Secondary Ions Mass Spectrometric Signal Enhancement of Peptides on Enlarged-Gold Nanoparticle Surfaces

Abstract

A high surface coverage of gold nanoparticles (AuNPs) is a prerequisite for enhancing the peptide signal intensity in time-of-flight secondary ion mass spectrometry (TOF-SIMS). Here, we demonstrate the TOF-SIMS signal amplification of peptides on a surface by enlarging surface-confined AuNPs using the NH2OH/Au3+ seeding method. Because of the increased surface area and spherical structure of the Au, the SIMS intensity of the peptides became significantly enhanced on the enlarged-AuNPs surface, especially at high concentrations of peptide solution (>10 mu M), compared to that of the bare gold surface or submonolyer of AuNPs. We are confident that this will be a useful method for diagnosis and bioassay with high sensitivity in a label-free manner.