Highly Sensitive Electrochemical Biosensor Based on Hairy Particles with Controllable High Enzyme Loading and Activity

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Milkin, Pavel ; Antony, Anila ; Cai, Hongtao ; Debevc, Antonia ; Topal, Ceyda ; Linhardt, Anne ; Synytska, Alla ; Ionov, Leonid:
Highly Sensitive Electrochemical Biosensor Based on Hairy Particles with Controllable High Enzyme Loading and Activity.
In: Advanced Functional Materials. (5 Juni 2025) . - 2507589.
ISSN 1616-3028
DOI: https://doi.org/10.1002/adfm.202507589

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Abstract

For the first time, a highly sensitive electrochemical biosensor based on SiO2 hairy particles grafted with polymerize poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) polymer brushes containing immobilized Laccase from Trametes versicolor (TvL) is reported. This system offers major advantages in enzyme loading, catalytic efficiency, and detection sensitivity. The biosensor achieves a high enzyme immobilization density of up to 0.57 g g−1 of polymer, while the enzymatic activity of the immobilized Laccase is enhanced 75-fold compared to the free enzyme in the buffer. These carriers are easy to handle and store, enabling reproducible sensor fabrication with well-defined enzyme content. The biosensor is tested for hydroquinone (HQ) detection, where Laccase rapidly catalyzes HQ oxidation near the electrode, generating a locally high quinone concentration. This suppresses direct HQ oxidation at the electrode surface, enhancing selectivity. The sensor demonstrates excellent analytical performance, with a sensitivity of 0.14 A·m−1, a detection limit of 0.1 µm, and a wide linear range of 0.3–750 µm—surpassing most comparable systems even without optimization. This work serves as a proof of concept and a promising platform for developing advanced biosensors. Furthermore, the approach can be adapted to other core–shell particle systems and enzyme-based electrochemical detection platforms.