A one-shot approach for serum vancomycin assessment using fluorescence-based molecularly imprinted polymer nanoparticles.

Novel fluorescence-based molecularly imprinted polymer nanoparticles (MIP NPs) were prepared by incorporating fluorescent thionine within the polymer matrix. Thionine functioned both as a functional monomer and as an internal signaling probe, enabling a direct fluorescence readout without the need for external fluorescent labels. MIP NPs served as the selective recognition element for vancomycin (VA) assessment. VA bound to the selective cavities of the MIP NPs and quenched the fluorescence via static quenching mechanism. The fluorescence intensity decreased with increasing concentrations of VA. For MIP NPs-based fluorescence spectrometry development, 1 mg/mL MIP NPs dispersed in DI water completely interacted with the VA-containing sample. The assay exhibited a linear response ranging from 1.55 to 100 mg/L (LOD = 0.46 mg/L), enabling highly sensitive measurement of low VA levels in serum. The recovery was 97-115%, with within-run precision of 2.7-6.2%. Furthermore, the developed assay shows relatively high selectivity toward VA over other antibiotics/medications, including gentamicin, ampicillin, and acetaminophen. Spiked VA in the serum sample analyzed by MIP NP-based fluorescence spectrometry compared to the particle-enhanced turbidimetric inhibition immunoassay gave less than 12% relative error for all samples, suggesting acceptable accuracy of the proposed method. This assay achieved rapid results within 10 min in a one-shot approach, compared to the multi-step nanoMIP-based ELISA at 90 min. The high binding ability and selectivity of the thionine-based MIP NPs showed promise as a selective material against VA for other applications.