PNNL

Abstract

The detection and quantification of proteins at sub-ng/mL concentrations in plasma/serum is of critical importance for candidate biomarker verification. Sensitive detection of serum proteins has typically been achieved by immunoassays; however, de novo development of antibodies is associated with high cost and long lead time. To address this challenge, we developed an antibody-free strategy, termed high-pressure high-resolution separations with intelligent selection and multiplexing (PRISM), for achieving accurate detection of proteins at ~50 pg/mL level in plasma/serum using selected reaction monitoring (SRM). This strategy is based on high resolution reversed phase liquid chromatographic separations for analyte enrichment along with intelligent selection of target fractions via on-line SRM monitoring of internal standards and fraction multiplexing prior to SRM quantification. Our work represents a major technological advance for achieving pg/mL level of serum protein quantification without specific affinity reagents and holds great promise for broad applications in biomarker verification and systems biology studies.