Raman and surface‐enhanced Raman scattering in the study of human rotator cuff tissues after shock wave treatment

Important improvements of diseases of the rotator cuff supraspinatus tendons are seen after shock wave (SW) treatment. Neo‐angiogenesis stimulation and hypercellularization result from short periods of treatment. The present work is an attempt to provide a first approach to these bioprocesses, most likely associated with structural aspects resulting from biochemical changes brought about by the SW. Immunohistochemical data indicate that collagen areas in the tissues are influenced the most by the SW. Presence of additional collagens I and III by the SW treatment is inferred from an observed increase of the tissue's tinctorial properties. The tools selected for our studies are Raman spectroscopy and the ultrasensitive surface‐enhanced Raman scattering (SERS). Here we extract information from 1016 SERS spectra of 52 biopsies of human tendon tissues on Ag nanoparticles before and after the SW treatment. The spectral information is analyzed on the basis of Raman and SERS data of collagen types I and III and their most abundant amino acid components. SERS spectra of tissues reveal the presence of characteristic modes related mainly to amino acids. It has been found that the main differences between both tissue samples could be correlated with the structural conformational aspects of collagen. Copyright © 2011 John Wiley & Sons, Ltd.     

长波紫外辐射对Ⅰ型胶原损伤的拉曼光谱研究

应用拉曼光谱技术研究了长波紫外(Ultraviolet-A,UV-A)辐射对Ⅰ型胶原的损伤,检测了Ⅰ型胶原及其经过90min的UV-A辐射后的拉曼光谱,得到了一个较完整的Ⅰ型胶原紫外损伤机制。实验结果表明:90min的UV-A辐射导致Ⅰ型胶原分子内氢键断裂、氢键体系发生变化,肽链的螺旋度减少,逐渐解螺旋,无规卷曲等无序构象增加。此外,UV-A辐射使Ⅰ型胶原分子内脯氨酸的羟基化程度降低。这些变化必然会引起Ⅰ型胶原三螺旋结构的损伤,并导致皮肤光老化过程中组织内胶原纤维的破坏。     

Characterisation of structural changes in collagen with Raman spectroscopy

Raman spectroscopy can detect conformational changes in collagen structures and these findings are reviewed in this article. More specifically, some progressive diseases are mainly caused by alterations of collagen molecules but what is occurring at the biochemical level of this complex molecule usually remains unclear. While it may be true that a number of analytical techniques can analyze collagen, most of them have a series of limitations that limit their applicability to a wide range of samples. To understand in more detail the progression of a disease due to changes in the collagen structure, a technique that can detect subtle alterations at the biochemical level is needed. Raman spectroscopy is a label-free and noninvasive technique that can easily pick up on any conformational changes reflected primarily at the lipids, amides and proline and hydroxyproline regions. This review is the first compilation of studies of conformational changes in collagen molecules, providing help to understand changes in collagen biochemistry that can be of relevance to the human wound healing, ageing and pathologies.     

Comparative Raman spectroscopic analysis of orientation in fibers and regenerated films of Bombyx mori silk fibroin

This study is focused on the Raman spectroscopic analysis of degummed silk fibroin (SF) fibers and regenerated Bombyx mori silk fibroin films: a correlation was found between some spectral features related to the methylene deformation modes and the molecular orientation of the samples. Polarized Raman spectra on SF fibers were used to obtain the orientation distribution function of carbonyl groups along the protein backbone. The variation of the intensity ratio of 1400/1450 cm⁻¹ for the peaks attributed to the wagging and bending deformation modes of CH₂ groups with respect to the angular orientation of the fiber was measured and quantitatively correlated with the orientation distribution function of the carbonyl groups. Unpolarized Raman spectra were measured for regenerated silk fibroin films and lyophilized solutions. The variation of the intensity ratio of 1415/1455 cm⁻¹, which is related to the deformation modes of CH₂ groups in SF regenerated materials, was qualitatively related to the microstructural orientation of the samples observed by scanning electron microscopy (SEM), and to the presence of Silk I phase as suggested by the analysis of samples obtained in different casting conditions and also by the measurements on mechanically deformed films. The results obtained showed the utility of the spectroscopic intensity ratio of 1400/1450 cm⁻¹ for the rapid assessment of molecular orientation in silk fibers, which could be useful for quality and process control of regenerated silk‐based textiles. Moreover, the qualitative dependence of the intensity ratio of 1415/1455 cm⁻¹ was found to be sensitive to both the microstructural orientation and Silk I content of regenerated silk fibroin films, suggesting a possible correlation of this Raman marker of the Silk I phase with the degree of molecular order brought about by this polymorph. Copyright © 2006 John Wiley & Sons, Ltd.     

Thermal,spectroscopic and structural characterization of isostructural phase transition in 4-hydroxybenzaldehyde

Polycrystalline samples of 4-hydroxybenzaldehyde (4-HOBAL) were investigated using differential scanning calorimeter (DSC), Raman spectroscopy and X-ray powder diffraction. The DSC data indicated that 4-HOBAL on heating undergoes a polymorphic transformation from polymorph I to polymorph II. The polymorph II formed remains metastable at ambient condition and transforms to polymorph I when annealed at ambient temperature for more than seven days. The structural information of polymorphs I and II obtained using its X-ray powder diffraction patterns indicated that 4-HOBAL undergoes an isostructural phase transition from polymorph I (monoclinic, P2₁/c) to polymorph II (monoclinic, P2₁/c). Raman data suggest that this structural change is associated with some change in its molecular interactions. Thus, in 4-HOBAL the polymorphic phase transformation (II to I) even though energetically favoured is kinetically hindered.     

Age-induced phase transitions on mechanically alloyed amorphous GaSe

After aging it for four years at room temperature, a mechanically alloyed amorphous GaSe powder was transformed to a multi-phase crystalline alloy, where major phase is the trigonal Se one. The structural, thermal and optical properties of this aged amorphous GaSe were investigated through systematic X-ray diffraction, differential scanning calorimetry and Raman scattering measurements. The X-ray diffraction results on the aged GaSe powder suggest the presence of oxides, and X-ray absorption spectroscopy was employed to further investigate it.     

Optical clearing of skin tissue ex vivo with polyethylene glycol

Alterations of the optical and structural (weight, thickness, and square) parameters of skin caused by polyethylene glycol (PEG) with molecular weights of 300 and 400 Da were studied experimentally. The objects of the study were ex vivo skin samples of albino laboratory rats. Collimated transmittance of the skin was measured in the wavelength range 500-900 nm. As a result of exposure to the agents, an increase in the collimated transmittance and a decrease in weight, thickness, and square of skin samples were observed. Analysis of the kinetics of parameters alterations allowed us to measure the diffusion coefficient of the agents in the skin as (1.83 ± 2.22) × 10^-6 and (1.70 ± 1.47) × 10^-6 cm²/s for PEG-300 and PEG-400, respectively, and the rate of alterations of the structural parameters. The results obtained in this study can be used for the improvement of existing and development of new methods of noninvasive diagnostics and therapy of subcutaneous diseases.     

高功率毫米波辐照对小鼠皮肤组织拉曼光谱的影响

运用显微激光拉曼仪测定了正常小鼠离体皮肤0～300 μm不同深度的拉曼光谱。实验还测定了8 mm辐照一定时间后小鼠受辐照皮肤组织的拉曼光谱。实验结果表明毫米波辐照后皮肤拉曼光谱峰位857,936,1 658 cm-1的相对强度随着辐照时间的增加而减少。这表明由于毫米波热效应皮肤组织中的胶原蛋白构象发生了改变甚至分解,从而进一步表明皮肤组织受到了不可恢复的损伤。     

基于拉曼光谱鉴定黑色签字笔笔迹的种类与书写时间

黑色签字笔字迹种类与书写时间的鉴定一直是国内外法庭科学研究领域的热点问题。基于拉曼光谱法的分辨率高、稳定性好、效率高以及无损检测等优点,对收集的16种品牌或牌号的黑色签字笔字迹样本进行测试。完成同一品牌或牌号同一时间在不同存储条件(暗室和光照)与不同纸张本底(复印纸和笔记本)字迹样本的制备。将样本字迹剪裁,双面胶固定在载玻片上,放入储存箱内避光保存,间隔一段时间对样品进行测试,测试工作共持续1年,形成图谱数据库。在考察实验条件如测量点、激光功率及共焦类型等因素影响的基础上,筛选出最佳条件。在此条件基础上,检测黑色签字笔在不同书写时间、储存环境、纸张本底等条件下的字迹样本。实验结果表明:(1)存储条件(暗室和光照)、纸张本底(复印纸和笔记本)等不同条件下,同种黑色签字笔字迹的拉曼位移相同,重复性好,受水和纸张等本底的干扰较小。(2)根据拉曼位移的差异可将16种黑色签字笔分成5类。(3)以2#样本为例, 1 140 cm^-1处拉曼光谱特征峰,归属为酯类化合物的C-O伸缩振动ν(CO)。酯类化合物的含量随着时间延长而不断减少,因此随着书写时间越久远,特征峰的相对强度越大(8→1)。通过拟合后计算出相对面积数值I,样本书写时间越早,I值越大,反之I值越小。研究结果可用于快速、准确、无损判定黑色签字笔字迹的种类和推断其相对书写时间。     

Preparation of nanocone ZnO thin film and its aging effect of photoluminescence

In this work, a nanocone ZnO thin film was prepared by electron beam evaporation on a Si (1 0 0) substrate. The structural properties of the film were investigated by X-ray diffraction (XRD), atomic force microscopy and laser Raman scattering, respectively. The aging effect of the nanocone ZnO thin film was studied by photoluminescence spectra. The structural analyses show that the prepared ZnO thin film has a hexagonal wurtzite structure and is preferentially oriented along the c-axis perpendicular to the substrate surface. The photoluminescence spectra show that with the increase of aging time, the green emission of the nanocone ZnO thin film gradually decreases while the ultraviolet emission somewhat increases. The reason for this phenomenon is likely that the green-emission-related oxygen vacancies in the film are gradually filled up. The Raman scattering analyses also suggest that the intensity of the Raman peak related to oxygen vacancies in the nanocone ZnO thin film declines after the film is aged in air for a year. Therefore, the authors think the green emission is mainly connected with oxygen vacancy defects.     

Raman spectroscopy reveals differences in collagen secondary structure which relate to the levels of mineralisation in bones that have evolved for different functions

Bone is a composite material comprising a collagen fibril scaffold surrounded by crystals of carbonated‐hydroxyapatite mineral. It is well established that the relative proportions of mineral and collagen in mature bone are not definite and are adapted in order to ‘tune’ its mechanical properties. It is not known, however, how the mineral to collagen ratio is controlled. This paper uses Raman spectroscopy (which permits the probing of both the mineral and the collagen phases of bone) to explore the hypothesis that the control mechanism is related to the nature of the collagen and that bones with different levels of mineralisation have qualitatively different collagen. Raman spectra of functionally adapted bones with varying levels of mineralisation are presented and features that indicate the differences in the collagen's secondary structure (amide I band profiles) and post‐translational modification (hydroxyproline/proline ratios) are highlighted. The study demonstrates that Raman spectroscopy can provide a means to investigate the mechanisms that control the mineral to collagen ratio of bone. Understanding these mechanisms could pave the way towards the therapeutic alteration of the mineral to collagen ratio and, thus, the control of the mechanical properties of bone. Copyright © 2012 John Wiley & Sons, Ltd.     

由荧光和反射光谱研究胶原蛋白与抗坏血酸对老化肌肤的吸收速率和治疗效果

胶原蛋白是皮肤组织中的结构性蛋白,其数量和健康关系到外表皱纹的生成与皮肤的老化现象;而抗坏血酸有良好的美白与抗氧化能力,可使肌肤外表更白皙亮丽和保持健康。由于胶原蛋白具有自体荧光,因此我们提出一个藉由皮肤光谱来检验胶原蛋白含量的方法,此检测法更具实时性与非侵入性。本研究使用胶原蛋白和抗坏血酸,涂抹于健康的、与有斑点、皱纹等问题的肌肤,以其荧光与反射光谱随时间的变化,归纳出胶原蛋白与抗坏血酸对不同部位肌肤的吸收难易与修复疗效。结果显示,皮肤会对适当浓度的胶原蛋白或抗坏血酸之吸收效果较佳;加上适当浓度的抗坏血酸,胶原蛋白可被有效吸收同时产生良好的除皱效果;而抗坏血酸之去斑效果也在此研究中明确证实。藉由此一系列科学性的实验,可确实验证美容保养品的作用,帮助爱美人士对化妆保养品的正确选择与正确使用,发挥最好的疗效。     

Self‐assembly and structure formation in liquid crystalline phthalocyanine thin films studied by Raman spectroscopy and AFM

This work presents an investigation of films prepared by doctor blade casting, the formation of self‐assembled microstructures of a liquid crystalline phthalocyanine with highly oriented molecules. Raman Spectroscopy in combination with atomic force microscopy is applied to study the structures within the films. By keeping the substrate at room temperature or at 353 K during coating, different geometric structures namely rods and islands form. Rod‐like structures are growing in coating direction, whereas directional growth of the islands is not observed. The distribution of the rod lengths varies widely, whereas the width appears more uniform. Annealing of the samples shows a different behavior of the two textures. Islands tend to melt, and rods smooth their structural form, which is extracted from Raman imaging in combination with atomic force microscopy. Additionally, Raman imaging gives insight into laterally different relative crystallinity. These observations are discussed in the context of the molecular orientation as probed by polarized Raman spectroscopy. These polarized Raman spectra indicate azimuthal alignment of the molecules within the rods (edge on alignment). This alignment occurs along and also perpendicular to the growth direction. In contrast to the alignment in the rods, the molecules inside the islands occurring at higher temperature do not show preferential molecular orientation. After annealing, no preferential molecular orientation is observed in rods because of the loss of anisotropy, too. Copyright © 2012 John Wiley & Sons, Ltd.     

便携式拉曼光谱仪用于合成大麻素类物质快速定性分析探究

我国于2021年7月将合成大麻素类物质整类列入管制,在一线查缉现场对疑似合成大麻素样品进行快速定性分析是办案民警的迫切需求。研究系统考察了拉曼光谱对合成大麻素的整体区分能力,比较了四款手持式拉曼光谱仪分析实际缴获样品时的结果差异,探讨了制约拉曼光谱在一线查缉现场广泛应用的原因。ProTT-EZRaman-A7便携式拉曼光谱仪的整体性能介于台式拉曼和手持式拉曼之间,选用该仪器采集了90种合成大麻素对照品的拉曼光谱,并利用兼容性强的KnowItAll软件建立了90种合成大麻素通用拉曼光谱库。分析90种合成大麻素的拉曼光谱,结果表明,当不存在荧光干扰时,拉曼光谱可以区分所有合成大麻素物质,但对部分结构相差一个甲基、卤素原子等的结构类似物区分度欠佳。不同款拉曼光谱仪的性能差异大,为考察其原因,本研究选用了四款手持式拉曼光谱仪分别对120份实际缴获合成大麻素样品进行了测定,随后使用KnowItAll软件并选用包含90种合成大麻素的通用拉曼光谱库对每张光谱图进行谱库检索。四款手持式拉曼光谱仪的正确匹配率分别为71.7%, 68.3%, 46.7%和24.2%。抗荧光干扰能力和分辨率的不同是造成不同...     

Micro Raman spectroscopy for monitoring alterations between human skin keratinocytes HaCaT and their tumorigenic derivatives A5RT3—toward a Raman characterization of a skin carcinoma model

Raman scattering provides molecular information about biochemical differences between healthy and cancerous cells in a non‐invasive and non‐destructive fashion. We have monitored such changes for the human skin keratinocyte cell line HaCaT and its cancerogenic counterpart A5RT3 at 514.5 and 647 nm excitations, with either fixed‐cell droplets or adherent fixed and living cells for repeated preparations over time in order to discriminate intrinsic characteristic changes. Cell droplets yielded average but rather reproducible information and helped to rapidly determine such changes. The Raman spectra show differences in the relative intensity ratios of the protein amide I band at 1656 cm⁻¹ and amide III bands around 1250 cm⁻¹ and of the phenylalanine ring mode at 1003.6 cm⁻¹ to the CH₂ deformation band at 1448 cm⁻¹, which are considerably greater for HaCaT cells than A5RT3 cells. Interestingly, these observations were accompanied by severe and consistent changes in the amide III region and in the collagen marker region around 936 cm⁻¹, therefore providing an unambiguous evidence of protein degradation and changes in the essential amino acid phenylalanine and in the lipid components in tumorigenic A5RT3 cells. Ultimately, in light of these intrinsic changes, the present findings are consistent with the passage number of the non‐tumorigenic HaCaT cells, because low pass HaCaT showed less pronounced alterations than high pass HaCaT, suggesting a correlation of tumorigenic transformation with primarily genetic instabilities in HaCaT cells. This work represents the first Raman spectroscopy discrimination of the skin carcinoma model cell lines, the non‐tumorigenic HaCaT and the cancerous A5RT3 cells, addressing the importance of delineating nonspecific variations from intrinsic characteristic changes and giving a spectroscopic indication for the influence of the passage number of HaCaT cells on the tumorigenic development. Copyright © 2009 John Wiley & Sons, Ltd.     

FTIR analysis of natural and synthetic collagen

Collagen is the most abundant protein in humans and animals, comprising of one third of the total proteins that accounts for three quarters of the dry weight skin in humans. Collagen containing a range of proteins has been reported for tissue engineering applications, but, only a small number of studies related to chemical structure evaluation of collagen are found in the literature. Collagen can be obtained from both the natural and synthetic sources and offers a wide range of biomedical applications due to its excellent biocompatibility and low immunogenicity. Hence, it is important to identify chemical structural properties of collagen and Fourier transform infrared (FTIR) appears to be a technique of choice to study their chemical structure. This review aims to highlight the use of FTIR to study collagen-based biomaterials, using it for characterization of collagen extracted from various sources. Characterization of collagen-based materials used in wound healing, skin substitutes, derma fillers, and aging of skin, collagen containing drug delivery agents, collagen-based materials used in tissue engineering, bone regeneration, and osteogenic differentiation is discussed in detail. FTIR analysis of collagen-containing materials used for dental applications, cleft-palate, and in alveolar-ridge preservation has also been highlighted.     

拉曼光谱和色差法在丝质文物色彩损伤评估中的比较

丝质文物是博物馆内的重要藏品之一,具有极高的文化、艺术、历史价值。作为一种性质不稳定的蛋白质有机构成材料,丝质文物极易受到光学辐射而发生泛黄等色彩损伤,尤其是在Light Emitting Diode(LED)得到广泛应用的博物馆光环境中。如何针对馆藏丝质文物色彩损伤进行科学评估是本研究要解决的主要问题。色差评估法是分析博物馆照明对文物色彩损伤的有效手段,但是存在相应的局限性,无法对色彩损伤的诱导期进行评估。由于文物发生色彩损伤的根本原因在于材料内部分子结构发生光化学反应,理论上说,从微观分子层面研究的拉曼光谱法能够更加科学地评估丝质文物色彩损伤。本研究将拉曼光谱引入博物馆照明领域,对比色差评估结果验证拉曼光谱色彩损伤评估的可行性和科学性。通过构成四基色LED的450, 510, 583和650 nm四种窄带光对丝质样品开展长周期照射实验,分别以CIE L*a*b*色差和拉曼光谱作为评估指标,计算得到基于两种评估方法的不同窄带光对丝质文物的色彩相对损伤系数,分别为450 nm∶510 nm∶583 nm∶650 nm=1.00∶0.63∶0.48∶0.32和450 nm∶510 nm∶583 nm∶650 nm=1.00∶0.69∶0.47∶0.27。结果一方面表明,两种方法得到的四种窄带光对丝质文物的色彩损伤趋势是一致的,即450 nm>510 nm>583 nm>650 nm,波长越短对丝质文物的色彩损伤程度越大,说明拉曼光谱是一种能够量化评估丝质文物色彩损伤的可行方法;另一方面表明,基于拉曼参数计算的色彩相对损伤系数的比例差异更大。丝质样品的老化过程中存在诱导期。色差法难以分析丝质样品诱导期的色彩变化,而拉曼光谱分析则可灵敏地检测出相应的分子结构变化,包括诱导期。因此,拉曼光谱法能够对丝质文物的色彩损伤进行更加科学地评估。同时,研究得到的构成LED光谱的四种窄带光对丝质文物色彩相对损伤系数,可以为这类光源在丝质文物照明中的损伤度评估和博物馆准入评估提供依据。     

A stable ‘sandwich’ system of Surface‐Enhanced Resonance Raman Scattering for the analysis of β‐carotenes in a photosynthetic pigment‐protein complex

In plants, Photosystem I (PSI) is composed of a core complex and a membrane‐associated antenna complex light‐harvesting complex I that captures light and funnels its energy to the core complex. To obtain Raman structural information on β‐carotenes embedded in the PSI core complex, a ‘sandwich’ system of roughened silver slice: target protein complexes: single silver nanoparticles was fabricated for Surface‐Enhanced Resonance Raman Scattering (SERRS) measurements. This study provided a method to overcome spectral irreproducibility, which is the main drawback of Surface‐Enhanced Raman Scattering/SERRS‐based studies. The Raman spectra of β‐carotenes embedded in the PSI core complex can be obtained at very low sample concentrations (1–5 µg Chl/ml) and high signal/noise ratios. The β‐carotenes in the spinach PSI core complex were predominantly all‐trans configuration. The membrane protein‐mediated adsorption of silver nanoparticles induced the uniform distribution of a large number of single nanoparticles, which contributed to achieving highly reproducible SERRS spectra. This study is the first to apply single silver nanoparticle‐based SERRS analysis in membrane proteins. Copyright © 2013 John Wiley & Sons, Ltd.     

Specific heat related to the Raman frequency shifts for the rotatory mode in ammonia solid I close to the melting point

This study gives an evidence for the validity of our spectroscopic modification of the Pippard relation as applied to ammonia solid I close to the melting point. We use our calculated frequencies for the rotatory lattice (librational) mode in ammonia solid I for the pressures of 0, 1.93 and 3.07 kbars. We obtain that the specific heat C_p varies linearly with the frequency shifts 1/ν(∂ν/∂T)_p for this Raman mode at those pressures studied in this crystalline system. Our values of the slope dP_m/dT that we deduced from the linear plots, are not in satisfactory agreement with the experimental values in ammonia solid I near the melting point.     

油纸绝缘老化状态判别的拉曼光谱特征研究

获取能准确反映油纸绝缘老化的有效特征量,对实现油纸绝缘老化的准确诊断具有重要意义。表面增强拉曼光谱技术在油纸绝缘老化诊断领域已表现出一定的应用潜力。对25#矿物变压器油和普通牛皮纸构成的油纸绝缘试品进行了加速热老化实验,结合共聚焦拉曼光谱检测平台和银纳米片表面增强基底获取其拉曼光谱信号,从多种角度提取了拉曼光谱特征量。使用竞争性自适应重加权算法在提取出光谱的关键变量,其结果对应了油纸绝缘老化特征物的主要特征峰;使用VOIGT函数对光谱进行解析,解析峰的轮廓参数与油纸绝缘老化程度之间呈现相关性;以绝缘纸聚合度为依据将样本进行老化程度分类,光谱的前8个主成分及其载荷不仅与老化特征物和老化程度呈现相关性,且能够对样本进行准确分类;最后对光谱进行了小波包能量熵分析,分析了油纸绝缘老化过程中拉曼光谱的能量变化情况。研究成果为表面增强拉曼光谱技术应用于油纸绝缘老化诊断提供了依据,为实现油纸绝缘设备故障与老化状态的快速、非接触的现场诊断奠定了基础。