Direct electrochemistry of cholesterol oxidase immobilized on gold nanoparticles-decorated multiwalled carbon nanotubes and cholesterol sensing

► GNPs-MWCNTs were synthesized based on the reduction of HAuCl4 using MWCNTs. ► GNPs-MWCNTs effectively facilitated electron transfer between ChOx and electrodes. ► A reagentless cholesterol biosensor with good performance was developed.