Highly electrocatalytic biosensor based on Hemin@AuNPs/reduced graphene oxide/chitosan nanohybrids for non-enzymatic ultrasensitive detection of hydrogen peroxide in living cells

A non-enzymatic and highly electrocatalytic H 2 O 2 biosensor was proposed by using a novel electrode composed of hemin-capped biomineralized gold nanoparticles ( [email protected] ), reduced graphene oxide (rGO) and chitosan (CS). Owing to the excellent electrocatalytic activity of [email protected] and great conductivity of rGO, this developed biosensor is capable of ultrasensitive measuring H 2 O 2 in real-time. In addition, the introduction of CS resulted in a film on the electrode, which can enhance the stability by protecting the biosensor from external disturbances . Taking advantages of the peroxidase-like activities of the nanohybrids , the developed electrode exhibited outstanding electrochemical performance toward H 2 O 2 with high selectivity , fast response, superior sensitivity and good stability. More importantly, the lower determination limit of 9.3 nM and wider linear ranges of 5 orders of magnitude enable this biosensor to detect H 2 O 2 releasing from living Hela cells accurately. This work provides tremendous potential for real-time monitoring the secretion of H 2 O 2 in living cells.