高效率辨識元蛋白固定之具電場操控型微懸臂梁生物感測器

Abstract

在邁入高齡化人口分布與醫療資源分配不均的今天，生物感測晶片於近年來引起各界高度重視，無論是學術界或是產業界皆投入大量的資金、人力積極開發與研究。在生物醫療檢測及疾病之診斷上，生物分子辨識之定量分析扮演著舉足輕重的地位，而微懸臂梁生物感測器(Microcantilever biosensor)具有免螢光標記、高靈敏度、低成本製作及潛在可大量平行化檢測之優點，並朝向微小化、可攜帶式系統發展。 在生物感測器之製作中，辨識元蛋白(Probing protein)之固定效率不良，往往造成生物樣品之浪費而導致檢測成本增加。本研究利用蛋白質於不同溶液環境下帶電性之不同，以電場操控之技術提升辨識元蛋白於微懸臂梁感測表面之固定效率。並利用銦錫氧化物(ITO)導電薄膜製作流體外電極，結合流體內金、鎳電極成為一具電場操控之微懸臂梁生物感測器。運用電場對於蛋白質操控之技術，討論不同電壓下對於辨識原蛋白固定效果之影響；在電場的施加下，實驗成功的將辨識原蛋白之固定效率提高8倍之多，並以微懸臂梁對於生物分子之連續性量測，以彎曲量探討免疫檢測之過程。 本實驗利用電場操控蛋白質之技術，達到增加辨識元蛋白之固定效率與降低生物樣品浪費之目標，並以加入符合上市前審查為標準之概念，對於未來微懸臂梁生物感測器之發展進行策略性之規劃。

Recognition and quantification of bio-molecules are irreplaceable in biomedical tests and disease diagnosis. A microcantilever biosensor embedded with electrodes for manipulation and enhancement of probing protein immobilization onto sensing surfaces has been demonstrated. The electrically protein-manipulated, nanomechanics-based biosensor is featured with significant reduction of usage in probing biomaterials, label-free, high sensitivity, low production cost and massive parallel analysis potential; in addition, miniaturization and portability are the tendency of its future development. For bio-sensor production, the probing protein immobilization process is ineffective, which invariably leads to a dramatic waste in proteins and thus a considerable increase of cost. Based on changes in electrical charges of the protein in different solution environments, the approach in this study enhanced the immobilization efficiency of probing protein onto the surfaces of microcantilever biosensors by applying electrical manipulation technique. With the merit of MEMS technique, it allows highly fabrication-compatible integration into microcantilever biosensors with electric devices. Connecting ITO conductive film created extrinsic fluidic electrodes with intrinsic fluidic gold and nickel electrodes, to make a microcantilever biosensor that is capable of manipulating electrical field. It is evident that higher amount of probing antibody molecules immobilized onto sensing surfaces captures more detected specific molecules, indicating greater deflection and stresses as well. This however leads to significant cost in biosensor. By applying electrical fields onto charged proteins, the protein manipulation exhibits a significant increase of probing immobilized proteins. As expected, most charged proteins distributed in solution are effectively attracted onto the sensing area within electric fields in high voltage. Under the influence of electrical field, the experiment successfully increased the effectiveness of probing protein immobilization by 8 times in which the microcantilever was used in real-time measurement of bio-molecules, and its deflection indicates a proportional concentration amount of antigen-antibody interaction. With such a novel approach, enhanced probing protein immobilization and thus dramatic reduction in protein usage have been greatly achieved in this work. Further effort for microcantilever biosensors is required in pursue of accreditation in pre-marketing censorship and new demonstration of its applications.