本研究係針對極小體積（小於或等於10 l）之血液樣本，使用電阻抗法（electric impedance method）及運用指狀電極（interdigital electrode），並直接將凝血所需之藥劑及活化劑塗布於電極表面，以測量活化（activated）及未活化的人類全血凝固時間。本研究顯示阻抗法全血凝固時間（impedance whole blood coagulation time）與標準化（normalized）活化部分凝血活酶時間（aPTT）及非標準化活化部分凝血活酶時間之間均有正相關（分別為R2=0.72及0.61）。在本實驗的架構下，雖然最佳頻段落在238.8 kHz及338.8 kHz之間，但使用250 kHz之頻率可以得到較佳的曲線，並可克服紅血球沉降於電極表面所造成之屏障效應。於電極表面（有效面積為0.3 × 0.4 cm）塗布10 l之3.0 M之氯化鈣可以對3.2%檸檬酸鈉化全血有最佳的再鈣化作用。在玻璃奈米顆粒（直徑平均大小分別為95.3 nm及6.4 m）的活化之下，所測得之活化阻抗法全血凝固時間與未活化之阻抗法全血凝固時間之間有顯著的差異（paired t test, p< 0.01），且兩者之間有線性相關（R2=0.79）。奈米等級（平均直徑95.3 nm）之玻璃顆粒對阻抗法全血凝固時間的活化能力，確實比微米等級（平均直徑6.4 m）之玻璃顆粒為佳。即使是奈米顆粒，玻璃決非良好的凝血活化物質，本研究中平均直徑95.3 nm之奈米玻璃顆粒對阻抗法全血凝固時間只縮短了30%。基於本研究之結果，阻抗分析法對於發展床邊照顧（point-of-care或near-patient care）之血液凝固時間測定儀器深具潛力，尤其當全血樣本體積小於10 m時更具意義。

　　Measuring of human whole blood coagulation by impedance method on paired interdigital electrodes with sample size equal or less than 10 l has been studied.　The study of whole blood coagulation by impedance method began early in 1905 by Frank RT with results difficult to reproduce. Rosenthal RL and Tobias CW (1948) had first repeatable results with great efforts. Ur A (1970) made the first standard curve of human whole blood coagulation and tried to inquire into the meaning of it. Von Kaulla KN (1975) developed a commercial device for measuring human blood coagulation, but quitted soon from the market. The study of human blood coagulation by impedance method was almost stopped for a long period of time. Spence N (2002) made a series of studies and concluded that impedance method can be used as end points of regular blood coagulation tests. All these studies were done with blood sample size more than 40 l tested on block electrodes. Mixing with reagents (either aqueous or powdered) to activate and initiate the coagulation process was necessary.　In my study, direct coating of reagents (calcium chloride) and activator (glass nanoparticles) on the surfaces of testing electrodes with sample size equal or less than10 l was achieved. There is fair correlation between impedance coagulation time and both normalized (R2=0.72) and non-normalized (R2=0.61) activated partial thromboplastin time (aPTT). The best frequency for impedance coagulation time measurements is also determined. Testing run at 250 kHz will yield best results under such system configuration. The optimum concentration of calcium chloride for in situ coating for recalcification of citrated whole blood (in 3.2% sodium citrate) is 10 l of 3.0 M on 0.3 x 0.4 cm of testing electrodes. Significant difference between activated and non-activated impedance clotting time (paired t test, p<0.01) and fair linear correlation (R2=0.758) were obtained. The 95.3 nm particles have better results for triggering human contact activation system than 6.4 m particles during whole blood coagulation.　Impedance method is an ideal tool for whole blood coagulation time measurement for very small samples and really promising for developing point-of-care coagulation devices.

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