title: Measurement of the localised plasmon penetration depth for gold nanoparticles using a non-invasive bio-stacking method.
abstract: We have used the formation of a bio-probe stack with up to 24 steps on gold nanoparticle and continuous gold surfaces to characterize the penetration depth of the plasmon field in a non-invasive manner by only involving biomolecules from standard bio-assays. An alternating anti-goat rabbit IgG and anti-rabbit IgG bio-probe stack is polymerized on protein A/G functionalized gold surfaces. The change in plasmon excitation angle or light scattering decreases exponentially with each stacking step although the bio-integrity of the antibody epitope is maintained. The exponential decay in the derived kinetic parameters is attributed to the change in the penetration depth and the step size is calibrated using a commercial continuous gold surface plasmon resonance surface to be 17.5 ± 0.8 nm, consistent with the expected dimension of the antibody. The penetration depth of the gold spherical nanoparticles of diameter 90 ± 13 nm is determined to be 93 ± 10 nm.
authors.affiliation: College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Read
authors.forename: Rouslan V
authors.initials: RV
authors.lastname: Olkhov
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Shaw
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000737:chemistry / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles / Q000737:chemistry*; D011817:Rabbits; D013205:Staphylococcal Protein A / Q000737:chemistry / Q000276:immunology; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D000888:Antibodies, Anti-Idiotypic; D001426:Bacterial Proteins; C034284:IgG Fc-binding protein, Streptococcus; D013205:Staphylococcal Protein A; C048844:anti-IgG; D006046:Gold