Pd–Ir Core–Shell Nanocubes: A Type of Highly Efficient and Versatile Peroxidase Mimic

• Published in: ACS nano Vol. 9; no. 10; pp. 9994 - 10004
• Main Authors: Xia, Xiaohu, Zhang, Jingtuo, Lu, Ning, Kim, Moon J, Ghale, Kushal, Xu, Ye, McKenzie, Erin, Liu, Jiabin, Ye, Haihang
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.10.2015
• Subjects: Biomimetic Materials - chemistry; Colorimetry - methods; Enzyme-Linked Immunosorbent Assay - methods; Humans; Iridium - chemistry; Limit of Detection; Nanoparticles - chemistry; Nanoparticles - ultrastructure; Palladium - chemistry; Peroxidases - chemistry; Prostate-Specific Antigen - analysis; iridium; nanocrystal; peroxidase mimic; catalytic efficiency; immunoassay
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/acsnano.5b03525

Peroxidase mimics with dimensions on the nanoscale have received great interest as emerging artificial enzymes for biomedicine and environmental protection. While a variety of peroxidase mimics have been actively developed recently, limited progress has been made toward improving their catalytic efficiency. In this study, we report a type of highly efficient peroxidase mimic that was engineered by depositing Ir atoms as ultrathin skins (a few atomic layers) on Pd nanocubes (i.e., Pd–Ir cubes). The Pd–Ir cubes exhibited significantly enhanced efficiency, with catalytic constants more than 20- and 400-fold higher than those of the initial Pd cubes and horseradish peroxidase (HRP), respectively. As a proof-of-concept demonstration, the Pd–Ir cubes were applied to the colorimetric enzyme-linked immunosorbent assay (ELISA) of human prostate surface antigen (PSA) with a detection limit of 0.67 pg/mL, which is ∼110-fold lower than that of the conventional HRP-based ELISA using the same set of antibodies and the same procedure.