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The steadily increasing demand for accurate analysis of vitamin D level, via measurement of its best general marker, 25-hydroxyvitamin D (25(OH)D), pushes for the development of novel automated assays capable of working at very low concentrations. Here, we propose a plasmonic biosensor of 25(OH)D3 (calcifediol) based on surface-enhanced infrared absorption spectroscopy, which exploits the resonant coupling between plasmonic nanoantennas and vibrational excitation of small molecules. Specifically, our proposed platform features a large-area (several mm2) metasurface made of gold nanoantennas fabricated on a silicon substrate, comprising different macroregions (“pixels”) of area 500 × 500 µm2. In each pixel, the nanoantenna geometrical parameters are tuned so as to support localized surface plasmon resonances (and hence large field enhancements at the nanoscale) within different regions of the infrared spectrum. As a result, a single chip is capable of performing analysis from the region of functional groups to that of fingerprint. Two different designs are fabricated via electron beam lithography, functionalized with a correlated antibody for the detection of 25(OH)D3, and characterized via Fourier-transform infrared spectroscopy. Our experiments demonstrate the capability to detect a concentration as low as 86 pmol/L, and an amount of immobilized small molecules of 25(OH)D3 monohydrate (molecular weight: 418.65 g/mol) as low as 4.31 amol over an area of 100 × 100 µm2.

Abstract Background: BPA (bisphenol A or 2,2-bis(4-hydroxy-phenol)propane) is present in the manufacture of polycarbonate plastic and epoxy resins, which can be used in impact-resistant safety equipment and baby bottles, as protective coatings inside metal food containers, and as composites and sealants in dentistry. Recently, attention has focused on the estrogen-like and carcinogenic adverse effects of BPA. Thus, it is necessary to investigate the cytotoxicity and apoptosis-inducing activity of this compound. Methods: Cell cycle, apoptosis and differentiation analyses; western blots. Results: BPA is able to induce cell cycle arrest and apoptosis in three different acute myeloid leukemias. Although some granulocytic differentiation concomitantly occurred in NB4 cells upon BPA treatment, the major action was the induction of apoptosis. BPA mediated apoptosis was caspase dependent and occurred by activation of extrinsic and intrinsic cell death pathways modulating both FAS and TRAIL and by inducing BAD phosphorylation in NB4 cells. Finally, also non genomic actions such as the early decrease of both ERK and AKT phosphorylation were induced by BPA thus indicating that a complex intersection of regulations occur for the apoptotic action of BPA. Conclusion: BPA is able to induce apoptosis in leukemia cells via caspase activation and involvement of both intrinsic and extrinsic pathways of apoptosis.

X-ray radiation treatments are largely adopted in radiotherapy, and Fourier-transform infrared microspectroscopy (μ-FTIR) has already been demonstrated to be a useful instrument for monitoring radiotherapy effects. Previous works in this field have focused on studying the changes occurring in cells when they are fixed immediately after the irradiation or 24 and 48 h later. In the present paper, changes occurring in SH-SY5Y neuroblastoma cells in the first hours after the irradiation are examined to obtain information on the processes taking place in this not-yet-investigated time window by using μ-FTIR. For this purpose, cell samples were fixed immediately after X-ray exposure, and 2 and 4 h after irradiation and investigated along with unexposed cells. Different data analysis procedures were implemented to estimate the changes in lipid, protein, and DNA spectral contributions. The present investigation on the effects of X-ray in the first hours after the exposure is helpful for better describing the processes occurring in this time window that offer the possibility of a timely check on the efficacy of X-ray treatments and can potentially be applied for planning personalized treatment as required by the most advanced medical therapy. [ABSTRACT FROM AUTHOR]

In recent years, the femtosecond laser ablation of hard dental tissues has stimulated great interest in preparing accurate and reproducible dental cavities. Many studies on the changes induced in the surface morphology, structure, and composition of human teeth have been performed using various advanced experimental techniques. Vibrational spectroscopies such as Fourier transform infrared (FT-IR) and Raman spectroscopy have been adopted for obtaining precise information about changes induced by femtosecond laser ablation in human teeth. Their two main components, dentin and enamel, have been carefully investigated. The analysis of the vibrational spectra has allowed for the identification of the optimal working parameters for efficient laser ablation processes. In the present review, a brief description of the abovementioned vibrational techniques is reported, and the principal results obtained by these two vibrational spectroscopies in the study of femtosecond laser ablated teeth are summarized and analyzed. [ABSTRACT FROM AUTHOR]

Collagen-based membranes are class III-medical devices widely used in dental surgical procedures to favour bone regeneration. Here, we aimed to provide biophysical and biochemical data on this type of devices to support their optimal use and design/manufacturing. To the purpose, four commercial, non-crosslinked collagen-based-membranes, obtained from various sources (equine tendon, pericardium or cortical bone tissues, and porcine skin), were characterized in vitro. The main chemical, biophysical and biochemical properties, that have significant clinical implications, were evaluated. Membranes showed similar chemical features. They greatly differed in morphology as well as in porosity and density and showed a diverse ranking in relation to these latter two parameters. Samples highly hydrated in physiological medium (swelling-ratio values in the 2.5–6.0 range) and, for some membranes, an anisotropic expansion during hydration was, for the first time, highlighted. Rheological analyses revealed great differences in deformability (150-1500kPa G') also alerting about the marked variation in membrane mechanical behaviour upon hydration. Samples proved diverse sensitivity to collagenase, with the cortical-derived membrane showing the highest stability. Biological studies, using human-bone-derived cells, supported sample ability to allow cell proliferation and to prompt bone regeneration, while no relevant differences among membranes were recorded. Prediction of relative performance based on the findings was discussed. Overall, results represent a first wide panel of chemical/biophysical/biochemical data on collagen-based-membranes that 1) enhances our knowledge of these products, 2) aids their optimal use by providing clinicians with scientific basis for selecting products based on the specific clinical situation and 3) represents a valuable reference for optimizing their manufacturing. [ABSTRACT FROM AUTHOR]

Previous work has demonstrated the relevance of Fourier Tr and IR investigation on gingival crevicular fluid (GCF) for monitoring orthodontic treatments. Previously, FT-IR spectra of GCF samples have been acquired in reflectance mode by dropping a few microliters of GCF on a reflecting support. A faster procedure for collecting GCF spectra can be obtained by exploiting the Attenuated Total Reflection (ATR) contact sampling method, which allows the collection of good-quality infrared spectra with almost no sample preparation. The objective of the present investigation is to validate the ATR approach for GCF analysis by comparing the spectra acquired in reflectance using the GCF samples extracted via paper cones versus those directly collected from the blotter, employing the ATR approach. [ABSTRACT FROM AUTHOR]

Lipids are organic compounds that contribute to numerous cellular functions. Fourier Transform Infrared spectroscopy can be particularly useful in investigating the biochemical features of the lipid content of cells and their changes induced by interaction with physicochemical external agents. In the present work, we aim to investigate the extract of lipids from human cells to compare the results obtained by using two different geometries: transmission and attenuated total reflectance. Multiple acquisitions of spectra were carried out and statistical criteria were applied for monitoring and comparing them. The positive and negative aspects of the two examined acquisition modes are presented and discussed. [ABSTRACT FROM AUTHOR]

Phenolic compounds (PheCs) are particularly relevant in many different frameworks due to their pro-oxidant and antioxidant activities. In fact, on the one hand, they are considered very dangerous pro-oxidant agents that can be present in the environment as pollutants in wastewater and soil from different industrial and agricultural industries. On the other hand, the antioxidant influence of PheCs available in natural products (including foods) is nowadays considered essential for preserving human health. Conventional techniques for detecting PheCs present some disadvantages, such as requiring expensive instrumentation and expert users and not allowing in situ measurements. This is the reason why there is a high interest in the development of simple, sensitive, specific, and accurate sensing methods for PheCs. Enzymes are often used for this purpose, and laccases with unique optical properties are adopted as bio-elements for sensing schemes. The present paper aims to revise the optical properties of laccases and their use for developing PheC detection and quantification methods used in different fields such as environment monitoring, food characterization and medical applications. In particular, the results offered by UV, visible and infrared absorption, fluorescence, Raman, and surface-enhanced Raman spectroscopy (SERS) have been considered. The enzymatic biosensing devices developed using the related optical signals have been reported, and a comparison of their performances has carried out. A brief description of the main characteristics of laccase and phenols is also given. [ABSTRACT FROM AUTHOR]

Fourier transform infrared (FTIR) spectroscopy is a powerful tool for analyzing the biochemical properties of biological samples such as proteins, cellular materials, and tissues. It provides objective information on samples and has been adopted in many research areas of biomedical and biotechnological interest. FTIR spectroscopy can be performed using different approaches at the macro and micro levels allowing the examination of an incredibly broad class of materials. However, it has become evident that the choice of proper spectra acquisition geometries and the modalities of sample preparation in FTIR spectroscopy analysis require special consideration, especially for certain classes of materials such as cells and tissues. In the present paper, we described the different procedures used for preparing and analyzing different types of biological and biotechnological samples when the more largely available approaches are employed using a commercial FTIR spectrometer. Some basic aspects of data analysis procedures are presented in an Appendix. A certain number of our previous experimental results are reported for demonstrating once more the versatility and the potentiality of FTIR spectroscopy. [ABSTRACT FROM AUTHOR]

Gelatin hydrogels by microbial-transglutaminase crosslinking are being increasingly exploited for tissue engineering, and proved high potential in bone regeneration. This study aimed to evaluate, for the first time, the combination of enzymatically crosslinked gelatin with hyaluronan and the newly developed biotechnological chondroitin in enhancing osteogenic potential. Gelatin enzymatic crosslinking was carried out in the presence of hyaluronan or of a hyaluronan–chondroitin mixture, obtaining semi-interpenetrating gels. The latter proved lower swelling extent and improved stiffness compared to the gelatin matrix alone, whilst maintaining high stability. The heteropolysaccharides were retained for 30 days in the hydrogels, thus influencing cell response over this period. To evaluate the effect of hydrogel composition on bone regeneration, materials were seeded with human dental pulp stem cells and osteogenic differentiation was assessed. The expression of osteocalcin (OC) and osteopontin (OPN), both at gene and protein level, was evaluated at 7, 15 and 30 days of culture. Scanning electron microscopy (SEM) and two-photon microscope observations were performed to assess bone-like extracellular matrix (ECM) deposition and to observe the cell penetration depth. In the presence of the heteropolysaccharides, OC and OPN expression was upregulated and a higher degree of calcified matrix formation was observed. Combination with hyaluronan and chondroitin improved both the biophysical properties and the biological response of enzymatically crosslinked gelatin, fastening bone deposition. [ABSTRACT FROM AUTHOR]