Highly sensitive aptamer based on electrochemiluminescence biosensor for label-free detection of bisphenol A

Bisphenol A (BPA), a typical endocrine disruptor, is widely used as a key monomer in the packaging industry. Residual monomer can transfer from the package material to the food and thereby pose a risk to the health of the consumer, so determination of BPA migration is highly important for food safety control. In this study, a simple but sensitive electrochemiluminescence (ECL) biosensor, which combines the characteristics of high selectivity of an aptamer and high sensitivity of ECL, has been developed to detect BPA from package materials. The aptamer was immobilized on a gold electrode surface through Au-S interaction. The aptamer was then hybridized with complementary DNA (CDNA) to form double-stranded DNA (dsDNA). Ru(phen)₃²⁺ can intercalate into the grooves of dsDNA and acts as an ECL indicator; high ECL intensity can therefore be detected from the electrode surface. In the presence of BPA, which can competitively bind with the aptamer owing to their high affinity, Ru(phen)₃²⁺ is released from the electrode surface and the ECL of the system is decreased. The decreasing ECL signal has a linear relationship with BPA in the range of 0.1-100 pM with a detection limit of 0.076 pM. The developed biosensor has been applied to detect migration of BPA from different categories of canned drink with satisfactory results.