荧光碳点的制备方法及其在生物医药领域应用的研究进展

近年来,随着科学技术的不断发展,人们对于纳米碳材料的探索与开发日益增多。荧光碳点作为一种新型的纳米碳材料逐渐出现在大众视野之中,因其具有优异的光学特性、物理与化学性质均较为稳定、生物相容性高,同时拥有高效、无毒或低毒的制备方法而在药物载体、生物成像、探针检测等领域均得到了广泛的应用。本文针对近年来荧光碳点制备方法以及其在生物医药领域的应用进行综述,对荧光碳点的研究前景进行了展望。     

水相一步法合成具有双光子效应的高效橙红荧光聚合物碳点

聚合物碳纳米点是近年来新兴的一种荧光纳米探针,具有较低的生物毒性、良好的水溶性、较高的量子产率、优异的光/化学稳定性以及良好的生物相容性.目前所制备的碳点大都表现出蓝、绿色荧光发射.为实现碳点长波荧光发射,扩大其在生物标记与成像及光电显示方面的应用,本文采用水相一步法交联聚合反应制备了具有橙红荧光发射性质且具有双光子效应的聚合物碳点,发射波长为604 nm,荧光量子产率达到30.64%,并且应用在生物活体成像中.     

复合型石墨氮化碳在生物荧光探针中的研究进展

g-C_3N_4是一种由碳和氮原子组成的新兴发光材料,具有石墨相结构、独特的光学和电子特性。与纯g-C_3N_4材料相比,复合型g-C_3N_4具有更高的检测性能和更广泛的检测应用,在生物成像和生物检测等领域具有很大的发展前景。本文主要对复合型g-C_3N_4在检测重金属离子、人体内生物大分子、细胞成像等荧光探针方面的应用进行了综述,并对复合型g-C_3N_4在将来的发展应用进行了展望。     

异元素掺杂碳点的制备及其在生物成像中的应用

荧光碳点具有良好的生物相容性和优良的抗光漂白能力,因此碳点在生物荧光成像方面的应用潜力受到广泛关注,但是碳点相对较低的荧光量子产率和缺乏近红外荧光发射的缺陷限制了碳点在荧光成像分析中的应用.随着异元素掺杂对碳点结构和荧光性质的改善,碳点被越来越广泛地用于生物成像.本文对近年来元素掺杂碳点的合成方法、异元素掺杂对碳点光学性质的影响和元素掺杂碳点在成像分析中的进展进行了综述,并对其应用前景进行了展望.     

碳点荧光探针的制备及其在食品分析中的应用

碳点作为一种新型荧光碳纳米材料,具有优良的光学性能和小尺寸特性,以及良好的生物相容性、低毒性以及易于实现表面功能化等特点,是潜在的可以代替传统半导体量子点等荧光探针的良好选择.基于其独特的荧光特性和高灵敏度,碳点荧光探针在食品分析领域具有很好的应用潜力.本文对近年来荧光碳点的研究进展进行了综述,简述碳点的性能并对碳点的制备方法进行总结对比,重点介绍了碳点荧光探针在食品分析领域的应用,对目前碳点应用的限制进行了分析,对其发展前景和展望.     

荧光碳点的制备及应用研究进展

荧光碳点是一种新型的荧光纳米材料。它不仅具有优良的光学性能,而且具有良好的生物相容性,易于实现表面功能化,在生物传感、荧光探针等领域具有很好的应用潜力。本文就近几年来荧光碳点的研究进行了综述,简述了碳点的特性,着重介绍了荧光碳点制备和应用的最新进展,对碳点发展过程中尚待解决的问题进行了总结,并对未来的发展方向进行了展望。     

钆掺杂碳量子点的制备及其双模态成像研究进展

荧光-磁共振成像(MRI)双模态分子探针突破了单一分子影像探针在灵敏度以及软组织分辨率等方面的局限性,在诊断和治疗等医学领域具有良好的应用潜力。钆掺杂碳量子点(Gd-CDs)是一种典型的荧光-MRI双模态分子探针,因其优异的荧光性能、良好的核磁共振成像能力和生物相容性等优点,在肿瘤的靶向性成像和监控诊疗方面具有广泛的应用前景。本文综述了目前Gd-CDs的制备、性能及其在双模态成像应用的研究现状,并提出目前存在的问题和前景展望。     

硫量子点的合成及其分析应用研究进展

硫量子点是近年发展起来的一类新型纳米荧光探针,该荧光探针具有优异的发光特性以及良好的生物相容性,受到研究者的广泛关注.本文在总结硫量子点合成方法及光学性质的基础上,系统介绍了其在离子及小分子分析、细胞成像等方面的应用研究进展.     

荧光碳点在分析传感中的应用进展

荧光碳点（CDs）是2004年发现的一种新型碳基纳米材料,呈球形、粒径在2～10 nm左右,具有优异的荧光性能、易于功能化修饰、抗光漂白性强、环境危害低、生物相容性好以及合成原料来源丰富等特点,被认为是有机荧光染料和半导体量子点的最佳替代品,在光电学、光催化、化学传感和生物成像等领域有着广阔的应用前景。本文主要介绍了CDs作为化学传感器的荧光检测机制,重点总结了近年来CDs在离子、有机小分子以及生物大分子检测等方面的应用,以期为荧光纳米探针的设计与应用提供理论和研究依据。     

基于功能核酸的细胞荧光成像

细胞是生物体基本的结构和功能单元,对活细胞中特定生物组分进行动态分析,将为相关生命活动过程的研究提供重要信息。荧光成像为细胞分析提供了一种操作简单、灵敏度高、可实时监测细胞微观动态分子过程的光学生物成像技术。发展高性能的荧光探针用于活细胞成像已成为研究热点。功能核酸是一类具有特殊化学和生物学功能的寡核苷酸分子,除了天然存在的核酶(Ribozyme)和核糖开关(Riboswitch)之外,还包括通过指数富集的配体系统进化技术(SELEX)筛选获得的核酸适体和脱氧核酶(DNAzyme)。功能核酸由于具有合成简单、免疫原性低、相对分子质量小、化学稳定性高、易于修饰等优点,在生物成像领域受到广泛关注。本文主要综述了基于功能核酸的荧光探针在细胞成像领域中的应用研究,总结了该领域面临的挑战,并对其未来发展方向进行了展望。     

Functionalization of Carbonaceous Nanodots from MnII‐Coordinating Functional Knots

Transition metal (TM)‐induced functionalization has been expected to be powerful for the modification of carbonaceous nanodots (CDs) for many years. Although some attempts have been made, relevant research evolutions are at a standstill. In this work, a coordination–carbonization protocol to gain Mn^II‐functionalized CDs (MCDs) was innovatively employed, and the modification of CDs based on metal‐coordinating functional knots was realized. By investigating the structural and photophysical properties, coordinating conformation of functional knots was confirmed and considered to be correlated with excitation‐independent photoluminescence as well as large Stokes shift of MCDs. Moreover, potential applications of MCDs have been extended from common bioimaging and fluorescent inks to new areas, such as chemosensors for volatile organic compounds and anticorrosion fluorescent films.     

Synthesis and Applications of Red‐Emissive Carbon Dots

Carbon dots (CDs), a new class of fluorescent carbon nanoparticles (less than 10 nm in size), have been widely applied in various fields, including sensors, bioimaging, catalysis, light‐emitting devices (LEDs), and photoelectronic devices, owing to their unique properties such as low toxicity, bio‐compatibility, high photostability, easy surface modification, and up‐conversion fluorescence, over the past decades. Recently, multiple‐color‐emissive CDs, especially red‐emissive CDs (RCDs), have drawn much attention owing to their unique advantages, like the ability to penetrate the animal bodies without the disturbance of strong tissue autofluorescence, multiple‐color fluorescence displaying or sensing, and the capacity to be one essential component to obtain white LED (WLED). In this review, we focused on the progress of recently‐emerging RCDs in the past five years, including their synthetic methods (hydrothermal, solvothermal, reflux condensation and microwave techniques), influencing factors (precursors, solvents, elements doping, surface chemistry) and various applications (bioimaging, sensor, photocatalysis and WLEDs), with a perspective on the future advancements.     

A Reversible Fluorescent Probe for Real‐Time Live‐Cell Imaging and Quantification of Endogenous Hydropolysulfides

The chemical biology of reactive sulfur species, including hydropolysulfides, has been a subject undergoing intense study in recent years, but further understanding of their “intact” function in living cells has been limited owing to a lack of appropriate analytical tools. In order to overcome this limitation, we developed a new type of fluorescent probe that reversibly and selectively reacts to hydropolysulfides. The probe enables live‐cell visualization and quantification of endogenous hydropolysulfides without interference from intrinsic thiol species such as glutathione. Additionally, real‐time reversible monitoring of oxidative‐stress‐induced fluctuation of intrinsic hydropolysulfides has been achieved with a temporal resolution on the order of seconds, a result which has not yet been realized using conventional methods. These results reveal the probe's versatility as a new fluorescence imaging tool to understand the function of intracellular hydropolysulfides.     

Preparation of Fluorescent Carbon Dots from Chinese Herbal Medicine Alisma and Its Potential Applications in Photocatalytic Degradation of Malachite Green and Cell Imaging

Natural plants and Chinese herbal medicines are valuable resources. It is one of the new tasks for medical workers to study the new application fields of these resources. In this work, one kind of traditional Chinese herbal plant, Alisma, was chosen as a carbon source to synthesize the carbon dots(CDs). This kind of CDs has an amorphous carbon structure and shows strong stability to time, temperature, and ion strength. The results show that the degradation efficiency of malachite green dye can reach 100% in 4.5 h without illumination, and the degradation efficiency is better than that in dark environment. In addition, the CDs have also been successfully applied to HeLa cell imaging. Simple synthesis method, stable properties, good photodegradation and bioimaging applications make this material of great application value.     

碳点在样品前处理及色谱分离中的应用

碳点（CDs）具有生物相容性好、毒性低、稳定性好等优点,目前已广泛应用于生物成像、传感、光催化等领域。近年来,以CDs为吸附剂和分离材料的样品前处理和色谱分离研究也引起了研究者的极大兴趣。该文对CDs在样品前处理和色谱分离中的应用进行了综述,并对其发展前景进行了展望。     

Nanocomposite hydrogels based on carbon dots and polymers

Nanocomposite hydrogels based on carbon dots(CDs) and polymers have emerged as new materials with integrated properties of individual components,leading to their important applications in the field of soft nanomaterials.This perspective highlights recent advances in the development of nanocomposite hydrogels from CDs and polymers.We review the preparation methods of nanocomposite hydrogels based on CDs and polymers,and emerging applications of these nanocomposite hydrogels such as environmental remediation,energy storage,sensing,drug delivery and bioimaging.We conclude with the discussion of new research directions in the development of new type of nanocomposite hydrogels based on CDs and polymers.     

Non-Metal-Heteroatom-Doped Carbon Dots: Synthesis and Properties

Carbon dots (CDs) are new materials with applications in bioimaging, optical devices, catalysis, and many other fields. Their advantages, such as ease of large-scale preparation, low-costing precursors, highly tunable photoluminescence, satisfactory biocompatibility, and photostability against photobleaching, make them competitive alternatives to conventional semiconductor-based quantum dots and organic dyes. To overwhelm other luminescent materials in applications, their functionalities still need to be improved in spite of the abovementioned advantages. In recent years, it has been proven that heteroatom doping is an effective approach to improve the optical and electronic performance of CDs by tuning their carbon skeleton matrices and chemical structures. In this review, the development of non-metal-heteroatom-doped CDs, including heteroatom categories, preparation methods, and physicochemical properties, are discussed. Progressive trends in heteroatom-doped CDs are also discussed at the end of this review.     

One‐pot synthesis of carbon dots@ZrO2 nanoparticles with tunable solid‐state fluorescence

In recent years, fluorescent carbon dots (CDs) have been developed and showed potential applications in biomedical imaging and light‐emitting diodes (LEDs) for their excellent fluorescent properties. However, it still remains a challenge to incorporate fluorescent CDs into the host matrix in situ to overcome their serious self‐quenching. Herein, a one‐pot hydrothermal method is used to prepare nano‐zirconia with CDs (CDs@ZrO₂) nanoparticles. During the reaction, CDs and nano‐zirconia are generated simultaneously and connected with silane coupling agent. The CDs@ZrO₂ nanoparticles exhibit tunable emission wavelength from 450 to 535 nm emission by regulating the content of citric acid in the feed. The quantum yield of the CDs@ZrO₂ is up to 23.8%. Furthermore, the CDs@ZrO₂ nanoparticles with regulable fluorescence emission can be used for the fluorescent material to prepare white LEDs. The prepared LED has significant white light emission with color coordinates of (0.30, 0.37) and its color rendering index (CRI) is 67.1. In summary, we have developed the solid‐state CDs@ZrO₂ nanoparticles with tunable emission by a valuable strategy, that is, one‐pot method, for white LEDs.     

Fluorescence Intensity Enhancement of Green Carbon Dots: Synthesis,Characterization and Cell Imaging

The hydrothermal treatment of green carbon dots (CDs) is an appropriate fluorescent probe synthesis method. CDs are exploited as biological staining agents, especially for cellular detection and imaging. The nitrogen-doped green carbon dots (N-CDs) formation can improve the fluorescence intensity property in a one-step process. Here, we report two N-CDs from lemon and tomato extraction in the presence of hydroxylamine. Lemon and tomato N-CDs showed the blue fluorescence under ultraviolet radiation of about 360 nm. The characterization of CDs and N-CDs showed the presence of N-H and C–N bonds which enhanced the fluorescence efficiency. The mean size of lemon and tomato N-CDs were about 2 and 3 nm with an increased quantum yield (QY) of 5% and 3.38%, respectively. The CDs and N-CDs cytotoxicity assay exhibited high cell viability approximately 85% and 73%, respectively. N-CDs show superior fluorescent intensity in different solvents and significant stability under long-time UV irradiation, different PH and high ionic strength. Our results indicated that the use of N-CDs in cell imaging can lead to fluorescence intensity enhancement as well as proper biocompatibility. Therefore, the safe and high fluorescence intensity of green N-CDs can be utilized for fluorescent probes in biolabeling and bioimaging applications.     

Targetable fluorescent sensors for advanced cell function analysis

Chemistry-based bioimaging techniques have contributed to the elucidation of intracellular physiological events. During the last few decades, many fluorescent sensors have been developed and used in live cell experiments. Owing to immense efforts by numerous research groups, several strategies have been developed to design fluorescent sensors based on various components such as small molecules and fluorescent proteins. Recently, site-specific targeting of fluorescent sensors has attracted increasing attention. Strategies for fluorescent sensor targeting were surveyed in this review with the aims to expand current knowledge on chemistry-based bioimaging and aid in the emergence of related innovative technologies. The first discussed strategy is based on the intrinsic properties of small molecules for localization at specific organelles, such as mitochondria, nuclei, and lysosomes. As a further elaboration of the topic, our recent study about in vivo targeting of pH sensors was briefly introduced. The second strategy exploits genetically encoded tags and their specific ligands. Here, fluorescent sensors with commercially available tags and corresponding ligands were mainly reviewed. As the final topic, our original protein labeling technique, which enables fluorogenic labeling as an advanced technology, was introduced.