Adsorption of 4-Biphenylmethanethiolate on Different-Sized Gold Nanoparticle Surfaces

Abstract

Adsorption of 4-biphenylmethanethiolate (BPMT) has been studied for different-sized gold nanoparticles, with mean diameters of 6, 11, 15, 27, 35, 43, and 97 nm, using surface-enhanced Raman scattering (SERS). Transmission electron microscopy (TEM) images and UV−visible absorption spectra were obtained to examine the monodispersity and BPMT derivatization of the gold nanoparticle samples. Changes in the UV−vis spectra indicated that BPMT-derivatized gold particles appeared to aggregate more extensively with increasing mean diameter. The SERS enhancement was found to be weak in diameter ranges smaller than 11 nm. BPMT was assumed to adsorb on gold, with a standing geometry on the surface, from the presence of the ν2 mode at ∼3065 cm-1 in the SERS spectra of 35-, 43-, and 97-nm particles. The disappearance of the νas(CH2) band in the SERS spectra of all the gold particle samples denoted a preference of sp3 hybridization for the sulfur atom in BPMT on gold particle surfaces. The TEM images showed that monodisperse 15-nm gold nanoparticles derivatized with BPMT could be arranged in a two-dimensional close-packed array. The results of simulated annealing molecular dynamics simulations showed that the close-packed structures of BPMT on a Au(111) surface exhibit ordered herringbone arrangements with almost vertical orientations.

Highly sensitive immunoassay based on Raman reporter-labeled immuno-Au aggregates and SERS-active immune substrate

“…Then the 4MBA-labeled Au aggregates were fabricated. 4MBA molecules were immobilized on the prepared nanoparticles by adsorption of mercapto groups (S-H) to gold surfaces (Jang et al, 2004). Typically, 1 mL pre-prepared colloidal gold was washed by centrifugation and re-suspended in 1 mL with water.…”

“…When being added into the citrate-stabilized colloidal gold, the 4MBA molecules absorb covalently to the surface of particles. Thus, the citrate layers around the gold nanoparticles are replaced by the S-Au bond (Jang et al, 2004). Then the negative surface charges formed by citrate ions are disrupted and the aggregation is induced via 'place exchange reaction' (Basu et al, 2007).…”

Synthesis of Hollow Gold Nanospheres and Their Applications in Surface‐enhanced Raman Scattering and DNA Biosensor

“…[6][7][8] Among various noble metals, Au-modification has been proved powerful for enhancing Raman scattering. [9][10][11] To date, most studies are focused on the size-depending of Au solid nanoparticles 12,13 and Au related core-shell nanoparticles on SERS applications. [14][15][16] However, little attention has been paid to the role of micro-architecture of Au nanoparticles played in enhancing Raman scattering.…”

In situ Raman monitoring triazole formation from self-assembled monolayers of 1,4-diethynylbenzene on Ag and Au surfaces via “click” cyclization

“…One of the most widely used self-assembled monolayers (SAMs) may be organic adsorbates on Au or Ag surfaces [1]. We have continued to study SAMs on Au or Ag surfaces [16][17][18][19][20][21][22][23][24][25], since they currently hold the best model system. Aromatic SAMs should have a number of advantages due to their rigidity and conjugated nature [26].…”