Microwave-Assisted Green Synthesis of Carbon Quantum Dots Derived from Calotropis Gigantea as a Fluorescent Probe for Bioimaging

Journal of Fluorescence - An eco-friendly, cost-effective, and convenient approach for synthesizing biocompatible fluorescent carbon quantum dots (CQDs) from the leaf extract of the medicinal plant...     

高效荧光碳点的制备及其对金属离子的检测研究

采用氮和硫元素共掺杂的水热法合成了一种发蓝光的碳点.经过一系列的光学和微观结构表征分析,发现氮和硫元素可以通过杂原子掺杂和表面官能团的形式充分参与到碳点中,这决定了所制备的蓝光碳点拥有最高54.27%的量子产率.由于其高效荧光,该碳点可以用作传感探头检测金属离子,且对Ag+和Fe3+具有高灵敏度和选择性,通过Stern-Volmer方程拟合发现,随着离子浓度的变化,两种金属离子不同的淬灭机制和检测极限为在实践中有效检测和区分Ag+和Fe3+提供了一种可行的新方法.     

反相微乳液法制备尺寸可调的高荧光碳量子点(英文)

在反相微乳液体系中,以抗坏血酸作为碳源制备具有高强度荧光的碳量子点。实验中通过调整水和表面活性剂的量比实现对碳量子点尺寸大小的控制,利用十六烷基胺修饰碳量子点。当激发波长为360 nm时,碳量子点的量子产率最高为47%。当水和表面活性剂的量比从20增加到50时,碳量子点的尺寸也随之而增大。     

氮掺杂碳量子点的合成及作为荧光探针对Hg~(2+)的检测

与传统量子点相比,碳量子点作为一种新型的荧光碳纳米材料,由于其良好的生物相容性、易于表面功能化、低毒性等优点受到了广泛关注。采用柠檬酸为碳源,氨水为氮源,热解法制备出水溶性好的氮掺杂碳量子点(NCDs)。透射电镜(TEM)观察NCDs的粒径在3nm左右;X射线光电子能谱(XPS)和傅里叶红外光谱(FIIR)证明NCDs的表面被羧基、氨基、羟基、羰基等官能团功能化,说明NCDs有很好的水溶性。研究还发现Hg~(2+)对NCDs的荧光有良好的猝灭作用,可作为荧光探针检测水中Hg~(2+)含量。在PBS缓冲液中(0.1mol·L~(-1) pH 7.0),NCDs的荧光猝灭率(F/F0)与汞离子浓度在0.001~0.1μmol·L~(-1)之间存在良好的线性关系,检出限为2.1nmol·L~(-1)。该方法灵敏度高、选择性好、方法简便,可应用于Hg~(2+)快速、灵敏的检测。     

Nitrogen and Sulfur-Doped Carbon Quantum Dots Used as Fluorescent Probes

Journal of Applied Spectroscopy - Using hydrolyzed olive leaves as a carbon source and thiourea as a dopant, nitrogen-sulfur co-doped carbon quantum dots (NS-CQDs) were synthesized in the present...     

生物分子包覆的荧光量子点的微波合成及表征

以N-乙酰基-L-半胱氨酸为稳定剂,采用控温控压微波辐射法在水溶液中快速合成了CdTe量子点.吸收光谱和荧光光谱表明所合成量子点具有优异的光学性能,量子产率最高可达50％左右,发射峰半峰宽最小在35nm左右,明显优于在相同实验条件下以3-巯基丙酸为稳定剂合成的CdTe量子点.透射电子镜显微镜(TEM)和X射线粉末衍射(XRD)进一步证实CdTe量子点具有较窄的粒径分布和好的晶体结构.电感耦合等离子体发射光谱(ICP-OES)分析表明量子点中重金属元素镉的含量随着荧光发射波长的增加而逐渐增大.     

生物质碳量子点的绿色制备及对Cu2+的检测

向日葵作为我国主要的油料作物之一,其秸秆是天然的纤维素材料,具有绿色无毒,成本低廉的优势,是制备生物质碳量子点的理想材料之一。近年来,由于含铜农药和化学肥料的不规范使用,大量含铜污染物被排放导致农田土壤和水环境中的铜含量远高于环境背景值。因此,迫切需要开发出一种选择性好、灵敏性强且对环境友好的Cu²⁺检测方法。碳量子点(CDs)是一种粒径小于10 nm的准球形荧光碳纳米材料,因其表面含有丰富的极性官能团,具有良好的水溶性而被广泛研究。与传统的半导体量子点(CdSe, CdTe)相比,CDs具有合成原料广泛、生物相容性好等优点。主要应用于生物成像、光催化、光电转化以及传感检测等领域。然而目前用于碳化合成CDs的前驱体大多为昂贵的化学品,且合成过程复杂污染环境,限制了CDs的大规模生产与应用。开发出一种生态友好,简单、廉价的CDs合成方法是很有意义的。本研究以废弃的向日葵秸秆为碳源,采用简便的水热法合成生物质碳量子点(S-CDs)作为荧光探针,用于检测识别Cu²⁺。通过对S-CDs的一系列光学性质分析与表征,鉴定出其表面官能团主要包括O—H, N...     

生物质焦油制备的碳量子点

利用生物质热解副产物焦油为碳前驱体,采用反相微乳液法和P_2O_5碳化法制备了荧光碳量子点。反相微乳液法制备的碳量子点为规则球状结构,粒径均一,平均粒度为4.3 nm,晶面间距为0.25 nm,对应于石墨碳的(100)晶面;P_2O_5碳化法制备的碳量子点为蜂窝状结构,平均粒径为6.8 nm,晶面间距为0.33 nm,对应于石墨碳的(002)晶面。两种方法制备的碳量子点均具备石墨结构特征,碳量子点荧光产率分别为85.3%和24.3%。     

氮掺杂高量子产率荧光碳点的制备及其体外生物成像研究

为获得高量子产率的碳点,以柠檬酸为碳源,苯二胺的3种同分异构体为氮源,采用两步溶剂热法制备了氮掺杂荧光碳点。利用透射电子显微镜(TEM)、紫外-可见吸收光谱(UV-Vis)、荧光光谱、红外光谱(FTIR)、X射线光电子能谱(XPS)对样品进行表征,并考察了碳点的细胞毒性和体外生物成像。实验结果表明:3种高量子产率碳点(Y=52%,60.4%,53.2%)的粒径均一,具有较好的分散性,平均尺寸分别为4.5,5.3,5.2 nm。碳点表面含有羟基、羧基、胺基等基团,在紫外光激发下均能发出明亮的蓝色荧光,并具有稳定的荧光性能。细胞实验表明:3种碳点具有较好的生物相容性,能够快速进入细胞并成功应用于细胞的荧光成像。     

Green Synthetic Approach for Synthesis of Fluorescent Carbon Dots for Lisinopril Drug Delivery System and their Confirmations in the Cells

In this work, highly luminescent carbon dots (CDs) were synthesized by the hydrothermal method at 170 °C for 12 h using pasteurized milk as a carbon source. The prepared CDs exhibited bright blue fluorescence under UV light illumination at 365 nm. The CDs show fluorescence life time of ~4.89 ns at excitation wavelength of 370 nm. The effect of different solvents on the fluorescence property of CDs was also investigated. The lisinopril (Lis)-loaded CDs were fabricated by self-assembly of lisinopril on the surfaces of CDs, which were characterized by UV-visible and FT-IR spectroscopic techniques. The controlled release of lisinopril from the Lis-CDs was realized at pH values of 5.2, 6.2 and 7.4, respectively. The results of the cytotoxicity and confocal laser scanning microscopic images indicate that the Lis-CDs were successfully uptaken by HeLa cells without apparent cytotoxicity. The synthesized CDs show great potential as drug vehicles with good biocompatibility, sustained release of lisinopril from CDs, indicating that the CDs can act as a promising drug delivery system for therapeutic delivery and/or bioimaging applications.     

Quantum Dots Based Fluorescent Probe for the Selective Detection of Heavy Metal Ions

Journal of Fluorescence - Heavy metal ions are one of the primary causes of environmental pollution. A marshal effect of heavy metal ions is a paramount ultimatum to humans, aquatic animals and...     

以花生碳量子点为探针基于其荧光猝灭-恢复测定多巴胺的研究

碳量子点(CQDs)是一种新型的荧光碳纳米功能材料,其良好的生物相容性和优异的光学性能引起了人们的广泛关注。选用富含蛋白质、脂肪和碳水化合物的花生仁(Peanut,PN)及水为原料,无需添加任何其他试剂,在水热反应釜中于190℃反应20 h,可一步合成绿色发光CQDs。透射电镜(TEM)结果显示,所制备的花生碳量子点(PN-CQDs)的粒径大约在10 nm左右,分布较为均匀;X射线衍射谱(XRD)和傅里叶变换红外光谱(FTIR)显示PN-CQDs晶型为无定型碳,表面富含-OH、-COOH、含氮官能团等亲水性基团,具有良好的水溶性。紫外-可见光谱(UV-Vis)和荧光发射光谱(FL)表明, PN-CQDs在275 nm处有一明显的吸收峰,为CQDs紫外特征吸收峰;该PN-CQDs具有激发波长依赖性,荧光发射峰的位置随激发波长的变化而移动;当激发波长λex为326 nm时,发射波长λem为408 nm处的荧光强度最大, PN-CQDs发出蓝色的荧光。以硫酸奎宁为参照物,利用参比法测得PN-CQDs的荧光量子产率φ为5.0%。基于该PN-CQDs良好的发光特性,以其为探针,构建了"关-开"型荧光体系用于多巴胺(Dopamine,DA)的高灵敏度检测。研究表明,在pH 3.80的HAc-NaAc缓冲介质中, Ce(Ⅳ)存在下, PN-CQDs与Ce(Ⅳ)之间的电子转移反应和Ce(Ⅳ)与该PN-CQDs表面基团结合使PN-CQDs发生的聚集作用共同导致PN-CQDs在λex/λem=326 nm/408 nm处的荧光发生猝灭,荧光信号"关闭";当加入DA后, DA与结合于PN-CQDs表面的强氧化性Ce(Ⅳ)发生反应,从而将Ce(Ⅳ)从PN-CQDs表面移除, PN-CQDs的荧光得以恢复,荧光信号重新"打开"。在优化的实验条件下, DA浓度与PN-CQDs在λex/λem=326/408 nm处的荧光恢复值ΔF呈良好线性关系,线性范围为2.5×10-7~1.0×10-5mol·L^-1,决定系数R2为0.997 6,检出限为9.0×10-8mol·L^-1。探讨了体系的荧光"猝灭-恢复"机理,对PN-CQDs和PN-CQDs-Ce(Ⅳ)体系进行了荧光寿命拟合,其加权平均荧光寿命分别为6.02与5.15 ns, Ce(Ⅳ)对PN-CQDs荧光猝灭类型为动态猝灭;反应中生成的Ce(Ⅲ)于λex/λem=251/350 nm处的荧光对DA的测定无影响。该方法灵敏、简便、快速,应用于实际样品中DA的测定,加标回收率(平均值±SD)在97.5%±1.3%~103%±1.5%之间,结果满意。该研究提供了一种新的DA荧光检测方法,实现了对DA的准确测定。     

Green Route for the Synthesis of Fluorescent Carbon Nanoparticles from Circassian Seeds for Fe(III) Ion Detection

Journal of Fluorescence - A facile and green strategy was carried out for the preparation of fluorescent carbon nanoparticles (CNp) using non-toxic circassian seeds as carbon precursor (CNp, named...     

壳聚糖基聚合物点荧光材料的合成及其对纸张的抗紫外老化性能

以壳聚糖、柠檬酸、N-(2-羟乙基)乙二胺为原料,通过水热法合成了壳聚糖基聚合点(P(CS-g-CA)Ds)荧光材料,发现柠檬酸的接枝可明显提高壳聚糖聚合物点的量子产率。对P(CS-g-CA)Ds进行了红外光谱、紫外光谱、光电子能谱、透射电镜、热分解性能及光致发光光谱表征,测试了不同p H值下的荧光强度。结果表明,P(CS-g-CA)Ds在p H=4~12范围内有良好的稳定性。通过测试紫外老化前后宣纸的羰基指数和乙烯基指数研究了P(CS-g-CA)Ds在宣纸中的应用,结果表明其具有良好的抗紫外老化性能。     

Fluorescent Carbon Quantum Dots Functionalized by Poly L-Lysine: Efficient Material for Antibacterial,Bioimaging and Antiangiogenesis Applications

Journal of Fluorescence - This study illustrates the synthesis of functionalized carbon quantum dots (CQDs) by the one-pot pyrolysis method. The functionalization agent used in CQD synthesis was...     

Construction of Hybrid Fluorescent Sensor for Cu2+ Detection Using Fluorescein-functionalized CdS Quantum Dots Via FRET

Journal of Fluorescence - A new hybrid fluorescent nanosensor (Flu@Mea-CdS) for the Cu2+ detection in aqueous solution was constructed through fluorescence resonance energy transfer (FRET). The...     

Green Sources Derived Carbon Dots for Multifaceted Applications

For the past decade, the Carbon dots (CDs) a tiny sized carbon nanomaterial are typically much attentive due to their outstanding properties. Nature is a fortune of exciting starting materials that provides many inexpensive and renewable resources which have received the topmost attention of researchers because of non-hazardous and eco-friendly nature that can be used to prepare green CDs by top-down and bottom-up synthesis including hydrothermal carbonization, microwave synthesis, and pyrolysis due to its simple synthetic process, speedy reactions and clear-cut end steps. Compared to chemically derived CDs, green CDs are varied by their properties such as less toxicity, high water dispersibility, superior biocompatibility, good photostability, bright fluorescence, and ease of modification. These nanomaterials are a promising material for sensor and biological fields, especially in electrochemical sensing of toxic and trace elements in ecosystems, metal sensing, diagnosis of diseases through bio-sensing, and detection of cancerous cells by in-vitro and in-vivo bio-imaging applications. In this review, the various synthetic routes, fluorescent mechanisms, and applications of CDs from discovery to the present are briefly discussed. Herein, the latest developments on the synthesis of CDs derived from green carbon materials and their promising applications in sensing, catalysis and bio-imaging were summarized. Moreover, some challenging problems, as well as upcoming perspectives of this powerful and tremendous material, are also discussed.

     

Highly Sensitive and Selective Detection of Amoxicillin Using Carbon Quantum Dots Derived from Beet

In the present work, we synthesized the carbon quantum dots (CQDs) by one step hydrothermal method using the dried beet powder as the carbon source without additional chemical reagents and functionalization. The as-prepared CQDs are quasi-spherical carbon nanoparticles with diameters of 4–8 nm as well as surface functional groups such as carboxyl and hydroxyl groups, and exhibit good water-solubility, biocompatibility, and strong fluorescence. It is confirmed that amoxicillin (AMO) could enhance the fluorescent intensity of CQDs, the I/I₀ showed a linear correlation between the intensity of fluorescence and the concentration of AMO in a broad range. These superior properties render a potential application of the CQDs in biomedical.