可自我定址與重覆使用之表面電漿共振感測平台及其在DNA運算上之相關應用

A Self-Addressing SPR Sensing Platform with Reusability and its Applications on DNA Computation

張宗堯(Tsung-Yao Chang)

指導教授 ： 林啟萬

國立臺灣大學/工學院/醫學工程學研究所/碩士(2007年)

https://doi.org/10.6342/NTU.2007.03046

摘要

本研究提出一之微流道生物檢測平台，該平台以表面電漿共振為基礎之可重複使用自動定址生物檢測平台。其特點乃在生物晶片的多個微陣列表面固定化不同序列的單股寡核甘酸，利用核甘酸特有之互補辨識能力做為定址系統之基礎並以此作為探針抓取先以共價鍵結合了抗體和特定核酸序列之分子，又利用雙股寡核甘酸間氫鍵的斷裂與鍵結造成之變性與雜合反應作為重複使用的關鍵。本研究中並且業已分析了濃度10 ng/ml~200 ng/ml的抗體-寡核苷酸分子，其單次反應時間為12分鐘。於實驗中也試驗檢測平台的效率、再現性、專一性以及重覆使用性。實驗結果證明，在通入了2.5 mg/ml小牛血清蛋白後本平台的非特異性鍵結以及Amine吸收所造成之雜訊不及特異性結合分子所造成訊號變動的百分之十。在重覆使用性上，系統在流道中連續實驗十次後所造成訊號遞減的效應仍然十分有限，且縱使每次實驗過後經歷清洗、乾燥、保存的步驟後依然可以確保每片晶片能夠使用六次以上，而每次的實驗可以在數分鐘內完成。
此外，為了具有更快速、大量平行篩檢及微型化之能力，本平台加入了微流道系統之概念，並且結合了一具有八個微流道通道的微流體晶片，這項技術使得本研究所需消耗之樣本量從過300 ul以上降為20 ul即可。此晶片之發展技術乃以常見無塵室製程為基礎進行改良，以實驗室通用之載玻片鈉玻璃為基材，經過清洗、曝光、顯影、蝕刻步驟後與一蒸鍍上多陣列金膜之晶片進行接合。其中，該接合製程有鑑於傳統的玻璃接合技術之費時、高成本且過於複雜等缺點，特開發ㄧ快速接合技術使得整個過程從過去的六個小時縮短到一分鐘內完成，使得該晶片具有容易生產、快速製造及低成本等長處。
為更廣泛的延伸此一平台的應用且引入具有鑑別智能生物晶片之概念，吾人進ㄧ步將DNA運算的想法應用在實驗之中。首先於該研究中將不同表面電漿共振強度的訊號定義成布林無、真值以及假值，而後我們將晶片系統設計成具有解答SAT邏輯問題之計算晶片。目前的實驗中ㄧ個方程式的計算需要花費約一到兩小時的時間，以此已證實此一晶片概念平台之潛力。

關鍵字

表面電漿共振 ； 微流體晶片 ； 生醫檢測 ； DNA電腦

並列摘要

We proposed a SPR-based microfluidic diagnostic platform with reusability in room temperature. The fabrication processes of this chip system are firstly to immobilize several sequence ssDNA probes on different gold spots. And then we would use the chip to collect the complementary sequence ssDNA probes that have chemically conjugated to different IgGs by Sulfo-SMPB which can links thiol group labeled on ssDNA and amine group existed on IgG.. After the DNA hybridization, we would inject various antibodies to that can react with immobilized IgGs. The repeatable and auto-addressing abilities are based on annealing and denaturing of the hydrogen bond between dsDNA. In this research, we have analyzed the IgG-ssDNA molecule from the concentration of 10 ng/ml~200 ng/ml. Besides, we also examined the efficiency, reproducibility, specificity and repeatability of this platform. We then proved that the intensity change caused by non-specific binding is about 10 percent after injecting BSA to block the non-specific absorption. Furthermore, results have shown that the fabricated platform can be reused for over 10 times.
DNA computation has shown its feasibility for mathematical and biomedical applications. It would thus allow embedded intelligence for diagnosis, single nucleotide polymorphism (SNP) detection, amplification, encryption and drug delivery etc. However, it still suffers from several practical limitations, which include time-consuming, lack of reusability and miniaturization.
In order to further improve current status of DNA computation, we incorporated this platform for the detection on the DNA array chip to solve a 3-clause satisfiability (SAT) problem with 3 variables of x, y and z. Each variable is defined by a 15-nt single strand DNA (ssDNA) which is immobilized on one spot of the gold surface. We further defined SPR reflective intensity changes 0, 0.2 and 2 A.U. caused by changes of molecular weight change on surface as Boolean signals False, True and None, respectively. Moreover, False signal represents a positive hybridization reaction via the hydrogen bond that binds the complementary ssDNA-IgG. And True signal represents the hybridization reaction that binds the complementary ssDNA-IgG-Antigen which can result in a much larger intensity change so that can make sure that we are able to distinguish different Boolean signals by different intensity changes. For a SAT problem of F=(XF∪YT) ∩(XT∪ZF) ∩(YT∪ZT), there are 8 possible answers. Therefore, we established a 3-spot array as a set which is immobilized sequence of x, y and z. After one calculation, we read out the solution of this set and then regenerate it by injecting 0.05 N sodium hydroxide solution.. Comparing to previous DNA computers which required days for a calculation, our proposed computational platform has significantly improved in time efficiency, chip reusability and realtime measurement for feasibility study.

並列關鍵字

SPR ； microfluidic ； bio-detection ； DNA computer

參考文獻

[2] D Armitage, “Micro spatial light modulator”, US Patent 4,698,602, 1987

[3] K Nagai, PC Appelbaum, TA Davies, LM Kelly, ”Fabrication of microstructures with high aspect ratios and great structural heights by synchrotron radiation lithography, galvanoforming, and plastic moulding (LIGA process)”, Microelectronic Engineering, 1986

[5] KL Drake, KD Wise, J Farraye, DJ Anderson, BeMent, S.L., “Performance of planar multisite microprobes in recordingextracellular single-unit intracortical activity”, Biomedical Engineering, IEEE Transactions, 1988

[6] AW Duggan, PJ Hope, B Jarrott, HG Schaible, “Release, spread and persistence of immunoreactive neurokinin A in the dorsal horn of the cat following noxious cutaneous stimulation. Studies with antibody microprobes.”, Neuroscience, 1990

[7] JP Smith, “Medical and biological sensors: a technical review”, Sensor Reviews, 2005