Combined Labelled and Label-free SERS Probes for Triplex Three-dimensional Cellular Imaging

Abstract

Cells are complex chemical systems, where the molecular composition at different cellular locations and specific intracellular chemical interactions determine the biological function. An in-situ nondestructive characterization of the complicated chemical processes (like e.g. apoptosis) is the goal of our study. Here, we present the results of simultaneous and three-dimensional imaging of double organelles (nucleus and membrane) in single HeLa cells by means of either labelled or label-free surface-enhanced Raman spectroscopy (SERS). This combination of imaging with and without labels is not possible when using fluorescence microscopy. The SERS technique is used for a stereoscopic description of the intrinsic chemical nature of nuclei and the precise localization of folate (FA) and luteinizing hormone-releasing hormone (LHRH) on the membrane under highly confocal conditions. We also report on the time-dependent changes of cell nuclei as well as membrane receptor proteins during apoptosis analyzed by statistical multivariate methods. The multiplex three-dimensional SERS imaging technique allows for both temporal (real time) and spatial (multiple organelles and molecules in three-dimensional space) live-cell imaging and therefore provides a new and attractive 2D/3D tracing method in biomedicine on subcellular level.

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

“…[197] By using Ag nanotriangles modified with aRaman reporter and folic acid, the SERS tags bound to the folate receptors of ahuman ovary cancer cell line,a nd the uptake of the nanoparticles was investigated by dark-field microscopy and SERS. [203] This enabled the 3D multilabel cell imaging of single HeLa cells,r endering this approach attractive for biomedical investigations on the subcellular level. [199] As anew Raman reporter, graphene oxide was used to modify AgNPs.…”

Raman spectroscopy: techniques and applications in the life sciences

“…Further studies also showed that AuNP SERS particle tracking in cytosol was able to correlate dynamic Raman features to particle motion [316]. Combined label/label-free nanoprobes were also recently used for 3D imaging [317]. Pavillon et al have also developed automated feature-based SERS spectra recognition in cells [318].…”

In situ and ex situ surface‐enhanced Raman spectroscopy (SERS) analysis of cell mitochondria

“…The results show that rich vibrational information is observed in the range of 400–1,800 cm −1 , from the contributions of all kinds of biomacromolecules in cells such as proteins, amino acids, nucleic acids, and carbohydrates . Characteristic peaks of MCF‐7 cells compared with HepG2 cells are highlighted in Figure , for example, 818, 926, and 1,241 cm −1 from protein, contributed to tyrosine, C─C stretching, and amide III, respectively.…”