Rapid Diagnostic Platform for Personalized Vitamin B6 Detection in Erythrocytes via PLP Cofactor Mimics

Personalized assessmentof vitamin levels in point-of-care(POC)devices is urgently needed to advance the recognition of diseasesassociated with malnutrition and unbalanced diets. We here introducea diagnostic platform, which showcases an easy and rapid readout ofvitamin B6 (pyridoxal phosphate, PLP) levels in erythrocytes as afirst step toward a home-use POC. The technology is based on fluorescentprobes, which bind to PLP-dependent enzymes (PLP-DEs) and therebyindirectly report their occupancy with endogenous B6. For example,low vitamin levels result in high probe binding, yielding a strongsignal and vice versa. Antibodies against signaturehuman PLP-DEs were immobilized on microarrays to capture probe labeledenzymes for fluorescent detection. Calibrating the system with definedB6 levels revealed a concentration-depended readout as well as sufficientsensitivity for its detection in erythrocytes. To account for individualdifferences in protein expression, a second antibody was used to normalizeprotein abundance. This sandwiched assay correctly reported relativeB6 levels in human erythrocyte samples, as confirmed by classicallaboratory diagnostics. In principle, the platform layout can be easilyexpanded to other crucial vitamins beyond B6 via ananalogous probe strategy.

Automated summary

Personalized assessment of vitamin levels in point-of-care (POC) devices is urgently needed. A diagnostic platform based on fluorescent probes was introduced, allowing easy and rapid readout of vitamin B6 levels in erythrocytes. The platform showed promising results in accurately reporting B6 levels in human erythrocyte samples.