A magnetic polymer adsorbent based on porous polystyrene microspheres for efficient extraction of conotoxins in biological fluids

Abstract

Conotoxins, isolated from the venom produced by marine snails of the Conus genus, are a range of bioactive, disulfide-rich peptides. However, their narrow therapeutic window and significant interindividual variability make the efficient and accurate detection of their concentration in biological fluids a "lifeline" for ensuring safe and effective clinical use. In this work, we employed α-conotoxin ImI (α-ImI) and ziconotide as model peptides. Inspired by the mechanisms through which these two peptides exert bioactivity, we fabricated and characterized porous polystyrene-based magnetic microspheres grafted with a terpolymer, poly (divinylbenzene-co-N-vinylpyrrolidone-co-vinylphosphonic acid), DVB-co-NVP-co-VPA, for the efficient capture of α-ImI and ziconotide from biofluid samples. The results implied that the modified DVB-co-NVP-co-VPA enhanced the selectivity and adsorption capability for α-ImI and ziconotide. The established method was characterized by good linearity (R² above 0.9993), acceptable sensitivity (LODs below 0.03 μg mL⁻¹), high accuracy (recoveries ranging from 85.3 % to 92.9 %) and excellent repeatability (RSDs varied from 1.3 % to 2.8 %). Furthermore, the adsorbent maintained good reusability over six adsorption-desorption cycles, indicating its potential as efficient candidates for pharmacokinetic studies of conotoxins.