Synchrotron FTIR Research Articles

Engineering of a Biomimetic Interface between a Native Dental Tissue and Restorative Composite and Its Study Using Synchrotron FTIR Microscopic Mapping.

The aim of this work is to develop a biomimetic interface between the natural tooth tissue and the restorative composite and to study it on the basis of synchrotron micro-FTIR mapping and multidimensional processing of the spectral data array. Using hierarchical cluster analysis of 3D FTIR data revealed marked improvements in the formation of the dentine/adhesive/dental hybrid interface using a biomimetic approach. The use of a biomimetic strategy (application of an amino acid–modified primer, alkaline calcium and a nano-c-HAp–modified adhesive) allowed the formation of a matrix that can be structurally integrated with natural dentine and dental composite. The biomimetic hybrid layer was characterised by homogeneous chemical composition and a higher degree of conversion of the adhesive during polymerisation, which should provide optimal integration of the dental composite with the dentine.

Characterization of Amino-Functionalized Ferromagnetic Nanoparticles with Glutaraldehyde Cross-linking

Characterization of amino-functionalised magnetic nanoparticles (FMNs) modified surfaces with glutaraldehyde cross linker, which enables the attachment to a specific antibody against Salmonella was examined using FTIR spectroscopy. The magnetism property of the particles before and after attachment to the target cells was studied. Synchrotron FTIR spectroscopy technique was employed to investigate the chemistry of the crosslinking reaction to amino-functionalized ferromagnetic nanoparticles. Results indicated that the bonding pattern imine bond (C=N) and amide bond (-CONH-) were detected. The finding indicated the attachment of aldehyde group (CHO) to amino region of the particle and the other free end to link to the antibodies against Salmonella. The bonding allowed the antibodies to bear reactive sites to catch the target Salmonella in food samples. The FMNs demonstrated hysteresis characteristics that could be changed due to cell attachment that caused reduction of loop coercive force (H). Results showed evidence of glutaraldehyde crosslinking that could be also used as quality control for immobilization of antibodies to the particles. Magnetism properties (the coercive force H) and FTIR characteristics could be further used for signal of attachment of cells to the FMNs as well.

Probing the Anti-Cancer Potency of Sulfated Galactans on Cholangiocarcinoma Cells Using Synchrotron FTIR Microspectroscopy, Molecular Docking, and In Vitro Studies

Sulfated galactans (SG) isolated from red alga Gracilaria fisheri have been reported to inhibit the growth of cholangiocarcinoma (CCA) cells, which was similar to the epidermal growth factor receptor (EGFR)-targeted drug, cetuximab. Herein, we studied the anti-cancer potency of SG compared to cetuximab. Biological studies demonstrated SG and cetuximab had similar inhibition mechanisms in CCA cells by down-regulating EGFR/ERK pathway, and the combined treatment induced a greater inhibition effect. The molecular docking study revealed that SG binds to the dimerization domain of EGFR, and this was confirmed by dimerization assay, which showed that SG inhibited ligand-induced EGFR dimer formation. Synchrotron FTIR microspectroscopy was employed to examine alterations in cellular macromolecules after drug treatment. The SR-FTIR-MS elicited similar spectral signatures of SG and cetuximab, pointing towards the bands of RNA/DNA, lipids, and amide I vibrations, which were inconsistent with the changes of signaling proteins in CCA cells after drug treatment. Thus, this study demonstrates the underlined anti-cancer mechanism of SG by interfering with EGFR dimerization. In addition, we reveal that FTIR signature spectra offer a useful tool for screening anti-cancer drugs’ effect.

Chelating Ligands as Electrolyte Solvent for Rechargeable Zinc-Ion Batteries

Rechargeable zinc-ion batteries (RZIBs) are mostly powered by aqueous electrolytes. However, uncontrolled water interactions often confer a small voltage window and poor battery capacity retention. Here, we explore replacing water with ethylene glycol as the primary solvent in zinc electrolyte formulations. The assembled batteries reveal suppressed electrolyte-induced parasitic reactions, leading to (1) expanded voltage stability windows up to 2.2 V, (2) prolonged zinc stripping/plating stability up to 2.4 times longer compared to the water-based counterparts, and (3) doubled cathode capacity retentions as observed in full-cell Zn-FeVO4 RZIBs. Using a combination of synchrotron EXAFS and FTIR, we investigate the molecular level salt-solvent interactions and explain how the chelation ability of EG ligands reduces parasitic reactions to enable the enhanced electrochemical performances. The structural insights should provide guidelines on the selection of salt, concentration, and chelating solvents for robust multivalent-ion battery systems.

A new typology of human hair medullas based on lipid composition analysis by synchrotron FTIR microspectroscopy.

Human hair is an organ that connects fundamental and applied research with everyday life through the cosmetic industry. Yet, the accurate compositional description of the human hair medulla is lacking due to their small size and difficulty with microextraction. Medullas are thus generally classified based on morphology. We investigated the chemical composition of the human hair medulla using synchrotron based infrared microspectroscopy. We confirmed that lipid signatures dominate the medulla infrared spectrum having 3-20 times higher lipid concentration compared to their surrounding cortex. Human hair medullas contain a mixture of non-esterified and esterified lipids, and carboxylate soaps in various proportions. We reveal the first direct spectroscopic evidence that medulla carboxylates are coordinated to calcium since they exhibit the specific calcium carboxylate signature. Using a representative sample, we observed a strong compositional variability between medullas that was unreported before. We detected calcium carboxylates in 76% of the medullas with one order of magnitude concentration variability between samples. All medullas contained esters with esterification varying by a factor of 30. Moreover, we detected the presence of crystalline calcium stearate in 9% of the medullas. We described a series of spectral markers to characterize medullas based on their lipid composition and propose to classify medullas in four to five groups. Our analysis provides a more detailed understanding of the chemical composition of human hair medullas that may impact cosmetics and biology. The origin and biological meaning of these variations must still be investigated.

SRCD and FTIR Spectroscopies to Monitor Protein-Induced Nucleic Acid Remodeling.

Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopies are fast techniques providing important information about the conformation of nucleic acids and proteins. These vibrational and electronic absorption spectroscopies are extremely sensitive to any change in molecular structure. While numerous reviews describe how to analyze DNA structure alone or in the presence of proteins using FTIR and CD, analyses of RNA are scarce. Nevertheless, RNA remodeling proteins are important factors involved in a multitude of roles in the cell. In this chapter, we present applications of synchrotron radiation circular dichroism (SRCD) and FTIR to analyze how proteins may change RNA structure. These include the analysis of RNA melting, or stabilization, of change in helical parameters and base stacking. The effects on the structure of RNA remodeling proteins are also presented.

The secondary structural difference between Lewy body and glial cytoplasmic inclusion in autopsy brain with synchrotron FTIR micro-spectroscopy

Lewy bodies (LBs) and glial cytoplasmic inclusions (GCIs) are specific aggregates found in Parkinson’s disease (PD) and multiple system atrophy (MSA), respectively. These aggregates mainly consist of α-synuclein (α-syn) and have been reported to propagate in the brain. In animal experiments, the fibrils of α-syn propagate similarly to prions but there is still insufficient evidence to establish this finding in humans. Here, we analysed the protein structure of these aggregates in the autopsy brains of patients by synchrotron Fourier-transform infrared micro-spectroscopy (FTIRM) analysis without extracting or artificially amplifying the aggregates. As a result, we found that the content of the β-sheet structure in LBs in patients with PD was significantly higher than that in GCIs in patients with MSA (52.6 ± 1.9% in PD vs. 38.1 ± 0.9% in MSA, P < 0.001). These structural differences may provide clues to the differences in phenotypes of PD and MSA.

Synchrotron FTIR microspectroscopy revealed apoptosis-induced biomolecular changes of cholangiocarcinoma cells treated with ursolic acid

BackgroundUrsolic acid (UA) is a natural triterpenoid which possesses anti-cancer activity. However, little is known regarding the activity and molecular mechanism of UA in cholangiocarcinoma (CCA). Thus, we investigated the effects of UA on growth inhibition and apoptosis induction through biomolecular changes in KKU-213 and KKU-055 CCA cell lines. MethodsThe anti-proliferative effect of UA against CCA cells was evaluated using SRB assay. Changes in biomolecules were assessed by SR-FTIR microspectroscopy combined with PCA and conventional methods (i.e., Annexin V-FITC/PI staining for lipid alteration and apoptosis induction; Western blot analysis and caspase-3/7 activity assay for apoptotic protein detection). ResultsUA suppressed the proliferation of CCA cells in a dose- and time-dependent manner. SR-FTIR data revealed a significant alteration in lipids attributable to changes in apoptotic cell membranes, confirmed by Annexin V-FITC/PI staining. SR-FTIR data showed that UA promoted changes in the protein secondary structure. Elevated expression of Bax and decreased expression of Bcl-2 and survivin/BIRC5 along with augmented caspase-3/7 activity supported alterations in apoptosis-related proteins. ConclusionsSR-FTIR microspectroscopy was successfully used as a label-free technique to monitor apoptosis-induced biomolecular changes in UA-treated CCA cells. UA exerted the cytotoxic and apoptotic activities in CCA cells through alterations in membrane lipids and apoptotic proteins. UA could be a potential anti-CCA candidate and a chemical starting point for the discovery of novel anti-cancer agents. SignificanceOur present study showed the first evidence that UA exhibited the anti-proliferative and pro-apoptotic activities toward CCA cells through changes in biomolecules, notably lipids and proteins.

Synchrotron FTIR Light Reveals Signal Changes of Biofunctionalized Magnetic Nanoparticle Attachment on Salmonella sp.

The objective of this research was to develop new technology for possible noncontact, nondestructive, and culture-independent rapid detection of Salmonella using ferromagnetic nanoparticles. Light signal changes of particles, cells, and their reaction stages were investigated. Amino-functionalized ferromagnetic nanoparticles (amino-FMNs) were synthesized and modified by glutaraldehyde to crosslink the attachment of specific antibodies to the particles. The nanoparticle complex was used to capture, concentrate, and isolate Salmonella in a culture broth. Signal changes of the four stages of the nanoparticles-amino-glutaraldehyde-antibodies-Salmonella cell attachments were tracked with sensitive Synchrotron FTIR spectroscopy (SR-FTIR). The unique peaks from these four steps were identified. Results can be applied to develop a new test method or a new test/universal reader for rapid, nondestructive, and culture-independent detection of Salmonella in food products using IR spectroscopy at wave numbers 1454 cm-1, 1542 cm-1, and 1414 cm-1, respectively.

InVivo Bioengineering of Fluorescent Conductive Protein-Dye Microfibers.

SummaryEngineering protein-based biomaterials is extremely challenging in bioelectronics, medicine, and materials science, as mechanical, electrical, and optical properties need to be merged to biocompatibility and resistance to biodegradation. An effective strategy is the engineering of physiological processes in situ, by addition of new properties to endogenous components. Here we show that a green fluorescent semiconducting thiophene dye, DTTO, promotes, in vivo, the biogenesis of fluorescent conductive protein microfibers via metabolic pathways. By challenging the simple freshwater polyp Hydra vulgaris with DTTO, we demonstrate the stable incorporation of the dye into supramolecular protein-dye co-assembled microfibers without signs of toxicity. An integrated multilevel analysis including morphological, optical, spectroscopical, and electrical characterization shows electrical conductivity of biofibers, opening the door to new opportunities for augmenting electronic functionalities within living tissue, which may be exploited for the regulation of cell and animal physiology, or in pathological contexts to enhance bioelectrical signaling.

Comparative analysis of dentine and gingival fluid molecular composition and protein conformations during development of dentine caries: A pilot study

BackgroundOne of the most important yet unresolved tasks facing therapeutic dentistry is the problem of efficient personalised diagnostics of pathological processes in the dentine tissues of human teeth. In this regard, dentine fluid is an ideal screening candidate, which acts as an important factor in the development of dentine caries. However, the serious difficulty and practical impossibility of dentine fluid sampling in vivo is the main obstacle to its use in advancing a new line of diagnostics. Extracting gingival crevicular fluid for diagnosing is a much simpler approach. Therefore, we sought to establish the molecular composition and protein conformation of blood, dentine fluid, and gingival fluid during the development of dentine caries using synchrotron FTIR investigations. MethodsTen participants aged 22–28 participated in the study. Each participant had teeth with lesion foci related to primary and secondary enamel surface caries (tooth decay). Three biological fluid samples were obtained for each participant: dentine fluid, gingival crevicular fluid, and blood. The molecular composition of the samples was investigated using FTIR synchrotron spectroscopy technique. FindingsBased on the mathematical simulation of absorption band Amide I in the FTIR spectra of the samples, it was found that the development of pathological processes of the carious type in dentine tissue affects the molecular composition of the biological fluids coming in contact with hard dental tissue. In addition, for the first time, we observed an increased content of thiocyanates and complex esters as well as the presence of anti-inflammatory cytokines, and their interaction with the secondary protein structure in the dentine fluid and gingival crevicular fluid for people with pathological carious processes in the dental tissues. ConclusionThe detected features in the FTIR spectra of biological fluids within the oral cavity in combination with the well-known in literature spectral markers of the development of carious process in dentine prove to be significant, reliable signatures of pathology that can relatively easily detected in the analysis of gingival fluid.

Advanced methods for the analysis of Roman wall paintings: elemental and molecular detection by means of synchrotron FT-IR and SEM micro-imaging spectroscopy

The reconstruction of Roman decorative apparatus from delocalized fragments is an arduous challenge for the archaeologists. An archaeometric approach may integrate the archaeological analyses, based on the stylistic observations, improving the ability to merge adjacent fragments, especially in the absence of distinctive ornamental elements. In this work, the capacity of reflection FT-IR spectroscopy combined with chemometric tools to identify groups of fragments that have similar chemical composition of the pictorial layers is tested. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy coupled with scanning electron microscopy (SEM) and energy-dispersive X-ray micro-analysis (EDX) performed on cross section were used to enhance the performance of conventional FT-IR technique and to localize micrometric-size compounds. The chemometric approach proposed in this work turns out to be a powerful way to discriminate pictorial layers with similar chemical composition, by the identification of different compounds. The use of SR source has permitted to improve the lateral resolution and to discriminate neighboring micro-compounds, such as quartz and cuprorivaite in Egyptian blue pigments.

A Cuboid Spider Silk: Structure-Function Relationship and Polypeptide Signature.

A unique cuboid spider silk from the outer egg sac of Nephila pilipes, with an unusual square cross-section, is disclosed. The structure-function relationships within this silk are first studied through structural characterization, mechanical measurement, protein conformation, and polypeptide signature of silk proteins. This silk maintains the higher stiffness property of egg sac silks, and also shows a species difference. Environmental response of the mechanical properties within this silk are observed. Synchrotron FTIR microspectroscopy is used to monitor the silk protein conformation in a single natural silk. The β-sheet structure aligns parallel to the fiber axis with a content of 22% ± 2.6%. The de novo resulting polypeptide from the solid silk fibers are novel, and an abundant polar amino acid insertion is observed. Short polyalanine (An , n ≤ 3), alternating serine and alanine (S/A)X, and alternating glycine and alanine (G/A)X, GGX, and SSX dominates in the resulting de novo polypeptide. This accords with the composition pattern of other egg sac silk proteins, besides the rarely observed GGX. This study broadens the library of egg sac spider silks and provides a new perspective to uncover structure-function relationships in spider silk.

Effect of site-disorder on microstructure and phase evolution of Ho1-xDyxMnO3

We present concerted local and overall crystal structure studies on Ho1-xDyxMnO3 specimens (x ​= ​0 to 1), using synchrotron powder XRD and FTIR, to probe the underlying microscopic changes during hexagonal to orthorhombic phase evolution. In orthorhombic phases, cationic substitution has stronger impact on MnO6 octahedral-tilt and Mn–O–Mn bond-angles keeping Mn–O subsystem almost unaltered unlike the cases of hexagonal phases, where MnO5 bipyramid suffers significant distortion due to their interconnected (with R3+ ion) layered structure. Ionic radii mismatch induces disorder (σ2) on A-site and results in a significant amount of mixed phase region in terms of <rA> and t (1.0198 ​≤ ​<rA> ​≤ ​1.0246 ​Å; 0.8354 ​≤ ​t ​≤ ​0.8371) at the cost of pure phases. A comparison between the phases of Ho1-xDyxMnO3 and other similar compounds like (Y,R)hRoMnO3 (YMnO3, RhMnO3 - hexagonal and RoMnO3 - orthorhombic) compounds reveals that mixed phase region expands linearly with σmax in such doped manganites.

Utilization of unsaponifiable matter from rice bran oil fatty acid distillate for preparing an antioxidant-rich oleogel and evaluation of its properties

Rice bran oil fatty acid distillate (RBOFAD) is an important by-product obtained from the physical refining process. This fatty acid distillate contains high a amount of Unsaponifiable Matter (γ-oryzanol 3.27 gm/100gm UM; total tocopherol 10.93 mg/100 g UM; total phytosterol 21.81 g/100g UM; squalene 1.15 g/100 g UM and total fatty alcohol 73.34 g/100 g UM) and free fatty acids. Antioxidant-rich Oleogels were obtained from rice bran wax (RBW), rice bran oil fatty acid distillate (RBOFAD) and refined rice bran oil. The main objective of this study was to utilize the antioxidant-rich unsaponifiable matter of RBOFAD (UMRBOFAD) as an organogelator along with rice bran wax, which also acts as a good organogelator. Antioxidant-rich oleogel was prepared using UMRBFAD, ethylcellulose (EC) and RBW at 2%, 2%, 3% on weight basis, respectively, in refined rice bran oil and this antioxidant-rich oleogel was compared with rice bran oil oleogel using RBW at 7% on weight basis of rice bran oil. These oleogels were evaluated using a combination of techniques such as differential scanning calorimetry (DSC), polarized light microscopy (PLM), Viscosity, synchrotron radiation X-ray diffraction (SR-XRD) and FTIR Spectroscopy. The differential scanning calorimetry (DSC) measured the thermal properties of rice bran oil oleogel and high antioxidant-rich oleogel. Polarized light microscopy images revealed needle-like crystals for RBW. SR-XRD measurements were used for clarification of the crystal structures of the building blocks of these oleogels. The antioxidant activities of oleogels were evaluated involving DPPH and ABTS assays.

Spectroscopic Discrimination of Sorghum Silica Phytoliths.

Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work, we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis, we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types.

A study on the performance of coke resistive cerium modified zeolite Y catalyst for the pyrolysis of scrap tyres in a two-stage fixed bed reactor

Catalytic pyrolysis is a useful technique for the conversion of scrap tyres into liquid fuels. Zeolite catalysts were employed in the pyrolysis of scrap tyres for the production of aromatic rich fuel. Deactivation of zeolite catalysts during pyrolysis reaction was investigated which played an important role in the product quality and composition. Herein, the performance of microporous zeolite catalysts and mesoporous MCM-41 catalyst was evaluated in a two-stage fixed bed reactor for the pyrolysis of scrap tyres. Comparative studies showed the increase in the production of aromatic compounds up to 23.7% over zeolite catalyst as compared to 18.7% over MCM-41 catalyst. However, Zeolite Y catalyst exhibited higher coke formation led to the rapid deactivation. The stability of zeolite catalysts is addressed by the incorporation of Cerium metal within the framework of two zeolite catalysts namely Zeolite Y and ZSM-5 through the ion-exchange technique. Parent and spent catalysts were characterised using synchrotron FT-IR spectroscopy, temperature-programmed desorption of ammonia (NH3-TPD), N2 Physisorption, scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectrometry (ICP-OES), energy-dispersive X-ray spectroscopy (EDX), and hydrogen temperature-programmed reduction (H2-TPD). A higher percentage of aromatics were produced over the large pore Zeolite Y. Cerium ion-exchange decreased the formation of coke from 8.1% to 5.7% over submicron and large pore Zeolite Y catalyst. Moreover, naphthalene production decreased over both Ce-Zeolite Y and Ce-ZSM-5.

Mechanisms of soft tissue and protein preservation in Tyrannosaurus rex

The idea that original soft tissue structures and the native structural proteins comprising them can persist across geological time is controversial, in part because rigorous and testable mechanisms that can occur under natural conditions, resulting in such preservation, have not been well defined. Here, we evaluate two non-enzymatic structural protein crosslinking mechanisms, Fenton chemistry and glycation, for their possible contribution to the preservation of blood vessel structures recovered from the cortical bone of a Tyrannosaurus rex (USNM 555000 [formerly, MOR 555]). We demonstrate the endogeneity of the fossil vessel tissues, as well as the presence of type I collagen in the outermost vessel layers, using imaging, diffraction, spectroscopy, and immunohistochemistry. Then, we use data derived from synchrotron FTIR studies of the T. rex vessels to analyse their crosslink character, with comparison against two non-enzymatic Fenton chemistry- and glycation-treated extant chicken samples. We also provide supporting X-ray microprobe analyses of the chemical state of these fossil tissues to support our conclusion that non-enzymatic crosslinking pathways likely contributed to stabilizing, and thus preserving, these T. rex vessels. Finally, we propose that these stabilizing crosslinks could play a crucial role in the preservation of other microvascular tissues in skeletal elements from the Mesozoic.

Exploring mechanochemical parameters using a DoE approach: Crystal structure solution from synchrotron XRPD and characterization of a new praziquantel polymorph

A rotated Doehlert matrix was utilized to explore the experimental design space around the milling parameters of Praziquantel (PZQ) polymorph B formation in terms of frequency and milling time. Three experimental responses were evaluated on the resulting ground samples: two quantitative responses, i.e. median particle size by Laser Light scattering (LLS) and drug recovery by HPLC, and one qualitative dependent variable, i.e. the obtained PZQ crystalline form, characterized through X-Ray Powder Diffraction (XRPD) and confirmed by Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). Temperature inside the jars was kept under constant control during the milling process by using temperature sensor equipped jars (thermojars), thus allowing evaluation of the obtained solid states at each experimental point, considering the specific temperature of the process. This explorative analysis led to the finding of a novel PZQ polymorph, named “Form C”, produced without degradation, then fully characterized, including by means of Synchrotron XRPD, Polarimetric, FT-IR, SS-NMR, ESEM and saturation solubility. Crystal structure was solved from XRPD data and its geometry was optimized by DFT calculations (CASTEP). Finally, Form C and Form A activity against adult schistosoma mansoni were compared through in vitro testing, and Form C's physical stability checked. The new polymorph, crystallizing in space group I2/c, physically stable for approximately 2 months, showed a m.p. of 106.84 °C and displayed excellent biopharmaceutical properties (water solubility of 382.69±9.26 mg/l), while preserving excellent activity levels against adult schistosoma mansoni.

Evaluating the biochemical changes of LPS-stimulated endothelial cells by synchrotron FTIR microspectroscopy at a single-cell level.

Endothelial damage is a major manifestation in many forms of heart and lung injuries induced by lipopolysaccharide (LPS), but the biochemical responses and activation mechanisms of endothelial cells have not been fully explicit. In this study, the biochemical changes to endothelial cells exposed to LPS were investigated by synchrotron FTIR microspectroscopy at a single-cell level. We found that the whole infrared spectrum of endothelial cells shifted after LPS treatment, indicating chemical component changes within cells. Principal component analysis (PCA) and t tests on subspectra (fatty acid region, protein region, and nucleic acid-sugar region, respectively) further showed that sugar components as well as fatty acids changed dramatically while proteins had no significant variation following LPS exposure. These results suggested that the glycocalyx layer structure on endothelial cell membrane may be mainly influenced by LPS and also proved that synchrotron FTIR microspectroscopy was a useful technique to evaluate the biochemical changes of endothelial damage at the single-cell level. Graphical abstract.