Identification and Quantification of Leptin in Serum by using a disposable electrochemical immunosensor Prof. Yun Seok HEO and Seong RYONG (School of Medicine, Keimyung University, Keimyung University)
Obesity has already become one of the most common medical condition in the world. Leptin has been reported that it has essential role in obesity control. The identification and quantification procedure of hormone leptin using disposable electrochemical immunosensor is described in this paper. Serum has been prepared from diet-induced obesity (DIO) model (C57BL/6J, male and female). DIO model is induced by high fat feed for over 2 months with above 30% of body weight. We used immune- assay method involving in the target analyte(leptin) and polyclonal anti-leptin antibody which has been immobilized on disposable electrodes by chemical linkers, 4-mercaptobenxoic acid (MBA), N-hydroxysuccinimide (NHS) and N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide (EDC). We demonstrated a linear calibration curve, in which leptin concentration ranges between 100pg/mL and 100ug/mL including the expected leptin level of normal and obesity conditons are measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The usefulness of the immune sensor was evaluated by comparing with enzyme-linked immunosorbent assay (ELISA). This attractive method with the simplicity and miniaturization of the requiredinstrumentation would be promising alternative in the development of portable devicesfor clinical analysis.
Point-of-care CD4 cell counting for monitoring HIV/AIDS patients in resource-confined regions Prof. Jung Kyung KIM, Myoung-Ock CHO, Subin KIM and Mohiuddin Khan SHOURAV (Kookmin University)
Microfluidic point-of-care (POC) devices that can enhance patient comfort through fewer visits to clinics and more gentle blood sampling due to reduced volume requirements, have been emerged for monitoring HIV/AIDS in resource-poor settings. We developed a prototype of the optical image analysis technology based POC devices that is able to detect CD4+ T-lymphocyte in human blood for HIV/AIDS monitoring. The proposed portable automated cell counting system, Helios CD4, is able to acquire sample images and analyze the particles or cells automatically, using a simple imaging module and a sample cartridge with a helical minichannel that has advantages over the existing devices because of its small size and simple scanning mechanism. We fabricated a sample cartridge with a thread-like microgroove formed at the cylindrical surface. The microgroove covered by a transparent adhesive tape can form a helical minichannel with variable channel width and depth. The blood was introduced to the channel through a hole at the end of the screw. A DC motor is installed to rotate the cylindrical sample cartridge at various speeds. Multiple images of the sample particles in the channel are obtained by a camera which is synchronized with the motor. A nut and bolt mechanism allows scanning large volume of sample along the helical minichannel by just rotating the cartridge, which greatly simplifies related electromechanical parts. The concentration of the particles can be measured by counting the total number of particles within the given sample volume. Two-hundred images were captured from individual samples using two filters that are suitable for CD4 and CD3 fluorescence detection, respectively. Those obtained images were divided into two parts CD4 image and CD3 image and then automatically analyzed by image analysis software (ImageJ; http://imagej.nih.gov/ij/). Each image set is firstly analyzed and counted the particles in the images using image analysis parameter set which is appropriate for CD4 and CD3 image feature, respectively. And finally count the particles that appear the same in both CD4 and CD3 images, using the ‘Image calculate’ process. The size of the one image is 0.6 mm in width, 0.49 mm in length and the channel height is 0.1 mm, that indicate one image correspond to 0.0294 microliter of blood. The CD4+ cell counting result from our device was compared with the result from PIMA analyzer (Pima™ CD4 Analyser, Alere) and FACS (FACSCalibur™, BD), and there was +/- 2~20% of difference compared to the PIMA result. It is still under study that optimizing of the image analysis parameter for analyzing the CD4 and CD3 images obtained from Helios CD4, and the improved result is expected as the image quality is improved by stably fixing the cartridge holder. We expect that the enhanced human health in resource-confined regions with a large number of HIV/AIDS patients, by efficiently managing the patients. Thus the health benefits and the medical services can be carried out on a larger scale with the use of the low-cost portable equipment. Also the potential job creation is possible in developing countries through local production and operation. The total cost of POC CD4 test depends on various individual pieces of information. Using this proposed method, a low-cost CD4 monitoring device can be developed for the near future replacing the huge and high-cost current analytical instrumentation.
Clinical Observation on the Life Expectancy of Artificial Pacemakers Implanted into Humans Dr. Yoon-Nyun KIM, Han-Jun BAE, Yun Seok HEO, Hyoung-Seob PARK and SeongWook HAN (Kemyung university dongsan medical center, School of Medicine, Keimyung University, Daegu, Korea)
As the life span has been extended, heart disease has also become increasingly serious, making it the second most recent death in Korea. There had been various changes in treatment, including cardiac device therapy. In the treatment of cardiac device (especially artificial pacemaker), which is mainly used for the treatment of arrhythmia, Korean cardiac patients are different from cardiac patients in other developed countries. Recently, the use of cardiac devices has been increasing, but there is not enough data or research of the Korea. The life expectancy of cardiac devices is often not consistent with laboratory results and clinical outcomes. There has been little research into the life expectancy of cardiac devices implanted into the human body in real world.
Patients who had implanted cardiac device for treatment of the cardiac arrhythmia at Keimyung University Dongsan Medical Center until August 2014 were collected the duration until replacement.
There were a total of 402 patients. 367 (91/3%) had only replacement of generator, and 32 (8%) patients were replaced with lead and generator. In case of the pacemaker, the duration of first and second replacement were 7.6 years(2778 days), 6.2 years (2256 days). There was the significant statistically reduction in second replacement. In case of defibrillator, the first and second replacement was 5.8 years(2124 days), 5.3 years(1940 days). The longer the time, the shorter the time to replacement.
The pacemaker or defibrillator, which is a cardiac device, is available for an average of about 5 to 7 years, so the patients who underwent intracardiac device to require careful observation during follow-up.
Selective Isolation of Heterogenic Circulating Tumor Cells (CTCs) Using Magnetic Gradient based Microfluidic System Dr. Bongseop KWAK, Jaehun LEE and Jeonghun LEE (Korea Institute of Machinery and Materials)
Circulating tumor cells(CTCs) is one of key marker of cancer metastasis in human body. Despite of the importance to diagnose the cancer metastasis by CTCs, still it is formidable challenge to use in the clinical purpose because of the rarity and the heterogeneity of CTCs in the cancer patient’s peripheral blood sample. To solve those addressed limitations, we have developed magnetic force gradient based microﬂuidic for isolating the total number of CTCs in the sample and characterizing the state of CTCs simultaneously with respect to the epithelial cell adhesion molecule (EpCAM) expression level. We have synthesized magnetic nanoparticles (MNPs) using hydrothermal method and functionalized anti-EpCAM on their surface for the speciﬁc binding with EpCAM on the tumor cell membrane. The microfluidic system designed to isolate and classify the CTCs by isolating at the different location in the chip using magnetic force differences depending on the EpCAM expression level. We observed 95.7% of EpCAM positive and 79.3% of EpCAM negative CTCs isolated in the microfluidic system. At the same time, the 71.3% of isolated EpCAM positive CTCs were isolated at the ﬁrst half area whereas the 76.9% of EpCAM negative CTCs were collected at the latter half area.