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Research paper : Biomarker analysis on microchips (M. Kataoka et al.)−49−Synthesiology - English edition Vol.3 No.1 (2010) 2640 yen while CRP measurement is 1560 yen, and adding the blood glucose measurement, the total is 4310 yen for the three items. In osteoporosis, the PICP measurement is 1700 yen and the NTx measurement is 2900, requiring a total of 4600 yen. The cost of the antigen-antibody reaction system is dominated by the cost of antibody used as the reagent. Therefore, if the antibody fixing method using the inkjet is employed, the amount of antibody used is about 1/10,000 in PICP compared to the 96-well plate method, and the cost of antibody can be reduced drastically. Also, by fixing multiple types of antibody on to one micro flow channel, the amount of detection reagent used can be greatly saved, and used with plastic substrate made of inexpensive material, sufficient economic feasibility can be expected.4 Future issuesWe have been working to construct the biomarker detection system based on the existing technologies such as the microchip and the electrophoresis using microchip from thestandpoint of users in the biology field. For the microchip electrophoresis, we were able to present the high potential of the current individual technologies in relatively short time, without spending time and effort on the development of the new device and software, but using the commercially-available chip, electrophoresis device, and analysis software for application to the biology and biochemistry experiments and clinical tests. However, for the realization of the POCT device, besides the biological approach, it is necessary to collaborate with engineers and researchers across the fields, including engineering and medical fields focusing on microfabrication, information fields for future database construction.While we were able to construct the core technology for the biomarker analysis on the microchip for glucose and protein, the following issues remain before the POCT device can be used in actual clinical practice. In the above microchip, the analysis is conducted after the conventional blood cell separation by centrifugation, and then adding the plasma components to the microchip. Therefore, to do the blood test during interviews by physicians in clinical practice, the blood cell separation process must be simplified. Therefore, it is required that the analysis, including blood cell separation, can be accomplished simply by adding the whole blood to the microchip. To enable tests with ultralow volume blood at µl level, we are working on an on-chip plasma separation system with a micro flow channel that incorporates a filter for separating the erythrocyte components from the blood drawn using currently available disposable microsampling needles. Moreover, we must construct a solution sending system using a micropump to send the necessary amount of plasma automatically and quantitatively to the sample well in the flow channel of microchip electrophoresis or microfluidics. Also, for the realization of the multiple biomarker detection chip, a complex micro flow channel design is required. In the design, it is necessary to install the separation and analysis systems that have different principles on one microchip, including the electrophoresis system where the substance is separated by the difference of migration speed due to the charge, size, and shape of the substance, and the micropumpTerm 3 used in antigen-antibody reaction system by sending ultralow volume liquid. For this, it is necessary to collaborate with companies with expertise in microfabrication technology including plastic forming.In addition to the above technological issues, a prototype of the POCT device will be fabricated as soon as possible, by integrating and constructing the peripheral technology such as the development of the detection system and analysis software. In this case, the subject will be the diagnostic chip for diabetes and osteoporosis that affect several million to ten million patients among Japanese adults. The efficacy as a POCT device is verified by comparisons with current clinical test data through joint research with university hospitals and specialized hospitals. Data will be collected to obtain approval of the Ministry and Health, Labour and Welfare based on the Pharmaceutical Affairs Law as a medical test device. After introducing this POCT device to clinical practice, we shall work on the introduction of the biomarker measurement device to monitor health at home.TerminologyBlocking: Prevention of the nonspecific bonding of the antibody to proteins other than the antigen proteins or to solid phase surface. Bovine serum albumin, gelatin, and skim milk are often used as the blocking agents.Nonspecific luminescence: Luminescence caused by the breakdown of peroxidase enzyme substrate, after the peroxidase-labeled secondary antibody bonds nonspecifically to the protein or solid phase surface, due to insufficient blocking or cleansing. It becomes background noise.Micropump: Liquid control element that generates pressure to move the ultralow volume of liquid.Term 1. Term 2.Term 3.G. D. Lundberg: How clinicians should use the diagnostic laboratory in a changing medical world, Clin. Chim. Acta 280, 3-11 (1999).M. Plebani: Pre and Post examination aspects, eJIFCC 15, 1-5 (2004) http//www.ifcc.org/ejifcc/vol15no4/150412200404.htm (2004).J. M. Hicks, R. Haeckel, C. P. Price, K. Lewandrowski and A. H. Wu: Recommendations and opinions for the use of point-of-care testing for hospitals and primary care: summary of a 1999 symposium, Clin. Chim, Acta 303, 1-17 (2001).M. Kataoka, S. Inoue, K. Kajimoto, Y. Shinohara and Y. Baba: Usefulness of microchip electrophoresis for reliable analyses [1][2][3][4]References

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