College of Chemical Engineering and Materials Science, Quanzhou Normal University, Quanzhou, 362000, Fujian Province, China.
The Education Ministry Key Laboratory of Resource Chemistry Shanghai Key Laboratory of Rare Earth Functional Materials and Shanghai Municipal Education Committee Key Laboratory of Molecular Imaging Probes and Sensors, Department of Chemistry, Shanghai Normal University, Shanghai, 200234, China.
Mikrochim Acta. 2018 Jun 26;185(7):338. doi: 10.1007/s00604-018-2861-z.
A sandwich-type electrochemical cytosensor is described for quantitative determination of CD44-overexpressing HeLa cells. Hyaluronic acid (HA) acts as a targeting molecule that was in-situ incorporated into the sensor based on the use of an indium tin oxide (ITO) electrode modified with multi-walled carbon nanotubes (MWCNTs). The 3D-MWCNT structure is shown to strongly improve the electronic properties and surface chemical reactivities. The HA-modified sensor exhibits a highly sensitive response to HeLa cells. A sandwiched hybridization protocol was then established using BIO [an N-butyl-4-(6'-aminohexyl)amino-1,8-naphthalimide probe modified with HA] as the tracing labels of the fluorescent probes for targeting CD44-positive tumor cells. The signal amplification was thereby maximized and measured by chronocoulometry. The binding of CD44-positive HeLa cells to the HA modified sensing layer causes a decrease in chronocoulometric response. The signal decreases linearly in the 2.1 × 10 to 2.1 × 10 HeLa cells·mL concentration range with a detection limit of 70 cells·mL. Such a sandwich-type assay may be tailored as a sensitive candidate for detecting low levels of tumor cells. Graphical abstract Schematic of a sandwich cytosensor based on hyaluronic acid-grafted 3D-MWCNT as biosensing interface and BIO as fluorescent probe. This biosensor possessed excellent electrochemical activity, high sensitivity and selectivity, providing a dynamical tracking and detecting platform for CD44-positive tumor cells.
夹心型电化学细胞传感器用于定量测定过表达 CD44 的 HeLa 细胞。透明质酸 (HA) 作为靶向分子，通过使用修饰有多壁碳纳米管 (MWCNT) 的氧化铟锡 (ITO) 电极原位掺入传感器中。3D-MWCNT 结构被证明可以极大地提高电子性能和表面化学反应性。HA 修饰的传感器对 HeLa 细胞表现出高度敏感的响应。然后，建立了夹心杂交方案，使用 BIO（一种用 HA 修饰的 N-丁基-4-（6'-氨基己基）氨基-1,8-萘二甲酰亚胺探针）作为荧光探针的示踪标签，用于靶向 CD44 阳性肿瘤细胞。通过计时库仑法最大程度地增强和测量信号放大。CD44 阳性 HeLa 细胞与 HA 修饰的传感层的结合导致计时库仑响应降低。信号在 2.1×10 到 2.1×10 HeLa 细胞·mL 浓度范围内呈线性下降，检测限为 70 个细胞·mL。这种夹心型测定法可作为检测低水平肿瘤细胞的敏感候选物。
