Enzymatic activity of cholesterol oxidase immobilized onto polymer nanoparticles mediated by Congo red

- Cholesterol oxidase adsorbed onto nanoparticles decorated with PEG or Congo red (CR).
- Conjugation effects between Cholesterol oxidase and CR favored enzymatic activity.
- Freeze-drying immobilized Cholesterol oxidase improved its stability.
- Immobilized Cholesterol oxidase responded linearly to cholesterol concentration.