MOE Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
MOE Key Laboratory of Analysis and Detection for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China; Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China.
Biosens Bioelectron. 2014 Aug 15;58:226-31. doi: 10.1016/j.bios.2014.02.066. Epub 2014 Mar 6.
Owning to the characteristics such as high sensitivity and simplicity of apparatus, electrochemiluminescence (ECL) has become a powerful analytical technique and has been widely used. Ru(phen)3(2+) can be intercalated into the grooves of dsDNA and act as an ECL probe efficiently, which has been applied to develop a sensitive ECL biosensor for folate receptor in this study. One ssDNA with a thiol group at its 3' termini had been modified on the Au electrode first, and the other ssDNA with folic acid at its 3' termini hybridized with the former one being modified on the electrode surface to form a dsDNA. In the absence of folate receptor, the 3'-terminus in the dsDNA region can be specificity hydrolyzed into mononucleotides by ExoIII and on dsDNA presents on the electrode surface, leading to the lower of ECL intensity detected. However, in the presence of the target (folate receptor), ExoIII failed to hydrolyze the dsDNA since the one 3'-terminus had been protected by the target and the other protected by the Au electrode, resulting in the enhancement of ECL intensity. The enhanced ECL intensity has a linear relationship with the logarithm of folate receptor concentration in the range of 0.66nmol/L and 26.31nmol/L with a detection limit of 0.1204nmol/L. The proposed biosensor had been applied to detect HeLa cells concentration with satisfied results.
由于电化学发光（ECL）具有灵敏度高、仪器简单等特点，已成为一种强大的分析技术，并得到了广泛的应用。钌（phen）3（2+）可以嵌入 dsDNA 的沟槽中，并有效地作为 ECL 探针，这在本研究中已被应用于开发一种用于叶酸受体的灵敏 ECL 生物传感器。首先在 Au 电极上修饰一条 3'末端带有巯基的 ssDNA，另一条 3'末端带有叶酸的 ssDNA 与修饰在电极表面的前一条 ssDNA 杂交形成 dsDNA。在没有叶酸受体的情况下，dsDNA 区域中的 3'-末端可以被 ExoIII 特异性水解成单核苷酸，并且在 dsDNA 存在于电极表面上，导致检测到的 ECL 强度降低。然而，在存在靶标（叶酸受体）的情况下，由于一个 3'-末端被靶标保护，另一个被 Au 电极保护，ExoIII 无法水解 dsDNA，导致 ECL 强度增强。增强的 ECL 强度与叶酸受体浓度的对数在 0.66nmol/L 和 26.31nmol/L 范围内呈线性关系，检测限为 0.1204nmol/L。该生物传感器已被用于检测 HeLa 细胞浓度，取得了令人满意的结果。
