An ultrasensitive SERS biosensor based on porous ZIF-8-encapsulated silver nanoflowers coordinated with host-gest recognition amplification strategy for the detection of bisphenol S

Herein, a dual-enhanced SERS biosensor has been developed for the detection of bisphenol S (BPS) based on silver nanoflowers coated zeolitic imidazolate-based metal-organic framework (AgNFs@ZIF-8) cooperate with host-guest recognition amplification technology. The biosensor utilizes the molecularly imprinted polymer (MIP) and BPS aptamer chain (APT) as dual recognition element to achieve a significant increase in selectivity. In the presence of the target, the APT on AgNFs@ZIF-8@β-cyclodextrin(β-CD) specifically binds with BPS, which further recognized by MIP to form a sandwich structure. At this time, due to the large surface area, and stable Raman enhancement ability, AgNFs@ZIF-8@β-CD could not only provide multiple active “hot spots” as the surface-enhanced Raman scattering (SERS) enhanced substrate, but also specific capture large number of methylene blue (MB, SERS tag) through the host-guest recognition. Moreover, multiple host-guest recognition can be achieved by further addition of AgNFs@ZIF-8@β-CD and MB, which greatly improve the detection sensitivity. This SERS sensor, characterized by an extensive linear detection range from 1.00 × 10 −13 to 1.00 × 10 −6  M and an exceptionally low limit of detection (LOD) of 1.36 × 10 −14  M, has been effectively utilized for the detection of BPS in plastic pacifiers, receipts, and river water samples. As an extremely sensitive and highly specific analytical method for detecting BPS, this SERS-based method has promising applications in the fields of environmental monitoring and food safety.