Raman Spectroscopy to Characterize Bladder Tissue for Multidimensional Diagnostics of Cancer in Urology

Fiber optic Raman spectroscopy offers labelfree identification of cancer in the bladder under in vivo conditions. However, state-of-the-art Raman technology does not enable to scan the entire bladder wall. Our multidimensional approach within the project Uro-MDD combines panoramic 3D-image reconstruction of white light cystoscopy and fluorescence lifetime imaging to define regions of interest for Raman-assisted diagnostics. First Raman results are presented from human control and cancer bladder specimens that demonstrated how to obtain specific molecular information. Such Raman images can be used in a clinical setting to determine cancer margins and the resection status. Fiber probes are under development to translate the technique to in vivo screening.

New methodology to process shifted excitation Raman difference spectroscopy data: a case study of pollen classification

Shifted excitation Raman difference spectroscopy (SERDS) is a background correction method for Raman spectroscopy. Here, the difference spectra were directly used as input for SERDS-based classification after an optimization procedure to correct for photobleaching of the autofluorescence. Further processing included a principal component analysis to compensate for the reduced signal to noise ratio of the difference spectra and subsequent classification by linear discriminant analysis. As a case study 6,028 Raman spectra of single pollen originating from plants of eight different genera and four different growth habits were automatically recorded at excitation wavelengths 784 and 786 nm using a high-throughput screening Raman system. Different pollen were distinguished according to their growth habit, i.e. tree versus non-tree with an accuracy of 95.9%. Furthermore, all pollen were separated according to their genus, providing also insight into similarities based on their families. Classification results were compared using spectra reconstructed from the differences and raw spectra after state-of-art baseline correction as input. Similar sensitivities, specificities, accuracies and precisions were found for all spectra with moderately background. Advantages of SERDS are expected in scenarios where Raman spectra are affected by variations due to detector etaloning, ambient light, and high background.

Sample preparation for Raman microspectroscopy

Raman spectroscopy and its variants allow for the investigation of a wide range of biological and biomedical samples, i. e. tissue sections, single cells and small molecules. The obtained information is on a molecular level. By making use of databases and chemometrical approaches, the chemical composition of complex samples can also be defined. The measurement procedure is straight forward, however most often sample preparation protocols must be implemented. While pure samples, such as high purity powders or highly concentrated chemicals in aqueous solutions, can be directly measured without any prior sample purification step, samples of biological origin, such as tissue sections, pathogens in suspension or biofluids, food and beverages often require pre-processing steps prior to Raman measurements. In this book chapter, different strategies for handling and processing various sample matrices for a subsequent Raman microspectroscopic analysis were introduced illustrating the high potential of this promising technique for life science and medical applications. The presented methods range from standalone techniques, such as filtration, centrifugation or immunocapture to innovative platform approaches which will be exemplary addressed. Therefore, the reader will be introduced to methods that will simplify the complexity of the matrix in which the targeted molecular species are present allowing direct Raman measurements with bench top or portable setups.

Biochemical alterations in the Musculus triceps brachii and Musculus longissimus thoracis during early postmortem period in pigs

Muscle-to-meat-transition is influenced by alterations of the energy metabolism. Porcine Musculus triceps brachii (MT) consisted of more fast-twitch-glycolytic muscle fibers and samples, collected 0, 10 and 20 min after slaughter (p.m.), showed higher mitochondrial respiratory activities and ATP concentrations than Musculus longissimus thoracis (LT) samples. Enzyme activities in MT were higher at 0 min (glycogen phosphorylase (GP)), 10 min (GP, citrate synthase (CS)) and at 20 min p.m. (CS). However, LT results were higher at 0 min (lactate dehydrogenase (LDH)), 10 min (phosphofructokinase (PFK), LDH) and at 20 min p.m. (PFK, F₀F₁-ATPase (F₀F₁)). Between 0 min and 10 min p.m. CS activities decreased in LT and MT samples, PFK increased in LT and GP in MT samples. Between 10 min and 20 min p.m. PFK and LDH decreased in LT and GP in MT samples, whereas F₀F₁ increased in LT and CS in MT samples. The data indicate that muscles with different mitochondria contents show clearly different energy metabolism characteristics.

Recent progress in surface-enhanced Raman spectroscopy for biological and biomedical applications: from cells to clinics

The application of surface-enhanced Raman spectroscopy (SERS) in biological and biomedical detection schemes is feasible due to its excellent molecular specificity and high sensitivity as well as the capability of SERS to be performed in complex biological compositions. SERS-based investigation of cells, which are the basic structure and functional unit of organisms, represents the starting point of this review. It is demonstrated that SERS provides a deep understanding of living cells as well as their microenvironment which is needed to assess the development of diseases. The clinical relevance of SERS is proved by its application for the detection of cancer cells and tumour margins under in vivo conditions and examples for theranostic approaches are discussed. This review article provides a comprehensive overview of the recent progress within the last 3 years.

A healing ionomer crosslinked by a bis-bidentate halogen bond linker: a route to hard and healable coatings

A bis-bidentate halogen bond linker was introduced into a fully organic, phosphate based ionomer, yielding a crosslinked network with healing abilities and improved mechanical properties.

Relations between personality changes and cerebrospinal fluid biomarkers of Alzheimer's disease pathology

Specific changes in personality profiles may represent early non-cognitive symptoms of Alzheimer's disease (AD). Evaluating the subject's personality changes may add significant clinical information, as well as help to better understand the interaction between personality change, cognitive decline, and cerebral pathology. With this study we aimed to describe the relationship between personality changes and cerebrospinal fluid (CSF) markers of AD pathology at early clinical stages of the disease. One hundred and ten subjects, of whom 66 cognitively impaired patients (57 with mild cognitive impairment (MCI), and 9 with mild dementia) and 44 healthy controls, had neuropsychological examination as well as lumbar puncture to determine concentrations of CSF biomarkers of AD pathology (amyloid beta_1-42 (Aβ_1-42), phosphorylated tau (ptau-181), and total-tau (tau)). The Revised NEO Personality Inventory (NEO-PI-R) was administered twice, once to evaluate subjects' current personality and once to assess personality traits retrospectively 5 years before evaluation. Subjects with an AD CSF biomarker profile showed significant increase in neuroticism and decrease in conscientiousness over time as compared to non-AD CSF biomarker group. In regression analysis controlling for global cognition as measured by the MMSE score, increasing neuroticism and decreasing extraversion, openness to experience and conscientiousness were associated with lower Aβ_1-42 concentrations but not with tau and ptau-181 concentrations. Our findings suggest that early and specific changes in personality are associated with cerebral AD pathology. Concentrations of CSF biomarkers, additionally to severity of the cognitive impairment, significantly contribute in predicting specific personality changes.

Surface-enhanced Raman spectroscopy and microfluidic platforms: challenges, solutions and potential applications

The review provides an overview of the development in the field of surface-enhanced Raman spectroscopy combined with microfluidic platforms.

Developments in spontaneous and coherent Raman scattering microscopic imaging for biomedical applications

First, the potential role of Raman-based techniques in biomedicine is introduced. Second, an overview about the instrumentation for spontaneous and coherent Raman scattering microscopic imaging is given with a focus of recent developments. Third, imaging strategies are summarized including sequential registration with laser scanning microscopes, line imaging and global or wide-field imaging. Finally, examples of biomedical applications are presented in the context of single cells, laser tweezers, tissue sections, biopsies and whole animals.

Cortisol, life events and cognition in non-demented subjects: A population-based study

Background

Older people are particularly exposed to stressful events, known to activate the hypothalamus-pituitary-adrenal axis. Many studies highlighted the possible deleterious effects of elevated cortisol on cognition, assuming a likely role of stressful events. Yet, very few studies actually examined these assumed links between life events, cortisol and cognition.

Objective

To examine associations between salivary cortisol, cognition and life events in a population of non-demented old individuals.

Methods

A cross-sectional analysis was conducted using data from Colaus/PsyColaus, a longitudinal population-based study involving 6733 Lausanne residents. Salivary cortisol samples (upon waking, 30 minutes after waking, at 11 am and at 8 pm) were obtained from 799 non-demented participants aged at least 60.

Life events, activities of daily life along with depressive symptoms were assessed using a standardized questionnaire. A comprehensive neuropsychological test battery was used to determine the Clinical Dementia Rating (CDR).

For multiple comparisons, P values were adjusted (P′) according to Holm-Bonferroni's method.

Results

Cortisol at 11 am and cortisol area under the curve (AUC) were positively correlated with CDR sum of boxes (CDRSOB) scores (P′ = 0.035; Rho = 0.097 and P′ = 0.024; Rho = 0.110, respectively). The association between cortisol AUC and CDRSOB remained significant after controlling for age, sex, body mass index, education, smoking and depression (P = 0.001; β = 0.001; R2 change = 0.016).

The number and the total impact of life events were associated neither with cortisol nor with CDRSOB.

Conclusions

Elevated cortisol was associated with poorer cognitive functioning yet independently of life events. This suggests that the increased cortisol associated with poorer cognition might be not a mere reflection of stressful events but rather explained by other factors, yet to be elucidated.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Specific personality changes in subjects with MCI and mild dementia are associated with cerebral Alzheimer's pathology as measured by CSF biomarkers

Introduction

Specific changes in personality profiles may represent early symptoms of Alzheimer's disease (AD). Knowledge about relationship between personality changes and biomarkers of cerebral pathology can contribute to early diagnosis of AD.

Objectives

To investigate to what extent the personality changes predict the cerebral AD pathology.

Aims

To describe the relationship between the personality changes and pathological cerebro-spinal fluid (CSF) biomarkers.

Method

One hundred and ten subjects, of whom 57 patients with mild cognitive impairment (MCI), 9 subjects with mild dementia, and 44 healthy controls had an extensive medical and neuropsychological examination as well as lumbar puncture to evaluate concentrations of CSF biomarkers of AD pathology [amyloid-β1-42 (Aβ1-42), phosphorylated tau (ptau-181), and total-tau (tau)]. The proxies of the participants completed the Revised NEO Personality Inventory (NEO-PI-R) to assess subjects’ personality at the time being and 5 years retrospectively.

Results

In a hierarchical multivariate regression analysis, including age, gender, education, Mini Mental State Examination (MMSE), and APOEe4 status, lower Aβ1-42 concentrations in CSF were associated with increasing neuroticism, and decreasing extraversion and conscientiousness. Decreasing extraversion, openness to experience and conscientiousness were associated with higher tau/Aβ1-42 ratio, and higher ptau-181/Aβ1-42 ratio was related to decreasing extraversion. Personality changes in the domain of agreeableness did not yield any significant effect as a predictor on any of CSF biomarkers.

Conclusions

Our findings suggest that early and specific changes in personality traits are associated with cerebral AD pathology, in particular with amyloid pathology, and may serve as clinical signs to consider when evaluating MCI and mild dementia.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

HD DVD substrates for surface enhanced Raman spectroscopy analysis: fabrication, theoretical predictions and practical performance

Commercially available HD-DVD templates have been used to theoretically predict the occurrence of surface plasmons supermodes which improve the detection of surface enhanced Raman signals.

Recognition of tumor cells by immuno-SERS-markers in a microfluidic chip at continuous flow

SERS active nanoparticles were labeled with a reporter molecule and conjugated with anti-EpCAM antibodies.

Molecular self-healing mechanisms between C60-fullerene and anthracene unveiled by Raman and two-dimensional correlation spectroscopy

C₆₀-fullerene–anthracene self-healing copolymers were studied by time-, temperature- and concentration-dependent FT-Raman spectroscopy and advanced 2D correlation analysis.

Discrimination and classification of liver cancer cells and proliferation states by Raman spectroscopic imaging

Discrimination of nodular lesions in cirrhotic liver is a challenge in the histopathologic diagnostics. For this reason, there is an urgent need for new detection methods to improve the accuracy of the diagnosis of liver cancer. Raman imaging allows to determine the spatial distribution of a variety of molecules in cells or tissue label-free and to correlate this molecular information with the morphological structures at the same sample location. This study reports investigations of two liver cancer cell lines, - HepG2 and SK-Hep1, - as well as HepG2 cells in different cellular growth phases using Raman micro-spectroscopic imaging. Spectral data of all cells were recorded as a color-coded image and subsequentially analyzed by hierarchical cluster and principal component analysis. A support vector machine-based classification algorithm reliably predicts previously unknown cancer cells and cell cycle phases. By including selectively the Raman spectra of the cytoplasmic lipids in the classifier, the accuracy has been improved. The main spectral differences that were found in the comparative analysis can be attributed to a higher expression of unsaturated fatty acids in the hepatocellular carcinoma cells and during the proliferation phase. This corresponds to the already examined de novo lipogenesis in cells of liver cancer.

Droplet based microfluidics: spectroscopic characterization of levofloxacin and its SERS detection

The determination of the absorption behavior of levofloxacin (levaquin) on the surface of silver nanoparticles and its determination in aqueous solution by droplet based microfluidics combined with surface enhanced Raman spectroscopy.

Two-dimensional Raman correlation spectroscopy reveals molecular structural changes during temperature-induced self-healing in polymers based on the Diels–Alder reaction

For the first time two-dimensional Raman correlation analysis has been used to study self-healing polymers based on the Diels–Alder reaction.

Spectrometer calibration protocol for Raman spectra recorded with different excitation wavelengths

The combination of Raman spectroscopy with chemometrics has gained significant importance within the last years to address a broad variety of biomedical and life science questions. However, the routine application of chemometric models to analyze Raman spectra recorded with Raman devices different from the device used to establish the model is extremely challenging due to Raman device specific influences on the recorded Raman spectra. Here we report on the influence of different non-resonant excitation wavelengths on Raman spectra and propose a calibration routine, which corrects for the main part of the spectral differences between Raman spectra recorded with different (non-resonant) excitation wavelengths. The calibration routine introduced within this contribution is an improvement to the known 'standard' calibration routines and is a starting point for the development of a calibration protocol to generate spectrometer independent Raman spectra. The presented routine ensures that a chemometric model utilizes only Raman information of the sample and not artifacts from small shifts in the excitation wavelength. This is crucial for the application of Raman-spectroscopy in real-world-settings, such as diagnostics of diseases or identification of bacteria.

The effect of silver thickness on the enhancement of polymer based SERS substrates

We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films.

The evolution of personality in patients with mild cognitive impairment

AIMS

To describe personality traits and their changes in mild cognitive impairment (MCI) and control subjects.

METHODS

Sixty-three MCI and 90 control subjects were asked to describe their current personality traits by the Structured Interview for the Five-Factor Model (SIFFM). For each subject, a close relative retrospectively assessed these descriptions both as to the previous and current personality traits, using the Revised NEO Personality Inventory, Form R (NEO-PI-R).

RESULTS

Self-assessed MCI subjects reported significantly lower scores in the openness dimension than control subjects [F(1, 150) = 9.84, p = 0.002, ηp(2) = 0.06]. In current observer ratings, MCI subjects had higher scores on neuroticism [F(1, 137) = 7.55, p = 0.007, ηp(2) = 0.05] and lower ones on extraversion [F(1, 137) = 6.40, p = 0.013, ηp(2) = 0.04], openness [F(1, 137) = 9.93, p = 0.002, ηp(2) = 0.07], agreeableness [F(1, 137) = 10.18, p = 0.002, ηp(2) = 0.07] and conscientiousness [F(1, 137) = 25.96, p < 0.001, ηp(2) = 0.16]. Previous personality traits discriminated the groups as previous openness [odds ratio (OR) = 0.97, 95% confidence interval (CI) = 0.95-0.99, p = 0.014] and conscientiousness (OR = 0.96, 95% CI 0.94-0.98, p = 0.001) were negatively related to MCI group membership. In MCI subjects, conscientiousness [F(1, 137) = 19.20, p < 0.001, ηp(2) = 0.12] and extraversion [F(1, 137) = 22.27, p < 0.001, ηp(2) = 0.14] decreased between previous and current evaluations and neuroticism increased [F(1, 137) = 22.23, p < 0.001, ηp(2) = 0.14], whereas no significant change was found in control subjects.

CONCLUSIONS

MCI subjects undergo significant personality changes. Thus, personality assessment may aid the early detection of dementia.

Phytoaccumulation potentials of two biotechnologically propagated ecotypes of Arundo donax in copper-contaminated synthetic wastewater

An in vitro experiment was carried out to evaluate the phytoremediation potentials of two somatic embryo-derived ecotypes of Arundo donax-BL (American ecotype) and 20SZ (Hungarian ecotype)-of copper from synthetic wastewater. The two ecotypes were grown under sterile conditions in tubes containing a nutrient solution supplied with increasing doses of Cu (0, 1, 2, 3, 5, 10, and 26.8 mg L(-1)) for 6 weeks. The translocation and bioaccumulation factors and removal rate were estimated. In general, increasing Cu concentration in nutrient solution slightly decreased root, stem and leaf biomass without toxicity symptoms up to 26.8 mg L(-1). Moreover, both ecotypes showed high Cu removal efficiency from aqueous solution. However, Cu removal rate ranged between 96.6 to 98.8% for BL ecotype and 97 to 100% for 20SZ ecotype. Data illustrated that both BL and 20SZ ecotypes may be employed to treat Cu-contaminated water bodies up to 26.8 mg L(-1).

Phytoaccumulation potentials of two biotechnologically propagated ecotypes of Arundo donax in copper-contaminated synthetic wastewater

An in vitro experiment was carried out to evaluate the phytoremediation potentials of two somatic embryo-derived ecotypes of Arundo donax-BL (American ecotype) and 20SZ (Hungarian ecotype)-of copper from synthetic wastewater. The two ecotypes were grown under sterile conditions in tubes containing a nutrient solution supplied with increasing doses of Cu (0, 1, 2, 3, 5, 10, and 26.8 mg L(-1)) for 6 weeks. The translocation and bioaccumulation factors and removal rate were estimated. In general, increasing Cu concentration in nutrient solution slightly decreased root, stem and leaf biomass without toxicity symptoms up to 26.8 mg L(-1). Moreover, both ecotypes showed high Cu removal efficiency from aqueous solution. However, Cu removal rate ranged between 96.6 to 98.8% for BL ecotype and 97 to 100% for 20SZ ecotype. Data illustrated that both BL and 20SZ ecotypes may be employed to treat Cu-contaminated water bodies up to 26.8 mg L(-1).

Deeper understanding of biological tissue: quantitative correlation of MALDI-TOF and Raman imaging

In order to achieve a comprehensive description of biological tissue, spectral information about proteins, lipids, nucleic acids, and other biochemical components need to be obtained concurrently. Different analytical techniques may be combined to record complementary information of the same sample. Established techniques, which can be utilized to elucidate the biochemistry of tissue samples are, for instance, MALDI-TOF-MS and Raman microscopic imaging. With this contribution, we combine these two techniques for the first time. The combination of both techniques allows the utilization and interpretation of complementary information (i.e., the information about the protein composition derived from the Raman spectra with data of the lipids analyzed by the MALDI-TOF measurements). Furthermore, we demonstrate how spectral information from MALDI-TOF experiments can be utilized to interpret Raman spectra.

[Traumatic dissection of the carotid artery: challenges for diagnostics and therapy illustrated by a case example]

Traumatic dissection of the carotid artery is an easily overlooked consequence of trauma with notable morbidity and mortality which can be observed in up to 4% of cases involving multiple trauma. Certain mechanisms and patterns of injury as well as specific symptoms should serve as indicators of a dissection and should therefore result in further diagnostic measures. An early diagnosis is of major relevance. This report describes the case of a 45-year-old victim of a traffic accident who showed symptoms of a dissection which had initially not been diagnosed.

Spectroscopic detection and quantification of heme and heme degradation products

Heme and heme degradation products play critical roles in numerous biological phenomena which until now have only been partially understood. One reason for this is the very low concentrations at which free heme, its complexes and the partly unstable degradation products occur in living cells. Therefore, powerful and specific detection methods are needed. In this contribution, the potential of nondestructive Raman spectroscopy for the detection, quantification and discrimination of heme and heme degradation products is investigated. Resonance Raman spectroscopy using different excitation wavelengths (413, 476, 532, and 752 nm) is employed to estimate the limit of detection for hemin, myoglobin, biliverdin, and bilirubin. Concentrations in the low micromolar range (down to 3 μmol/L) could be reliably detected when utilizing the resonance enhancement effect. Furthermore, a systematic study on the surface-enhanced Raman spectroscopy (SERS) detection of hemin in the presence of other cellular components, such as the highly similar cytochrome c, DNA, and the important antioxidant glutathione, is presented. A microfluidic device was used to reproducibly create a segmented flow of aqueous droplets and oil compartments. Those aqueous droplets acted as model chambers where the analytes have to compete for the colloid. With the help of statistical analysis, it was possible to detect and differentiate the pure substances as well as the binary mixtures and gain insights into their interaction.