Jungyoup Han

A novel microfluidic microplate as the next generation assay platform for enzyme linked immunoassays (ELISA)

In this work we introduce a novel microfluidic enzyme linked immunoassays (ELISA) microplate as the next generation assay platform for unparalleled assay performances. A combination of microfluidic technology with standard SBS-configured 96-well microplate architecture, in the form of microfluidic microplate technology, allows for the improvement of ELISA workflows, conservation of samples and reagents, improved reaction kinetics, and the ability to improve the sensitivity of the assay by multiple analyte loading. This paper presents the design and characterization of the microfluidic microplate, and its application in ELISA.

Highly sensitive rapid, reliable, and automatic cardiovascular disease diagnosis with nanoparticle fluorescence enhancer and mems.

Cardiovascular diseases (CVDs) have been the leading threat to human life. An effective way for sensitive and accurate CVD diagnosis is to measure the biochemical markers released from the damaged myocardial cells in the bloodstream. Here, a multi-analyte, fluorophore mediated, fiber-optic immuno-biosensing system is being developed to simultaneously and rapidly quantify four clinically important cardiac markers, myoglobin, C-reactive protein, cardiac troponin I, and B-type natriuretic peptide. To quantify these markers at a pico-molar level, novel nanoparticle reagents enhancing fluorescence were used and signal enhancement was obtained as high as approximately 230%. Micro-electro-mechanical system (MEMS) was integrated to this system to ensure a reliable and fully-automated sensing performance. A point-of-care, automatic microfluidic sensing system for four cardiac marker quantification was developed with the properties of 3 cm sensor size, 300 microL sample volume, 9-minute assay time, and an average signal-to-noise ratio of 35.

A disposable plastic biochip cartridge with on-chip power sources for blood analysis

This paper presents the development of a disposable plastic biochip with embedded on-chip power sources and integrated biosensor array for applications in clinical diagnostics and point-of-care systems. A cartridge type disposable plastic biochip has been successfully developed and demonstrated for precise sample volume control with smart microfluidic manipulation without costly on-chip active microfluidic components. In addition, the disposable plastic biochip has successfully been tested for the measurements of partial oxygen concentration, glucose, and lactate level in human blood using an integrated biosensor array.

An innovative sample-to-answer polymer lab-on-a-chip with on-chip reservoirs for the POCT of thyroid stimulating hormone (TSH)

A new sample-to-answer polymer lab-on-a-chip, which can perform immunoassay with minimum user intervention through on-chip reservoirs for reagents and single microchannel assay, has been designed, developed and successfully characterized as a point-of-care testing (POCT) cartridge for the detection of thyroid stimulating hormone (TSH). Users only need to drop a sample to the POCT cartridge to obtain test results within 30 minutes. The analyzed results of TSH showed a linear range up to 55 μIU/mL with the limit of detection (LOD) of 1.9 μIU/mL at the signal to noise ratio (SNR) of 3. The reagents stored in the on-chip reservoirs maintained their volume more than 97 % of initial volume for 100 days of storage time while the detection antibody retained its activity above 97 %.

An on-chip blood serum separator using self-assembled silica microsphere filter

In this paper, we report a disposable on-chip blood serum separator using self-assembled silica microsphere filter, which can passively separate serum from human blood. A self-assembly packing method was developed for packing silica microspheres through a microfluidic channel on cyclic olefin copolymer (COC) substrate. Using the self-assembled microsphere filter, serum has been successfully separated from diluted human blood. The filters realized in this work are suitable for incorporating into a disposable polymer lab-on-a-chip, which can perform point-of-care testing (POTC) for clinical diagnostics using human blood.

Development of a rotary disc voltammetric sensor system for semi-continuous and on-site measurements of Pb(II).

Atomic absorption spectrometry and inductively coupled plasma-mass spectrometry are widely used for determination of heavy metals due to their low detection limits. However, they are not applicable to on-site measurements of heavy metals as bulky equipment, and highly skilled laboratory staffs are needed as well. In this study, a novel analytical method using a rotary disc voltammetric (RDV) sensor has been successfully designed, fabricated and characterized for semi-continuous and on-site measurements of trace levels of Pb(II) in non-deoxygenating solutions. The square wave anodic stripping voltammetry was used to improve the sensitivity of the Pb(II) detection level with less than 10nM (2μgL(-1)). The RDV sensor has 24-sensing holes to measure concentrations of Pb(II) semi-continuously at sampling sites. Each sensing hole consists of a silver working electrode, an integrated silver counter, and a quasi-reference electrode, which requires only a small amount of samples (<30μL) for measurement of Pb(II) without disturbing and/or clogging the sensing environment. In addition, the RDV sensor showed a correlation coefficient of 0.998 for the Pb(II) concentration range of 10nM-10μM at the deposition time of 180s and its low detection limit was 6.19nM (1.3μgL(-1)). These results indicated that the advanced monitoring technique using a RDV sensor might provide environmental engineers with a reliable way for semi-continuous and on-site measurements of Pb(II).

Novel Biomarkers Detection and Identification by Microfluidic- Based MicroELISA

Miniaturized, high throughput detection technologies including microfluidics systems represent powerful tools for biomarker discovery and analysis. Optimiser™ microplate technology combines microfluidics technology with standard SBS-configured 96-well microplate architecture and allows for the improvement of ELISA workflows. In this review, we present the “standard” and “high sensitivity” capabilities of the Optimiser™ ELISA in detecting human cytokine biomarker; IL-4, resulting in improving sensitivity by 1000-fold higher than the typical conventional ELISA. The Optimiser™ ELISA microplate employs standard ELISA equipment and protocols, selectively reduces sample volume 10-20 fold (Static Mode) and has the capability to amplify assay sensitivity by 1,000 fold (Repetitive Loading Flow-Through Mode) relative to conventional high sensitivity ELISA approaches. Optimiser™ allows sensitive and quantitative detection of biomarkers with demonstrated reproducibility, speed and linearity. In this study we demonstrate the utilization of OptmiserTM in the amplification of low-concentration markers. Optimiser™ microfluidic-based technology represents a revolutionary advancement in ELISA technology, and holds great promise for accurate, sensitive detection of novel biomarkers and its potential applications in clinical diagnosis.

Automated Fluidic System with a Chaotic Microfluidic Reaction Chamber for Rapid, Multi-Analyte Immunosensing

In this paper, a fully automated fluidic system with a chaotic reaction chamber for rapid and accurate fiber-optic immuno-sensing has been developed and applied for the measurement of cardiac biomarkers. A new microchannel with serpentine bump structures has improved the sensor performance by generating local turbulence near the sensor surface. A full immunoassay with the automated fluidic system has been successfully performed, and the total assay time spent for detecting four cardiac markers was less than 10 minutes.