bacterial infection and antibiotic resistance owing to their relatively long test times. We describe a novel AST called single-cellmorphological analysis (SCMA) that can determine antimicrobial susceptibility by automatically analyzing and categorizing morphological changes in single bacterial cells under various antimicrobial conditions. The SCMAwas testedwith four Clinical and Laboratory Standards Institute standard bacterial strains and 189 clinical samples, including extended-spectrum b-lactamase-positive Escherichia coli and Klebsiella pneumoniae, imipenem-resistant Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococci from hospitals. The results were compared with the gold standard broth microdilution test. The SCMA results were obtained in less than 4 hours, with 91.5% categorical agreement and 6.51% minor, 2.56% major, and 1.49% very major discrepancies. Thus, SCMA provides rapid and accurate antimicrobial susceptibility data that satisfy the recommended performance of the U.S. Food and Drug Administration. Copyright © 2014 American Association for the Advancement of Science.


Choi J.,Seoul National University | Yoo J.,QuantaMatrix Inc. | Lee M.,QuantaMatrix Inc. | Kim E.-G.,QuantaMatrix Inc. | And 10 more authors.
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015 | Year: 2015

A rapid antibiotic susceptibility test (AST) is desperately needed in clinical settings for fast and appropriate antibiotic administration. Traditional ASTs, which rely on cell culture, are not suitable for urgent cases of bacterial infection and antibiotic resistance owing to their relatively long test times. Here, we describe a novel AST called single-cell morphological analysis (SCMA) that can determine antimicrobial susceptibility by automatically analyzing and categorizing morphological changes in single bacterial cells under various antimicrobial conditions. The SCMA was tested with four Clinical and Laboratory Standards Institute standard bacterial strains and 189 clinical samples from hospitals. The results were compared with the gold standard broth microdilution test. The SCMA results were obtained in less than 4 hours with 91.5% categorical agreement and 6.51% minor, 2.56% major, and 1.49% very major discrepancies. Thus, SCMA provides rapid and accurate antimicrobial susceptibility data. © 2015 IEEE.


Kim J.,Seoul National University | Kim E.-G.,Seoul National University | Kim E.-G.,QuantaMatrix Inc. | Bae S.,Seoul National University | And 3 more authors.
Analytical Chemistry | Year: 2013

The parallelization of microfluidic cytometry is expected to lead to considerably enhanced throughput enabling point-of-care diagnosis. In this article, the development of a microfluidic potentiometric multichannel cytometer is presented. Parallelized microfluidic channels sharing a fluid path inevitably suffer from interchannel signal crosstalk that results from electrical coupling within the microfluidic channel network. By employing three planar electrodes within a single detection channel, we electrically decoupled each channel unit, thereby enabling parallel analysis by using a single cytometer microchip with multiple microfluidic channels. The triple-electrode configuration is validated by analyzing the size and concentration of polystyrene microbeads (diameters: 1.99, 2.58, 3, and 3.68 μm; concentration range: ∼2 × 105 mL-1 to ∼1 × 10 7 mL-1) and bacterial microdispersion samples (Bacillus subtilis, concentration range: ∼4 × 105 CFU mL-1 to ∼3 × 106 CFU mL-1). Crosstalk-free parallelized analysis is then demonstrated using a 16-channel potentiometric cytometer (maximum cross-correlation coefficients |r|: < 0.13 in all channel combinations). A detection throughput of ∼48 000 s-1 was achieved; the throughout can be easily increased with the degree of parallelism of a single microchip without additional technical complexities. Therefore, this methodology should enable high-throughput and low-cost cytometry. © 2012 American Chemical Society.


PubMed | QuantaMatrix Inc. and Seoul National University
Type: Journal Article | Journal: Biomicrofluidics | Year: 2015

Fabrication methods for the development of multiplexed immunoassay platforms primarily depend on the individual functionalization of reaction chambers to achieve a heterogeneous reacting substrate composition, which increases the overall manufacturing time and cost. Here, we describe a new type of low-cost fabrication method for a scalable immunoassay platform based on cotton threads. The manufacturing process involves the fabrication of functionalized fibers and the arrangement of these fibers into a bundle; this bundle is then sectioned to make microarray-like particles with a predefined surface architecture. With these sections, composed of heterogeneous thread fragments with different types of antibodies, we demonstrated quantitative and 7-plex immunoassays. We expect that this methodology will prove to be a versatile, low-cost, and highly scalable method for the fabrication of multiplexed bioassay platforms.


A testing method is disclosed. The testing method includes: providing a mixture solution of a gelling agent and a microbe to a gelling device; solidifying the mixture solution to form a solid thin film in which the microbe is immobilized; supplying a bioactive agent to the solid thin film and allowing the bioactive agent to diffuse into the solid thin film; and imaging the individual responses of the single microbial cells to the bioactive agent, and determining the minimum inhibitory concentration (MIC) of the bioactive agent based on the analysis of the images to obtain AST results.


A testing method is disclosed. The testing method includes: providing a mixture solution of a gelling agent and a microbe to a gelling device; solidifying the mixture solution to form a solid thin film in which the microbe is immobilized; supplying a bioactive agent to the solid thin film and allowing the bioactive agent to diffuse into the solid thin film; and imaging the individual responses of the single microbial cells to the bioactive agent, and determining the minimum inhibitory concentration (MIC) of the bioactive agent based on the analysis of the images to obtain AST results.


A testing method is disclosed. The testing method includes: providing a mixture solution of a gelling agent and a microbe to a gelling device; solidifying the mixture solution to form a solid thin film in which the microbe is immobilized; supplying a bioactive agent to the solid thin film and allowing the bioactive agent to diffuse into the solid thin film; and imaging the individual responses of the single microbial cells to the bioactive agent, and determining the minimum inhibitory concentration (MIC) of the bioactive agent based on the analysis of the images to obtain AST results.

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