A boronate affinity sandwich assay: an appealing alternative to immunoassays for the determination of glycoproteins.

Immunoassay has been an essential tool in many areas, including clinical diagnostics. However, it suffers from drawbacks, such as poor availability of high specificity antibodies, limited stability of biological reagents, as well as damage to health and susceptibility of chemical labels to the sample environment. Here we present a new approach, a boronate-affinity sandwich assay (BASA), for the specific and sensitive determination of trace glycoproteins in complex samples. BASA relies on the formation of sandwiches between boronate-affinity molecularly imprinted polymers (MIPs), target glycoproteins, and boronate-affinity surface-enhanced Raman scattering (SERS) probes. The MIP ensures the specificity, while the SERS detection provides the sensitivity. BASA overcomes the drawbacks of traditional immunoassays and offers a great prospect for application.