Fourier Transform Infrared Spectroscopy of Skin Cancer Cells and Tissues

Abstract

The aim of this review is to combine all the information related to the characterization of skin tissues and cells, focusing on the identification of the specific biochemical characteristics of skin cancer. We have characterized two types of melanoma by FTIR spectroscopy: a murine melanoma (B16F10 cell line) and a human melanoma (C8161 cell line). The cells were deposited on IR transparent CaF₂ windows, the spectral range used lay between 900-4000 cm^{? 1}, transmission mode with 2 cm^{? 1} resolution, and 32 scans. A biochemical association is presented for all the absorption bands identified in this study. Besides the characterization of both cell lines above, a collection of works done in the area of skin cancer was also carried out, in this review; some interesting results obtained by different authors with respect to the characterization of different samples (melanomas, follicle sheath, basal cell carcinoma, epidermis tissues, dermis tissue, and human stratum corneum) are presented and compared to the chemical and biological associations performed in each case. The identification of biochemical injuries provides important information that, associated with clinical examination, can assist the diagnosis of diseases. Several FTIR techniques can be used in the diagnosis of biochemical changes in biological tissues, by identifying molecular markers associated with malignant and benign changes or variations in the composition of amino acids in tissues and cells. In the near future, a further study to compare histopatological analysis and biochemical characterization by FTIR spectroscopy would be interesting, in order to verify the accuracy and validate the applicability of this technique in the diagnosis of skin lesions from a statistical viewpoint.     

Isotropic Raman spectra of liquid (isotope) mixtures: Intermolecular coupling of vibrational modes

The theory presented in this paper investigates the isotropic Raman spectra of liquid binary mixtures. It is found that the collective vibrational modes of different molecular species can be significantly coupled. This is a consequence of the (nearly) resonant vibrational transfer processes, which give rise to distinct vibrational correlations (i.e. correlations between adjacent molecules). The coupling, however, occurs only with weakly-separated or overlapping bands. The more general results of the theory are applied to isotope mixtures. The spectral information available from relevant dilution experiments is interpreted. In particular it is shown that the spectral properties of the vibrational self-correlation part can be concluded from the observed collective correlation function. The significance of the distinct vibrational correlations with respect to the infrared and depolarized Raman spectra is discussed.     

Optical Observation of Lung Cancer With Attenuated Total Reflectance–Fourier Transform Infrared Microscope (ATR-FTIR) and Confocal Raman Microscope

ABSTRACT

Optical observation of lung cancer tissues using attenuated total reflectance–Fourier transform infrared microscope (ATR-FTIR) and confocal Raman microscope were performed. A total of six malignant tissues, seven tissues adjacent to cancer, and nine normal tissues from nine patients with known lung cancer were studied. High-quality spectra from human tissues were obtained only in a few seconds. The results revealed that some of the spectral characteristics varied significantly between normal and malignant tissues, that is, IR peak positions, Raman shift, and the spectral intensities. Differences in positions of 10 main peaks in IR shifts and 13 main peaks in Raman shifts were listed, and the intensity changes were also studied between the malignant and normal tissues. The ratios of 1453-cm^?1/1645-cm^?1 intensity in IR spectrum and 1245-cm^?1/1571-cm^?1 intensity in Raman spectrum were found with the most significant difference (p < 0.0001 and p < 0.05 separately) in statistics and may be used in combination to differentiate the normal and malignant tissues. ATR-FTIR spectrum and Raman spectrum were mutually complementary in the observation of many materials and were both found with high sensitivities and spatial resolutions in the observation of human tissues. This study will be helpful to developing rapid and accurate cancer detection techniques in future clinical diagnosis.     

Application of FTIR Spectroscopy for Identification of Blood and Leukemia Biomarkers: A Review over the Past 15 Years

Abstract

Fourier transform infrared (FTIR) spectroscopy is an effective and nondestructive method for monitoring cellular alterations. Combining the advantages of FTIR spectroscopy with the challenge of cellular characterization, the main objective of this review is to collect information related to the spectroscopic identification of blood cells, focusing on specific biochemical features of leukemia cells detected through FTIR spectral analysis. Some interesting results obtained by different authors regarding human promyelocytic leukemia, white blood cells, chronic lymphocytic leukemia, and human peripheral blood mononuclear cells are presented. In addition, the characterization of two types of cells, namely, leukemia T and a healthy human blood cells, is reported and the identification of biochemical markers provides important information that, associated with clinical examination, can assist in the diagnosis of diseases.     

Raman Spectroscopy of Biological Tissues

Abstract

We previously published a comprehensive review paper reviewing the Raman spectroscopy of biological molecules. This research area has expanded rapidly, which warranted an update to the existing review paper by adding the recently reported studies in literature. This article reviews some of the recent advances of Raman spectroscopy in relation to biomedical applications starting from natural tissues to cancer biology. Raman spectroscopy, an optical molecular detective, is a vibrational spectroscopic technique that has potential not only in cancer diagnosis but also in understanding progression of the disease. This article summarizes some of the most widely observed peak frequencies and their assignments. The aim of this review is to develop a database of molecular fingerprints, which will facilitate researchers in identifying the chemical structure of the biological tissues including most of the significant peaks reported both in the normal and cancerous tissues. It has covered a variety of Raman approaches and its quantitative and qualitative biochemical information. In addition, it covers the use of Raman spectroscopy to analyse a variety of different malignancies including breast, brain, cervical, gastrointestinal, lung, oral, and skin cancer. Multivariate analysis approaches used in these studies have also been covered.     

Correlation of monomer structures of tripalmitin with the spectroscopic fingerprint of polymorphs: infrared,Raman, and DFT study

In the light of application of vibrational spectroscopy in medical diagnosis, it is necessary to have a tool to distinguish between different lipids that may be present in biochemical samples such as cells and tissues. One of the most common lipids in the human body are triglycerides. Therefore, the aim of this work was to investigate the model triglyceride, namely tripalmitin in order to find the differences between the vibrational signatures of its polymorphs and interpret them with the help of quantum‐chemical computations. Although monomeric models are not sufficient to reproduce polymorphs structure, analysis of these models is very helpful in understanding of relations between the structure and changes in vibrational spectra. Copyright © 2012 John Wiley & Sons, Ltd.     

Molecular Force Field of Methanol

Abstract

Normal coordinate analysis was carried out on the vapor phase Raman and i.r. spectral data of methanol and its deuterated species to determine a vibrational force field. Based on the results of calculations, the 25-parameter molecular force field was analyzed and compared with the earlier studies and the vibrational band assignments were discussed in terms of the vibrational mode mixings, particularly, in the wavenumber region below 1500 cm^?1.     

Vibrational Spectroscopy as a Promising Tool to Study Enzyme-Carrier Interactions: A Review

Abstract

The high selectivity and specificity together with the catalytic activity of enzymes lead them to be a key tool in biotechnology industries. The enzyme immobilization on a carrier material facilitates the reuse of the enzyme and improves its stability. This article is a comprehensive review that reports papers in which different enzymes have been immobilized on distinct carrier materials and enzyme-carrier interactions were evaluated by infrared and/or Raman spectroscopy. Vibrational spectroscopy was used to inspect the spectral bands of different classes of enzymes before and after their immobilization on carriers. In fact, the characteristic spectral bands that prove the interaction enzyme-carrier are related with the amide functional groups of enzymes. In addition, those interactions are characterized by the shift, broadening, or increment on intensity of specific bands in reference to the spectrum of their carrier material. In this review, 20 of these studies used infrared spectroscopy and only three used Raman spectroscopy. The use of both vibrational spectroscopy techniques is increasingly due to their proved capacity to characterize the enzyme-carrier interactions without damaging them.     

Near-Infrared Spectroscopy of Organic Substances

Abstract

The near-infrared spectral region is generally defined as the wavelength range from 700 nm to about 2500 nm, although there is considerable variation in wavelength ranges of the different instrument types. The absorption bands in this region are due to overtones and combinations of the fundamental mid-IR molecular vibration bands. The energy transitions are between the ground state and the second or third excited vibrational states. Because higher energy transitions are successively less likely to occur, each overtone is successively weaker in intensity. Since the energy required to reach a second o r third level excited.     

Oxygenated hemoglobin diffuse reflectance ratio for in vitro detection of human gastric pre-cancer

Oxygenated hemoglobin diffuse reflectance (DR) ratio (R540/R575) method based on DR spectral signatures is used for early diagnosis of malignant lesions of human gastric epithelial tissues in vitro. The DR spectra for four different kinds of gastric epithelial tissues were measured using a spectrometer with an integrating sphere detector in the spectral range from 400 to 650 nm. The results of measurement showed that the average DR spectral intensity for the epithelial tissues of normal stomach is higher than that for the epithelial tissues of chronic and malignant stomach and that for the epithelial tissues of chronic gastric ulcer is higher than that for the epithelial tissues of malignant stomach. The average DR spectra for four different kinds of gastric epithelial tissues show dips at 542 and 577 nm owing to absorption from oxygenated Hemoglobin (HbO₂). The differences in the mean R540/R575 ratios of HbO₂ bands are 6.84% between the epithelial tissues of normal stomach and chronic gastric ulcer, 14.7% between the epithelial tissues of normal stomach and poorly differentiated gastric adenocarcinoma and 22.6% between the epithelial tissues of normal stomach and undifferentiated gastric adenocarcinoma. It is evident from results that there were significant differences in the mean R540/R575 ratios of HbO₂ bands for four different kinds of gastric epithelial tissues in vitro (P < 0.01).     

Raman spectral properties of squamous cell carcinoma of oral tissues and cells

Early diagnosis is the key of the improved survival rates of oral cancer. Raman spectroscopy is sensitive to the early changes of molecular composition and structure that occur in benign lesion during carcinogenesis. In this study, in situ Raman analysis provided distinct spectra that can be used to discriminate between normal and malignant tissues, as well as normal and cancer cells. The biochemical variations between different groups were analyzed by the characteristic bands by comparing the normalized mean spectra. Spectral profiles of normal, malignant conditions show pronounced differences between one another, and multiple Raman markers associated with DNA and protein vibrational modes have been identified that exhibit excellent discrimination power for cancer sample identification. Statistical analyses of the Raman data and classification using principal component analysis (PCA) are shown to be effective for the Raman spectral diagnosis of oral mucosal diseases. The results indicate that the biomolecular differences between normal and malignant conditions are more obviously at the cellular level. This technique could provide a research foundation for the Raman spectral diagnosis of oral mucosal diseases.     

窄带快照式多光谱成像色彩还原方法

由于兼具光谱分辨和空间分辨能力, 快照式窄带多光谱成像在资源遥感、精准农业、医疗检测等领域将有广泛应用。由于该方法使用窄带成像来提高光谱分辨率及图像对比度,所获得的图像是灰度信息,失去了场景的色彩信息,不便专家对图像鉴别、评价与赏析。已有的色彩还原算法主要针对光谱波段带宽较宽或者多个波段叠加基本覆盖整个可见光谱范围等两种光谱成像仪,不适合窄带多光谱成像方法的色彩还原。该研究适合于快照式窄带多光谱成像的色彩还原方法,提出建立窄带多光谱彩色相机的概念。首先,提出两种窄带多光谱色彩还原方法：(1)基于CIE色度系统三刺激值色的,(2)基于贝尔阵列插值算法的;其次,分别应用两种算法还原快照式窄带多光谱相机所获得的植物、手臂及宫颈组织等三种代表性场景窄带多光谱灰度图像;之后,计算并比较表征两种算法所得的代表性场景彩色图像的均值、方差、熵及梯度等表征图像质量的参数数值,确定出适合快照式窄带多光谱成像的色彩还原方法;最后,对所确定的色彩还原算法进行色偏校正。实验结果表明,基于CIE三刺激值色彩还原方法比贝尔阵列插值法更适用于窄带多光谱成像颜色复原。配合使用CIE三刺激值色彩还原方法及灰度图象校正算法,从窄带光谱成像所获得的植物、手臂皮肤及宫颈组织的灰度图像所还原出的近彩色图像逼近物体真实色彩,满足人眼观察习惯。介绍了仅覆盖可见光光谱范围30%的窄带多光谱图像进行色彩还原的方法,该方法证明快照式窄带多光谱成像可以兼具光谱分辨能力,同时保持可供人主观辨识的色彩信息。所提出实现快照式窄带多光谱彩色成像的方法,有望设计不同于传统RGB相机的彩色相机实施方案。     

Accelerated metallic artifact reduction imaging using spectral bin modulation of multiacquisition variable-resonance image combination selective imaging

ObjectivesTo assess the clinical utility of a prototype sequence for metal artifact reduction, the multiacquisition variable–resonance image combination selective (MAVRIC-SL) at 3 T. This sequence allows a surgical prosthesis-dependent reduction in the number of spectral bins. We compared the prototype MAVRIC SL to the conventional two-dimensional fast spin-echo (FSE) sequences and MAVRIC SL images acquired with all spectral bins to those acquired with the optimized number of spectral bins.MethodsMAVRIC SL images were acquired in 25 image sets from August 2017 to April 2018. For each subject, the optimized number of spectral bins was determined using a short spectral calibration scan. The image sets obtained with magnetic resonance imaging that were used for the analysis consisted of MAVRIC-SL proton density (PD)-weighted or short inversion time inversion recovery (STIR) images acquired with all 24 spectral bins, the corresponding images with the optimized number of spectral bins, and the conventional two-dimensional FSE or STIR PD-weighted images. A musculoskeletal radiologist reviewed and scored the images using a five-point scale for artifact reduction around the prosthesis and visualization of the prosthesis and peri-prosthetic tissues. Quantitative evaluation of the peri-prosthetic tissues was also performed. The Wilcoxon rank-sum test was used to test for significance.ResultsThe MAVRIC SL images enabled a significantly improved reduction in metallic artifacts compared to the conventional two-dimensional FSE sequences. The optimized number of spectral bins ranged from 6 to 20, depending on the prosthesis susceptibility difference, size, and orientation to the B₀ field. The scan times significantly decreased with a reduced number of spectral bins (354.0 ± 139.1 versus 283.0 ± 89.6 s; 20% reduced scan time; p < .05). Compared to the MAVRIC SL images acquired with all 24 bins, the artifact reduction and visualization of the prosthesis and peri-prosthetic tissues on the MAVRIC SL images acquired with calibrated bins were not significantly different.ConclusionsCompared to the MAVRIC SL images acquired with all 24 spectral bins, those acquired with an optimized number of spectral bins can reduce metallic artifacts with no significant image quality degradation while providing reduced scan time.     

Detection of wave aberrations in the human eye using a retinoscopy-like technique

The influence of optical aberrations on the retinoscopic reflex is theoretically analyzed from a geometrical point of view. The relationship between the wave aberrations to the ray aberrations is applied to explain the appearance of the retinoscopic patterns for different types of ocular aberrations. Several schematic models of the human eye are tested numerically, showing that a careful retinoscopic examination can detect the usual eye aberrations.     

A wavefront aberrometer for dynamic high-order aberration measurement

This research studied the dynamic aberration of human eyes at near vision. A wavefront aberrometer was developed based on the Hartmann-Shack theory. This aberrometer can achieve dynamical aberration measurement of the human eye. The Aberrometer induces ocular accommodation by a moving target at near vision, and records the vision information of human eyes simultaneously during ocular accommodation process using a Hartmann-Shack sensor. Nineteen eyes of 10 volunteers are tested. Eighty-four percent eyes have induced accommodation amplitude between 3 diopter (D) and 8D. The highest induced accommodation amplitude is 8.6D. The aberrometer produces results with high precision and repeatability, i.e. an accuracy root-mean-square (RMS) of 1/50^λ and a repeatability RMS of 1/500^λ.     

Spectroscopy of Molecular Ions

Abstract

Traditionally, molecular ions have been studied by mass spectrometers or ion-counting techniques. The great sensitivity and versatility of these techniques are clearly attested to by the vast amount of mass spectrometric literature. However, it is equally true that mass spectroscopy has its limitations; basically, it provides one only with a charge-to-mass ratio for an ion. Obviously, all quantum state information is lost, particularly the vibrational and rotational, and usually even the electronic distributions of the ions. Similarly, no structural information such as bond lengths and angles is obtained. Indeed, in some cases the information obtained is so slight that one cannot even write a structural formula for the ion or distinguish between different chemical isomers.     

Laser Raman Investigation of Solid State Reactions

Abstract

Traditionally, molecular ions have been studied by mass spectrometers or ion-counting techniques. The great sensitivity and versatility of these techniques are clearly attested to by the vast amount of mass spectrometric literature. However, it is equally true that mass spectroscopy has its limitations; basically, it provides one only with a charge-to-mass ratio for an ion. Obviously, all quantum state information is lost, particularly the vibrational and rotational, and usually even the electronic distributions of the ions. Similarly, no structural information such as bond lengths and angles is obtained. Indeed, in some cases the information obtained is so slight that one cannot even write a structural formula for the ion or distinguish between different chemical isomers.     

Optical Diagnosis for Thyroid and Parathyroid Tissues—A Review

Abstract

This article presents an overview of optical methodologies to aid the diagnosis and differentiation of thyroid and parathyroid tissues. In particular, we review the several techniques and associated methodologies that allow in vivo and ex vivo optical characterization of thyroid and parathyroid tissues. Emphasis is placed on the research potential of these techniques and whether intrinsic characteristics can provide useful contrast for the diagnosis of human thyroid and parathyroid malignant lesions.     

Spectral unmixing combined with Raman imaging,a preferable analytic technique for molecule visualization

This article reviews spectral unmixing used as a new method for Raman imaging. Raman spectroscopy explores the vibrational information about specific chemical bonds in molecules, which can be used for label-free molecular visualization. However, chemical bonds are usually shared among different molecules, which results in closed or mixed Raman peaks of many molecules. Therefore, the acquired spectra cannot be directly used to reconstruct the Raman images, as pure component spectra are hidden under the acquired spectra. Spectral unmixing is an effective method to provide a meaningful spectrum of each component with no priori spectral information and to also reconstruct the compositional distribution images. This article summarizes some representative spectral unmixing approaches used for Raman imaging and many related researches. This review strives to introduce the combination of spectral unmixing and Raman imaging as an efficient analytic technique to characterize various constituents and make subtle understanding of those complex structures.     

Submillimeter measurements of isotopes of nitric acid

The ground and low-lying vibrational states of nitric acid are observable with current instrumentation in the Earth’s thermal submillimeter atmospheric emission. Remote sensing continues to improve to higher sensitivity and future missions will allow these measurements with minimal integration time. Sensing of weaker spectral features will require signal averaging, and choices of spectral windows for these features will require knowledge of the higher vibrational states and rare isotopes of the strongly emitting species. Nearly comprehensive information on vibrational states and isotopically substituted species is now available from wide bandwidth scans of natural and isotopically enriched nitric acid. In this work, ground state rotational spectra of five isotopically substituted species of nitric acid are analyzed in the submillimeter spectral range. We present the Hamiltonian parameters necessary for prediction and identification of isotopic features across the nitric acid ground state rotational spectrum.