Antiepileptic/teratogen valproate (VPA) is a histone deacetylase inhibitor/epigenetic drug proposed for the antitumor therapy where it is generally crucial to target poorly or undifferentiated cells to prevent a recurrence. Transplanted rodent gastrulating embryos‐proper (primitive streak and three germ layers) are the source of teratoma/teratocarcinoma tumors. Human primitive‐streak remnants develop sacrococcygeal teratomas that may recur even when benign (well differentiated). To screen for unknown VPA impact on teratoma‐type tumors, we used original 2‐week embryo‐derived teratoma in vitro biological system completed by a spent media metabolome analysis. Gastrulating 9.5‐day‐old rat embryos‐proper were cultivated in Eagle's minimal essential medium (MEM) with 50% rat serum (controls) or with the addition of 2 mmVPA. Spent media metabolomes were analyzed by FTIR. Compared to controls, VPA acetylated histones; significantly diminished overall teratoma growth, impaired survival, increased the apoptotic index, and decreased proliferation index and incidence of differentiated tissues (e.g., neural tissue). Control teratomas continued to grow and differentiate for 14 days in isotransplants in vivo, but in vitro VPA‐treated teratomas resorbed. Principal component analysis of FTIR results showed that spent media metabolomes formed well‐separated clusters reflecting the treatment and day of cultivation. In metabolomes of VPA‐treated teratomas, we found elevation of previously described histone acetylation biomarkers [amide I α‐helix and A(CH3)/A(CH2)]) with apoptotic biomarkers within the amide I region for β‐sheets, and unordered and CH2 vibrations of lipids. VPA may be proposed for therapy of the undifferentiated component of teratoma tumors and this biological system completed by metabolome analysis, for a faster dual screening of antitumor/embryotoxic agents.

Microporous and macro-mesoporous silicon templates for surface-enhanced Raman scattering (SERS) substrates were produced by anodization of low doped p-type silicon wafers. By immersion plating in AgNO3, the templates were covered with silver metallic film consisting of different silver nanostructures. Scanning electron microscopy (SEM) micrographs of these SERS substrates showed diverse morphology with significant difference in an average size and size distribution of silver nanoparticles. Ultraviolet-visible-near-infrared (UV-Vis-NIR) reflection spectroscopy showed plasmonic absorption at 398 and 469 nm, which is in accordance with the SEM findings. The activity of the SERS substrates was tested using rhodamine 6G (R6G) dye molecules and 514.5 nm laser excitation. Contrary to the microporous silicon template, the SERS substrate prepared from macro-mesoporous silicon template showed significantly broader size distribution of irregular silver nanoparticles as well as localized surface plasmon resonance closer to excitation laser wavelength. Such silver morphology has high SERS sensitivity that enables ultralow concentration detection of R6G dye molecules up to 10(-15) M. To our knowledge, this is the lowest concentration detected of R6G dye molecules on porous silicon-based SERS substrates, which might even indicate possible single molecule detection.

Light emitting porous silicon samples with different porosities, i.e. crystalline sizes, were produced from the low level doped p‐type silicon wafers by the anodization process. The effects of strong phonon confinement, redshift and broadening, were found on the O(Γ) phonon mode of the Raman spectra recorded at non‐resonant excitation condition using a near infrared 1064 nm laser excitation wavelength. Similarly, the blueshift of the photoluminescence peak was observed by reducing the crystalline sizes. Vibrational and optical findings were analysed within the existing models of confinement on the vibrational and electronic states of silicon nanocrystals. Since the energy of the photoluminescence peak of small nanocrystals also depends on the oxygen content on the surface of nanocrystals, the surface oxidation states were examined using infrared and energy dispersive spectroscopy. The partial coverage of the surface of nanocrystals was found due to the sample exposure to air. As a consequence, the photoluminescence energy did not increase as would be expected from the quantum confinement model. These results further indicate that the oxygen passivation along with the quantum confinement determines the electronic states of the silicon nanocrystals in porous silicon. Copyright © 2014 John Wiley & Sons, Ltd.

Porous silicon (PSi) samples were prepared by electrochemical anodisation of silicon on insulator layers. Structural and optical properties of prepared samples were investigated by Raman and photoluminescence (PL) spectroscopy and field emission scanning electron microscopy (FE-SEM). The anodisation of silicon on insulator layers was performed by alternating currents (AC) of the mains frequency of 50 Hz. A very intensive PL was observed at the circular edge of the samples that exhibited micrometer sized island-like porous structure, while the central part of the samples showed moderate PL signal. The formation of such porous island-like structures with strong intensity PL was interpreted with stress induced due to difference of the piezoelectric coefficient of silicon and quartz layers (buried SiO2). Micro-Raman spectra of islands show strong phonon confinement with the cluster size between 1.4 and 3.5 nm.

Porous silicon (PSi) samples were prepared by galvanostatic electrochemical anodization of epitaxial silicon, polycrystalline silicon and silicon on insulator layers. Structural and optical properties of prepared samples were investigated by Raman and photoluminescence (PL) spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS). Epitaxial silicon layers of n-type and {111} orientation grown on n-type {111} oriented silicon substrates were anodized as a function of concentration of 48 % HF in ethanol solution and anodization time. Electrical resistivities of the epitaxial layers and of the silicon substrate were ∼2 and ∼0.015 Ω cm, successively. Within the epitaxial layer and on the substrate surface, micro- and nano-pores of different sizes in dependence on HF concentration and anodization time were obtained. For anodization times longer than 30 min epitaxially grown layer detached from the substrate. A high density of micrometer sized pores with regions of three-dimensional photonic crystal expressed in an intersecting <113> oriented macropore lattice on {111} oriented crystal was observed. After detaching the epitaxial layer, the black colored substrate consisted of fine nanometer sized cobweb-like silicon structures whose morphology and density depended on HF concentration and anodization time was found. The Raman spectra of such structures show broadened and red-shifted optical phonon band O(Γ), depending on the size of silicon nanostructures. The intensity of PL of such fine porous substrate shows the sensitivity on the level of the optical phonon confinement. Polycrystalline p-type silicon film were prepared by low pressure chemical vapor deposition (LPCVD) and anodized in aqueous hydrofluoric acid (HF)/ethanol electrolyte. The FE-SEM images showed preferential anodization and macro-PSi formation along grain boundaries. Weak PL signal was detected in all samples, while Raman measurements indicated minimal or no confinement effects. The anodization of silicon on insulator layers was performed by direct and alternating currents at 50 Hz. Raman spectra of DC samples showed no significant shift of c-Si peak while PL spectra showed intensive luminescence over the entire surface. When etched with AC, a very intensive PL was observed at the circular edge of the sample that exhibited micrometer sized island-like porous structures, while the center of the sample showed moderate PL signal similar to DC samples. The formation of such island-like structures was interpreted as stress due to difference of the piezoelectric effect of silicon and quartz layers (buried SiO2). Micro-Raman spectra of islands show strong phonon confinement in the range 1.4–3.5 nm.

The healing effect of BPC 157 on rat femoral head osteonecrosis was monitored by Raman spectroscopy. Three groups of rats were defined: an injured group treated with BPC 157 (10 μg/kg/daily ip), an injured control group (treated with saline, 5 ml/kg/daily ip), and an uninjured healthy group. The spectra were recorded and the healing effect assessed on samples harvested from animals which were sacrificed 3 and 6 weeks after being injured. The statistical analysis of the recorded spectra showed statistical differences between the BPC 157-treated, control, and healthy groups of animals. In particular, after 6 weeks the spectral resemblance between the healthy and BPC 157 samples indicated a positive BPC 157 influence on the healing process of rat femoral head.

Porous silicon (PSI) samples were prepared by electrochemical etching of n-type (111) epitaxialy grown silicon layer on n-type silicon (111) substrates, by varying the concentration of 48% HF in ethanol solution, and by varying the etching time. Electrical resistivity of epitaxial layer was ∼2 Ω cm and of silicon substrate was ∼ 0.015 Ω cm. Within the epitaxial layer, and on the substrate surface, the micro- and nano-pores of different sizes in dependence on HF concentration and etching time were obtained. With the etching time longer than 30 minutes, the epitaxially layer was detached from the substrate. The structural and optical properties of prepared samples were investigated by Raman and photoluminescence spectroscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS) spectroscopy. The FE-SEM images showed high density of micrometer sized pores on epitaxial layers. After detaching the epitaxial layer, the substrate showed fine nanometer sized cobweb-like silicon structures whose morphology and density depend on HF concentration and etching time. The Raman spectra of such structures show transversal optical (TO) phonon band that broadens and red-shifts depending on the size of silicon nanostructures. The size distributions of the silicon basic structural units where determined by applying the phonon confinement model and were compared with those determined by FE-SEM. The intensity of phtoluminescence peak of such fine porous substrate shows the sensitivity on a degree of optical phonon confinement.

Luminescent porous silicon (PS) was obtained by galvanostatic electrochemical anodisation of p-type polycrystalline silicon (poly-Si) film in aqueous hydrofluoric acid (HF)/ethanol electrolyte. Poly-Si film was prepared and boron delta-doped on n-type silicon wafers by low pressure chemical vapor deposition (LPCVD) process. Porous poly-Si surface morphology varied as a function of anodisation time. Scanning electron microscope (SEM) images have shown macro-porous Si formation along grain boundaries. S-band photo-luminescence (PL) was measured in all samples, while Raman measurements indicated minimal or no confinement effects.

Silicon epitaxial wafers, consisting of 280 μm thick n-type substrate layer and 4–5 μm thick epitaxial layer, were electrochemically etched in hydrofluoric acid ethanol solution, to produce porous silicon samples. The resistivity of epitaxial layer was 1 Ω cm, while the substrate was much better conductor with resistivity 0.015 Ωcm. By varying the etching time, the different structures were obtained within the epitaxial layer, and on the substrate surface. Due to the lateral etching the epitaxial layer was partially detached from the substrate and could be peeled off. The influence of etching time duration on the structural properties of porous samples was investigated by Raman, spectroscopy. The samples were analysed immediately after the etching and six months later, while being stored in ambient air. The Raman spectra showed the shift in positions of transversal optical (TO) phonon bands, between freshly etched samples and the one stored in ambient air.

N-type silicon wafers, consisting of 280μm upper and 20μm thick lower layers, were electrochemically etched in a hydrofluoric acid (HF) ethanol solution. The resistivity of the upper layer was 0.015Ωcm, while the lower layer was a much worse conductor with a resistivity of 2Ωcm. Porous silicon (PS) samples were produced by etching the rough (upper) side of single-side polished wafers at a constant current density. The process of etching was monitored at different HF concentrations. The samples were investigated by Raman spectroscopy, photoluminescence (PL) and scanning electron microscopy (SEM). Due to the roughness of the unpolished surface, different surface orientations were exposed to electrochemical etching, which resulted in different etching speed and consequently a different morphology (plateaus, valleys) produced by etching. The porous plateaus showed the most intensive PL observable, even by optical microscope. PL spectra exhibited a decrease of peak intensity and the blue shift of maximum with an increase of HF concentration. The presence of nanometer-size Si structures was confirmed by the broadening and red shift of the transversal optical (TO) phonon band in the Raman spectra. The quantum confinement model was used to determine the average size of these structures. SEM images showed pores of different morphology and several nanometers in diameter. The largest pores and thinnest walls were obtained when etched with the lowest HF concentration.

Chalcogenide glass thin films (Ge2S3)x(As2S3)1−x, with x=0.3, 0.5, 0.7, and 0.9, were prepared by flash thermal evaporation of glass powders on c-Si substrate. We have investigated their structural properties for different average coordination numbers Z=2.52, 2.6, 2.68 and 2.78. Structural changes were monitored by Raman scattering with two different excitation lines, λ=1064nm and λ=514.5nm. Recorded spectra confirmed that structural changes of the samples are connected with the change of average coordination number. Shift between spectra recorded with two different excitation lines is observed. The shift was discussed in terms of structural ordering at the threshold Z and its connection with the band-tail states.

The direct interaction of high density lipoprotein (HDL) with nicotine, one of the major compo- nents of cigarette particulate matter, has been studied here at molecular level. Nicotine affects the vibra- tion modes of HDL due to its embedment within the lipid monolayer. The changes in the positions and in- tensities of vibration bands in protein and lipid domain of the particle were studied by IR and Raman spectroscopy. Three types of samples were prepared: native HDL sample and two HDL samples with added nicotine. The molecular ratio of nicotine / phospholipids in two samples was 1 : 12 and 1 : 6. The same types of samples were prepared from liposomes containing phosphatidylcholine, and sphingomyelin with addition of cholesterol. Spectra of liposome samples were used for distinguishing and attribution of lipid bands in spectra of HDL samples, where the majority of changes were observed. The incorporation of nicotine into lipid monolayer induces changes in the lipid bands from the vibrations in acyl chains and head groups of phospholipids. The changes in vibration bands from particular amino acids' residues con- firm that nicotine molecule is located within lipid monolayer but close to lipid-protein interface.

We focused on Raman spectroscopy as a method for monitoring healing process i) bone healing, ii) intestinal anastomosis healing and iii) stomach healing. To accelerate and improve healing we used pentadecapeptide BPC 157, either ip application (10ug, 10 ng/kg, once daily) (i, ii) or topical application of one drop at the site of injury (2mg, 2ug, 2 ng, 2pg/ml) (iii) . i. Raman spectra were recorded at the edge of the circular bone defect of a rat skull, 3, 7, 14 and 21 days after the defect was induced. Some changes of characteristic Raman bands appeared in spectra recorded from bone of BPC 157 rats already after 3 and 7 days while in controls effect was observes after 14 days. ii. Raman spectra were recorded at the site of the intestinal anastomosis 1, 2, 3, 7 and 14 days after the ileoileal anatomosis was created. Differences of spectra were demonstrated using principal component analysis to maximize the spectral variances. Separations of the spectra with different healing period on PC scores scatterplot indicated some changes of Raman spectra recorded from intestine of BPC 157 rats. iii. The 3x3mm samples were excided from the rats stomach, and either kindly brushed or leaved intact, and one drop of distilled water with or without BPC 157 was inserted to the specimen through the holder. Five Raman spectra were recorded in intervals of 10 minutes. Principal component analysis was applied on all recorded spectra and separation according to concentration and time was noticed. Separations of the spectra with different post-application period and different BPC 157 concentrations on PC scores scatterplot indicated definitive changes of Raman spectra recorded from both damaged and non damaged stomach of BPC 157 rats in either of tested post-application intervals.