Quantitative Chemical Imaging of the Intracellular Spatial Distribution of Fundamental Elements and Light Metals in Single Cells

Abstract

We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10(6) atoms/μm(3). This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.

Repeatability and reproducibility of intracellular molar concentration assessed by synchrotron-based x-ray fluorescence microscopy

“…The one-way ANOVA test did not show any significant difference between the runs both for the N and for the O molar concentration. In conclusion, our approach that combines off-line AFM with Synchrotron based XRF and SXTM, allows to quantitatively determine the intracellular molar concentration of light elements [4]. It is worth recalling the concept that concentration is indeed the relevant information, since the molecular interactions occurring in chemical reactions follows the law of definite proportions which requires the use of moles and not mass.…”

“…[4] To obtain the intracellular molar concentration distribution we use the following equation based on the fundamental parameter method: ( 1 ) where:…”

“…Synchrotron radiation is an extremely sensitive technique to analyze single cells. In particular, it allows the elemental map of distribution and concentration by using low energy X-Ray microscopy [3,4]. Although it provides information not detectable by other instruments, the intrinsic limitation of the technique, which is not affordable in any traditional laboratory, and the laboriousness of sample preparation make it difficult to create a large statistics in single cells population.…”

Alterations in Low-Z Elements Distribution in Heart Tissue after Treatments to Breast Cancer Using LEXRF Technique

“…Zone plate, sample, and SDDs were in vacuum, thus avoiding any absorption and scattering by air [8] [24] [27]. …”

Towards a multi‐element silicon drift detector system for fluorescence spectroscopy in the soft X‐ray regime

“…Because those are the main constituents of organic matter, their detection may be of paramount importance when studying biological systems. [1][2][3][4][5][6][7][8][9] Although diffraction grating-based LEXRF possesses excellent energy resolution better than 0.2 eV at Al-L emission on Al metal, [10] its use is limited to narrow energy windows and to certain geometries. LEXRF systems relying on the intrinsic energy resolution of spectroscopic, solid-state X-ray detectors such as silicon drift detectors (SDDs) offer more flexibility and faster specimen mapping at the expenses of an inferior energy resolution.…”