A Quantification of Target Protein Biomarkers in Complex Media by Faradaic Shotgun Tagging

The progressive emergence of protein biomarkers promises a revolution in the healthcare industry and a shift of focus from disease management to much earlier intervention. Here, we introduce a facile shotgun tagging of ensemble proteins in clinically relevant media prior to specific target capture at antibody-modified electrodes. This facilitates a convenient voltammetric quantification of markers down to sub-pg/mL levels and across several orders of concentration. A translation of the methodology to an automated microfluidic platform enables marker quantification from 25 mu L of sample in less than 15 min, demonstrated here with a simultaneous assaying of CRP and cardiac troponin I (cTnI). The assays show a good correlation with a standard immunoassay when applied to real patient serum samples. The platform is simple, generic, highly sensitive and requires no secondary labeling/binding or amplification.

Automated summary

The emergence of protein biomarkers promises a revolution in healthcare, shifting the focus from disease management to earlier intervention. This study introduces a convenient method for protein tagging prior to target capture, allowing for easy quantification of biomarkers. When translated to an automated microfluidic platform, the method enables rapid and accurate quantification of markers, showing good correlation with standard immunoassays. The platform is simple, versatile, highly sensitive, and does not require secondary labeling/binding or amplification.