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

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.This work was supported by the Basic Science Research Program (Grant 2011-0022757), the Bio-Signal Analysis Technology Innovation Program (Grant 2011-0027718), and the International Research & Development Program (Grant K21003001810-11E0100-01510) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST) of Korea and the Seoul R&D Program (Grant 10919)