等离子体增强上转换发光及其应用

稀土上转换纳米材料（UCNPs）是一类在近红外光激发下发出可见光的纳米材料。与有机荧光染料、量子点等发光材料相比,UCNPs具有化学稳定性高、光稳定性强、荧光寿命长、反斯托克斯位移大、发光谱带窄和光穿透深度大等诸多优点,在生物成像、传感器、激光器、光动力疗法和太阳能电池等领域有潜在的应用价值。但是由于UCNPs激活离子的吸收截面太小,导致其发光效率偏低,限制了UCNPs的进一步应用。因而如何提高上转换发光强度成为当前的研究热点。针对上述问题,本文系统阐述了金属表面等离子体共振（SPR）增强上转换发光领域的研究进展。首先介绍了SPR增强上转换发光的三种机制,随后重点介绍了化学法和物理法这两种SPR-UCNPs体系的构建方法以及其在太阳能电池、生物成像、生物检测、光热治疗和光催化等领域的应用。文章最后指出了SPR增强上转换发光领域存在的不足和未来的研究方向。     

稀土氟化物上转换荧光增强及应用

稀土氟化物上转换纳米材料具有化学稳定性高、反斯托克位移大、无光漂白、荧光寿命长、发光谱带窄和穿透深度深等优点,在荧光成像和光热疗、传感器、太阳能电池及防伪技术等领域具有广泛的应用前景,是一种极具发展潜力的荧光材料。然而该类材料在实际应用时还存在有荧光效率低、吸收截面小等亟待解决的瓶颈问题。针对以上问题,本文系统阐述了离子共掺杂、核壳结构、表面等离子耦合、光子晶体、宽频敏化和热效应等增强稀土氟化物上转换荧光的方法及其近年的研究进展。并在此基础上,总结了近年来荧光增强稀土氟化物上转换纳米材料在生物成像和光热疗、生物传感、太阳能电池及防伪技术等领域的应用研究现状。最后,分析了稀土氟化物UCNPs目前仍存在的不足,并对将来的发展方向进行了展望。     

稀土上转换发光纳米材料的防伪安全应用

与有机荧光染料、量子点等传统发光材料相比,稀土上转换发光纳米材料(UCNPs)具有反斯托克斯位移大、发光谱带多且狭窄、荧光寿命长、光化稳定性高、无光闪烁和光漂白等独特优势,将其与图形编码、防伪印刷技术结合可获得难以仿冒的隐形荧光图案,这已经成为防伪安全领域的应用研究热点。本文首先介绍了UCNPs的上转换发光机理及其合成方法,然后阐述近年来UCNPs在防伪安全领域的研究现状,归纳总结出上转换防伪安全图案的四种形式(NIR单波长激发、NIR双波长激发、NIR/UV双波长激发以及三波长激发)。最后,本文指出UCNPs应用于防伪安全领域所面临的问题与挑战,并对未来的发展方向进行了展望。     

稀土元素掺杂上转换纳米材料在卫生分析领域中的应用

稀土元素掺杂上转换纳米材料(REEs-UCNPs)作为新兴一代的荧光纳米探针,具备反斯托克斯发光的独特转换性质,具有光学/化学稳定性好、荧光寿命长、激发光生物组织穿透深度大,且对组织损伤小等显著优点,近年来在卫生分析领域的研究和应用获得了广泛的关注。本文重点综述了REEs-UCNPs对卫生样品中金属离子、有机小分子、激素、生物毒素、活性氧自由基和生物大分子等分析检测的最新研究成果及进展,展望了REEs-UCNPs进一步的研究开发及应用。     

稀土上转换纳米发光材料研究进展

上转换纳米发光材料(UCNPs)是一种能在长波长光激发下发出短波长光的发光材料.在较多的研究中UCNPs在980 nm红外光激发下,能发出不同颜色的可见光,可以显著提高信噪比,所以UCNPs在三维立体显示、上转换激光器、红外探测、防伪识别、生物检测等诸多领域都具有广阔的应用前景.从稀土上转换纳米发光材料的基质和稀土离子及其光学性能方面概述了近几年稀土上转换纳米发光材料的研究进展.     

具有红光发射的稀土上转换发光纳米晶及其介孔直接功能化

红光发射稀土上转换发光纳米晶(UCNPs)在光动力治疗(PDT)等方面具有特定的优势。将油溶性的UCNPs通过表面改性转变为水溶性,对其在生物医疗、疾病诊断等方面的应用具有重要意义。利用一种简单易行的方法将具有红光发射的UCNPs进行介孔直接功能化表面修饰,制备了一种具有良好水溶性的纳米材料NaYF4:Yb/Er/Mn@mSiO2。实验结果表明该材料核-壳结构明显,形貌均一,在980 nm的激发下保持了上转换发光特性。该材料在光动力治疗等方面具有良好的潜在应用价值。     

荧光碳点的合成、性质和应用

与传统半导体发光材料相比,荧光碳点作为一种新型的碳纳米发光材料,因其优异的生物相容性、良好的发光性能、简单的合成工艺、低廉的成本等优点而备受关注。荧光碳点在生物荧光标定、医学传感器、光诊疗剂以及发光器件等方面具有广阔的应用潜力。本文重点阐述了荧光碳点的合成方法、显微结构分析、荧光机理及应用的最新成果,希望为荧光碳点合成与应用研究的发展提供参考。     

长余辉纳米材料的控制合成及在疾病诊断中的应用

长余辉纳米材料具有独特的发光性质, 能在激发光关闭后持续发光. 通过收集激发光关闭后的长余辉发光信号可以有效消除背景信号的干扰. 此外, 长余辉材料在成像时无需原位激发, 可以减少生物体系的组织自发荧光和光散射干扰, 提高生物成像和检测的灵敏度. 由于这种独特的光学特性, 长余辉纳米材料在生物传感/生物成像以及疾病治疗等领域被广泛应用. 近年来, 为满足疾病相关生物标志物的体外检测及体内生物成像的应用要求, 控制合成发光性能优异、 生物相容性好的长余辉纳米材料成为研究热点.     

1,8-萘酰亚胺类荧光探针在双光子成像中应用的研究进展

荧光成像技术由于其灵敏度高、操作简单、可实时动态进行细胞、组织以及生物活体成像而受到极大关注,相对于单光子荧光成像技术,双光子成像技术具有高分辨率、强组织穿透性以及低的组织自发荧光干扰等显著的优越性.1,8-萘酰亚胺作为典型的电子供体-π-电子受体(D-π-A)双光子荧光染料,具有光稳定性、大斯托克斯/反斯托克斯位移等优点被广泛应用于酶、活性碳簇、活性氧簇、活性氮簇、生物硫醇、离子等的双光子成像中.依据1,8-萘酰亚胺类荧光探针发光机制,即分子内电荷转移、光诱导电子转移、荧光共振能量转移等发光机制,综述1,8-萘酰亚胺近些年来在双光子成像领域中的应用,并展望了其未来的发展趋势.     

稀土纳米材料在高分辨活体成像及诊疗中的应用

荧光成像具有时空分辨率高、 反馈快、 非侵入和无电离辐射等优点, 是一种重要的生物成像技术. 与传统用于荧光成像的可见光和近红外一区(NIR-I, 600~950 nm)相比, 近红外二区(NIR-Ⅱ, 1000~1700 nm)窗口具有低生物组织散射系数和低生物自发荧光, 采用NIR-Ⅱ光进行活体荧光成像能有效提高成像的分辨率、 信噪比和穿透深度. 稀土纳米颗粒(RENPs)具有大斯托克斯位移、 高化学稳定性、 可调的荧光寿命以及较窄的发射带, 是一种重要的荧光成像探针. 近年来, 一系列具有优异的NIR-Ⅱ发光性能的稀土纳米材料被用于高分辨活体荧光成像. 本文综合评述了近年来RENPs用于高分辨活体成像及诊疗中的研究进展, 概述了RENPs的掺杂调控、 基质晶格选择和复合敏化等NIR-Ⅱ发光增强策略, 介绍了其在多种生物医学场景中的靶向聚集、 荧光传感和疾病治疗等功能, 并总结了其在多路成像、 多模态成像和疾病诊疗中的应用. 最后, 简要分析了RENPs在未来生物医学应用中面临的挑战和发展的方向.     

Recent Advances in Controlled Synthesis of Upconversion Nanoparticles and Semiconductor Heterostructures

It's of great importance for construction of upconversion nanoparticles (UCNPs)/semiconductor heterostructures activated by near infrared light, which have gained worldwide research interests owing to important applications in photocatalysis, solar cells, nanomedicine, and etc. In this review, we highlight the synthetic strategies developed to fabricate upconversion nanoparticles based heterostructures, such as chemical epitaxial growth method, electrospinning technique, self‐assembly method, hydrothermal method, and etc. Numerous examples are given concerning the use of the strategies to fabricate various microstructures/nanostructures incorporated with UCNPs and semiconductors materials. The latest advances and perspectives in the synthetic strategies and preparation of this kind of composite nanostructures are made.     

Upconversion nanomaterials: a platform for biosensing,theranostic and photoregulation

Upconversion nanoparticles (UCNPs) are a kind of unique optical material, that are able to emit ultraviolet (UV), visible or near infrared (NIR) luminescence upon NIR light excitation. Because of their excellent physic-chemical characters including enormous anti-Stokes spectral shift, high resistance to photobleaching, fairly long luminescent lifetime, excellent chemical stability, sharp emission band, and deep tissue penetration depth, UCNPs have become a useful tool in bioimaging, biosensing, as well as cancer therapy. In particularly, the emissions light from UCNPs can activate photosensitive molecules, which has the potential to realize the regulation of cell behaviors, including cell growth, adhesion and differentiation. This review consequently introduces the principle and achievements of UCNPs in biomedical field to the general readers for promoting both fundamental research and bio-applications of UCNPs. After the brief introduction of the physical mechanism of upconversion luminescence (UCL), we introduce several strategies to enhance the emissions brightness in detail, then discuss various biomedical applications of UCNPs.     

以上转换纳米颗粒和光动力疗法为基础的肿瘤联合治疗研究进展

光动力疗法作为一种非侵入性治疗手段已广泛应用于肿瘤的临床治疗。然而其疗效却深受紫外-可见光组织穿透深度的限制。镧系掺杂上转换纳米颗粒可以将近红外光转换为紫外-可见光,被广泛用于与传统光敏剂结合实现更为高效的光动力治疗。近年来,以上转换纳米颗粒和光动力疗法为基础的肿瘤联合治疗研究备受关注,本文重点介绍了该领域的最新研究进展,并对其未来发展方向作出了展望。     

Upconversion nanophosphors for small-animal imaging

Rare-earth upconversion nanophosphors (UCNPs), when excited by continuous-wave near-infrared light, exhibit a unique narrow photoluminescence with higher energy. Such special upconversion luminescence makes UCNPs promising as bioimaging probes with attractive features, such as no auto-fluorescence from biological samples and a large penetration depth. As a result, UCNPs have emerged as novel imaging agents for small animals. In this critical review, recent reports regarding the synthesis of water-soluble UCNPs and their surface modification and bioconjugation chemistry are summarized. The applications of UCNPs for small-animal imaging, including tumor-targeted imaging, lymphatic imaging, vascular imaging and cell tracking are reviewed in detail. The exploration of UCNPs as multifunctional nanoscale carriers for integrated imaging and therapy is also presented. The biodistribution and toxicology of UCNPs are further described. Finally, we discuss the challenges and opportunities in the development of UCNP-based nanoplatforms for small-animal imaging (276 references).     

优化稀土上转换纳米材料发光的方法

稀土上转换纳米材料(Upconversion Nanoparticles,UCNPs)可将近红外光转换为可见光,其发光性能优异、化学性质稳定、激发光能有效避免自荧光,因此在生物医学领域应用广泛。但UCNPs的低发光效率限制了其进一步发展。本文综述了近年来研究较多的几种优化稀土上转换纳米材料发光的方法,主要包括调整基质材料和掺杂离子、过渡金属离子与镧系离子共掺杂、引入协同敏化剂减少热效应、有机染料与UCNPs协同作用以及金属表面等离子体共振增强法等。文中分别论述了上述方法的最新研究进展,并总结了这些方法目前存在的问题,指出上转换发光领域的研发重点:一是着重分析各种优化发光方法的作用机理,提出更加完备清晰的理论体系;二是探索更容易被生物体降解的UCNPs,使其副作用降到最低。     

Liquid Marbles Based on Magnetic Upconversion Nanoparticles as Magnetically and Optically Responsive Miniature Reactors for Photocatalysis and Photodynamic Therapy

Magnetic liquid marbles have recently attracted extensive attention for various potential applications. However, conventional liquid marbles based on iron oxide nanoparticles are opaque and inadequate for photo‐related applications. Herein, we report the first development of liquid marbles coated with magnetic lanthanide‐doped upconversion nanoparticles (UCNPs) that can convert near‐infrared light into visible light. Apart from their excellent magnetic and mechanical properties, which are attractive for repeatable tip opening and magnetically directed movements, the resultant UCNP‐based liquid marbles can act as ideal miniature reactors for photodynamic therapy of cancer cells. This work opens new ways for the development of liquid marbles, and shows great promise for liquid marbles based on UCNPs to be used in a large variety of potential applications, such as photodynamic therapy for accelerated drug screening, magnetically guided controlled drug delivery and release, and multifunctional actuation.     

Rational design and biomedical applications of DNA-functionalized upconversion nanoparticles

In this review, we mainly introduced recent progress of DNA-functionalized upconversion materials, providing an overview of the design and applications in biosensing, bioimaging and disease therapy. The challenges and future perspectives are also discussed, aiming to promote their applications in materials science and biomedicine.     

核酸适配体功能化的稀土上转换纳米材料在生物检测中的应用

稀土上转换纳米材料可以吸收近红外光并发射出可见光或紫外光,在生物传感领域得到了广泛研究。核酸适配体能高特异性和高亲和性地与靶标物结合,被广泛应用于生物传感、疾病诊断等领域。将稀土上转换纳米材料与核酸适配体结合构建的检测体系,可实现对目标物灵敏、高选择性的检测。本文介绍了近几年核酸适配体功能化的稀土上转换纳米材料在生物小分子、蛋白质、核酸、病原微生物、细胞等方面的应用,并展望了其在分析检测领域的发展前景。     

A Uniform Sub‐50 nm‐Sized Magnetic/Upconversion Fluorescent Bimodal Imaging Agent Capable of Generating Singlet Oxygen by Using a 980 nm Laser

Upconverting nanoparticles (UCNPs) with fascinating properties hold great potential as nanotransducers for solving the problems that traditional photodynamic therapy (PDT) has been facing. In this report, by using well‐selected bifunctional gadolinium (Gd)‐ion‐doped UCNPs and water‐soluble methylene blue (MB) combined with the water‐in‐oil reverse microemulsion technique, we have succeeded in developing a new kind of UCNP/MB‐based PDT drug, NaYF₄:Er/Yb/Gd@SiO₂(MB), with a particle diameter less than 50 nm. Great efforts have been made to investigate the drug‐formation mechanism and provide detailed physical and photochemical characterizations and the potential structure optimization of the as‐designed PDT drug. We envision that such a PDT drug will become a potential theranostic nanomedicine for future near‐infrared laser‐triggered photodynamic therapy and simultaneous magnetic/optical bimodal imaging.     

Contemporary Synthesis of Ultrasmall (sub-10 nm) Upconverting Nanomaterials

Due to their unique photophysical properties, upconverting nanoparticles (UCNPs), i. e. particles capable of converting near-infrared (NIR) photons into tunable emissions in the range of ultraviolet (UV) to NIR, have great potential for use in various biomedical fields such as bioimaging, photodynamic therapy and bioanalytical applications. As far as biomedical applications are concerned, these materials have a number of advantageous properties such as brilliant luminescence and exceptional photostability. Very small “stealth” particles (sub-10 nm), which can circulate in the body largely undetected by the immune system, are particularly important for in vivo use. The fabrication of such particles, which simultaneously have a defined (ultrasmall) size and the required optical properties, is a great challenge and an area that is in its infancy. This minireview provides a concise overview of recent developments on appropriate synthetic methodologies to produce such UCNPs. Particular attention was given to the influence of both surfactants and dopants used to precisely adjust size, crystalline phase and optical properties of UCNPs.