Peroxidase-mimicking Pt nanodots supported on polymerized ionic liquid wrapped multi-walled carbon nanotubes for colorimetric detection of hydrogen peroxide and glucose

Pt nanoparticles have been actively researched as enzyme mimetic nanomaterials for bioanalysis, catalysis and environment treatment over the past years. However, the general issues with individual Pt nanoparticles are stabilization and reproducibility, which lead to the search of Pt based nanocomposite to enhance their activity. In this work, we developed a novel kind of surfactant-free nanocomposites (Pt-PIL-MWCNTs) containing Pt nanodots highly dispersed on polymerized ionic liquid wrapped multi-walled carbon nanotubes, and demonstrated their intrinsic peroxidase-like activity for use in colorimetric detection of hydrogen peroxide and glucose. The Pt-PIL-MWCNTs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The as-prepared Pt-PIL-MWCNTs were used to catalyze the oxidation of a peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) by H2O2 to the oxidized colored product. Based on the excellent catalytic activity of Pt-PIL-MWCNTs, two colorimetric sensors for detecting H2O2 and glucose, respectively, were constructed with a wide linear range of 10-1000 mu M (for H2O2) and 160-900 mu M (for glucose), as well as a relative lower limit of detection [5.5 mu M (for H2O2Y) and 50 mu M (for glucose)]. The excellent performance of the sensor exhibited that the Pt-PIL-MWCNTs composite could be used as a promising mimetic peroxidase for applications in biosensing.