Hollow Ruthenium Nanoparticles with Enhanced Catalytic Activity for Colorimetric Detection of C-Reactive Protein

Abstract

Hollow structures can improve thephysical and chemical characteristicsof nanoparticles. In the present work, we synthesized hollow rutheniumnanoparticles (HRNs) using a galvanic replacement reaction. Comparedto normal nanoparticles, the hollow structures had greater surfacearea, leading to enhanced transport of reactants. Transmission electronmicroscopy images revealed the formation of distinct hollow structureswith an average size of 30 nm. As a peroxidase mimic, the HRNs showedexcellent catalytic activity for the oxidation of 3,3 & PRIME;,5,5 & PRIME;-tetramethylbenzidinedue to the increased surface area of the hollow structure. Moreover,the catalytic efficiency of the HRNs was greater than that of horseradishperoxidase, due to the presence of hollow structures. The HRNs wereapplied to the colorimetric detection of C-reactive protein (CRP)by enzyme-linked immunosorbent assay (ELISA). The results displayedgreat sensitivity for CRP levels of 0.12-7.8 ng/mL and a limitof detection of 33.2 pg/mL. In the recovery test, the assay showedaccurate detection of CRP in spiked human serum with recovery valuesof 97.0-98.0%. The results of the present study reveal thevalidity and possibility of HRNs as alternatives to natural enzymesfor application to conventional ELISA.