Ultrasensitive detection strategy for CAP by molecularity imprinted SERS sensor based on multiple synergistic enhancement of SiO2@AuAg with MOFs@Au signal carrier

A biosensor was constructed by combining the highly selective molecularly imprinted polymer (MIP) technology with aptamers (Apt) to achieve high selectivity for chloramphenicol (CAP). Furthermore, the MOFs material enriched with Au NPs were prepared, and after the addition of Toluidine bule (TB) and Apt, MOFs@Au@TB@Apt with enhanced signals was formed. Subsequently, a highly uniform 3D SERS substrate was prepared. When CAP was present, it could be captured by the rMIP (CAP was eluted) on the SERS substrate through a covalent bond. Upon adding MOF@Au@TB@Apt, the aptamer recognized CAP, thereby linking MOFs@Au@TB with SiO2@AuAg, achieving dual selectivity for the analyte and dual signal enhancement of Raman signal. [Display omitted] •The molecularly imprinted polymer and CAP aptamers both have specific recognition to CAP, which can achieve dual recognition for CAP to improve specificity of the SERS aptasensor.•MOFs@Au@TB as an excellent SERS tag can significantly enhance Raman signals to improve CAP detection sensitivity.•SiO2@AuAg nanocentrum was orderly and uniformly assembled on silicon wafers to improve sensitivity and homogeneity.•The molecularly imprinted SERS sensor can achieve detect CAP with a detection limit of 7.59×10−13 mol/L. Chloramphenicol (CAP) residue in food can cause great harm to human health, it is important to develop a rapid and sensitive method to detect CAP. Here, molecularly imprinted polymer (MIP) was combined with metal-organic frameworks@Au (MOFs@Au) collaborative construction surface-enhanced Raman spectroscopy (SERS) based aptasensor for CAP ultrasensitive detection. MOFs@Au first carried the Raman signal molecule toluidine blue (TB) and aptamer to form MOFs@Au@TB@Apt. In addition, rMIP (CAP was removed) was dropped onto the uniform three-dimensional (3D) SERS substrate SiO2@AuAg to form SiO2@AuAg@rMIP. In the presence of target CAP, it could be specifically captured with rMIP by covalent interaction and was recognised by the aptamer. During this time, SiO2@AuAg@rMIP@CAP could selectively connect MOFs@Au@TB@Apt to realise synergistic enhance the Raman signal. Based on this principle, the proposed SERS aptasensor exhibits excellent sensitivity with a detection limit of 7.59×10−13 M for CAP, providing a new strategy for trace detection in food.