共查询到19条相似文献,搜索用时 171 毫秒
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菁染料是一种商品化的近红外荧光染料, 其光谱范围位于近红外区域, 此光谱区域内生物基体光吸收或荧光强度较小, 因此利用菁染料对生物体进行成像, 可以降低背景干扰. 吲哚七甲川菁染料是一类具有代表性的菁染料, 其由吲哚杂环、七甲川链和N-取代基侧链组成, 由于具有溶解性好, 最大吸收波长可调, 摩尔消光系数大等优良的光学性质, 被广泛用于肿瘤靶向治疗、蛋白标记、痕量金属离子检测等生物方面. 以吲哚七甲川为母体, 通过向母体中引入活性基团或改变它们的结构, 使探针具有不同的功能, 这已成为生物领域荧光成像的研究热点. 分别从检测金属阳离子、pH变化、小分子和靶向标记肿瘤细胞、蛋白质等方面综述了近年来用于生物体荧光成像的吲哚七甲川类荧光探针的研究进展, 其中也对荧光探针在生物体内(模型)分布、光学成像及代谢方面进行了介绍, 最后讨论了这类荧光探针存在的问题及发展趋势. 相似文献
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近红外荧光生物成像技术由于具有深的组织穿透性、低背景荧光干扰、最小生物样本光损伤等特点引起人们越来越多的关注。开发高荧光效率、低毒性的近红外荧光染料是近红外荧光成像技术发展的关键所在。本文综述了五类主要的有机近红外荧光染料(菁类、BODIPY类、罗丹明类、方酸类、卟啉类)的研究进展,重点分析其结构与光学性质等构效关系,为近红外荧光染料的设计和制备提供指导。另外,总结了有机近红外荧光材料功能化修饰的主要方法以改善生物相容性、靶向性能等,最后对近红外荧光染料存在的主要问题以及未来的热点方向进行了分析和展望。 相似文献
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《影像科学与光化学》2021,39(4)
吲哚菁绿(ICG)是一种阳离子型花菁类染料,具有毒性低、亲和力高、荧光发射位于近红外区等优点。因此,作为一种可临床使用的近红外有机荧光染料,其已被广泛应用于生物成像、疾病诊断等领域。本文从吲哚菁绿的临床应用和肿瘤诊断治疗展开论述,通过实例全面介绍ICG的相关信息。 相似文献
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Chun-Lin Sun Qing Liao Ting Li Jun Li Jian-Qiao Jiang Zhen-Zhen Xu Xue-Dong Wang Rong Shen De-Cheng Bai Qiang Wang Sheng-Xiang Zhang Hong-Bing Fu Hao-Li Zhang 《Chemical science》2015,6(1):761-769
Small organic dyes with large two-photon absorption (TPA) cross sections (δ) are more desirable in many applications compared with large molecules. Herein, we proposed a facile theoretical method for the fast screening of small organic molecules as potential TPA dyes. This method is based on a theoretical analysis to the natural transition orbitals (NTOs) directly associated with the TPA transition. Experimental results on the small indolic squaraine dyes (ISD) confirmed that their TPA cross sections is strongly correlated to the delocalization degree of the NTOs of the S2 excited states. Aided by this simple and intuitive method, we have successfully designed and synthesized a small indolic squaraine dye (ISD) with a remarkable δ value above 8000 GM at 780 nm. The ISD dye also exhibits a high singlet oxygen generation quantum yield about 0.90. The rationally designed TPA dye was successfully applied in both two-photon excited fluorescence cell imaging and in vivo cerebrovascular blood fluid tracing. 相似文献
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With an objective to develop β‐amyloid destabilizing agents, we have investigated the interactions of a few water‐soluble near‐infrared (NIR)‐absorbing squaraine dyes 1 – 3 with lysozyme and its amyloid aggregates through photophysical and biophysical techniques. These dyes exhibited strong interactions with lysozyme and β‐amyloids in addition to serum albumins as evidenced by the absorption and emission changes. The interactions were found to be spontaneous with association constant values in the range of approximately 104–105 m ?1, as confirmed through half‐reciprocal analysis and isothermal calorimetric measurements. Uniquely, such effective interactions of the dyes have led to the complete disassembly of the β‐amyloid fibrillar structures to form spherical particles approximately 350 nm in size, as confirmed through photophysical, thioflavin assay, circular dichroism (CD), atomic force microscopy (AFM), TEM, and selected‐area electron diffraction (SAED) techniques. These results demonstrate that the squaraine dyes 1 – 3 under investigation act as effective protein‐labelling and destabilizing agents of the protein amyloidogenesis. 相似文献
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Srinivas K Prabhakar Ch Devi CL Yesudas K Bhanuprakash K Rao VJ 《The journal of physical chemistry. A》2007,111(17):3378-3386
We apply many criteria to estimate the diradical character of the ground state singlets of several oxyallyl derivatives. This is carried out as the oxyallyl derivatives like squaraine and croconate dyes can be represented by both mesoionic and diradical formulas, the domination of which would characterize its lowest energy transition. One criterion applied is the singlet-triplet gap, which is known to be inversely proportional to the diradical character. Another criterion is the occupation number; this is determined for the symmetry broken state of the molecules in the unrestricted formalism, and the difference of occupation in the HOMO and LUMO is related to the diradical character. The diradical character of all of the croconates and few squaraines is estimated to be large. All of these have absorption above 750 nm and can be classified as near infrared (NIR) dyes, leading to the inference that NIR absorptions in these molecules are largely due to the dominance of the diradical character. To understand the reliability of the DFT methods for the absorption property predictions of these molecules, TD-DFT studies to calculate the vertical excitation energies have been carried out, using the B3LYP/ BLYP exchange correlation functionals and the LB94 asymptotic functional with and without the inclusion of solvent. The deviations, in both the squaraine series (average lower diradical character), are found to be systematic, and with the inclusion of the solvent in the calculation, the deviations decrease. The best least-squares fit with the experimentally observed values using B3LYP /6-311G(d, p) for the symmetric squaraines yields an R value of 0.92 and, for the unsymmetric squaraines, an R value of 0.936. With inclusion of the solvent, the R value is 0.96 for the symmetric squaraines and 0.961 for the unsymmetric squaraines, indicating that these DFT functionals with linear scaling may be used to study these systems. The croconate dyes, however, have larger deviation from the experimentally observed values in all of the functionals studied even after inclusion of the solvent effects. The deviations are also not systematic. The deviation with respect to the experiment in this case is attributed to the average larger diradical character in this series. 相似文献
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Arthur Turkin Dr. Marco Holzapfel Mohit Agarwal David Fischermeier Prof. Dr. Roland Mitric Dr. Ralf Schweins Prof. Dr. Franziska Gröhn Prof. Dr. Christoph Lambert 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(32):8380-8389
A protecting group strategy was employed to synthesise a series of indolenine squaraine dye oligomers up to the nonamer. The longer oligomers show a distinct solvent dependence of the absorption spectra, that is, either a strong blue shift or a strong red shift of the lowest energy bands in the near infrared spectral region. This behaviour is explained by exciton coupling theory as being due to H- or J-type coupling of transition moments. The H-type coupling is a consequence of a helix folding in solvents with a small Hansen dispersity index. DOSY NMR, small angle neutron scattering (SANS), quantum chemical and force field calculations agree upon a helix structure with an unusually large pitch and open voids that are filled with solvent molecules, thereby forming a kind of clathrate. The thermodynamic parameters of the folding process were determined by temperature dependent optical absorption spectra. 相似文献
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The sensitization properties of two squaraine dyes adsorbed onto the van der Waals surface of n-doped tin disulfide single crystals were studied using atomic force microscopy (AFM), vis-NIR absorption spectroscopy, and photoelectrochemical techniques. Quantum yield per absorbed photon (QYAP) values of near unity were observed for submonolayer coverages of 2,4-bis(4-(N-methyl-N-hexylamino)phenyl)squaraine (1-6SQ) in aqueous electrolyte when a sufficiently positive bias was applied, demonstrating the advantages of SnS(2) as a photoanode for fundamental studies of dye sensitization. Islandlike and microcrystalline morphologies, associated with aggregate formation and revealed by AFM, could be correlated with spectral shifts in both the absorbance and photoaction spectra. A related dye, 2,4-bis(4-(N,N-dimethyl)-2-hydroxyphenyl)squaraine (1-1OHSQ), at similar coverages showed slightly lower QYAP, ascribed to a recombination path due to the different aggregate structures. 相似文献
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Cosmin Butnarasu Carlotta Pontremoli Maria Jesus Moran Plata Nadia Barbero Sonja Visentin 《Photochemistry and photobiology》2023,99(2):562-569
Mucins are a family of long polymeric glycoproteins which can be overexpressed in several types of cancers, and over recent years, great attention was addressed to identify mucins as an important biomarker of adverse prognosis. Fluorometric detection mediated by fluorescent probes could represent a winning strategy in the early diagnosis of different pathologies. Among promising biological fluorescent probes, squaraines are gaining particular attention, thanks to their sharp and intense absorption and emission in the NIR region. In this contribution, three squaraine dyes bearing different substituents and with different lipophilicity have been investigated for their ability to detect mucin. The turn-on response upon the addition of mucin has been investigated by means of absorbance and fluorescence spectroscopy. After a preliminary screening, the squaraine (S6) bearing bromine as a substituent and C4 aliphatic chains showed the highest fluorescence turn-on and highest affinity for mucin than albumin. To further highlight the selectivity of S6 for mucin, the fluorescence response has been evaluated in the presence of serum and site-specific proteins different than albumin. Absorption spectroscopy was used to characterize the binding mechanism of squaraine to mucin. 相似文献
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A squaraine rotaxane endoperoxide with a truncated squaraine chromophore undergoes a cycloreversion reaction and emits green light that can be transferred to red acceptor dyes. The results demonstrate that chemiluminescence emission for squaraine rotaxane endoperoxides comes from the excited squaraine inside the rotaxane. 相似文献
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The sensitivity of contactless conductivity detection to amino acids, peptides and proteins in CE was studied for BGE solutions of different pH values. The LOD and analytical characteristics were compared for acidic and basic conditions and better results were in most cases found for buffers of low pH values. Linear dynamic ranges varied between two orders of magnitude for amino acids and peptides and three orders of magnitude for larger proteins. The concentration detection limits were found to be between 1.2 and 7.5 microM for the amino acids tested and for the larger molecules they varied between 2.6 microM for leucine enkephalin and 0.2 microM for HSA when using a buffer at pH 2.1. 相似文献
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Chemically converted graphene (CCG) was found to greatly enhance the fluorescence response of squaraine (SQ) dyes to bovine serum albumin (BSA). Addition of BSA to the SQ-CCG solution, where squaraine dyes absorbed on the CCG surface, raised the fluorescence intensity by as much as 80 fold. 相似文献