Characterization and immobilization of trypsin on tannic acid modified Fe3O4 nanoparticles

- Fe3O4 NPs were synthesized by coprecipitation method.
- Fe3O4 NPs were modified by tannic acid (TA-MNPs).
- Trypsin enzyme was immobilized onto TA-MNPs.
- Immobilization enhanced free trypsin activity.
- A possible mechanism of trypsin immobilization onto Fe3O4 NPs was proposed.