HMOX1 and type 2 diabetes mellitus: The high‐fat diet‐induced type 2 diabetic mouse model was intravenously injected with 1 mg kg−1 of nanoparticles once a week for 4 weeks and ZnPP, an HO‐1 inhibitor, was intraperitoneally injected to study competitive inhibition with PBP‐NPs containing HO‐1 inducers.