利用指叉式電極生物感測器結合阻抗式量測法檢測LL-37

Functionalized interdigitated electrodes for sensing LL-37 using impedimetric measurement

李佳怡(Jia-yi Lee)

指導教授 ： 王鐘毅

大同大學/工程學院/生物工程學系所/碩士(2010年)

摘要

細菌抗藥性演變的速度，遠超過人類新藥的研發。人和小老鼠的尿道在細菌侵入時都會快速分泌帶正電荷的抗菌肽LL-37，它可以辨別外來侵入以及自體細胞的不同，對帶負電荷細菌細胞膜進行破壞，且其抗菌性不受細菌抗藥性的影響，因此LL-37可作為尿道感染的標記。LL-37感測電極的設計，包含指叉式電極的測量夾具，可將LL-37濃度變量轉換成感測器電路的阻抗R、X=(1/2πfC)變量。指叉電極的幾何面積不同於傳統電極，因此在有限的空間下，可以整齊排列出的感測面積優於普通傳統電極，使得指叉電極具有將感測訊號放大的功能，靈敏度提高。
　　藉由指叉電極測量出的阻抗經由計算扣除夾具的阻抗效應得到相應電容的改變，來檢測LL-37濃度的變化。並在不同頻率下測量阻抗的變化，以選出最適之頻率。並於高鹽、緩衝溶液(PB Buffer)、及不同之pH值的干擾環境下測量。由於干擾嚴重影響測量結果，因此更進一步使用金電極與SAMs固定LL-37之抗體IgG，藉由IgG固定干擾環境中之LL-37後，移除干擾背景並以水置換測量。希冀日後能利用這個方法在不同環境下仍然可監測到LL-37的變化，作為判斷尿道感染的指標。

關鍵字

生物感測器 ； 抗菌肽LL-37 ； 指叉式電極

並列摘要

The secretion of positively charged antimicrobial peptides, AMP LL-37, is
an innate defense mechanism in human and mouse when their urinary tracts
are infected by bacteria. They can interact and destroy the negatively charged
bacteria membranes, and are ignorant of any possible bacterial resistance
derived from drug treatments. Thus LL-37 is considered a good marker of
urinary tract infections. We design an interdigitated type sensing electrode on
a printed-circuit board (PCB) to measure the electrical characteristics
associated with the change of LL-37 concentration. The change in the
concentration of LL-37 is reflected in the corresponding resistance and
capacitance changes measured by the probe. The advantage of our probe
design lies in the fact that, due to the array arrangement, the geometric area
of the total sensitive area of the interdigitated electrode is larger than the
traditional electrodes in a limited space. Thus the signal and sensitivity are
both improved.
　　An optimum frequency is selected by measuring under different
frequencies. Measurements are also performed under various interfering
conditions, including high salt concentration, buffer solutions, and different
pH’s. In order to reduce the effect of interference, we try a gold electrode
with SAMs to bind the antibody IgG of LL-37. After LL-37 has be bound
by antibody IgG, we use DI water instead of the interferences.

並列關鍵字

Antimicrobial peptides LL-37 ； interdigitated electrode ； biosensor

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