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International audience; The present work aims to study the effects that acute exposure to low concentrations of silver nanoparticles (AgNPs) cause in digestive glands of terrestrial isopods (Porcellio scaber). The experiments were designed to integrate different analytical techniques, such as transmission electron microscopy, atomic absorption spectroscopy, proton induced X-ray emission, and Fourier transform IR imaging (FTIRI), in order to gain a comprehensive insight into the process from the AgNPs’ synthesis to their interaction with biological tissues in vivo. To this aim, terrestrial isopods were fed with AgNPs having different shapes, sizes, and concentrations. For all the tested conditions, no toxicity at the whole organism level was observed after 14 days of exposure. However, FTIRI showed that AgNPs caused detectable local changes in proteins, lipids, nucleic acids and carbohydrates at the tissue level, to an extent dependent on the interplay of the AgNPs’ properties: shape, size, concentration and dissolution of ions from them.

Fourier-Transform Infrared microspectroscopy, a largely used spectroscopic technique in basic and industrial researches, offers the possibility to analyze the vibrational features of molecular groups within a variety of environments. In the bioclinical field, and, in particular, in the study of cells, tissues and biofluids, it could be considered a supporting objective technique able to characterize the biochemical processes involved in relevant pathologies, such as tumoral diseases, highlighting specific spectral markers associable with the principal biocomponents (proteins, lipids and carbohydrates). In this article, we review the applications of infrared spectroscopy to the study of tumoral diseases of oral cavity compartments with the aim to improve understanding of biological processes involved during the onset of these lesions and to afford to an early diagnosis. Spectral studies on mouth, salivary glands and oral cystic lesions, objectively discriminate normal from dysplastic and cancer states characterizing also the grading.

Melatonin is an important hormone for the synchronization of the reproductive response to appropriate environmental conditions in photoperiodic animals. Even if a large amount of scientific evidences supports its positive impact on oocyte quality and fertilization rate, the biochemical processes involved are not completely understood. Fourier transform infrared (FT-IR) imaging technique has been applied to analyze the variations induced by melatonin administration on both growth and maturation phases of zebrafish oocytes. Chemical maps were acquired on thin ovary sections, from which average spectra were extracted for each class of oocytes. All average spectra were submitted to multivariate analysis, that separated them into different clusters according to oocyte class and treatment. The vibrational analysis highlighted modifications both in the proteic pattern, with an increment in helical structures with respect to β-sheets (amide I and II bands), and in the aliphatic chains and phosphate moieties for oocytes deriving from melatonin treated females. In addition, real time-PCR and enzyme-linked immunosorbent assay (ELISA) analyses showed that the administration of this hormone favoured the synthesis of vitellogenin. The reduction in gene expression involved in preventing oocyte maturation, such as bone morphogenetic protein ( bmp15 ) and transforming growth factor ( tgfβ1 ), was also observed together with the increase of the luteinizing hormone receptor ( lhr ), involved in the induction of oocyte maturation.

Zebrafish oocytes growth causes relevant modifications in protein components; in fact, the proteolytic cleavage of vitellogenin, a large sex-specific phospholipoglycoprotein synthesized in the female liver, leads to three main yolk protein components (phosphovitin and lipovitellins 1, 2), present as a complex in the oocyte. FT-IR Microspectroscopy could have the potentiality of monitoring these biochemical changes during the maturation process. Representative spectra for I–II, IIIA, IIIB and IV classes oocytes (Hierarchical Clustering Analysis and Principal Component Analysis) were investigated to find specific vibrational patterns corresponding to different maturation degrees. On going from I–II to IV class oocytes, relevant spectral differences were found with III class exhibiting an intermediate spectroscopic behaviour. In particular, the increase of the convoluted band at 2925 cm−1 (CH2 and CH3 stretching modes), as well as of intensity band ratios at 2926/2954 cm−1 (νasym CH2/CH3), 2854/2873 cm−1 (νsym CH2/CH3) and 1452/1392 cm−1 ( δ CH 2 / 3 / ν sym COO - ), suggest longer lipidic chains; broadening of Amide I and II bands and absorptions at 1737 (νC O, phospholipids) and 1157 cm−1 (νC O and νC OH carbohydrates) in lipovitellin and vitellogenin spectra, are present in III and IV classes.

Microimaging Fourier transform infrared spectroscopy is able to monitor differentiation between normal and malignant tissues. All the specimens, previously submitted to histological analysis, displayed abnormal spectra compared with the corresponding normal tissues with changes in many diagnostic bands like those arising from phosphate, C–O and CH stretching vibrational modes. The comparison between cancer (K) and connective (C) spectra evidenced the following differences: in the v CH region 3000–2800 cm −1 no hypomethylation effect was evident in K; the convolution of the bands of connective indicated an expected higher membrane fluidity; in the neoplastic zone, Amide I and II modes showed convoluted bands with maxima at 1651 and 1547 cm −1 , respectively, indicating an α-helix conformation of proteins due to changes in the secondary structure proteins upon carcinogenesis. Other signature bands, such as the deformation O–P–O phosphate band at 965 cm −1 , suggested DNA conformational changes in solid cancer, infiltrating cancer and neoplasia in the region 1350–800 cm −1 . These characteristic bands have been monitored as a function of the degree of cancer progression. Chemometric methods, such as principal component analysis (PCA) and hierarchical clustering analysis (HCA) have been used in order to distinguish spectra of neoplastic and normal zones.

Micro-imaging infrared spectroscopy has been performed on atheromatous plaques in order to localize and characterize substances responsible for the cytotoxic effects that prevent macrophages clearance of lipidic and calcified materials. In plaques with different graded atherosclerotic lesions, infrared determinations allowed to visualize gruel and ceroid toxic components and variously calcified zones. Compare correlations let to visualize the progression of the lesion on going from the lumen to the outer media of the plaque.

The new lipid 1,2-O-dioleyl-3-O-{2-[(12-crown-4)-methoxy]-ethyl}-sn-glycerol, 12C4L, has been synthesized. This molecule can coordinate different cations that should make the corresponding liposome a good candidate as vector of genetic material for possible applications in gene therapy. An important feature of the molecule is the possibility to modulate the net surface charge of their complexes with metal cations, which is important to provide efficient DNA transfections. The molecule and its complexes with some metal cations (Mg2+, Ca2+, Mn2+) have been characterized by FT-IR spectroscopy and band attributions confirmed by Density Functional Theory calculations. The net surface charge has been determined by Z potential determinations.

FT-IR microimaging was performed on colon tissues with the aim to characterize spectral ‘markers’ to distinguish healthy from pathological tissues. Evidences of spectral peculiarities were mainly found in the finger print region even in the presence of a low grade adenocarcinoma. The occurrence of inflammation and necrotic states can also be demonstrated. Through statistical analysis as well as custom map procedures it was possible to reconstruct the topological distribution of different biochemical states and to verify results from the histopathological analysis. Preliminary results from FT-NIR analysis are in substantial agreement with those in the mid infrared region.

High resolution holographic polymer dispersed liquid crystal gratings are photo-induced periodic structures commonly affected by shrinkage. This phenomenon represents a problem in several application fields such as in high density optical storage. In this work we observed that, by directly monitoring the blue-shift of the reflection peak of the periodic structure, an evident shrinkage reduction occurs using the nitroxide radical Tinuvin770- N -yloxy [(bis(2,2,6,6-tetramethyl-piperidine-1-yloxy-4-yl)-sebacate] as inhibitor of polymerization. This compound is a stable hindered amine light stabilizer-derived free radical, which plays a significant role in the photo-polymerization dynamics.

This study has been undertaken to investigate spectral features of cystic lesions of the jaw with the aim to understand their tumoral progression and to evidence initial signals of neoplastic changes. Three important groups (according to the World Health Organization classification) representing inflammatory (radicular) and developmental (orthokeratinized odontogenic, OOC) cysts as well as keratocystic odontogenic tumor (KCOT) of the jaw have been studied by microimaging infrared spectroscopy. From the spectral data analysed with the multivariate pattern recognition procedure, representative spectra were isolated and used to build correlation maps to localize the biochemical components in the tissue. The procedure enabled to better understand spectral features of these classes of cysts and to discriminate tumoral from non-tumoral spectra through the analysis of ‘vibrational markers’. In KCOT, the correlation of calcium derivatives (in metaplastic or displastic bones) with the tumor has been highlighted, too. The distribution of various biochemical components in the tissues, achieved through correlation maps of representative spectra, resulted in satisfactory agreement with the histopathological analysis. ‘Spectral isolation’ of micro tumorigenic zones in some normal OOC cysts, demonstrated the potentiality of infrared spectroscopy to evidence the early stage of a hidden lesion.

Stem cells are a promising source in a wide range of medical fields, included bone tissue regeneration. In this study, we investigated the molecular structure of dental pulp stem cells (DPSCs), during their differentiation towards the osteoblastic phenotype. DPSCs, easily achievable even from human young adults, were isolated from dental pulp of included third molar teeth and then cultured with appropriate medium to induce osteoblast differentiation. The FT-IR analysis of undifferentiated and differentiated DPSCs well pin-pointed biological changes during the osteogenic differentiation, above all in the Amide I, II and III vibrational modes as well as in the phosphate stretching vibrations. The spectroscopic study was supported by reverse transcriptase-polymerase chain reaction (RT-PCR) for the expression of specific osteoblastic markers, such as type I collagen (Coll-I), alkaline phosphatase (ALP), osteocalcin (OCN) and runt-related transcription factor 2 (RUNX2).

A FT-IR microspectroscopy study on reactive lymph nodes and non-Hodgkin lymphomas is reported. Mid infrared absorption spectra collected at diffraction limit spatial resolution from reactive and neoplastic lymph nodes resulted sufficiently different once analysed by multivariate pattern recognition analysis to distinguish tumoral from non tumoral samples. The potential of infrared spectroscopy as a post-operative screening is gained by the use of a multielement Focal Plane Array detector. Spectral differences between normal and malignant spectra were mainly in the methyl stretching and in the low frequency region.

The knowledge of cell cycle phase distribution is of paramount importance for understanding cellular behaviour under normal and stressed growth conditions. This task is usually assessed using Flow Cytometry (FC) or immunohistochemistry. Here we report on the use of FTIR microspectroscopy in Microfluidic Devices (MD-IRMS) as an alternative technique for studying cell cycle distribution in live cells. Asynchronous, S- and G0-synchronized B16 mouse melanoma cells were studied by running parallel experiments based on MD-IRMS and FC using Propidium Iodide (PI) staining. MD-IRMS experiments have been done using silicon-modified BaF2 devices, where the thin silicon layer prevents BaF2 dissolution without affecting the transparency of the material and therefore enabling a better assessment of the Phosphate I (PhI) and II (PhII) bands. Hierarchical Cluster Analysis (HCA) of cellular microspectra in the 1300-1000 cm(-1) region pointed out a distribution of cells among clusters, which is in good agreement with FC results among G0/G1, S and G2/M phases. The differentiation is mostly driven by the intensity of PhI and PhII bands. In particular, PhI almost doubles from the G0/G1 to G2/M phase, in agreement with the trend followed by nucleic acids during cellular progression. MD-IRMS is then proposed as a powerful method for the in situ determination of the cell cycle stage of an individual cell, without any labelling or staining, which gives the advantage of possibly monitoring specific cellular responses to several types of stimuli by clearly separating the spectral signatures related to the cellular response from those of cells that are normally progressing.