Cystinuria and cystinosis are usually related to L-cystine: is this really the case for cystinosis? A physicochemical investigation at micrometre and nanometre scale

Exploration of utility of combined optical photothermal infrared and Raman imaging for investigating the chemical composition of microcalcifications in breast cancer

Microcalcifications play an important role in cancer detection. They are evaluated by their radiological and histological characteristics but it is challenging to find a link between their morphology, their composition and the nature of a specific type of breast lesion. Whilst there are some mammographic features that are either typically benign or typically malignant often the appearances are indeterminate. Here, we explore a large range of vibrational spectroscopic and multiphoton imaging techniques in order to gain more information about the composition of the microcalcifications. For the first time, we validated the presence of carbonate ions in the microcalcifications by O-PTIR and Raman spectroscopy at the same time, the same location and the same high resolution (0.5 μm). Furthermore, the use of multiphoton imaging allowed us to create stimulated Raman histology (SRH) images which mimic histological images with all chemical information. In conclusion, we established a protocol for efficiently analysing the microcalcifications by iteratively refining the area of interest.

Surface Heterogeneity in Amorphous Silica Nanoparticles Evidenced from Tapping AFM-IR Nanospectroscopy

In this work, we propose to evaluate and validate an emerging spectroscopic space-resolved technique: atomic force microscopy coupled with infrared spectroscopy (AFM-IR) for inorganic materials in tapping mode at the nanoscale. For this aim, a preliminary investigation of sample preparation techniques was done and the stability of tapping AFM-IR spectra was evaluated on reference samples [poly(methyl methacrylate) and silica]. It was concluded that for a homogeneous polymer, it is possible to compare AFM-IR spectra with conventional Fourier-transform infrared (FTIR) spectra obtained in transmission. When an inorganic solid is considered, AFM-IR spectra are different from the global FTIR spectrum which indicates that the AFM-IR technique probes a volume which is not representative of global composition, that is, the external surface layer. Moreover, local infrared spectra recorded in the tapping mode of the external surface are significantly different depending on the analyzed regions of the same particle and between particles of the amorphous silica, implying surface heterogeneity. The AFM-IR technique allows surface description of amorphous inorganic materials at the nanoscale and opens new frontiers in the characterization of functional nanoscale and crystalline materials.