Carbon nanotube–mediated antibody-free suspension array for determination of typical endocrine-disrupting chemicals

A carbon nanotube (CNT)–mediated antibody-free suspension array (CASA) by integration of functionalized CNTs and aptamer (Apt) into xMAP® technology for simultaneous determination of typical endocrine-disrupting chemicals (EDCs) was developed . The interaction between CNTs and Apt acts as an effective and straightforward signal recognition, transformation, and amplification strategy. The amino-functionalized CNTs are covalently modified on the carboxyl-functionalized magnetic bead (MB) and further physically bridging with biotinylated Apt. CNTs on the surface of MBs not only increase the amount of Apt for target binding and signal amplification but also maintain the biological activity of Apt. After magnetic separation, the encoded MB address was distinguished and the concentration of the target in the liquid was negatively correlated with median fluorescence intensity. A series of environmental water samples were analysed by CASA, traditional immuno-SA, and competitive inhibition enzyme-linked immunosorbent assay for validation. The results obtained using CASA well matched for the multiplexed detection of various targets with dynamic concentration range from 6.40 × 10−5 to 4.00 μg L−1 within 1 h. The method also confirmed good selectively, accuracy, and consistency with high-performance liquid chromatography.