冠狀動脈疾病為造成全球致死的主因之一，隨著罹患病患數量大幅增加，檢測的方便性及快速性是亟需克服的重要課題。近期廣泛使用的免疫檢測法，雖可以達到靈敏及準確的目標，但是傳統的免疫檢測法需要使用螢光標的及酵素呈色反應，與抗原利用擴散作用和抗體結合，而使檢測時間冗長，最後需要配合大型光學儀器分析。因此，快速、靈敏、低成本及簡便的檢驗方法便為生醫檢測器的目標。
為了增加靈敏度及偵測極限，結合電動力學交流電滲流 (ACEO) 及不須標記之電化學偵測可藉流體對流以增加抗體-抗原反應。此外，本研究藉最佳化金電極之修飾實驗流程以建立良好再現性，例如：自主性單層膜、化學鏈結劑、抗體及阻滯劑。多種電化學偵測法包含循環伏安法、方波伏安法及電化學阻抗分析法被用於定量心肌梗塞指示劑-心肌肌鈣蛋白蛋白I (cTnI)。
實驗結果顯示，在同心圓電極施加偏壓0.5 Vpp、內圈電壓8 Vpp及外圈電壓15 Vpp，與最佳頻率800 Hz的條件下，能產生最佳濃縮效果，不僅能減少反應時間至20秒，且藉由短暫的暫停造成的再次攪拌能增加代測物的結合率，以期未來能結合自動化，達到更快速檢測之效果。

Myocardial infarction (MI) is mostly induced by coronary artery disease (CAD) which is one of the major lethality worldwide and it is predicted to rise. Although conventional immunoassays achieve good sensitivity and specificity, the long reaction time and bulky optical instruments are needed. Therefore, the sensing performances involving fast, high sensitivity, low cost and reproducibility are critical for the development of biosensors.
For increasing the sensitivity and decreasing the reaction time, the integration of electrokinetic alternating current electro-osmosis (ACEO) into label-free electrochemical detection could facilitate antibody-antigen reaction by driving fluidic convection. Furthermore, a good reproducibility was achieved by optimizing the procedures of surface modification on gold electrode, such as self-assembled monolayer, chemical linker, antibody, and blocker. Various electrochemical detections consisting of cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were used to quantify cardiac troponin I (cTnI) which is an important indicator of MI.
The data showed that applying concentric electrode optimal frequency 800 Hz, inner 8 Vpp and outer 15 Vpp with bias 0.5 Vpp to generate the concentrated effect which can eliminate reaction time from 15 min to 20 s, and with a pause enhances the binding rate of analyte due to the re-stirring. With the prospect of automation, faster and more accurate detection can be achieved.

1. Thygesen, K.; Alpert, J. S.; White, H. D., Universal Definition of Myocardial Infarction. Journal of the American College of Cardiology 2007, 50, 2173-2195.
2. Thygesen, K.; Alpert, J. S.; Jaffe, A. S., Third Universal Definition of Myocardial Infarction. Journal of the American College of Cardiology 2013, 61, 598-598.
3. Leisy, P. J.; Coeytaux, R. R.; Wagner, G. S.; Chung, E. H.; McBroom, A. J.; Green, C. L.; Williams Jr, J. W.; Sanders, G. D., Ecg-Based Signal Analysis Technologies for Evaluating Patients with Acute Coronary Syndrome: A Systematic Review. Journal of Electrocardiology 2013, 46, 92-97.
4. Gaze, D. C.; Collinson, P. O., Multiple Molecular Forms of Circulating Cardiac Troponin: Analytical and Clinical Significance. Annals of clinical biochemistry 2008, 45, 349-355.
5. Bahadır, E. B.; Sezgintürk, M. K., Applications of Electrochemical Immunosensors for Early Clinical Diagnostics. Talanta 2015, 132, 162-174.
6. Fathil, M. F. M., et al., Diagnostics on Acute Myocardial Infarction: Cardiac Troponin Biomarkers. Biosensors and Bioelectronics 2015, 70, 209-220.
7. Eggins, B. R., Chemical Sensors and Biosensors; John Wiley & Sons, 2008; Vol. 28.
8. Ronkainen, N. J.; Halsall, H. B.; Heineman, W. R., Electrochemical Biosensors. Chemical Society Reviews 2010, 39, 1747-1763.
9. Daniels, J. S.; Pourmand, N., Label‐Free Impedance Biosensors: Opportunities and Challenges. Electroanalysis 2007, 19, 1239-1257.
10. Sharma, R.; Deacon, S. E.; Nowak, D.; George, S. E.; Szymonik, M. P.; Tang, A. A. S.; Tomlinson, D. C.; Davies, A. G.; McPherson, M. J.; Wälti, C., Label-Free Electrochemical Impedance Biosensor to Detect Human Interleukin-8 in Serum with Sub-Pg/Ml Sensitivity. Biosensors and Bioelectronics 2016, 80, 607-613.
11. Feynman, R. In There's Plenty of Room at the Bottom, Presentation to American Physical Society, 1959.
12. Manz, A.; Graber, N.; Widmer, H. á., Miniaturized Total Chemical Analysis Systems: A Novel Concept for Chemical Sensing. Sensors and actuators B: Chemical 1990, 1, 244-248.
13. Squires, T. M.; Bazant, M. Z., Induced-Charge Electro-Osmosis. Journal of Fluid Mechanics 2004, 509, 217–252.
14. Ramos, A., Electrokinetics and Electrohydrodynamics in Microsystems; Springer Science & Business Media, 2011; Vol. 530.
15. Ramos, A.; Morgan, H.; Green, N. G.; Castellanos, A., Ac Electrokinetics: A Review of Forces in Microelectrode Structures. Journal of Physics D: Applied Physics 1998, 31, 2338.
16. Ratner, B. D.; Hoffman, A. S.; Schoen, F. J.; Lemons, J. E., Biomaterials Science: An Introduction to Materials in Medicine, Third Edition ed.; Academic press, 2013.
17. Storey, B. D.; Edwards, L. R.; Kilic, M. S.; Bazant, M. Z., Steric Effects on Ac Electro-Osmosis in Dilute Electrolytes. Physical Review E 2008, 77, 036317.
18. Rangharajan, K. K.; Prakash, S., Surface-Modified Microfluidics and Nanofluidics, 2015.
19. Hughes, M. P., Ac Electrokinetics: Applications for Nanotechnology. Nanotechnology 2000, 11, 124.
20. Gagnon, Z.; Chang, H. C., Aligning Fast Alternating Current Electroosmotic Flow Fields and Characteristic Frequencies with Dielectrophoretic Traps to Achieve Rapid Bacteria Detection. Electrophoresis 2005, 26, 3725-3737.
21. Morgan, H.; Hughes, M. P.; Green, N. G., Separation of Submicron Bioparticles by Dielectrophoresis. Biophysical journal 1999, 77, 516-525.
22. Wu, J., Biased Ac Electro-Osmosis for on-Chip Bioparticle Processing. Nanotechnology, IEEE Transactions on 2006, 5, 84-89.
23. Lastochkin, D.; Zhou, R.; Wang, P.; Ben, Y.; Chang, H.-C., Electrokinetic Micropump and Micromixer Design Based on Ac Faradaic Polarization. Journal of Applied Physics 2004, 96, 1730-1733.
24. Schrum, D. P.; Culbertson, C. T.; Jacobson, S. C.; Ramsey, J. M., Microchip Flow Cytometry Using Electrokinetic Focusing. Analytical Chemistry 1999, 71, 4173-4177.
25. Bi, O. P.; Simon, S., Effects of Multiple Electrode Pairs on the Performance of a Micromixer Using Dc-Biased Ac Electro-Osmosis. Journal of Micromechanics and Microengineering 2012, 22, 115034.
26. Wu, J. J., Ac Electro-Osmotic Micropump by Asymmetric Electrode Polarization. Journal of Applied Physics 2008, 103, 024907.
27. González, A.; Ramos, A.; Green, N. G.; Castellanos, A.; Morgan, H., Fluid Flow Induced by Nonuniform Ac Electric Fields in Electrolytes on Microelectrodes. Ii. A Linear Double-Layer Analysis. Physical Review E 2000, 61, 4019.
28. Bazant, M. Z.; Squires, T. M., Induced-Charge Electrokinetic Phenomena: Theory and Microfluidic Applications. Physical Review Letters 2004, 92, 066101.
29. Green, N. G.; Ramos, A.; González, A.; Morgan, H.; Castellanos, A., Fluid Flow Induced by Nonuniform Ac Electric Fields in Electrolytes on Microelectrodes. I. Experimental Measurements. Physical Review E 2000, 61, 4011.
30. Melvin, E. M.; Moore, B. R.; Gilchrist, K. H.; Grego, S.; Velev, O. D., On-Chip Collection of Particles and Cells by Ac Electroosmotic Pumping and Dielectrophoresis Using Asymmetric Microelectrodes. Biomicrofluidics 2011, 5, 034113.
31. Morgan, H.; Green, N., Ac Electrokinetics: Colloids and Nanoparticles, 2003.
32. Green, N. G.; Ramos, A.; González, A.; Morgan, H.; Castellanos, A., Fluid Flow Induced by Nonuniform Ac Electric Fields in Electrolytes on Microelectrodes. Iii. Observation of Streamlines and Numerical Simulation. Physical Review E 2002, 66, 026305.
33. Arefin, M. S. In Biased Ac Electroosmosis Device for the Detection of DNA Molecules with Piezoresistive Microcantilever, Advanced Materials Research, Trans Tech Publ: 2013; pp 202-207.
34. Wu, J.; Ben, Y.; Battigelli, D.; Chang, H.-C., Long-Range Ac Electroosmotic Trapping and Detection of Bioparticles. Industrial & engineering chemistry research 2005, 44, 2815-2822.
35. Hart, R.; Lec, R., Enhancement of Heterogeneous Immunoassays Using Ac Electroosmosis. Sensors and actuators B: Chemical 2010, 147, 366-375.
36. Chen, A.; Shah, B., Electrochemical Sensing and Biosensing Based on Square Wave Voltammetry. Analytical Methods 2013, 5, 2158-2173.
37. Bard, A. J.; Faulkner, L. R., Electrochemical Methods: Fundamentals and Applications. 2001.
38. Mirceski, V.; Gulaboski, R.; Lovric, M.; Bogeski, I.; Kappl, R.; Hoth, M., Square‐Wave Voltammetry: A Review on the Recent Progress. Electroanalysis 2013, 25, 2411-2422.
39. Liu, X.; Duckworth, P. A.; Wong, D. K., Square Wave Voltammetry Versus Electrochemical Impedance Spectroscopy as a Rapid Detection Technique at Electrochemical Immunosensors. Biosensors and Bioelectronics 2010, 25, 1467-1473.
40. Suni, I. I., Impedance Methods for Electrochemical Sensors Using Nanomaterials. TrAC Trends in Analytical Chemistry 2008, 27, 604-611.
41. Lisdat, F.; Schäfer, D., The Use of Electrochemical Impedance Spectroscopy for Biosensing. Analytical and bioanalytical chemistry 2008, 391, 1555-1567.
42. Prodromidis, M. I., Impedimetric Immunosensors—a Review. Electrochimica Acta 2010, 55, 4227-4233.
43. Chang, B.-Y.; Park, S.-M., Electrochemical Impedance Spectroscopy. Annual Review of Analytical Chemistry 2010, 3, 207-229.
44. Holmes, M.; Keeley, J.; Hurd, K.; Schmidt, H.; Hawkins, A., Optimized Piranha Etching Process for Su8-Based Mems and Moems Construction. Journal of Micromechanics and Microengineering 2010, 20, 115008.
45. Ding, S.-J.; Chang, B.-W.; Wu, C.-C.; Lai, M.-F.; Chang, H.-C., Impedance Spectral Studies of Self-Assembly of Alkanethiols with Different Chain Lengths Using Different Immobilization Strategies on Au Electrodes. Analytica Chimica Acta 2005, 554, 43-51.
46. Bhadra, P.; Shajahan, M.; Bhattacharya, E.; Chadha, A., Studies on Varying N-Alkanethiol Chain Lengths on a Gold Coated Surface and Their Effect on Antibody–Antigen Binding Efficiency. Royal Society of Chemistry Advances 2015, 5, 80480-80487.
47. Reverberi, R.; Reverberi, L., Factors Affecting the Antigen-Antibody Reaction. Blood Transfusion 2007, 5, 227-240.
48. Bogomolova, A.; Komarova, E.; Reber, K.; Gerasimov, T.; Yavuz, O.; Bhatt, S.; Aldissi, M., Challenges of Electrochemical Impedance Spectroscopy in Protein Biosensing. Analytical Chemistry 2009, 81, 3944-3949.
49. Wong, P. K.; Chen, C.-Y.; Wang, T.-H.; Ho, C.-M., Electrokinetic Bioprocessor for Concentrating Cells and Molecules. Analytical Chemistry 2004, 76, 6908-6914.
50. Wu, J.; Ben, Y.; Chang, H.-C., Particle Detection by Electrical Impedance Spectroscopy with Asymmetric-Polarization Ac Electroosmotic Trapping. Microfluidics and Nanofluidics 2005, 1, 161-167.
51. Lian, M.; Wu, J., Ultrafast Micropumping by Biased Alternating Current Electrokinetics. Applied Physics Letters 2009, 94, 064101.
52. Fischer, L. M.; Tenje, M.; Heiskanen, A. R.; Masuda, N.; Castillo, J.; Bentien, A.; Émneus, J.; Jakobsen, M. H.; Boisen, A., Gold Cleaning Methods for Electrochemical Detection Applications. Microelectronic Engineering 2009, 86, 1282-1285.
53. Cheng, I-F.; Yang, H.-L.; Chung, C.-C.; Chang, H.-C., A Rapid Electrochemical Biosensor Based on an Ac Electrokinetics Enhanced Immuno-Reaction. Analyst 2013, 138, 4656-4662.