Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients

Silvia Dortez, Nùria DeGregorio-Rocasolano, Mónica Millán, Teresa Gasull, Agustín G Crevillen, Alberto Escarpa. Anal Chem. 2023 Aug 22;95(33): 12391-12397. DOI: 10.1021/acs.analchem.3c01982. PMID: 37486019

Abstract: For the first time, a paper-based analytical device (PAD) was developed for the assessment of transferrin saturation (TSAT), which is defined as the ratio between iron bound to transferrin (Tf) and the total iron-binding capacity (TIBC) of Tf. Both parameters were simultaneously measured on the same PAD using ferrozine as a chromophore and a smartphone as the color reader. To this end, Tf was first isolated from serum using anti-Tf immunomagnetic beads to ensure that only the Tf-bound iron was measured, improving the selectivity and accuracy of TSAT assessment. To demonstrate the practical utility of the device, it was validated by analyzing a certified reference material, showing excellent accuracy (Er < 4%) and good precision (RSD ≤ 6%). Finally, 18 diagnosed serum samples from ischemic stroke patients were analyzed by this approach, and the results were compared with those obtained by urea-PAGE, showing not only an excellent correlation (r = 0.93, p < 0.05) but that the PAD approach has become statistically identical to the free-interference urea-PAGE. In comparison with the slow, tedious, and non-miniaturized-PAGE, this PAD approach exhibited attractive characteristics such as low cost, disposability, and connectivity, showing great potential for future point-of-care testing, especially in developing countries and/or remote areas, where access to medical or clinical facilities is limited.

Funding: This work has been financially supported by the TRANSNANOAVANSENS program from the Community of Madrid (P2018/NMT-4349) (A.E.), by the grant PID2020 118154GB-I00 funded by MCIN/AEI/ 10.13039/ 501100011033 (A.E.), by the RICORS RD21/0006/0024 and 2021SGR00925 (T.G.), and by the Spanish Ministry of Economy and Competitiveness (CTQ2017-86441-C2-1-R, FPI fellowship (S. D.)).