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 ([N4444]Cl) and tetrabutylphosphonium bromide ([P4444]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.

Rapid Microfluidic Immuno-Biosensor Detection System for the Point-of-Care Determination of High-Sensitivity Urinary C-Reactive Protein

“…As the microfluidics field has advanced, many microfluidic lab-on-a-chip (LOC) devices have been developed that can achieve sample injection, separation, mixing, coating, transmission, and detection on a single platform [ 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. LOC-based immunoassays have thus emerged as a powerful tool for biomedical research and clinical diagnostics [ 49 , 50 , 51 , 52 , 53 ]. By integrating multiple laboratory functions into a single microchip, LOC-based immunoassays offer significant advantages over traditional laboratory-based immunoassays, including superior portability, miniaturization, high throughput, sensitivity, rapid analysis, automation, and cost-effectiveness.…”

Ionic liquid-based aqueous biphasic systems as one-step clean-up, microextraction and preconcentration platforms for the improved determination of salivary biomarkers

“…IL-based ABSs have been successfully used for the analysis of biofluids, especially urine 19–21 and blood byproducts. 22,23 Despite their successful use as bioanalytical platforms, to the best of our knowledge, IL-based ABSs have not been explored for the analysis of saliva. This mostly relies on the low available volume of saliva that makes its pretreatment with IL-based ABSs quite challenging, as ABSs intended for preconcentration normally benefit from the scalability of the sample ( i.e.…”