Research | Hahn's Lab

Research Focus

The Hybrid Multiplexed Nanobiosensor Lab is conducting research on the development of noble platforms for the disease diagnosis and therapy by converging nano-bioengineering and biotechnology. Specifically, the HMN lab focuses on the development of biosensors, microfluidic devices, and lab on a chip for biological sample processing, biomolecule separation/analysis, and ultra-high sensitive detection by utilizing nano/micro fabrication technology. These studies can be widely applied to point-of-care testing based on various biomarkers and biomolecules detection, cell-based treatment and screening technologies, and nanobio-device development.

Hybrid Multiplexed Nanobiosensor 연구실은 나노바이오공학 및 생명과학 분야기술을 융합하여 새로운 질병 진단/치료 플랫폼 개발 연구를 수행하고 있습니다. 구체적으로는 나노/마이크로 가공 공정기술을 활용하여 생물학적 시료 전처리, 생체분자 분리 및 분석, 초고감도 검출을 위한 바이오센서, 미세유체소자 및 랩온어칩(lab on a chip) 개발에 중점을 두고 있습니다. 이러한 연구는 바이오마커 및 다양한 생체시료 검출을 이용한 현장진단기기(point-of-care testing), 세포 기반 치료 및 스크리닝 기술, 나노바이오 소자 개발 등에 널리 활용될 수 있습니다.

Magnetophoresis is a phenomenon explaining migration behavior of magnetic or diamagnetic micro/nanoparticle driven by external magnetic field exerted on a particle. In a microchannel, magnetic force induced by an external magnetic field exerts an object to move toward the denser or sparser magnetic field. Based on this principle, we have previously developed a variety of magnetophoretic assay systems for the diagnosis of allergy, prostate cancer, breast cancer and so on. Especially, in case of the diagnosis of breast cancer, we have developed a new concept of magnetophoresis, isomagnetophoresis that discriminates subtle differences in magnetic susceptibility by using a magnetic susceptibility gradient in a microfluidic channel. The magnetic force a particle receives by an external magnetic field depends on the difference in magnetic susceptibility between the particle and the surrounding environment if the other conditions are the same. Therefore, if the magnetic susceptibility gradient is formed in the microchannel, the particles will move according to the magnetic susceptibility difference and stop at the position where the magnetic susceptibility difference becomes zero. Using this principle, particles with similar magnetic susceptibility that could not be distinguished in traditional magnetophoresis can be separated by isomagnetophoresis. We have applied this new concept to the breast cancer biomarkers detection platform that discriminates subtle differences of protein concentration and improves the sensitivity.

The demand for multiplexed assay of important target analytes is high, and has recently attracted much attention. Multiplexed assay provides quantitative information on the target analytes of great physiological significance in high throughput way, accelerating disease diagnosis and biomedical studies as well as screening of interesting biomolecules. Recently, encoded microparticles have been suggested as diagnostic tools for a rapid, multiplexed assay due to their advantages in detection and quantification. By integrating magnetophoresis technology into the multiplexed assay system, we have developed simple but powerful platforms with multiplexing capability. As a representative example, a new magnetophoretic position detection platform for multiplexed immunoassay using colored microspheres as an encoding tool in a microchannel was developed. In addition, we have developed polymeric microparticles encoded by the magnetic axes from aligned superparamagnetic nanoparticles (SMNP). When placed in a parallel magnetic field, the encoded microparticles tilted aligning the external magnetic field and their magnetic axes. Then the encoded microparticles were decoded by simply measuring their tilting angles. We successfully classified various pathogens simultaneously by decoding the encoded microparticles and quantitatively analyzed the concentration of pathogens with the intensity of only one fluorescent label.

A lot of latest studies have shown that heterogeneity exists even in small groups of cells. The average analysis data of uniform cell populations cannot consider small but significant changes in individual cells. The cell size, the protein levels, the RNA transcription of each cell can vary widely, and these differences are the key to solving problems that have not been solved in the past in cancer research, stem cell biology, immunology, and neurology. In this context, we are developing a single cell analysis platform based on microfluidics by combining with other technologies such as expansion microscopy. This convergence research will investigate and disclose the cytoskeleton structures including microtubules, actins and intermediate filaments or specific proteins as a biomarker in a single cell

POCT (point-of-care testing) is defined as medical testing that is performed near or at the site of a patient. Representative items of the POCT include blood glucose test, blood gas analysis, cardiac marker test, complete blood count (CBC), routine chemistry tests, urine test, immunoenzyme test, blood electrolyte test, microbiological test, occult blood test, and lactate test. For making these tests easier and more accurate, a lot of POCT technologies are being developed and dramatically becoming requisite components in healthcare applications such as biosensors, lab-on-a-chip, smartphone apps and wearable devices. We are also conducting a variety of research on the noble POCT technologies. First, we have developed a sensitive and reproducible surface acoustic wave (SAW) immunosensor to diagnose acute myocardial infarction. This platform detects cardiac troponin I (cTnI) in blood and plasma, and the high sensitivity and excellent reproducibility of this system can be obtained by introducing reference sensor. In addition, we have developed a new integrated optode sensor platform that directly detects potassium, sodium, and chloride ions in blood plasma without pretreatment to adjust pH. This integrated clinical system has shown the excellent performance with high accuracy and sufficient selectivity. Based on these technologies and clinical experience, our laboratory will have more effort for the research on noble POCT technologies with convenient usability, compact size, sensitivity, and reliability.