Characterization of diamine oxidase-based biosensors for biogenic amines detection assembled onto functionalized SiO2 substrates using aliphatic and aromatic di-aldehydes as crosslinkers

Development of two biosensors to detect biogenic amines was carried out using immobilized diamine oxidase from Pisum sativum on 3-APTMS-functionalized SiO2 substrates with either glutaraldehyde or terephthalaldehyde as crosslinkers. The assembly process was validated by FT-IR, SEM-EDX, and AFM. Biosensor responses to biogenic amines were c.a. 3-fold lower compared to the free enzyme kinetics as assessed by UV/VIS spectrophotometry. The calculated initial velocities (& UDelta;Abs & BULL;min-1) for glutaraldehyde and terephthalaldehyde biosensors in the given order were (3.2 & PLUSMN; 0.68) x 10-2, (0.48 & PLUSMN; 0.09) x 10-2 for putrescine; (4.6 & PLUSMN; 1.2) x 10-2, (0.35 & PLUSMN; 0.47) x 10-2 for cadaverine; (5.8 & PLUSMN; 2.4) x 10-3, (19.0 & PLUSMN; 155) x 10-3 for spermidine, and (3.0 & PLUSMN; 2.0) x 10-4, (0.0 & PLUSMN; 7) x 10-4for histamine. The 2-way t-tests indicated that the crosslinker type affected the catalytic activity of immobilized diamine oxidase as the responses of glutaraldehyde biosensors to putrescine and cadaverine were significantly higher than those of the terephthalaldehyde. Molecular Docking simulations showed that glutaraldehyde has a stronger affinity for DAO's lysine and arginine residues while terephthalaldehyde to phenylalanine.

Automated summary

This study developed two biosensors to detect biogenic amines using immobilized diamine oxidase from Pisum sativum on 3-APTMS-functionalized SiO2 substrates with either glutaraldehyde or terephthalaldehyde as crosslinkers. The assembly process was validated using various analytical techniques. The biosensor responses to biogenic amines were significantly lower compared to the free enzyme kinetics, and the crosslinker type affected the catalytic activity of the immobilized diamine oxidase. Molecular docking simulations revealed different affinities of glutaraldehyde and terephthalaldehyde for specific residues in the enzyme.