Combined Use of Ionic Liquid-Based Aqueous Biphasic Systems and Microfluidic Devices for the Detection of Prostate-Specific Antigen

abstract

Prostate cancer (PCa) is one of the cancer types that most affects males worldwide and is among the highest contributors to cancer mortality rates. Therefore, there is an urgent need to find strategies to improve the diagnosis of PCa. Microtechnologies have been gaining ground in biomedical devices, with microfluidics and lab-on-chip systems potentially revolutionizing medical diagnostics. In this paper, it is shown that prostate-specific antigen (PSA) can be detected through an immunoassay performed in a microbead-based microfluidic device after being extracted and purified from a serum sample through an aqueous biphasic system (ABS). Given their well-established status as ABS components for successful bioseparations, ionic liquids (ILs) and polymers were used in combination with buffered salts. Using both IL-based and polymer-based ABS, it was demonstrated that it is possible to detect PSA in non-physiological environments. It was concluded that the ABS that performed better in extracting the PSA from serum were those composed of tetrabutylammonium chloride ([N-4444]Cl) and tetrabutylphosphonium bromide ([P-4444]Br), both combined with phosphate buffer, and constituted by polyethylene glycol with a molecular weight of 1000 g/mol (PEG1000) with citrate buffer. In comparison with the assay with PSA prepared in phosphate-buffered saline (PBS) or human serum in which no ABS-mediated extraction was applied, assays attained lower limits of detection after IL-based ABS-mediated extraction. These results reinforce the potential of this method in future point-of-care (PoC) measurements.

keywords

THIN-FILM PHOTODIODES; BOVINE SERUM-ALBUMIN; 2-PHASE SYSTEMS; EXTRACTION; PROTEINS; PURIFICATION; DESIGN; DNA; BIOMARKERS; SEPARATION

subject category

Chemistry; Science & Technology - Other Topics; Instruments & Instrumentation

authors

Flora, FC; Relvas, SB; Silva, FAE; Freire, MG; Chu, VRN; Conde, JP

Groups

G5 - Biomimetic, Biological and Living Materials

Projects

Integration of human fluids pretreatment and detection of cancer biomarkers using ionic-liquid-based aqueous biphasic systems in microfluidic devices (ILSurvive)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT) by funding the research project ILSurvive (PTDC/EMD-TLM/3253/2020) and the Research Unit INESC MN (UID/05367/2020) through BASE and PROGRAMATICO financing. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020, financed by national funds through the FCT/MEC (PIDDAC). F.A.eS. acknowledges FCT-Fundacao para a Ciencia e a Tecnologia, I.P. for the researcher contract CEECIND/03076/2018 under the Scientific Employment Stimulus-Individual Call 2018.