Polydopamine-Functionalized Magnetoliposomes as Magnetic Probes for Lectin–Glycan Interaction Analysis through Brownian Relaxation

Polydopamine-coated magnetoliposomes (PDA-MLs) are adhesive biocomposite nanomaterials commonly employed in intracellular applications such as controlled drug delivery, theranostics, and biosensing. However, the influence of their adhesive properties on lectin-glycan interactions remains unexplored. In this study, we developed PDA-MLs as magnetic sensing labels for the rapid detection of lectin-glycan binding using alternating current (AC) magnetization measurements in liquid media. The adhesive PDA-ML surface enables facile biomolecule adsorption, facilitating their integration into biosensors. The effects of dopamine-polymerization time on the morphological and functional properties of PDA-MLs were systematically investigated. Extended polymerization resulted in a thicker PDA layer that enhanced lectin immobilization on the ML surface. Multivalent N-glycan-clustered albumin facilitated cross-linking among lectin-immobilized PDA-MLs, leading to remarkable changes in the AC magnetization, compared with interactions with monovalent Gal-N-glycan and Sia-N-glycan. Specific lectin-glycan pairs produced distinct changes in AC magnetization spectra, whereas mismatched combinations showed minimal changes. These findings reveal that structure-property relationships are critical to the design of PDA-ML-based biorecognition systems, highlighting their potential in biosensing and bioanalytical applications.