Bimetallic Pt/Pd encapsulated mesoporous-hollow CeO2 nanospheres for signal amplification toward electrochemical peptide-based biosensing for matrix metalloproteinase 2

•A sensitive MMP-2 biosensor was constructed based on specific cleavage of peptide.•Pt/Pd/mhCeO2NS was used as nanocarriers and electrocatalysts for the biosensor.•The transduction of peptide cleavage events was combined with the electrocatalysts.•The catalytic capacity of Pt/Pd/mhCeO2NS was optimal to the signal amplification.•The electrochemical analytical performance was significantly improved and enhanced.

A facile electrochemical biosensor for matrix metalloproteinase 2 (MMP-2) was developed based on the target induced cleavage of a special designed peptide by using bimetallic Pt and Pd nanoparticles encapsulated mesoporous-hollow ceria nanospheres (Pt/Pd/mhCeO2NS) as nanocarriers and electrocatalysts. Briefly, employing l-lysine as bridge and linker, Pt/Pd/mhCeO2NS simply synthesized was used as a loading platform to immobilize electroactive thionine (Thi) and streptavidin (SA), resulting in the final formation of SA/Thi/Pt/Pd/mhCeO2NS nanoprobes. A specific biotin-labeled peptide (biotin-GPLGVRGKGGC, P1) acted as a molecular recognition element was firstly anchored on the Au nanoparticles modified electrode surface. In the presence of MMP-2, the P1 was specifically cleaved into two fragments at a certain site between G and V, while SA/Thi/Pt/Pd/mhCeO2NS nanoprobes were bonded onto the resulting electrode surface through the inherent interaction between streptavidin and biotin derived from uncleaved P1. In the proposed protocol, the electrochemical signal amplification was achieved by the effectively catalysis of Pt/Pd/mhCeO2NS to the decomposition of H2O2. This could result in the significant enhancement of the electrochemical response for determining MMP-2 in the range of 0.1 pg mL−1–10 ng mL−1 with a detection limit of 0.078 pg mL−1. The present work demonstrated that the combination of the direct transduction of peptide cleavage events with the efficient Pt/Pd/mhCeO2NS catalysis method, providing a promising effective strategy for MMP-2 detection.

Graphical abstractBased on specific target-induced cleavage of peptide, a sensitive electrochemical biosensor for MMP-2 was constructed by using Pt/Pd/mhCeO2NS as nanocarriers and electrocatalysts.Figure optionsDownload full-size imageDownload as PowerPoint slide