Hotspot Stabilization of Gold Nanoparticles for Application of Quantitative Sers in Bioanalytical Systems

Abstract

A complete procedure including synthesizing gold nanoparticles and further hotspots stabilization is presented. Colloidal gold synthesis followed a citrate reducing reaction, then, an ideal condition for SERS enhancement with quantitative purposes was reached by searching equilibrium between salt-and analyte-induced aggregation. Under this condition, a mild aggregation is produced, along with "free sites" available on the metal surface where analyte could easily interact. As a consequence, suitable linear concentration intervals and high quality SERS spectra were obtained allowing building multivariate quantitative models. For adenine as probe molecule, LOD values were around 10-8 mol L-1 , even at low laser power and short exposure time during spectral acquisition. The hotspot stabilization procedure, as shown here, allows dealing with samples or highly complex analytical matrices that can easily cause undesirable agglomerate formation like those from biological origin.

Development and Validation of a SERS-Based Serological Test Combined with PLS-DA Method for Leishmaniasis Detection

“…We determined that both buffer and PSAdP 23–47 peptide final concentrations were relevant parameters to be investigated using initial UV–vis experimental analysis. Moreover, the pre-activation by salt addition, such as KCl, produces controlled aggregation resulting in more stable hotspots across time, as observed by Mamián-López and Temperini . Consequently, it was also considered a suitable parameter to be tested using the KCl solution.…”

“…Moreover, the pre-activation by salt addition, such as KCl, produces controlled aggregation resulting in more stable hotspots across time, as observed by Mamiań-Loṕez and Temperini. 41 Consequently, it was also considered a suitable parameter to be tested using the KCl solution. Those parameters were evaluated using a two-level complete factorial design with two center point replicates, resulting in 10 experiments.…”