Relating surface-enhanced Raman scattering signals of cells to gold nanoparticle aggregation as determined by LA-ICP-MS micromapping

Abstract

The cellular response to nanoparticle exposure is essential in various contexts, especially in nanotoxicity and nanomedicine. Here, 14-nm gold nanoparticles in 3T3 fibroblast cells are investigated in a series of pulse-chase experiments with a 30-min incubation pulse and chase times ranging from 15 min to 48 h. The gold nanoparticles and their aggregates are quantified inside the cellular ultrastructure by laser ablation inductively coupled plasma mass spectrometry micromapping and evaluated regarding the surface-enhanced Raman scattering (SERS) signals. In this way, both information about their localization at the micrometre scale and their molecular nanoenvironment, respectively, is obtained and can be related. Thus, the nanoparticle pathway from endocytotic uptake, intracellular processing, to cell division can be followed. It is shown that the ability of the intracellular nanoparticles and their accumulations and aggregates to support high SERS signals is neither directly related to nanoparticle amount nor to high local nanoparticle densities. The SERS data indicate that aggregate geometry and interparticle distances in the cell must change in the course of endosomal maturation and play a critical role for a specific gold nanoparticle type in order to act as efficient SERS nanoprobe. This finding is supported by TEM images, showing only a minor portion of aggregates that present small interparticle spacing. The SERS spectra obtained after different chase times show a changing composition and/or structure of the biomolecule corona of the gold nanoparticles as a consequence of endosomal processing.

Label‐Free Molecular Imaging of Biological Cells and Tissues by Linear and Nonlinear Raman Spectroscopic Approaches

“…[173] Moreover,a ggregates were formed within the cells,w hich were being responsible for strong SERS signals during mapping.Asafurther approach, the complex assembly of nanoparticles and nanorods was illustrated based on the selective modification of nanorods with DNAo ligomers. When AuNPs were taken up by cells,t he SERS spectra indicated that the nanoparticle surface was coated mainly by proteins.…”

Identification of Individual Exosome-Like Vesicles by Surface Enhanced Raman Spectroscopy

“…[25,26] In this respect, different types of SERS-substrates have been developed to obtain plasmon enhancement and record Raman spectra from (sub)cellular components down to the single biomolecule level. [27] These can be, but are not limited to, well defined nanostructured surfaces of gold [28] or silver [29] and (intracellular) aggregated Ag [30] or AuNP [31] . Both Ag-nanograin coated chips and precipitated AuNP clusters were recently applied for bulk EV measurements.…”

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view

“…Modification of ICP-MS such as single nanoparticle ICP-MS are available that allow some quantification of individual NPs [10]. Other modifications such as laser-ablation-ICP-MS allow imaging of the sub-cellular localization of NPs with a μm-resolution [11]. …”