Surface plasmon resonance (SPR) has increasingly made the transition from affinity-based pharmaceutical applications to a broader base of use-cases. One of the methods of delivering this technology to industry is in the form of SPR imaging (SPRi), which overcomes the low-throughput limits of conventional SPR. Mass spectrometry is a powerful tool for identification of chemical molecules, but lack of quantification ability and large data sets complicate the screening of biological contaminants in large array format. We report a novel chemical interface that enables coupling of SPRi to matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), or SPR-MALDI. A silicated gold microwell array was functionalized with perfluorodecyltrichlorosilane (PFTDS) that both mimics a typical MALDI hydrophobic surface and can be further functionalized for analyte capture and analysis. As a proof of concept, we functionalized the array with a small-molecule probe, monoganglioside GM1. This generated a bilayer-type interface to use for capture and sensing of bacterial toxins, in particular cholera toxin (CT). Using the multifunctional array alone enables SPR imaging detection of CT at clinically relevant levels in both buffer and spiked river water, and several CT fingerprints were identified in the MALDI-MS spectra of the surface after capture, giving unambiguous identification of the target. This orthogonal methodology allows the sensitivity and finger-printing utility of mass spec to be used on a surface where the desired biomarker is sensed in a biologically relevant context, and may offer a new technical avenue in the bioanalysis in complex media.

SPR-MALDI Biosensing via carbohydrate small molecule probes

2019 Fall National Meeting

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