人類絨毛膜性腺激素是一般大家所熟知的懷孕測試指標，但在近幾年的研究中發現，人類絨毛膜性腺激素同時也是子宮外孕流產的判斷指標、部分癌症的腫瘤標記及具有唐氏症篩檢與臨床上藥物使用的用途。由於原子力顯微術具有高度的空間解析力及力學敏感度，可在氣態、液態及真空環境下進行量測，作為奈米微結構的檢測工具。在本研究中使用原子力顯微術量測人類絨毛膜性腺激素與其抗體在不同酸鹼度下的動態反應，並針對蛋白-蛋白之間的作用力進行分析與探討酸鹼度的影響。 實驗方法是固定人類絨毛膜性腺激素於玻璃基材上，同時將其抗體固定至原子力顯微鏡的探針上，選擇pH 2.2、pH 4.2、pH 6.2、pH 7.2、pH 8.2及pH 10.2六種緩衝溶液來測量其抗體-抗原間的解離力。發現在酸性條件（pH 2.2）中，得到的解離力較小，其值為252.4 ± 29.4(pN)；在鹼性條件中(pH 10.2)，得到的解離力也較小，其值為263.8 ± 41.3(pN)，而在中性條件下(pH 6.2)，可以得到最大解離力，其值為503.8 ± 77.6(pN)。 Human chorionic gonadotropin (hCG) is a well-known index of the pregnancy test. There are some studies also indicated that the hCG exhibits many functions such as the diagnosis of ectopic pregnancy miscarriages, tumor markers of some cancers, Down’s syndrome screens and clinical medications. Atomic force microscopy (AFM) possess the high spatial resolution and immense force sensitivity, it is regarded as a powerful instrument to investigate the nanostructures of samples in air, liquid or vacuum environment. In this study, dynamic responses of hCG with anti-hCG under different pH environments were studied by AFM, and the unbinding forces were also be discussed. The hCG and anti-hCG were immobilized on the glass surface and the AFM tips, respectively. The unbinding forces have measured by AFM under different buffer solutions (pH 2.2, pH 4.2, pH 6.2, pH 7.2, pH 8.2 and pH 10.2). Within the acidic range, the mean value of the unbinding force between the hCG and anti-hCG complex showed a rapidly increase from pH 2.2 to 6.2. A maximum value of 503.8 ± 77.6 (pN) was measured at neutral environment, followed by a sharp decreasing with rising pH values (pH 6.2 ~ 10.2).
