Novel fluorescent biosensor for carcinoembryonic antigen determination via atom transfer radical polymerization with a macroinitiator

Abstract

In this paper, a high sensitivity and accuracy biosensor for CEA detection based on atom transfer radical polymerization (ATRP) with β-cyclodextrin (β-CD) and 2-bromoisobutyryl bromide (BIBB) as a macroinitiator is reported for the first time. Carcinoembryonic antigen (CEA), as a tumor-associated antigen, can be of great significance in the diagnosis of illness. Herein, thiolated CEA-aptamer 1 (Apt 1) at the 5′-terminal is first immobilized on amino magnetic beads (MBs) via a cross-linking agent to specifically recognize the antigen of CEA. After the sandwich-type structure formed, β-CD, with a bridging effect, is linked to the carboxylation CEA-aptamer 2* (Apt 2*) and BIBB via esterification reaction and substitution reaction, respectively. Remarkably, the combination of β-CD and the initiators BIBB can provide a large number of active sites for monomers and significantly amplify the fluorescent signal. Under optimum experimental conditions, the proposed biosensor for detecting CEA has a strong linear relationship in the wide detection range of 1.0 × 10⁻¹⁵–1.0 × 10⁻⁷ g mL⁻¹ (R² = 0.9989), and it is capable of detecting as low as 6.76 ag mL⁻¹ CEA. Furthermore, the fluorescence biosensor exhibits splendid analytical performance in practical sample analysis. More importantly, the excellent sensitivity with outstanding anti-interference properties of this proposed biosensor makes it of great potential in the field of bioanalytical applications.