Raman and fluorescence investigations on retrieved Biolox® delta femoral heads

Since the introduction of ceramic‐on‐ceramic couplings in total hip arthroplasty, continuous efforts have been performed to improve the performance of the prosthetic components. To expand the applications of ceramics, in 2000 an innovative alumina–zirconia composite was introduced in the market. The present study represents the first investigation aimed at characterising at the molecular level Biolox® delta retrievals implanted between 1999 and 2009. Fluorescence and Raman results showed that a progressive improvement of the material properties has occurred in the period between 1999 and 2009. Raman spectroscopy showed that wear was the main cause of the in vivo tetragonal‐to‐monoclinic zirconia transformation. Our findings validated the in vitro accelerated ageing protocols proposed in the literature to simulate the effects of the in vivo wear, because the mechanism operating in vivo was found to be the same active in vitro. The in vitro fracture of a new femoral head appeared to be an extreme wear condition that determined the most significant changes in the residual stress state and monoclinic content both in the section of the fragments and on their surface. The micro‐Raman mapping of the fractured articulating surface showed that the tetragonal‐to‐monoclinic transformation involved a region much more extended than as reported in the literature. Copyright © 2012 John Wiley & Sons, Ltd.     

Non‐invasive time‐course imaging of apoptotic cells by confocal Raman micro‐spectroscopy

Confocal Raman micro‐spectroscopy (CRMS) was used to measure time‐course spectral images of live cells undergoing apoptosis without using molecular labels or other invasive procedures. Human breast cancer cells (MDA‐MB‐231) were exposed to 300 µM etoposide to induce apoptosis, and Raman spectral images were acquired from the same cells at 2‐h intervals over a period of 6 h. The purpose‐built inverted confocal Raman micro‐spectrometer integrated an environmental enclosure and wide‐field fluorescence imaging. These key instrumental elements allowed the cells to be maintained under sterile physiological conditions (37 °C, 5% CO₂) and enabled viability and apoptosis assays to be carried out on the cells at the end of CRMS measurements. The time‐course spectral images corresponding to DNA Raman bands indicated an increase in signal intensity in apoptotic cells, which was attributed to DNA condensation. The Raman spectral images of lipids indicated a high accumulation of membrane phospholipids and highly unsaturated non‐membrane lipids in apoptotic cells. This study demonstrates the potential of CRMS for label‐free time‐course imaging of individual live cells. This technique may become a useful tool for in vitro toxicological studies and testing of new pharmaceuticals, as well as other time‐dependent cellular processes, such as cell differentiation, cell cycle and cell–cell interactions. Copyright © 2010 John Wiley & Sons, Ltd.     

Identification of epidermal L‐tryptophan and its oxidation products by in vivo FT‐Raman Spectroscopy further supports oxidative stress in patients with vitiligo

In the past, non‐invasive in vivo FT‐Raman spectroscopy has been used to detect H₂O₂‐mediated oxidation of methionine to methionine sulfoxide and methionine sulfone, as well as cysteine to cysteic acid, in the sequence of proteins in the epidermis of patients with vitiligo. L ‐tryptophan (Trp) is another potential target for this oxidation. Owing to the presence of 10⁻³M epidermal albumin which contains one Trp residue, it was tempting to follow the oxidation of this amino acid. Using in vivo and in vitro FT‐Raman spectroscopy, we show for the first time that epidermal Trp is oxidised in patients with vitiligo, yielding 5‐OH‐Trp at 930 cm⁻¹ and other oxidation products (i.e. N‐formyl kynurenine and kynurenine) from indole ring oxidation peaking at 1050 cm⁻¹. On the basis of detailed in vitro results, we could conclude that 5‐OH‐Trp as well as formyl kynurenine and kynurenine are formed via H₂O₂‐mediated Fenton chemistry. These results once again bring out the strength of non‐invasive in vivo FT‐Raman Spectroscopy in dermatology to follow the effect of oxidative stress in the skin of patients with vitiligo. Copyright © 2008 John Wiley & Sons, Ltd.     

Raman characterisation of conventional and cross‐linked polyethylene in acetabular cups run on a hip joint simulator

Five sets of differently sterilised conventional ultra‐high molecular weight polyethylene (UHMWPE) and cross‐linked polyethylene (XLPE) acetabular cups were run for 5 million cycles on a hip joint simulator in order to evaluate their wear behaviour in relation to material properties (PE grade, conventional or cross‐linked) and sterilisation method (ethylene oxide (EtO) treatment or γ‐irradiation). Gravimetric measurements revealed that conventional UHMWPE wore significantly more than XLPE. The differences in wear behaviour could be partly related to the orthorhombic contents obtained by Raman spectroscopy in the unworn areas of the cups: XLPE cups showed a significantly higher crystallinity degree than the UHMWPE specimens. Raman analysis showed that wear testing did not significantly modify the orthorhombic content of any of the tested acetabular cups. However, the set of cups that showed the highest weight loss, i.e. γ‐sterilised PE GUR1020, appeared the most homogeneously polished upon wear testing; from a molecular point of view, only this set of cups showed a significant increase of the I₁₁₃₀/I₁₀₆₀ intensity ratio, suggesting the occurrence of chain orientation. On the other hand, XLPE cups, despite the lowest weight loss undergone, showed a decrease in the amorphous content upon wear testing as well as a limited orthorhombic → monoclinic transformation, which did not appear detrimental. Copyright © 2011 John Wiley & Sons, Ltd.     

Micro‐Raman analysis of GaAs Schottky barrier solar cell

Gallium arsenide (GaAs) cells have been in the race with silicon single‐crystal cells for the highest efficiency photovoltaic devices. The annealed, irradiated Schottky barrier (SB) solar cells were characterised using micro‐Raman spectroscopy at three different regions: namely, at the (1) ohmic contact region, (2) unirradiated region and (3) irradiated region. We also present a micro‐Raman study of the damage process in annealed GaAs SB solar cells bombarded by high‐energy ions. A Gaussian line shape was fitted to the Raman spectra of the longitudinal optical phonon A₁(LO), and parameters such as intensity, full width at half maximum (FWHM) and the area under the peak were obtained for the different annealing temperatures. Biaxial stress (σ), carrier concentration (n), depletion length (L_d), dislocation velocity (ν) and life time of the first‐order optical phonon (τ) of the A₁(LO) mode of the irradiated region of the samples annealed at different temperatures were calculated. Copyright © 2010 John Wiley & Sons, Ltd.     

Comparison of molecular images as defined by Raman spectra between normal mucosa and squamous cell carcinoma in the oral cavity

Raman spectroscopy has been effectively applied to clinically differentiate normal and cancerous mucosal tissues. Micro‐Raman spectroscopy provides a tool to better understand the molecular basis for the Raman clinical signal. The objective of the current study was to utilize micro‐Raman spectroscopy to define the molecular/spectral differences between normal and abnormal squamous cell carcinoma (SCC) in oral mucosa (in vitro). Understanding this may help in identifying unique spectra or may be useful for in vivo application of this technology. Micro‐Raman (confocal) spectroscopy was used to obtain molecular images of normal and SCC cells of human oral mucosa. Four fresh flashed‐frozen tumor and four matched normal tongue specimens were studied. The spectra covered a wavenumber range from 300 to 4000 cm⁻¹ with a spectral resolution of 8 cm⁻¹ and a spatial resolution of 1.0 µm. The cells were located within thin sections of tongue mucosa biopsies. The excitation wavelength of 515 nm was used. We were able to obtain Raman images with rich information about the spectroscopic and structural features within the cytoplasm, cell membrane, and cell nuclei. Significant spectral differences were observed between the Raman images of normal and malignant squamous cells. The heterogeneity of tumor cells within the abnormal tissue was also demonstrated. Spectral differences demonstrated between both tissue types have provided important information regarding the origins of specific signals within the cells of each tissue type. In our search for specific spectral biomarkers, we believe that a cell surface protein, greatly upregulated in SCC cells, was discovered at 1583 cm⁻¹. Copyright © 2010 John Wiley & Sons, Ltd.     

Raman spectroscopy measurement of levofloxacin lactate in blood using an optical fiber nano‐probe

Liquid chromatography and mass spectrometry were time‐consuming and expensive as the main methods for the drug analysis at present, and the samples must be pretreated. The Raman spectroscopy measurement methods were fast and simple, so the Raman spectroscopy methods for the drug analysis were explored in this paper. An optical fiber nano‐probe coated with gold nanoparticles was fabricated and used with surface‐enhanced Raman spectroscopy (SERS) to measure levofloxacin lactate. The resulting SERS spectra of levofloxacin lactate in mouse blood that was detected by the optical fiber nano‐probe clearly showed the characteristic wave numbers of levofloxacin lactate, indicating that optical fiber nano‐probes can be used with spectral techniques to analyze drugs in vitro or potentially even in vivo. Copyright © 2015 John Wiley & Sons, Ltd.     

Raman spectroscopy monitoring of the cellular activities of a tissue‐engineered ex vivo produced oral mucosal equivalent

To ensure quality control and assurance in tissue engineering, noninvasive, real‐time and aseptic evaluation of cell‐based devices is required before product release. In this study, Raman spectroscopy was applied to monitor the cellular activities of an oral mucosa equivalent (EVPOME) produced ex vivo from cultured autogenous oral keratinocytes and acellular dermis—AlloDerm. Raman spectra showed a positive correlation of the peak area ratio of amide I (1655 cm⁻¹)/phenylalanine (1004 cm⁻¹) with a negative linear regression (R² > 0.95) according to the number of cultured days, especially on the 14thand 21st day. This work demonstrates the successful application of Raman spectroscopy for quantitatively monitoring and evaluating the maturity of EVPOME. Copyright © 2010 John Wiley & Sons, Ltd.     

In vitro confocal Raman micro‐spectroscopic approach to screen the mode of action of Chinese herbs on oxidative damaged human sperm

This paper presented a rapid and reliable approach to screen the antioxidant active ingredients on human sperm from Chinese herbs by means of confocal Raman micro‐spectroscopy. For the first time with the proposed approach, we performed the studies of rationalizing the active ingredients from several Chinese herbs. In this study, the FeSO₄/H₂O₂‐induced oxidative damaged sperm after co‐culture with compounds or active fraction extracted from some Chinese herbs commonly used in the treatment of male infertility were observed by using confocal Raman micro‐spectroscopy. The Raman spectral fingerprints of the damaged sperm were very different from the normal ones, and the further statistical analysis were successfully used to support the results, these differences were shorten after co‐culture with the compounds or active fraction we had chosen, and the results were almost consistent with the traditional clinical trial results and other published data, all which showed that these compounds or active fraction were the chemogenomics of the Chinese herbs on anti‐oxidative damaged sperm. In brief, we demonstrated that by means of confocal Raman micro‐spectroscopy, in vitro is a rapid, reliable and large‐scale approach to screen the antioxidant active ingredients on human sperm from Chinese herbs. Copyright © 2016 John Wiley & Sons, Ltd.     

An assessment study of tiles from Topkapı Palace Museum with energy‐dispersive X‐ray and Raman spectrometers

A limited number of studies concerning Ottoman ceramic technology have been performed using the scanning electron microscopy‐energy dispersive X‐ray spectrometry and micro‐Raman spectroscopy techniques. The discovery of the ceramics, which were described as ‘Iznik’, at excavation sites outside of the city of Iznik, caused disagreements over the exact origin of Iznik products. In this study, bodies, glazes, and pigments of 46 tile/ceramic shards of unknown origin, which were supplied from the vaults of Topkapı Palace Museum, and two reference tile fragments, known as Kütahya products, supplied from the demolished Surp Krikor Lusavoriç church and, additionally, two Iznik reference tiles were examined using the scanning electron microscopy‐energy dispersive X‐ray spectrometry and micro‐Raman spectroscopy techniques. Results of both techniques were evaluated together for the first time to determine the power of nondestructive Raman spectroscopy technique in differentiation of Ottoman tiles. In this work, bodies of the Kütahya tiles were found to be different than Iznik and Tekfur stone‐paste bodies, which are rich in clay rather than quartz. Two different lead‐alkali glaze compositions were found for Kütahya tiles; one was rich in PbO (over 35%) and the other one was rich in alkali (PbO less than 25%). Barite inclusions were detected in the bodies and in the glazes of some Ottoman tiles, which could be the fingerprint for the Kütahya products. It was found that the under glaze red decoration is essentially a mixture of hematite and quartz in different proportions. Shades of red decoration mainly depend on the amount of hematite in the mixture. Sixteenth century tomato red decoration contains more quartz compared with 17th century dark red decoration. This study showed that a similar technology was also applied at Kütahya in the 16th century. A linear correlation was found between the position of the Raman intense stretching peak Q₃ and lead oxide content of lead‐alkali glazes, which could allow for the differentiation of Ottoman tiles based on the nondestructive Raman analysis. This study provides an important additional reference data and discussion for the Ottoman tiles. Copyright © 2011 John Wiley & Sons, Ltd.     

Subsurface analysis of painted sculptures and plasters using micrometre‐scale spatially offset Raman spectroscopy (micro‐SORS)

A recently developed variant of spatially offset Raman spectroscopy (SORS) for the non‐invasive analysis of thin painted layers, micro‐SORS, has been applied, for the first time, to real objects of Cultural Heritage – namely painted sculptures and plasters. Thin layers of paint originating from multiple restoration processes often applied over many centuries have been analysed non‐destructively using micro‐SORS to depths inaccessible to, or unresolvable into separate layers, by conventional confocal Raman microscopy. The concept has been demonstrated on several artistic artefacts of historical significance originating from Italy and dating from the medieval to the 18th century. The technique extends the depth applicability of Raman spectroscopy and with its inherently high chemical specificity that expands the portfolio of existing non‐destructive analytical tools in Cultural Heritage permitting to avoid cross‐sectional analysis often necessitated with this type of samples with conventional Raman microscopy. Currently, the method is non‐invasive only for artworks that can be placed under Raman microscope although there is a prospect for its use in a mobile system with largely removed restrictions on sample dimensions. © 2015 The Authors Journal of Raman Spectroscopy Published by John Wiley & Sons Ltd.     

Depth‐resolved in vivo micro‐Raman spectroscopy of a murine skin tumor model reveals cancer‐specific spectral biomarkers

We have developed a micro‐Raman spectrometer system for use to differentiate tumor lesions from normal skin using an in vivo animal model. A study of 494 Raman spectra from 24 mice revealed different spectral patterns at different depths and between normal and tumor‐bearing skin sites. A peak at 899 cm⁻¹ (possibly from proline or fatty acids) and one with higher intensity in the 1325–1330 cm⁻¹ range (assigned to nucleic acids) were correlated with the presence of tumors, which can potentially be used as biomarkers for skin cancer detection. Spectral diagnosis performed on the murine tumor model achieved a diagnostic sensitivity of 95.8% and specificity of 93.8%. These results encourage us to develop further the use of confocal Raman spectroscopy as a clinical tool for noninvasive human skin biochemical analysis, particularly in relation to skin cancer. Copyright © 2010 John Wiley & Sons, Ltd.     

Wettability conundrum: Discrepancies of soft contact lens performance <Emphasis Type="Italic">in vitro</Emphasis> and <Emphasis Type="Italic">in vivo</Emphasis>

The recognition and appreciation of soft contact lenses as simple, efficient and aesthetically gratifying vision-correction devices is ever growing, especially among younger population. Stable thin tear film uniformly spread over corrective lens surface is essential for acute vision, and also for comfortable and safe contact lens wear. The significant efforts have been invested by the contact lens industry to develop soft lens surface that is completely wet by tear aqueous in the ocular environment. Number of the publications dedicated to the wettability properties of the soft hydrogel lenses is on the steady rise. However, the clinical results show that no unambiguous correlation emerges when lens surface wettability in vitro is judged against tear film stability evaluated in vivo. This paper assesses and compares the modern techniques used for evaluation of soft contact lens surface wettability and reports some findings regarding relations between lens surface wettability in vitro and in vivo.     

Characterization of pottery from Republic of Macedonia. III. A study of comparative mineralogical detection efficiency using micro‐Raman mapping and X‐ray diffraction

Point‐to‐point micro‐Raman and X‐ray diffraction (XRD) techniques were employed for characterization of minerals present in the pottery body of 27 glazed Byzantine and Ottoman pottery shreds, excavated at two different archaeological sites in the Republic of Macedonia: in Skopje (Skopsko Kale) and in Prilep (Markovi Kuli and Sv. Atanas Church). The Raman spectra of 18 Byzantine samples (dating from 12th−14th century) and nine Ottoman samples (dating from 17th−19th century) revealed 26 different minerals. XRD measurements were further performed on the same powder samples to validate the mineralogical assessment obtained by point‐to‐point micro‐Raman spectroscopy. Although only 13 different mineral phases were obtained by the XRD, the results obtained from the Raman and XRD spectra for the most abundant minerals in the investigated pottery bodies match quite well. However, the identification of the less abundant minerals in the clay matrixes from the XRD data was very difficult, if at all possible. The results emphasize the specifics of the applied techniques and their limits. Additionally, wavelength dispersive X‐ray fluorescence spectroscopy was used for the elemental analysis. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis and Raman spectroscopic investigation of a new self‐assembly monolayer material 4‐[N‐phenyl‐N‐(3‐methylphenyl)‐amino]‐benzoic acid for organic light‐emitting devices

We have synthesized 4‐[N‐phenyl‐N‐(3‐methylphenyl)‐amino]‐benzoic acid (4‐[PBA]) and investigated its molecular vibrations by infrared and Raman spectroscopies as well as by calculations based on the density functional theory (DFT) approach. The Fourier transform (FT) Raman, dispersive Raman and FT‐IR spectra of 4‐[PBA] were recorded in the solid phase. We analyzed the optimized geometric structure and energies of 4‐[PBA] in the ground state. Stability of the molecule arising from hyperconjugative interactions and charge delocalization was studied using natural bond orbital analysis. The results show that change in electron density in the σ* and π* antibonding orbitals and E₂ energies confirm the occurrence of intramolecular charge transfer within the molecule. Theoretical calculations were performed at the DFT level using the Gaussian 09 program. Selected experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumbers by their total energy distribution. The good agreement between the experimental and theoretical spectra allowed positive assignment of the observed vibrational absorption bands. Finally, the calculation results were applied to simulate the Raman and IR spectra of the title compound, which show agreement with the observed spectra. Copyright © 2011 John Wiley & Sons, Ltd.     

Polarized Raman mapping study of the microheterogeneity in 0.67PbMg1/3 Nb2/3O3‐0.33PbTiO3 single crystal

Polarized micro‐Raman spectroscopy was carried out on the (001) face of a 0.67PbMg_1/3Nb_2/3O₃‐33%PbTiO₃ (PMN‐33%PT) single crystal. The Raman images revealed the spatial variations of the intensity of the Raman bands, suggesting that the structure in the PMN‐33%PT single crystal varied from one micro‐area to another. When changing the polarization direction of the incident light with respect to the selected crystalline axes, the intensities of the Raman modes varied periodically. According to the Raman selection rules (RSRs), the angular dependences of the Raman modes indicated that the PMN‐33%PT single crystal is in the monoclinic phase. Furthermore, the color patterns in the Raman images were associated with the coexistence of the M_A‐ and M_C‐type monoclinic phases in the PMN‐33%PT single crystal. Our results provide useful information for understanding the microheterogeneity of the relaxor PMN‐xPT single crystals with compositions near the morphotropic phase boundary region. Copyright © 2010 John Wiley & Sons, Ltd.     

In situ monitoring of solid‐state transition of p‐aminobenzoic acid polymorphs using Raman spectroscopy

The purpose of this study is to investigate the mechanism of solid‐state polymorphic transition of p‐aminobenzoic acid (PABA) using in situ Raman spectroscopy measurement. The polymorphic transition experiments were conducted on a micro quartz vessel mounted on a microscope, hot and cold stage, under isothermal conditions. The temperature was precisely controlled by a standalone temperature controller equipped with liquid nitrogen cooling system. The Raman spectroscopy probe was positioned on the surface of the solid sample in the micro vessel. The polymorphic transition progression was in situ monitored and recorded by Raman spectroscopy. Based on the polymorphic transition rate resulted from the quantitative analysis of Raman spectra, the mechanism of solid‐state polymorphic transition of PABA was examined by various empirical kinetic models. An Arrhenius analysis was also performed to calculate activation energies from 134.7 kJ mol⁻¹ to 137.7 kJ mol⁻¹ for the transition. The results demonstrated that in situ Raman spectroscopy is a valuable and accurate technique to probe polymorphic transition process. Copyright © 2009 John Wiley & Sons, Ltd.     

In vivo study on the protection of indole‐3‐carbinol (I3C) against the mouse acute alcoholic liver injury by micro‐Raman spectroscopy

Micro‐Raman spectroscopy (MRS) was utilized for the first time to evaluate the effect of indole‐3‐carbinol (I3C) on acute alcoholic liver injury in vivo. In situ Raman analysis of tissue sections provided distinct spectra that can be used to distinguish alcoholic liver injury as well as ethanol‐induced liver fibrosis from the normal state. Sixteen mice with liver diseases including acute liver injury and chronic liver fibrosis, and eight mice with normal liver tissues, and eight remedial mice were studied employing the Raman spectroscopic technique in conjunction with biomedical assays. The biochemical changes in mouse liver tissue when liver injury/fibrosis occurs such as the loss of reduced glutathione (GSH), and the increase of collagen (α‐helix protein) were observed by MRS. The intensity ratio of two Raman peaks (I₁₄₅₀/I₆₆₆) and in combination with statistical analysis of the entire Raman spectrum was found capable of classifying liver tissues with different pathological features. Raman spectroscopy therefore is an important candidate for a nondestructive in vivo screening of the effect of drug treatment on liver disease, which potentially decreases the time‐consuming clinical trials. Copyright © 2008 John Wiley & Sons, Ltd.     

Dipole‐like backscatter stimulated Raman scattering for in vivo imaging

Stimulated Raman scattering (SRS) scanning microscopy has the potential to enable label‐free in vivo imaging for research and clinical medicine. Volume SRS from focus occurs in the forward scattered direction. Therefore, multiple scattering events are required to direct the light out of the tissue, reducing imaging depth and resolution. Here, a method called Stokes interference SRS (SISRS) is introduced that operates by the addition to the standard pump and stimulated emission probe beams a third beam called the donut beam. The donut is close in wavelength to the probe beam and, after passage through a π phase plate, forms an annular beam in the focal plane with bright nodes above and below focus. The donut beats with the probe beam, and when they destructively interfere with each other, the microscope's 3‐D stimulated emission focal spot is reduced to subwavelength dimensions. A subwavelength focal volume emits a dipole pattern of SRS with forward and backscatter lobes, enabling high‐resolution single‐backscatter imaging from deep within tissues. The reduction of the focal volume also increases the resolution of the scanning image creating imaging beyond the diffraction limit. SISRS imaging may provide in vivo label‐free Raman images comparable with that achieved in stained in vitro tissues in all planes of section. Copyright © 2014 John Wiley & Sons, Ltd.     

Density functional theory calculations and vibrational spectra of p‐bromonitrobenzene

FT‐IR and FT‐Raman spectra of p‐bromonitrobenzene (p‐BNB) have been recorded in the region 4000–400 cm⁻¹ and 4000–50 cm⁻¹, respectively. The molecular structure, geometry optimization, vibrational wavenumbers have been investigated. The spectra were interpreted with the aid of normal coordinate analysis based on the density functional theory (DFT) using the standard B3LYP/6‐31G method and basis set combination and was scaled using multiple scale factors yielding good agreement between observed and calculated wavenumbers. The results of the calculations are applied to simulate infrared and Raman spectra of the title compound which showed reasonable agreement with the observed spectra. Copyright © 2009 John Wiley & Sons, Ltd.