Enhancing biomarker detection in human serum for lung cancer diagnosis: Aqueous biphasic systems for simultaneous depletion of high-abundance proteins and efficient extraction of CYFRA 21–1

Abstract

Analysing biomarkers in human serum could be used as an effective and less invasive approach for the diagnosis of lung cancer; however, biomarker detection reliability is highly limited due to matrix effects. Herein, aqueous biphasic systems (ABS) are studied as platforms for human serum pretreatment, allowing the simultaneous depletion of high abundant proteins and biomarker extraction. By using ABS varying the polyethylene glycol (PEG) molecular weight between 400 and 6000 g·mol⁻¹ and adopting phosphate buffer as the other phase-forming component, the depletion of the high abundance serum proteins immunoglobulin G (IgG) and human serum albumin (HSA) is induced at the ABS interphase, through precipitation, forming a three-phase partitioning system (ABS-TPP). Maximum depletion efficiencies of 99 % for IgG and 70 % for HSA were achieved in one step using PEG 1500-based ABS-TPP. On the other hand, lung cancer biomarkers, such as CYFRA 21–1, are extracted to the PEG-rich phase of the same ABS-TPP with recovery yields of 91 %. This work shows that a proper selection of the PEG molecular weight in the ABS composition leads to the efficient depletion of high-abundance proteins and extraction of cancer biomarkers from human serum, in a single step, confirming the potential of ABS for sample pretreatment to improve biomarker analysis.