Aqueous Two-Phase Systems as Multipurpose Tools to Improve Biomarker Analysis

Biomarker analysis in biological samples can boost risk profiling, diagnosis, prognosis and clinical decision-making, overall improving patient care. However, due to the complexity of most biological samples, biomarker analysis is a time-, cost-, labor-and resource-intensive task, commonly struggling with the lack of accurate results. To improve biomarker analysis, it is critical to develop efficient strategies to remove main contaminant/interfering molecules and to enrich/concentrate intact biomarkers prior to detection/quantifica-tion. Also, the development of more reliant and cost-effective quantification techniques and improved point-of-care (PoC) approaches are on demand. To bridge these gaps, properly designed aqueous two-phase systems (ATPSs) are potential candidates due to their high-water content, structural versatility and high selectivity. Over the past years, ATPSs have been shown to improve biomarker analysis, including proteins, nucleic acids, extracellular vesicles, bacteria, and viruses, in the following areas: (i) proteomic studies to expand proteome coverage; (ii) extraction of biomarkers to improve laboratory analysis; (iii) confinement strategies to improve enzyme-linked immunosorbent assays; and (iv) PoC applications, including the development of lateral flow immunoassays and one-pot reactions, and the miniaturization of extraction and purification techniques. This review describes and critically addresses the main applications of ATPSs in each of the mentioned areas by focusing on the types of ATPSs, biological samples, biomarkers, diseases, and detection/quantification techniques. Main technological advancements in the last two decades and challenges faced in research/clinical laboratories or at the PoC are highlighted. To gain insight on the societal pertinence of the field, the importance of clinical validation towards commercialization is discussed using IsoPSATM as a case study, while pinpointing the respective contributions for the United Nations Sustainable Development Goals. Considering the reviewed information, main conclusions and future perspectives are finally provided.