腸道病毒(Enterovirus)又稱為腸病毒，是一種主要生長於腸道的RNA病毒，例如最近幾年在亞洲流行的腸病毒71型(EV71)即為其中一種，感染病徵類似流感症狀，如發燒、喉嚨痛、頭暈噁心等，亦容易在手掌，腳掌及口腔出現紅疹潰瘍與水泡等手足口症(hand-foot-mouth disease，HFMD)的病徵。部分五歲以下感染腸病毒之幼兒可能會併發重症，尤其以EV71最常出現神經系統的病徵如抽蓄、肢體麻痺、腦膜炎及呼吸困難等症狀。儘管EV71於人體內的傳染途徑已廣泛地被研究，但是EV71與受體P-selectin glycoprotein ligand-1(PSGL-1)之間的作用關係仍未被完全理解。
　　本研究係以原子力學顯微鏡(Atomic Force Microscopy，AFM)作為分子鍵結之解離力量測工具，以近年常見的腸病毒71型(EV71)作為研究之對象，並將EV71外鞘膜蛋白VP-1利用矽烷偶聯劑 ((3-Aminopropyl)triethoxysilane)與戊二醛(glutaraldehyde) 接枝於AFM之探針上，進一步對利用同樣方法固定於矽基板表面的PSGL-1來進行配體和受體之間解離力之量測及評估。評估部分包含PSGL-1有無經過硫化後修飾的處理、量測位置對於解離力的影響。結果顯示，無論使用何種探針 (Anti-sulfo antibody tip、VP-1 tip)與PSGL-1之解離力數據，分佈情況並不會因為量測點位的改變而使得量測的結果有顯著差異。Anti-sulfo antibody 與VP-1由於對硫化PSGL-1具有的專一性關係，造成分子間的解離力量較未硫化PSGL-1增強1.82倍。此外，同樣與硫化PSGL-1具有專一性鍵結的Anti-sulfo antibody 及VP-1，由於與硫化PSGL-1間的關係不同，如Anti-sulfo antibody 與硫化PSGL-1為抗體與抗原；VP-1與硫化PSGL-1為配體與受體，以及Anti-sulfo antibody 與VP-1在分子量相差6.75倍的情況下，使得兩者雖然同樣存在有專一性關係，解離力量卻出現差異。

Enteroviruses are a genus of positive-sense single-stranded RNA viruses associated with several human and mammalian diseases, for example, an epidemic of EV71 always occurs in Southeast Asian areas, mainly in summer and early autumn. EV71 is notable as one of the major causative agents for hand, foot and mouth disease (hand-foot-mouth disease, HFMD). It also associated with severe central nervous system diseases like twitch, paralysis, meningitis and difficulty breathing, etc. Despite lots of researches focus on the main route of infection about EV71, the interactions mechanism between EV71 and a functional cellular receptor, P-selectin glycoprotein ligand-1(PSGL-1) remains largely unknown.
Atomic force microscopy (AFM) was used as force apparatus to measure the unbinding force between the outer sheath protein VP-1 of EV71 and PSGL-1. Through (3-Aminopropyl)triethoxysilane silane (APTES) and glutaraldehyde(GA), proteins were, respectively, covalently attached on the apex of AFM tip and silicon substrate. Then the unbinding forces between the proteins were analyzed. With the tyrosine sulfation of PSGL-1, unbinding force between Anti-sulfo antibody & sulfat-ed-PSGL-1(antigen) and VP-1(ligand) & sulfated-PSGL-1(receptor) obviously stronger than those of nonsulfated-PSGL-1 since the specific bonding between the proteins would affect the unbinding force. Besides, owing to the different roles in physiological reaction and the gap between molecular weight, had much stronger chemical binding to sulfated-PSGL-1 than VP-1, resulting in the binding strength of Anti-sulfo antibody and sulfated-PSGL-1 is thus larger than that between VP-1 and sulfated-PSGL-1.

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