Poly(sodium acrylate-co-acrylamide) hydrogel beads as selective enhancement platforms for biomarker detection in tear fluid

• The concentration of biomarkers in tear fluids was enhanced using, poly(sodium acrylate-co-acrylamide) hydrogel beads that were employed for selective enrichment. • Three proteins, widely recognized as standard tear biomarkers, with distinct surface charges were selected. • After 24 h of swelling, the hydrogel beads achieved selective recoveries of 121% for bovine serum albumin, 83% for immunoglobulin G, and 6% for lysozyme. • Hydrogel beads are effective platforms for biomarker enrichment, offering promising applications in tear fluid-based diagnostics. The concentration of biomarkers in tear fluids was enhanced using poly(sodium acrylate-co-acrylamide) hydrogel beads that were employed for selective enrichment. Swelling behavior studies demonstrated the hydrogel’s water absorption capacity in simulated tear fluid, revealing an initial diffusion-dominated swelling phase followed by relaxation-dominated behavior. Three proteins, widely recognized as standard tear biomarkers, with distinct surface charges at pH 7.5, including bovine serum albumin (−18.1 mV), immunoglobulin G (−3.6 mV), and lysozyme (+5.3 mV), were selected based on their representative surface charges commonly found in tear fluid. After 24 h of swelling, the hydrogel beads achieved selective recoveries of 121% for bovine serum albumin, 83% for immunoglobulin G, and 6% for lysozyme, as quantified using the bicinchoninic acid (BCA) assay. FT-IR spectroscopy and adsorption kinetics analyses indicated that immunoglobulin G and lysozyme primarily undergo physical adsorption, with lysozyme additionally exhibiting intraparticle diffusion at later stages. Molecular docking studies revealed that adsorption is predominantly driven by hydrogen bonding and electrostatic interactions between the cationic and polar amino acid residues of the biomarkers and the carboxylate and amide groups of the hydrogel matrix. These findings highlight the strong potential of poly(sodium acrylate-co-acrylamide) hydrogel beads as effective platforms for biomarker enrichment, offering promising applications in tear fluid-based diagnostics.