Monitoring allergic reaction to penicillin based on ultrasensitive detection of penicilloyl protein using alkyne response SERS immunosensor.

The evaluation of true penicillin allergy is significant to reduce its occurrence and the overdiagnosis before anti-infective treatment. However, the currently available methods with high specificity still face the problem of low sensitivity, thereby easily leading to false negatives. Herein, an alkyne responsive surface-enhanced Raman scattering (SERS) immunosensor is reported for ultrasensitive detection of penicillin allergen penicilloyl protein (P-protein) by using Au-Ag alloy nanoparticles@(antibody + alkyne probe) (as SERS immunoprobe) together with Ag nanofilm modified by antibody (as SERS capture substrate). The SERS immunoassay integrates the interference-free Raman response of high wavenumber region (2212 cm-1) and specific capture antibody with high affinity to selectively recognize P-protein from complicated sample. Meanwhile, the target-induced near-field coupling effect between localized surface plasmon resonances of individual SERS immunoprobe and capture substrate enables the detection of P-protein as low as pg/mL level, and the limit of detection can reach 0.329 pg/mL that is about 6 orders of magnitude lower than the limit defined protein residue (causing penicillin allergy). With the ultrasensitivity and specific selectivity, the proposed SERS immunoassay platform can precisely evaluate the content of P-protein in blood sample or penicillin drugs. It will be a potential tool to monitor allergic reaction to penicillin and better understand the mechanism of penicillin hypersensitivity.