Methods and Applications in Fluorescence最新文献_第10页

A novel AIEE active anti-B18H22 derivative-based Cu2+ and Fe3+ fluorescence off-on-off sensor 一种新型AIEE活性抗B18H22衍生物Cu2+和Fe3+荧光开关传感器

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-28 DOI: 10.1088/2050-6120/ac6b88

Linli Xiong, Yong Zheng, Haibo Wang, Jiangyang Yan, Xuguang Huang, Hongyun Meng, Chunhua Tan

A novel fluorescence sensor for successive detection of Cu2+ and Fe3+ based on anti-B18H22 derivative which possesses 5-hydroxyisoquinoline as an ionophore was synthesized via a one-pot and its structure and photophysical properties were characterized by NMR, HRMS, FTIR, UV–vis, PL and theoretical calculation. The fluorophore displays two emission peaks at 460 nm and 670 nm in THF solution coming from the emission of the locally excited state and intramolecular charge transfer fluorescence, respectively. The complex exhibited obvious aggregation-induced emission enhancement (AIEE) characteristics in THF/H2O solution by increasing the aqueous concentration from 70% to 95%. The AIEE molecules showed a high selectivity towards Cu2+ over other metal ions by forming a 2:1 metal-to-ligand complex in THF/H2O (fw = 20%) solution, the fluorescence intensity increased as a linear function of the Cu2+ concentration at 460 nm due to the inhibition of PET effect. The fluorescent emission was quenched linearly by the addition of Fe3+, which provides a method for successive determination of Cu2+ and Fe3+ based on ‘off-on-off’ fluorescence of the fluorescent. The detection limit of Cu2+ and Fe3+ was 5.7 × 10−6 M and 7.2 × 10−5 M respectively. Morever, a rapid identification of Cu2+ in the aqueous solution by naked eyes can be realized. In addition, the molecules were pH-sensitive, the fluorescence quenching can be observed in strongly alkaline environment. The method has been applied to the determination of copper ions in water samples with satisfactory results.

以5-羟基异喹啉为离子载体的抗B18H22衍生物为基础，通过一锅法合成了一种新的连续检测Cu2+和Fe3+的荧光传感器，并用NMR、HRMS、FTIR、UV–vis、PL和理论计算对其结构和光物理性质进行了表征。荧光团在THF溶液中分别在460nm和670nm处显示出两个发射峰，分别来自局部激发态和分子内电荷转移荧光的发射。当水溶液浓度从70%提高到95%时，复合物在THF/H2O溶液中表现出明显的聚集诱导发射增强（AIEE）特性。通过在THF/H2O（fw=20%）溶液中形成2:1的金属-配体络合物，AIEE分子对Cu2+表现出比其他金属离子高的选择性，由于PET效应的抑制，荧光强度在460nm处作为Cu2+浓度的线性函数而增加。通过添加Fe3+线性猝灭荧光发射，这提供了一种基于荧光的“断断续续”荧光连续测定Cu2+和Fe3+的方法。Cu2+和Fe3+的检出限分别为5.7×10−6M和7.2×10−5M。此外，还可以实现用肉眼快速鉴定水溶液中的Cu2+。此外，分子对pH敏感，在强碱性环境中可以观察到荧光猝灭。该方法已用于水样中铜离子的测定，结果令人满意。

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引用次数: 3

Review on long afterglow nanophosphors, their mechanism and its application in round-the-clock working photocatalysis 综述了长余辉纳米荧光粉及其机理及其在全天候工作光催化中的应用

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-28 DOI: 10.1088/2050-6120/ac6b87

Dipti Bidwai, Niroj Kumar Sahu, S. J. Dhoble, Ashutosh Mahajan, D. Haranath, G. Swati

Semiconductor assisted photocatalysis is one of the most efficient methods for the degradation of complex organic dyes. A major limiting factor of semiconductor assisted photocatalysis is the requirement of a continuous source of light to perform a redox reaction. One of the upcoming solutions is photon energy-storing long afterglow/persistent phosphors. They are an unusual kind of rechargeable, photon energy capturing/trapping phosphors that can trap charge carriers (electrons/holes) in their meta-stable energy levels, thereby resulting in persistent luminescence. Persistence luminescence from such materials can range from minutes to hours. The coupling of long afterglow phosphors (LAP) with the conventional semiconductor is a promising way to support the photocatalytic process even in dark. In addition, dissimilar band structures of LAPs and semiconductor results in formation of heterojunction which further suppresses the recombination of charge. Such an encouraging idea of LAP for round-the-clock working photocatalytic system is in its premature stage; which is required to be investigated fully. Thus, we present a state-of-art review on the potential materials for assisting round-the-clock photocatalysis, trapping-detrapping mechanism in LAP materials, fabrication strategies and their associated characterization tools. Review also covers LAP materials and their photocatalytic mechanism briefly.

半导体辅助光催化是降解复杂有机染料最有效的方法之一。半导体辅助光催化的一个主要限制因素是需要连续光源来进行氧化还原反应。即将到来的解决方案之一是储存光子能量的长余辉/持久荧光粉。它们是一种不寻常的可充电光子能量捕获/捕获磷光体，可以将电荷载流子（电子/空穴）捕获在其亚稳定能级，从而产生持久发光。这种材料的持久发光可以在几分钟到几小时的范围内。长余辉磷光体（LAP）与传统半导体的耦合是一种很有前途的方法，即使在黑暗中也能支持光催化过程。此外，LAP和半导体的不同能带结构导致异质结的形成，这进一步抑制了电荷的复合。LAP用于全天候工作的光催化系统的这种令人鼓舞的想法还处于早期阶段；这需要进行充分的研究。因此，我们对有助于全天候光催化的潜在材料、LAP材料中的捕获-去捕获机制、制造策略及其相关表征工具进行了综述。综述还简要介绍了LAP材料及其光催化机理。

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引用次数: 2

Simultaneous effects of synthesis temperature and dopants on MgWO4 UC phosphors 合成温度和掺杂剂对MgWO4-UC荧光粉的同时影响

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-26 DOI: 10.1088/2050-6120/ac6ab7

M. Prasad, V. K. Rai

A sequence of coactivated divalent-metal tungstate Er3+/Yb3+/Mn4+: MgWO4 phosphors have been successfully developed to study the effect of synthesis temperature on the crystal structure, surface morphology, fluorescence, temperature sensing and the dynamics involved in the processes. Upconversion (UC) intensity of the Er3+/Yb3+: MgWO4 phosphors increased by ∼109 and ∼778 times on increasing the synthesis temperature from 800 °C to 1000 °C and 1200 °C. UC intensity of the Er3+/Yb3+/Mn4+: MgWO4 phosphors has been significantly improved up to ∼90 times via charge compensation. The incorporation of Mn4+ in the Er3+/Yb3+ codoped crystal system shifted the UC spectra from sharp green peaks to broadband emission along with amended sensing abilities. The ratiometric techniques of thermally coupled stark sublevels of the Er3+ have been used to achieve a wide temperature range (300–623 K). The prepared nanophosphors show maximum absolute & relative sensitivities ∼25.86 × 10−3 K−1 @453 K and ∼10.39 × 10−3 K−1 @303 K respectively with an accuracy of ±0.42 K@303 K.

成功地开发了一系列共活化的二价金属钨酸盐Er3+/Yb3+/Mn4+:MgWO4荧光粉，研究了合成温度对晶体结构、表面形貌、荧光、温度传感和过程动力学的影响。当合成温度从800°C增加到1000°C和1200°C时，Er3+/Yb3+:MgWO4磷光体的上转换（UC）强度增加了～109和～778倍。通过电荷补偿，Er3+/Yb3+/Mn4+:MgWO4磷光体的UC强度显著提高了~90倍。Mn4+在Er3+/Yb3+共掺杂晶体系统中的掺入使UC光谱从尖锐的绿色峰值转变为宽带发射，同时提高了传感能力。Er3+的热耦合斯塔克亚能级的比率测量技术已被用于实现宽温度范围（300–623 K）。制备的纳米磷光体在453 K下显示出最大绝对和相对灵敏度～25.86×10−3 K−1和～10.39×10−3K−1，在303 K下的精度为±0.42 K。

引用次数: 7

Thienoguanosine brightness in DNA duplexes is governed by the localization of its ππ* excitation in the lowest energy absorption band DNA双链体中Thienoguanosine的亮度由其ππ*激发在最低能量吸收带的定位决定

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-26 DOI: 10.1088/2050-6120/ac6ab6

Stefano Ciaco, Krishna Gavvala, V. Greiner, Viola Mazzoleni, P. Didier, M. Ruff, L. Martínez-Fernández, R. Improta, Y. Mély

Thienoguanosine (thG) is an isomorphic fluorescent guanosine (G) surrogate, which almost perfectly mimics the natural G in DNA duplexes and may therefore be used to sensitively investigate for example protein-induced local conformational changes. To fully exploit the information given by the probe, we carefully re-investigated the thG spectroscopic properties in 12-bp duplexes, when the Set and Ring Associated (SRA) domain of UHRF1 flips its 5′ flanking methylcytosine (mC). The SRA-induced flipping of mC was found to strongly increase the fluorescence intensity of thG, but this increase was much larger when thG was flanked in 3′ by a C residue as compared to an A residue. Surprisingly, the quantum yield and fluorescence lifetime values of thG were nearly constant, regardless of the presence of SRA and the nature of the 3′ flanking residue, suggesting that the differences in fluorescence intensities might be related to changes in absorption properties. We evidenced that thG lowest energy absorption band in the duplexes can be deconvoluted into two bands peaking at ∼350 nm and ∼310 nm, respectively red-shifted and blue-shifted, compared to the spectrum of thG monomer. Using quantum mechanical calculations, we attributed the former to a nearly pure ππ* excitation localized on thG and the latter to excited states with charge transfer character. The amplitude of thG red-shifted band strongly increased when its 3′ flanking C residue was replaced by an A residue in the free duplex, or when its 5′ flanking mC residue was flipped by SRA. As only the species associated with the red-shifted band were found to be emissive, the highly unusual finding of this work is that the brightness of thG in free duplexes as well as its changes on SRA-induced mC flipping almost entirely depend on the relative population and/or absorption coefficient of the red-shifted absorbing species.

Thienoguanosine（thG）是一种同构的荧光鸟苷（G）替代物，它几乎完全模拟DNA双链体中的天然G，因此可以用于敏感地研究例如蛋白质诱导的局部构象变化。为了充分利用探针提供的信息，我们仔细地重新研究了当UHRF1的集环相关（SRA）结构域翻转其5′侧翼甲基胞嘧啶（mC）时，12bp双链体中的thG光谱性质。发现SRA诱导的mC翻转强烈增加了thG的荧光强度，但与a残基相比，当thG在3′侧有C残基时，这种增加要大得多。令人惊讶的是，无论SRA的存在和3′侧翼残基的性质如何，thG的量子产率和荧光寿命值几乎恒定，这表明荧光强度的差异可能与吸收性质的变化有关。我们证明，与thG单体的光谱相比，双链体中的thG最低能量吸收带可以去卷积为峰值在~350nm和~310nm的两个带，分别为红移和蓝移。利用量子力学计算，我们将前者归因于位于thG上的几乎纯ππ*激发，而后者归因于具有电荷转移特性的激发态。当其3′侧的C残基在自由双链中被A残基取代时，或当其5′侧的mC残基被SRA翻转时，thG红移带的幅度强烈增加。由于只有与红移带相关的物种被发现是发射的，这项工作的极不寻常的发现是，自由双链体中thG的亮度及其在SRA诱导的mC翻转上的变化几乎完全取决于红移吸收物种的相对种群和/或吸收系数。

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引用次数: 2

Recent advances in near infrared upconverting nanomaterials for targeted photodynamic therapy of cancer 用于癌症靶向光动力学治疗的近红外上转换纳米材料的最新进展

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-21 DOI: 10.1088/2050-6120/ac6937

Carla Arnau del Valle, T. Hirsch, María J. Marín

Photodynamic therapy (PDT) is a well-established treatment of cancer that uses the toxic reactive oxygen species, including singlet oxygen (1O2), generated by photosensitiser (PS) drugs following irradiation of a specific wavelength to destroy the cancerous cells and tumours. Visible light is commonly used as the excitation source in PDT, which is not ideal for cancer treatment due to its reduced tissue penetration, and thus inefficiency to treat deep-lying tumours. Additionally, these wavelengths exhibit elevated autofluorescence background from the biological tissues which hinders optical biomedical imaging. An alternative to UV–Vis irradiation is the use of near infrared (NIR) excitation for PDT. This can be achieved using upconverting nanoparticles (UCNPs) functionalised with photosensitiser drugs where UCNPs can be used as an indirect excitation source for the activation of PS drugs yielding to the production of singlet 1O2 following NIR excitation. The use of nanoparticles for PDT is also beneficial due to their tumour targeting capability, either passively via the enhanced permeability and retention (EPR) effect or actively via stimuli-responsive targeting and ligand-mediated targeting (i.e. using recognition units that can bind specific receptors only present or overexpressed on tumour cells). Here, we review recent advances in NIR upconverting nanomaterials for PDT of cancer with a clear distinction between those reported nanoparticles that could potentially target the tumour due to accumulation via the EPR effect (passive targeting) and nanoparticle-based systems that contain targeting agents with the aim of actively target the tumour via a molecular recognition process.

光动力疗法(PDT)是一种成熟的癌症治疗方法，它使用有毒的活性氧，包括单线态氧(1O2)，由光敏剂(PS)药物在特定波长照射后产生，以破坏癌细胞和肿瘤。可见光通常用作PDT的激发源，由于其组织穿透性降低，因此对深部肿瘤的治疗效率低下，因此不适合用于癌症治疗。此外，这些波长表现出来自生物组织的升高的自身荧光背景，这阻碍了光学生物医学成像。紫外-可见照射的另一种选择是使用近红外(NIR)激发进行PDT。这可以通过使用光敏剂药物功能化的上转换纳米颗粒(UCNPs)来实现，其中UCNPs可以用作近红外激发后产生单线态1O2的PS药物激活的间接激发源。纳米颗粒用于PDT也是有益的，因为它们的肿瘤靶向能力，无论是被动地通过增强的渗透性和保留(EPR)效应，还是主动地通过刺激反应靶向和配体介导的靶向(即使用识别单元，可以结合特异性受体仅存在或过度表达在肿瘤细胞上)。在这里，我们回顾了用于癌症PDT的近红外上转换纳米材料的最新进展，并明确区分了那些由于EPR效应(被动靶向)的积累而可能潜在靶向肿瘤的纳米颗粒和基于纳米颗粒的靶向剂，其目的是通过分子识别过程主动靶向肿瘤。

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引用次数: 6

Fluorescent cysteine probe based on a signal amplification unit, a catalyzed hairpin assembly reaction and Förster resonance energy transfer 荧光半胱氨酸探针基于一个信号放大单元，催化发夹组装反应和Förster共振能量转移

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-20 DOI: 10.1088/2050-6120/ac6664

Sirirat Ouiganon, Chongdee Thammakhet-Buranachai, P. Thavarungkul, P. Kanatharana, C. Buranachai

This work developed a sensitive DNA-based fluorescent probe comprising a cysteine binding unit and a signal amplification unit based on a catalyzed hairpin assembly (CHA) reaction. The cysteine binding unit comprises a homodimer of single-stranded DNA (ssDNA) rich in cytosine and held together by silver ions. In the presence of cysteine, the homodimer is disintegrated because of cysteine-silver binding that liberates the ssDNA, which drives the CHA reaction in the signal amplification unit. Förster resonance energy transfer (FRET) was used to report the generation of the amplified double-stranded DNA (dsDNA) product. Under the optimal conditions, the probe provided a good linearity (100–1200 nM), a good detection limit (47.8 ± 2.7 nM) and quantification limit (159.3 ± 5.3 nM), and a good sensitivity (1.900 ± 0.045 μM−1). The probe was then used to detect cysteine in nine real food supplement samples. All results provided good recoveries that are acceptable by the AOAC, indicating that it has potential for practical applications.

这项工作开发了一种基于DNA的敏感荧光探针，该探针包括半胱氨酸结合单元和基于催化发夹组装（CHA）反应的信号放大单元。半胱氨酸结合单元包括富含胞嘧啶并通过银离子结合在一起的单链DNA（ssDNA）的同源二聚体。在半胱氨酸存在的情况下，同源二聚体由于半胱氨酸-银结合而分解，从而释放ssDNA，从而驱动信号放大单元中的CHA反应。Förster共振能量转移（FRET）用于报道扩增的双链DNA（dsDNA）产物的产生。在最佳条件下，该探针具有良好的线性（100–1200 nM）、良好的检测限（47.8±2.7 nM）和定量限（159.3±5.3 nM），以及良好的灵敏度（1.900±0.045μM−1）。随后，该探针被用于检测九个真实食品补充剂样品中的半胱氨酸。所有结果都提供了AOAC可接受的良好回收率，表明它具有实际应用的潜力。

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引用次数: 0

Phasor-based multi-harmonic unmixing for in-vivo hyperspectral imaging 基于相量的体内高光谱成像多谐波分解

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-04-01 DOI: 10.1101/2022.03.31.486485

A. Vallmitjana, Paola Lepanto, F. Irigoín, Leonel Malacrida

Hyperspectral imaging (HSI) is a paramount technique in biomedical science, however, unmixing and quantification of each spectral component is a challenging task. Traditional unmixing relies on algorithms that need spectroscopic parameters from the fluorescent species in the sample. The phasor-based multi-harmonic unmixing method requires only the empirical measurement of the pure species to compute the pixel-wise photon fraction of every spectral component. Using simulations, we demonstrate the feasibility of the approach for up to 5 components and explore the use of adding a 6th unknown component representing autofluorescence. The simulations show that the method can be successfully used in typical confocal imaging experiments (with pixel photon counts between 101 and 103). As a proof of concept, we tested the method in living cells, using 5 common commercial dyes for organelle labeling and we easily and accurately separate them. Finally, we challenged the method by introducing a solvatochromic probe, 6-Dodecanoyl-N,N-dimethyl-2-naphthylamine (LAURDAN), intended to measure membrane dynamics on specific subcellular membrane-bound organelles by taking advantage of the linear combination between the organelle probes and LAURDAN. We succeeded in monitoring the membrane order in the Golgi apparatus, Mitochondria, and plasma membrane in the same in-vivo cell and quantitatively comparing them. The phasor-based multi-harmonic unmixing method can help expand the outreach of HSI and democratize its use by the community for it does not require specialized knowledge.

高光谱成像（HSI）是生物医学科学中的一项重要技术，然而，对每个光谱成分的分解和量化是一项具有挑战性的任务。传统的分解依赖于需要来自样品中荧光物种的光谱参数的算法。基于相量的多谐波分解方法只需要对纯物种进行经验测量，即可计算每个光谱分量的逐像素光子分数。通过模拟，我们证明了该方法对多达5个成分的可行性，并探索了添加代表自发荧光的第六个未知成分的用途。仿真表明，该方法可以成功地用于典型的共焦成像实验（像素光子计数在101到103之间）。作为概念的证明，我们在活细胞中测试了该方法，使用5种常见的商业染料进行细胞器标记，我们可以轻松准确地将它们分离出来。最后，我们通过引入溶剂化变色探针6-十二烷基-N，N-二甲基-2-萘胺（LAURDAN）来挑战该方法，该探针旨在利用细胞器探针和LAURDAN之间的线性组合来测量特定亚细胞膜结合细胞器上的膜动力学。我们成功地监测了同一体内细胞中高尔基体、线粒体和质膜的膜序，并对它们进行了定量比较。基于相量的多谐波分解方法可以帮助扩大HSI的推广范围，并使其在社区中的使用民主化，因为它不需要专业知识。

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引用次数: 1

Analysis of constituents present in smokeless tobacco (Nicotiana tabacum)using spectroscopic techniques. 利用光谱技术分析无烟烟草（Nicotiana tabacum）中的成分。

IF 2.4 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-03-25 DOI: 10.1088/2050-6120/ac5e11

Pratima Mishra, Rohit Kumar, Abhishek Dwivedi, Awadhesh Kumar Rai

Laser-Induced Breakdown Spectroscopy (LIBS) is an analytical technique used to identify and quantify the elements present in any type of material present in any phase (solid, liquid, gas, and aerosol). In the present work, our objective is to find the presence of toxic and other elements in chewing tobacco (Nicotiana tabacum) using LIBS. Spectral signatures of elements like C, Fe, Si, Mg, Mn, Ca, Ti, Na, H, N, K, O, along with some toxic elements Al, Sr, Li, Cu, Sb, and Cr are observed in the LIBS spectra of these tobacco samples. The spectral intensity ratio is measured for quantitative analysis of elements present in the samples. Further, Atomic Absorption Spectroscopy is used for determining absolute concentration in these samples. A relation between the AAS result and the relative intensity of spectral lines measured in the LIBS is obtained using regression analysis. The multivariate technique, Principal Component Analysis (PCA), discriminates all the samples based on their toxicity and other constituents. Molecular study (Photoacoustic spectroscopy (PAS), UV-Visible (UV-vis), and FT-IR) of tobacco samples were performed to analyze the molecules present in the tobacco samples.

激光诱导击穿光谱法（LIBS）是一种分析技术，用于识别和量化存在于任何阶段（固态、液态、气态和气溶胶）的任何类型物质中的元素。在本研究中，我们的目标是利用 LIBS 发现咀嚼烟草（Nicotiana tabacum）中存在的有毒元素和其他元素。在这些烟草样品的 LIBS 光谱中观察到了 C、Fe、Si、Mg、Mn、Ca、Ti、Na、H、N、K、O 等元素的光谱特征，以及一些有毒元素 Al、Sr、Li、Cu、Sb 和 Cr。测量光谱强度比可以对样品中的元素进行定量分析。此外，原子吸收光谱法还用于确定这些样品中的绝对浓度。使用回归分析法得出原子吸收光谱分析结果与 LIBS 测得的光谱线相对强度之间的关系。多变量技术--主成分分析法（PCA）可根据样品的毒性和其他成分对所有样品进行鉴别。对烟草样品进行了分子研究（光声光谱（PAS）、紫外可见光（UV-vis）和傅立叶变换红外光谱（FT-IR）），以分析烟草样品中存在的分子。

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引用次数: 0

Lifetime based axial contrast enable simple 3D-STED imaging 基于寿命的轴向对比使简单的3D-STED成像成为可能

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-03-15 DOI: 10.1088/2050-6120/ac5e10

Yuanqing Ma, Alex Macmillan, Ying Yang, K. Gaus

Stimulated Emission Depletion (STED) microscopy increase spatial image resolution by laterally sharpening the illumination profile of the confocal microscope. However, it remains compromised in axial resolution. To improve axial STED resolution, constructive interference of the STED depletion beam must be formed surrounding the focal plane to turn off the fluorophores beyond the focal plane. For isotropic 3D-STED resolution, this axial STED interference pattern must be overlayed with the doughnut STED beam at nanometer accuracy. Such optical configurations can be challenging in alignment. In this current work, we introduced a straightforward lifetime based axial contrast in STED microscope by imaging the samples on an ITO coated glass coverslip. The STED laser generates surface plasmon resonance on the ITO surface that enhanced the metal induced energy transfer MIET effect on the ITO surface. The enhanced MIET effect established a lifetime gradient with ∼20% dynamic range that extend for mor than 400 nm from the ITO surface. The axial contrast based on the lifetime gradient was directly used for 3D-STED imaging of tubulin fibers inside COS-7 cells, where the vertical displacement of single tubulin fiber was revealed. Lifetime gating could be applied to further improve lateral spatial resolution. Considering that most common implementation of STED microscopes uses pulsed lasers and timing electronics, there is no optical modification of the microscope is required in the current 3D-STED approach.

受激发射损耗(STED)显微镜增加空间图像分辨率通过横向锐化共聚焦显微镜的照明轮廓。然而，它仍然在轴向分辨率上有所妥协。为了提高轴向STED分辨率，必须在焦平面周围形成STED耗尽光束的建设性干涉，以关闭焦平面以外的荧光团。对于各向同性三维STED分辨率，这种轴向STED干涉图案必须与纳米精度的甜甜圈STED光束叠加。这种光学配置在对准时可能具有挑战性。在当前的工作中，我们通过在ITO涂层玻璃盖上成像样品，在STED显微镜中引入了一种直接的基于寿命的轴向对比度。STED激光在ITO表面产生表面等离子体共振，增强了ITO表面金属诱导能量转移的MIET效应。增强的MIET效应建立了一个具有20%动态范围的寿命梯度，从ITO表面延伸超过400nm。基于寿命梯度的轴向对比直接用于COS-7细胞内微管蛋白纤维的3D-STED成像，显示单个微管蛋白纤维的垂直位移。寿命门控可以进一步提高横向空间分辨率。考虑到STED显微镜最常见的实现使用脉冲激光和定时电子，在目前的3D-STED方法中不需要对显微镜进行光学修改。

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引用次数: 1

Microwave-assisted synthesis and upconversion luminescence of NaYF4:Yb, Gd, Er and NaYF4:Yb, Gd, Tm nanorods. NaYF4:Yb, Gd, Er和NaYF4:Yb, Gd, Tm纳米棒的微波辅助合成及上转换发光

IF 3.2 3区化学 Q3 CHEMISTRY, ANALYTICAL

Methods and Applications in Fluorescence

Pub Date : 2022-03-09 DOI: 10.1088/2050-6120/ac58e6

Shivanand H Nannuri, Simranjit Singh, Superb K Misra, Santhosh C, Sajan D George

Anisotropic rare earth ion (RE³⁺) doped fluoride upconversion particles are emerging as potential candidate in diverse areas, ranging from biomedical imaging to photonics. Here, we develop a facile strategy to synthesize NaYF₄: Yb, Gd, Er, and NaYF₄: Yb, Gd, Tm upconversion nanorods via microwave synthesis route by controlling the synthesis time and compared the optical properties similar nanorods prepared via solvothermal technique. With the increase in synthesis time, the phase of the particle found to change from mixed phase to purely hexagonal and morphology of the particles change mixed phase of spherical and rod-shaped particles to completely nanorods for a synthesis time of 60 min. Further, the intrinsically hydrophobic particles changed to hydrophilic by removal of oleic capping via acid treatment and the amine functionalized silica coating. The upconversion luminescence as well as laser power dependent emission properties of the surface modified particles elucidate that surface modification route influence the upconversion luminescence as well as solvent dependent emission properties. Moreover, the laser power dependent studies elucidate that the upconversion process in a multi-photon process.

各向异性稀土离子(RE3+)掺杂氟化物上转换粒子正在成为从生物医学成像到光子学等各个领域的潜在候选者。本文通过控制合成时间，采用微波合成方法合成了NaYF4: Yb, Gd, Er和NaYF4: Yb, Gd, Tm上转换纳米棒，并比较了溶剂热法制备的类似纳米棒的光学性能。随着合成时间的增加，颗粒的相由混合相转变为纯六边形，颗粒的形态由球形和棒状颗粒的混合相转变为完全的纳米棒状颗粒，合成时间为60 min。此外，通过酸处理和胺官能化二氧化硅涂层去除油盖，颗粒从本质上的疏水性转变为亲水性。表面修饰颗粒的上转换发光和依赖激光功率的发射特性表明，表面修饰途径影响上转换发光和依赖溶剂的发射特性。此外，激光功率依赖性的研究阐明了多光子过程中的上转换过程。

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引用次数: 1