免疫生物感測器是藉由偵測在生物晶片表面上抗體(antibody)與抗原
(antigen)之間的辨識行為，以檢測溶液相中之有害物、病原體或是特定的標
示物(marker)，而偵測的靈敏度會受到下列因素的影響：儀器感測訊號的機
制、抗體在晶片表面的數量、抗體固定化的位向性。而抗體在晶片表面上
隨機的固定化會造成偵測訊號下降，因此為了提升抗體抗原之間的辨識效
率，抗體於基材表面的位向性固定化方式被廣為研究。
我們提出一個策略設計與抗體 Fc 區域有高結合親和力(binding affinity)的
胜肽配體(peptide ligand)。結合分子嵌合及分子動態模擬(molecular dynamics
simulation，MD simulation)成功地設計、篩選出一條與Fc 區域有高親和力
的胜肽配體，以此作為理想配體之主要序列並改質於金片表面上，使用表
面電漿共振儀(surface plasmon resonance，SPR)量測Mouse IgG2a 在金片表面
的吸附量，以及PSA 與Mouse IgG2a 的二抗(secondary antibody，2nd Ab)被
辨識到的量，經計算後可得到Mouse IgG2a 的抗原辨識效率及位向因子。根
據我們提出之設計策略，可設計出用於抗體位向性固定之胜肽配體，並改
善抗體於表面之位向性，提升抗原辨識效率。
Immunosensors utilize specific bio-affinity interaction between antibody and
antigen to detect toxicants, pathogens, or specific markers in complex mixtures.
Antibodies need to be immobilized on the detection surface before targeted
antigen can be captured. The recognition sensitivity depends on the sensitivity of
signal sensing mechanism, the amount of immobilized antibody, and the
orientation of antibody immobilized. Signal can be significantly reduced due to
the random orientation of antibody on chip surface. Therefore, the methods for
oriented immobilization of antibody were studied by many research groups in
order to improve the recognition efficiency.
We propose a strategy to design a small peptide ligand which has high binding
affinity to the Fc region of antibody. It is expected that antibodies can be
oriented immobilized on surface through the affinity between the desired Fc
region and peptide ligand. Human prostate specific antigen (PSA) and PSA
specific antibody derived from Mouse IgG2a are selected as the targeted antigen
and antibody in this study. A peptide with a high Fc binding affinity is
successfully designed and selected by combining the molecular docking and MD
simulation. The recognition efficiency and orientation factor are measured by
the adsorption amounts of PSA and the secondary antibody of Mouse IgG2a
iii
through the help of surface plasmon resonance (SPR). Our approach provided a
new strategy for oriented immobilization of antibody by small ligands, which
can significantly improve the recognition efficiency.
