SERS spectra of a single nasopharyngeal carcinoma cell based on intracellularly grown and passive uptake Au nanoparticles

Abstract

The intracellularly-grown-Au-nanoparticles (IGAuNs) technique was employed to analyze the surface-enhanced Raman scattering (SERS) spectra of nasopharyngeal carcinoma cells (CNE-1 cell line). There are only six obvious Raman bands (718, 1001, 1123, 1336, 1446, 1660 cm−1) in the normal Raman spectrum of living CNE-1 cells. However, over twenty SERS Raman bands have been detected in the SERS spectra of IGAuNs-induced cells, among which five bands are of the DNA backbone (673, 1097, 1306, 1336 and 1585 cm−1). There are four vibrations of the DNA backbone (1026, 1097, 1336 and 1585 cm−1) in the SERS spectra of living CNE-1 cells induced by the passive uptake gold nanoparticles (PUAuNS), but one more DNA backbone and many nucleus Raman peaks appeared in the IGAuNs-induced SERS spectra. Many Raman peaks in the PUAuNs-induced SERS spectra are stronger than those in the IGAuNs-induced ones. This study has shown that the PUAuNs technique can achieve stronger Raman signals, and that the IGAuNs technique can enable the gold element to access to the nucleus more easily, which could help to obtain more surface-enhanced Raman signals of the intracellular biochemical molecules. Thus, the two techniques can work together to attain the Raman spectral information of the cytoplasm and the nucleus in a better way, which might provide a sensitive method for broad biomedical applications such as intracellular SERS analysis of living cells.

Single Cell Optical Imaging and Spectroscopy

“…517 More Raman bands could be assigned in the SERS spectra than the normal Raman spectrum of the cells. While the locations of many peaks in the spectra were the same for the intracellularly grown and passively uptaken SERS spectra, the intensities of the peaks were quite different across the two spectra.…”

Properties of in situ generated gold nanoparticles in the cellular context

“…Gold nanoparticles are formed in cell cultures of animal cell lines and in their supernatant after incubation with tetrachloroauric acid (HAuCl 4 ) in buffer. [11][12][13][14] Also hybrid structures with graphene oxide could be obtained in this way. 14 Even inside epithelial cells of the skin 15 and in intact tumor tissues, 16 formation of nanoparticles and nanoclusters is observed.…”

“…Upon the in situ reduction of gold and silver salts in or by cells, several excellent plasmonic substrates were reported, and the nanostructures obtained in such in situ syntheses were exploited for optical nanospectroscopy, specifically in surfaceenhanced Raman scattering (SERS). 1,4,12,13,25 From the perspective of analytical and diagnostic applications, in situ synthesis of metal nanostructures that serve as probes for optical detection enables us to obtain them in direct proximity to their target. 1,16,[26][27][28] In order to apply gold nanoparticles that are generated in situ as optical probes inside animal cells, it is crucial to know the biomolecular species involved in their formation, as the biomolecular corona will determine the processing of the nanostructures inside the cells and their physical properties.…”

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

“…516 More Raman bands could be assigned in the SERS spectra than the normal Raman spectrum of the cells. While the locations of many peaks in the spectra were the same for the intracellularly grown and passively uptaken SERS spectra, the intensities of the peaks were quite different across the two spectra.…”