CMOS 0.35µm線寬標準製程之振動式自感測微懸臂樑感測器應用於微量流體黏度檢測及人體血漿之凝血時間監測

Abstract

隨著時代的進步，心血管疾病也越來越普及，為了防止血管栓塞，目前對於心血管疾病之病患治療方式為使用抗凝血藥物，而為了避免用藥不當須定期監測使用情況，以免因服用過多而造成凝血功能不佳，或是服用過少而達不到因有得療效。病患為了監測用藥情況，常需往返於住家及醫療院所間，且檢驗十分耗時。而目前針對定點照護及可攜式的檢驗儀器十分昂貴，對使用者是一大負擔。因此本研究致力於研發低成本可攜式之凝血監測儀器。 本研究使用了台灣積體電路製造股份有限公司(TSMC) CMOS 0.35µm 2P4M標準製程，開發出了由polysilicon 作為壓阻感測層之微懸臂樑晶片，針對內源路徑、外源路徑及纖維蛋白原轉換為纖維蛋白是否正常之標的¬─凝血酶原時間(PT)、部分凝血活酶原時間(APTT)及凝血酶時間(TT)做監測。而本研究參考市售測量血液凝固狀況的Sonoclot凝血分析儀，利用外部激振器驅動微懸臂樑使其能在待測液體中振動，利用凝血樣本黏度產生變化時微懸臂樑之受力變形也會不同的基礎。透過壓阻層將變形轉為電阻訊號做量測，藉此訊號量測反推待測樣品性質之變化。本研究為了濾除其他頻率之雜訊，將原始訊號經由快速傅立葉轉換得到特定頻率之振幅值，並以此值來反映微懸臂樑於凝血樣本中的受力情形，再經分析得到凝血酶原時間(PT)、部分凝血活酶原時間(APTT)、活化凝血時間(ACT)以及凝血酶時間(TT)。 利用配置不同體積百分濃度之甘油水溶液，進行實驗以了解微懸臂樑在不同黏度與雷諾數環境下之受力情形。由實驗結果可以得知，微懸臂樑在待測液體中振動之變形量能與液體之黏度與雷諾數建立正相關之趨勢ΔR/R_0 =1.335×〖10〗^(-5) [Absolute Viscosity]+1.165×〖10〗^(-3)、ΔR/R_0 =2.189×〖10〗^(-6) [1/Re]+1.152×〖10〗^(-3) 且有相當高之線性度(R^2=0.9985與R^2=0.9984)，由實驗證實振動式壓阻微懸臂樑感測器可用於黏度及雷諾數之監測且準確度相當高。 接著改變量測標的，監測實際凝血狀況並搭配自行設計之快速傅立葉演算法，將凝血狀況之特定頻率(10Hz)之阻值振幅訊號取出，並以阻值振幅達初始振幅六個單位所需之時間做為微懸臂樑監測之凝血時間，實驗結果得到第一級凝血樣本之PT為10.167秒(標準差1.528秒)、APTT為23.833秒(標準差4.042秒)、TT為12.833秒(標準差2.082秒)；第二級凝血樣本之PT為21.833秒(標準差0.577秒)、APTT為48.833秒(標準差3.055秒)、TT為24.833秒(標準差2.309秒)；第三級凝血樣本之PT為31.333秒(標準差2.363秒)、APTT為98.833秒(標準差8.505秒)、TT為29.5秒(標準差1.732秒)，實驗結果皆落在凝血樣本之參考區間內，證實本研究所開發之微懸臂樑感測器用於凝血反應監測之可行性。 本研究使用之振動壓阻式微懸臂樑感測器是透過半導體CMOS標準製程所製作，因此有易微型化、低成本、良率高之優點，且後端電路亦可設計於晶片中，對於定點照護或是可攜式儀器之領域開發有很大的空間。相較市面上之監測凝血反應技術，能夠量化數值以描述凝血過程的不多，如Sonoclot凝血分析儀，而本感測器也屬其中之一，但除了凝血時間能準確量測外，其他凝血資訊之準確度仍屬研究階段。綜觀以上可知，利用本研究所開發之振動壓阻式微懸臂樑感測器所量測之血液黏度及雷諾數變化用來描繪凝血反應之過程具有相當之發展潛力。

This study has developed a real-time coagulation monitoring sensor by using a standardized CMOS processed externally vibrated, self-sensing piezo-resistive micro-cantilever for portable coagulation devices. With the increasing use of oral anti-coagulant drugs and increasing adverse drug events, the need for point-of-care coagulation devices has become necessary. Prothrombin time (PT), activated partial thromboplastin time (APTT) and Thrombin time (TT) are important index for anticoagulant therapy to determine the blood condition in blood clotting reaction. In this study, the measurement was performed by vibrating the piezo-resistive micro-cantilever immersed in the sample liquid with a fixed frequency and fixed amplitude. The acquired blood clotting signal of resistance change in micro-cantilever was processed by Fast Fourier Transform algorithm, and the amplitude of resistance change in 10 Hz indicated the amount of force acting on the cantilever. In blood clotting reaction, the viscosity and Reynolds number of samples was sharply changed because of the clot formation, and the increased force acting on the cantilever can be sensed when the resistance amplitude in 10 Hz rises. Prothrombin time, activated partial thromboplastin time and thrombin time can be obtained by the time needed for fibrin clot formation. The method was initiated by Sonoclot analysis. The amplitude of resistance change was found in a good linear correlation with absolute viscosity of glycerin/water solutions (R2 > 0.99). Also, the Reynolds number correlation can be achieved to present the relation of vibrated micro-cantilevers in sample liquid. Thus, ΔR/R_0 =2.189×〖10〗^(-6) [1/Re]+1.152×〖10〗^(-3) (R^2=0.9984) was derived to successfully describe the relation between acquired signals and Reynolds number. In addition, three types of commercially standard human plasma samples for measurement of coagulation prothrombin time, activated partial thromboplastin time and Thrombin time were used for characterizing micro-cantilever sensors. The measured results of resistance change amplitude in specific frequency with specific patterns of signature indicated the viscoelastic changes in blood clotting reaction process. In coagulation reaction of human plasma control level 1, the PT measured by the micro-cantilever was 10.167 sec with std. of 1.528 sec, the APTT was 23.833 sec with std. of 4.042 sec and the TT was 12.833 sec with std. of 2.082 sec; PT = 21.833 sec with std. of 0.577 sec, the APTT was 48.833 sec with std. of 3.055 sec and the TT was 24.833 sec with std. of 2.309 sec in human plasma control level 2; and PT = 31.333 sec with std. of 2.363 sec, the APTT was 98.833sec with std. of 8.505 sec and the TT was 29.5 sec with std. of 1.732 sec in human plasma control level 3. The experiment results demonstrate that the PT, the APTT and TT can be measured by vibrated micro-cantilever sensors accurately and precisely. Thus, this micro-cantilever sensors have demonstrated the real-time measurement for point-of-care and portable devices for blood clotting monitoring, and shown its potential in miniaturization for personal diagnosis.