Korea University · Engineering
Professor Jeong Hoon Lee's research lab specializes in micro- and nanofluidic systems, with a focus on developing innovative, low-cost, and disposable devices for biomedical diagnostics and single-cell analysis. The lab pioneers novel fabrication techniques—such as plasma bonding, ion-selective membrane printing, and junction gap breakdown—for creating high-performance protein and enzyme preconcentrators in PDMS. Their work emphasizes enhancing sensitivity and reaction kinetics in biochemical assays, particularly for low-abundance biomolecules, enabling rapid, high-throughput detection with minimal sample volumes. The lab also explores functional materials, including PZT-based microcantilevers and metallic photonic crystals, for applications in biosensing and tailored thermal emission.
Figures are computed from collected data and may differ slightly.
In this paper, we report a new method of fabricating a high-throughput protein preconcentrator in poly(dimethylsiloxane) (PDMS) microfluidic chip format. We print a submicron thick ion-selective membrane on the glass substrate by using standard patterning techniques. By simply plasma-bonding a PDMS microfluidic device on top of the printed glass substrate, we can integrate the ion-selective membrane into the device and rapidly prototype a PDMS preconcentrator without complicated microfabrication
Simple and efficient sample concentration tools are the key to the application of proteomics in a biological system. In this paper, we developed a method to realize a nanofluidic preconcentrator on a poly(dimethylsiloxane) (PDMS)-based microfluidic channel. The originality of our preconcentration device is the simple nanogap formation using the junction gap breakdown phenomenon between two PDMS microchannels, without using any photolithography and etching techniques. From the dc current measurem
A micromachined PZT (52/48) thin film cantilever composed of SiO2/Ta/Pt/PZT/Pt/SiO2 on a SiNx supporting layer for simultaneous self-exciting and sensing was fabricated. We present the resonant frequency change of piezoelectric microcantilevers due to a combination of mass loading and spring constant variation arisen from antigen-antibody interaction of C-reactive protein (CRP). Experimentally measured resonant frequency shift is larger than that of theoretically calculated resonant frequency by
We report a novel method of increasing both the reaction rate and the sensitivity of low-abundance enzyme assay using a micro/nanofluidic preconcentration chip. The disposable preconcentration device made out of PDMS with a surface-patterned ion-selective membrane increases local enzyme/substrate concentrations for rapid monitoring of enzyme activity. As a model system, we used trypsin as the enzyme and BODIPY FL casein as the fluorogenic substrate. We demonstrated that the reaction rate of tryp
In this paper, we reported a simple, disposable PDMS micro/nanofluidic preconcentration chip for in vitro concentration-enhanced cell kinase assays. Utilizing the preconcentration (electrokinetic trapping) directly from cell lysate (1 mM ATP) samples, we could achieve at least a 25-fold increase in reaction velocity and 65-fold enhancement in sensitivity. In addition, we shorten the assay time down to less than 10 min, with the sample volume requirements of down to approximately 5 cells. This de
Woodpile metallic photonic crystals are fabricated by using soft lithography and electrodeposition (see figure) for tailored thermal emission. This method produces a highly layered full-metallic structure with excellent structural fidelity. By adding a homogeneous monolithic backplane to the conventional woodpile structure, the difficulty of alignment in layer-by-layer fabrication is alleviated, while preserving characteristic enhanced thermal emission.
Two-polymer microtransfer molding (2P-μTM), an advanced microtransfer molding technique, is developed for fabrication of 3D microstructures. The use of two different photocurable prepolymers and a simple and robust filling and coating method allows an extremely high yield in layer-by-layer microfabrication able to produce highly layered microstructures with high structural fidelity (see Figure).
In recent years, Kelvin probe force microscopy (KPFM) has emerged as a versatile toolkit for exploring electrical properties on a broad range of nanobiomaterials and molecules. An analysis using KPFM can provide valuable sample information including surface potential and work function of a certain material. Accordingly, KPFM has been widely used in the areas of material science, electronics, and biomedical science. In this review, we will briefly explain the setup of KPFM and its measuring princ
The ability to measure pressure and force is essential in biomedical applications such as minimally invasive surgery (MIS) and palpation for detecting cancer cysts. Here, we report a force sensor for measuring a shear and normal force by combining an arrayed piezoelectric sensors layer with a precut glass top plate connected by four stress concentrating legs. We designed and fabricated a thin film piezoelectric force sensor and proposed an enhanced sensing tool to be used for analyzing gentle to
Paper-based analytical devices (e.g. lateral flow assays) are highly advantageous as portable diagnostic systems owing to their low costs and ease of use. Because of their low sensitivity and detection limits for biomolecules, these devices have several limitations in applications for real-field diagnosis. Here, we demonstrate a paper-based preconcentration enhanced lateral flow assay using a commercial β-hCG-based test. Utilizing a simple 9 V battery operation with a low power consumption of ap
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