Optical Signal Comparison of Single Fluorescent Molecules and Raman Active Gold Nanostars

Abstract

The relevant photophysical properties of single fluorescent molecules and single SERS active surface-coated gold nanostars tagged with the Raman reporter molecule 4-mercaptopyridine are compared for imaging purposes. Mean count rate distributions are built from the single molecule/single probe level. The individually observed variance and count rates of both systems are compared as well as the behavior over multiple image acquisitions.

SERS labels for quantitative assays: application to the quantification of gold nanoparticles uptaken by macrophage cells

“…4,6,18,19,25,27,32,40 We observed a relevant variability on the Fig. 2 Superposition of the UV-visible spectra of AuNP in water (black line) and of the MG dye with variable molecules to gold nanoparticles ratio.…”

“…[4][5][6] Several bright examples about the application of SERS labels in nanobiotechnology and nanomedicine have been reported in recent years and various SERS labels have been developed. 18,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] For instance, gold nanoparticles capped with thiol terminated oligonucleotides composed of a Raman active molecule on the inner end and a DNA capture sequence have been used for the multiplexed detection of femtomolar amounts of more than six different DNA sequences in the same microarray. 20 In an analogous microarray set up, gold nanoparticles (AuNPs) with a targeting protein allowed the ultrasensible detection of proteins.…”

Gold Nanostar Synthesis and Functionalization with Organic Molecules

“…It is worth noting that in 2009 a comparison study was published in which relevant photophysical properties of single-fl uorescent molecules and single-SERSactive surface-coated gold nanostars tagged with the Raman reporter molecule 4-mercaptopyridine were compared for imaging purposes [ 86 ]. The nanostar-based SERS NP presented in this paper eliminates the traditional challenges of signal consistency and strength and demonstrates the viability of SERS probes for imaging applications.…”

Effect of Multimodal Plasmon Resonances on the Optical Properties of Five-Pointed Nanostars

“…Nevertheless, the plasmonic properties of star-shaped particles have also attracted some interest [17][18][19][20][21][22][23][24] because it is expected that they will generate regions of enhanced electric field around their perimeter. It is agreed that the attractive feature of nanostars is that they provide a greater number of locations of enhanced electric field than simpler shapes [21][22][23][24], although there is certainly an optimum number of sharp points per particle beyond which overall electric field intensity declines again [23]. Both three-dimensional [17,19,21,22,24] and two-dimensional [23,24] examples of nanostars have been studied.…”

“…It is agreed that the attractive feature of nanostars is that they provide a greater number of locations of enhanced electric field than simpler shapes [21][22][23][24], although there is certainly an optimum number of sharp points per particle beyond which overall electric field intensity declines again [23]. Both three-dimensional [17,19,21,22,24] and two-dimensional [23,24] examples of nanostars have been studied. The interest is driven by the possibility that these shapes may have applications in surface-enhanced Raman spectroscopy [19][20][21][22]24], and as plasmonic heat sources [21,22,24] in anti-cancer therapies [28] and refractometric sensing [17,23].…”