Simultaneous label-free live imaging of cell nucleus and luminescent nanodiamonds

Abstract

In recent years, fluorescent nanodiamond (fND) particles containing nitrogen-vacancy (NV) centers gained recognition as an attractive probe for nanoscale cellular imaging and quantum sensing. For these applications, precise localization of fNDs inside of a living cell is essential. Here we propose such a method by simultaneous detection of the signal from the NV centers and the spectroscopic Raman signal from the cells to visualize the nucleus of living cells. However, we show that the commonly used Raman cell signal from the fingerprint region is not suitable for organelle imaging in this case. Therefore, we develop a method for nucleus visualization exploiting the region-specific shape of C-H stretching mode and further use k-means cluster analysis to chemically distinguish the vicinity of fNDs. Our technique enables, within a single scan, to detect fNDs, distinguish by chemical localization whether they have been internalized into cell and simultaneously visualize cell nucleus without any labeling or cell-fixation. We show for the first time spectral colocalization of unmodified high-pressure high-temperature fND probes with the cell nucleus. Our methodology can be, in principle, extended to any red- and near-infrared-luminescent cell-probes and is fully compatible with quantum sensing measurements in living cells.

Why nanodiamond carriers manage to overcome drug resistance in cancer

“…Subsequently, the nanodiamonds usually accumulate in the cytoplasm, close to the nuclear envelope, but rarely enter the nuclei [ 8 , 10 , 11 , 28 - 30 ] . There is a recent report regarding the detection of nanodiamonds in nuclei [ 31 ] ; however, it is more likely that the nanodiamonds were embedded within the nuclear membrane as described by Gismondi et al [ 32 ] . A different situation may occur in the case of coated nanodiamonds.…”

Specific Intracellular Signature of SARS-CoV-2 Infection Using Confocal Raman Microscopy

“…Cells could respond to different steps of viral infection, including virus entry, tra cking through the cell organelles for replication and egress of viral particles or their entry into lysosomes for degradation of viral proteins 11,12 . As Raman microscopy allows the analysis of on the single-cell level [13][14][15] , the biochemical modi cations due to the cell reaction to the virus could be detected in the early stage. The conventional diagnostic methods are applicable after symptoms appearance which might be too late to avoid serious consequences.…”

“…As Raman identi es the chemical modi cation, by investigation of spectral changes induced by a virus in any environment, there is no requirement for any genetic or proteomic information of the virus, 8, 16-18 presenting an additional advantage for the Raman spectroscopy in viral detection. Biomedical applications of Raman spectroscopy have been reported previously due to its noninvasive examination of a single live cell without labeling 15,[19][20][21] . Raman spectroscopy imaging is known as a well-established method for chemical analysis of intra/extracellular environment 22,23 .…”

“…Data analysis on this information reveals precise cell comportments identi cations as well as slight modi cations. Usual data analysis on Raman spectra is categorized into two groups of supervised and unsupervised approaches 15 . The unsupervised methods only depend on Raman spectra to classify into different categories.…”

Adsorption of proteins on TiO2 particles influences their aggregation and cell penetration

“…The high spatial resolution and possibility of imaging in aqueous environment make Raman 5 microscopy an ideal tool for life and fixed imaging of a single cell (Salehi et al, 2014). The adequate data analysis according to the vibrational spectra of different cellular organelles, anticancer drugs or nanoparticles provides alternative to existing methods for cell imaging under normal physiological conditions (Gulka et al, 2020;Salehi et al, 2018). The unique spectral signature of nanoparticles enable tracing coated/ non-coated TiO2 cellular penetration.…”