Mimetic biomembrane–AuNPs–graphene hybrid as matrix for enzyme immobilization and bioelectrocatalysis study

•Phospholipids-AuNPs-graphene biocomposite (PLs-AuNPs-G) was prepared.•PLs-AuNPs-G was demonstrated as an effective matrix for MP-11 immobilization.•A third generation biosensor based on PLs-AuNPs-G was constructed for H2O2 detection.•The biosensor exhibited high sensitivity and good stability.•The biosensor realized real-time detection of H2O2 released from living cells.

A hybrid composite constructed of phospholipids bilayer membrane, gold nanoparticles and graphene was prepared and used as matrices for microperoxidase-11 (MP11) immobilization. The direct electrochemistry and corresponding bioelectrocatalysis of the enzyme electrode was further investigated. Phospholipid bilayer membrane protected gold nanoparticles (AuNPs) were assembled on polyelectrolyte functionalized graphene sheets through electrostatic attraction to form a hybrid bionanocomposite. Owing to the biocompatible microenvironment provided by the mimetic biomembrane, microperoxidase-11 entrapped in this matrix well retained its native structure and exhibited high bioactivity. Moreover, the AuNPs–graphene assemblies could efficiently promote the direct electron transfer between the immobilized MP11 and the substrate electrode. The as-prepared enzyme electrode presented good direct electrochemistry and electrocatalytic responses to the reduction of hydrogen peroxide (H2O2). The resulting H2O2 biosensor showed a wide linear range (2.0×10−5–2.8×10−4 M), a low detection limit (2.6×10−6 M), good reproducibility and stability. Furthermore, this sensor was used for real-time detection of H2O2 dynamically released from the tumor cells MCF-7 in response to a pro-inflammatory stimulant.

Graphical abstractA hybrid composite constructed of phospholipids bilayer membrane, gold nanoparticles and graphene was prepared and used as matrices for microperoxidase-11 (MP11) immobilization. The composites promoted the direct electron transfer between MP11 and the underlying electrode. Moreover, the biosensor successfully realized the detection of H2O2 releasing from cancer cells.Figure optionsDownload full-size imageDownload as PowerPoint slide