Fabrication of polydopamine/hemin-cyclodextrin supramolecular assemblies for mimicking natural peroxidases and their sensitive detection of cholesterol

The development of peroxidase mimics can overcome shortcomings of natural peroxidases and expand their biological applications. Herein, inspired by Hemeproteins family such as peroxidase and cytochromes, polydopamine/hemin-β-cyclodextrin (PDA/Hemin-CD) supramolecular assemblies were prepared to mimick natural peroxidases using hemin as the active center. Polydopamine acts as skeleton material which could encapsulate hemin molecules during the self-assembly procedure. Mono-(6-Mercapto-6-deoxy)-β-Cyclodextrin (β-CD-SH) were decorated on the surface of PDA/Hemin serving as the molecular recognition elements. Interestingly, the addition of cholesterol could “turn off” the peroxidase activity of PDA/Hemin-CD due to the specific recognition of β-CD to cholesterol. The excellent peroxidase activity as well as molecular recognition nature of PDA/Hemin-CD make it promising candidate to construct biosensors. Based on this, a colorimetric assay for the detection of cholesterol was developed.