两亲性壳聚糖基聚合物碳点的合成及其在载药方面的应用

通过水热法合成了系列具有高荧光量子产率（42.9%）辛基化壳聚糖基两亲性聚合物碳点荧光材料。利用红外光谱、紫外吸收光谱、光电子能谱、透射电镜、X射线衍射及荧光光谱对聚合物碳点进行了表征。以阿霉素为模型药物,研究了聚合物碳点对阿霉素的载药性能。当辛基取代度为76.42%时,其最大载药量和包封率分别为49.6%与47.4%。在磷酸盐缓冲液中,载药纳米胶束呈前期快速释放,后期缓慢释放的双相特征。将载药纳米胶束与鼻咽癌细胞作用,发现其存活率随着载药纳米胶束加入量的增加而降低,说明该纳米胶束对鼻咽癌细胞有一定的抑制作用。总之,该聚合物碳点材料在药物载体与荧光示踪方面有潜在的应用价值。     

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。     

壳聚糖基聚合物碳点荧光材料合成及其自组装载药应用（英文）

荧光碳点具有化学稳定性好、毒性小、可表面功能化等优点,引起了人们极大的兴趣。近年来,由高分子多糖合成的聚合物碳点成为另一研究热点。本文通过水热法合成了一种壳聚糖基荧光聚合物碳点材料(P(CS-g-m PEG-CA)CDs),并用于载药研究。基于壳聚糖和聚乙二醇既是碳点的碳源也是碳点的钝化试剂,本文选择壳聚糖接枝聚乙二醇单甲醚和柠檬酸衍生物作为聚合物碳点的碳源,以提高聚合碳点的量子产率。另外,聚合物碳点还可以保留聚乙二醇与壳聚糖分子结构,为其在载药方面的应用提供有利条件。采用红外光谱、紫外光谱、X射线衍射、光电子能谱、透射电子显微镜和光致发光光谱对P(CS-g-m PEG-CA)CDs进行了结构表征以及p H值稳定性的测试。结果表明,所合成的P(CS-g-m PEG-CA)CDs具有较高的荧光量子产率(66.81%)、较长的荧光寿命(15.247 ns)、良好的p H稳定性。以阿霉素为模型药物,利用该聚合物碳点进行了负载研究,结果表明,当聚乙二醇单甲醚取代度为11.9%时,聚合物碳点的载药量最高为51.3%,最大药物释放率为28.7%,此外,药物的装载和释放可以通过m PEG的接枝率进行控制。采用MTT法评价了聚合物的碳点对鼻咽癌细胞(CNE-2)的毒性作用。研究表明,空白聚合物碳点无明显细胞毒性,CNE-2细胞存活率随着载药胶束的增加而降低,说明载药胶束对CNE-2细胞有较强的抑制作用。可见该P(CS-g-m PEG-CA)CDs在荧光标记、药物递送、荧光示踪系统和控制释放方面,具有一定的应用前景。     

壳聚糖衍生物基聚合物碳点对Pd2+的传感性能

以柠檬酸与壳聚糖为主要原料,以1-乙基-(3-二甲基氨基丙基)碳酰二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)为偶合剂,合成了一种壳聚糖衍生物(CS-g-CA)。然后将CS-g-CA与掺杂试剂N-(2-羟乙基)-乙二胺通过水热法合成了壳聚糖衍生物聚合物碳点(P(CS-g-CA)Ds)。采用荧光光谱、紫外光谱、透射电镜对P(CS-g-CA)Ds进行了表征和性能测试。结果表明该聚合物碳点具有良好的荧光性能,有较高的量子产率(54.7%)和较长的荧光寿命(13.12 ns)。将P(CS-g-CA)Ds应用于金属离子检测中,发现P(CS-g-CA)Ds对Pd~(2+)有良好的选择性,其检测极限为63.3 nmol/L。通过紫外吸收光谱、荧光寿命以及不同温度下猝灭常数的测定研究了Pd~(2+)对P(CS-g-CA)Ds的荧光猝灭机制,结果均表明其猝灭机制为静态猝灭。     

以固态法一步合成的荧光碳点为探针测定人体尿液中阿霉素

以柠檬酸和尿素为碳源和氮源,采用固态法一步合成出量子产率高达23%的荧光碳点。表征结果表明,所合成的荧光碳点为平均粒径为3~4 nm的球形,表面富含羟基、羧基和胺基等基团。此外,碳点的XRD谱图显示出无定型碳的特征峰。以所制备的碳点为荧光探针,基于碳点和阿霉素之间的共振能量转移而猝灭碳点的荧光,建立了阿霉素定量分析新方法。实验中考察了溶液的pH值和孵化时间的影响。在最佳实验条件下,阿霉素浓度在0.67~16.67 μg·mL-1范围之间与碳点的荧光猝灭值ΔF呈良好的线性关系(R2=0.995),检出限为0.22 μg·mL-1,回收率为83.0%～89.2%,相对标准偏差小于2.5%(n=5)。尿样中常见物质对测定干扰较小,显示出所建立的方法具有较好的选择性。     

一步微波法合成碳点及其荧光性质研究

近年来合成水溶性的荧光碳点受到越来越多研究者的关注。相对于传统的镉基、硅基量子点和有机染料,碳点毒性低,性质稳定,可以进行化学修饰,并且可以和多种有机,无机,生物分子相容,在众多领域中得到广泛应用。以抗坏血酸为原料经过一步微波反应制备了荧光碳点。并通过X射线衍射(XRD),透射电镜(TEM),紫外-可见吸收光谱,荧光光谱,傅里叶红外光谱(FTIR)进行表征。结果显示以抗坏血酸为原料制备的碳点近似球形,大小均匀,分散性良好,无团聚现象,荧光强度大;表面富含羧基和羟基,发射波长依赖于激发波长,并且具有很强的亲水性。在pH 3～11的范围内具有良好的荧光性能。     

荧光碳点在指纹检测中的应用

碳点是一类尺寸在1～10 nm、以碳为主要元素的纳米粒子,因其合成原料广泛、生物安全性高、荧光信号强、光学性质稳定等众多优点在荧光分析检测领域展现出美好的前景.潜指纹是人的手指分泌物留在固体接触面上靠肉眼难以分辨的痕迹,需要经过物理化学处理来增强成像的效果.把荧光碳点应用于潜指纹的增强成像充分发挥了碳点自身的优势,最近...     

荧光碳量子点在药物分析中的应用研究进展

碳量子点(Carbon quantum dots,CQDs)作为一种新型的荧光碳纳米材料,具有原材料来源广泛、制备简单、易操作、灵敏度高、发光性能优异和易可视化等优势,近年来在药物分析和生物小分子检测方面极具应用潜力.本文主要综述了CQDs作为荧光传感器在部分抗菌药物、抗炎药物、抗肿瘤药物、多种维生素以及一些药物小分子...     

溶剂热法合成橙-绿双波段荧光碳点

荧光碳点具有激发波长依赖的独特性质,有望基于此制备检测溶液pH值的荧光探针。以柠檬酸和尿素为原料、N,N-二甲基甲酰胺为溶剂,采用一步溶剂热法在200℃下保温12 h制备了一种新型的具有橙-绿双波段荧光发射性能的水溶性碳点。采用透射电子显微镜、X射线衍射、拉曼光谱、傅里叶变换红外光谱和X射线光电子能谱等方法对荧光碳点的组成和形貌进行了表征,还通过荧光发射光谱和紫外-可见吸收光谱对其光学性能进行了研究。结果表明,制备的碳点粒径为2.7～4.3 nm,表面带有大量含氧官能团,具有良好的水分散性。在440 nm和540 nm波长光激发下分别呈现绿色(500 nm)和橙色(590 nm)双波段荧光发射。合成的荧光碳点发光性能对pH值具有敏感性:在强碱性溶液中,590 nm的荧光强度比水溶液中提高了6.71倍,同时吸收峰的蓝移使得自然光下其溶液颜色发生了明显改变,具有强碱性指示剂的作用;在pH值为2～6的酸性溶液中,500 nm与590 nm发光峰强度比与pH值之间呈现良好的线性关系,展现了作为pH值比率荧光探针的应用潜力。     

荧光碳量子点的制备与生物医学应用研究进展

碳量子点是一类具有优异的荧光性能和高生物相容性的纳米材料,在很多领域有广泛的应用,是目前研究的热点材料。本文介绍了碳量子点不同的合成方法,以及碳量子点的荧光、化学发光、电化学发光、类过氧化物酶的活性及毒性等性能的最新研究进展。此外,还对碳量子点在生物传感、生物成像及药物传递等生物医学应用进行了概述。     

Influence of sulfur doping on the molecular fluorophore and synergistic effect for citric acid carbon dots

In citric acid-based carbon dots, molecular fluorophore contributes greatly to the fluorescence emission. In this paper,the nitrogen and sulfur co-doped carbon dots(N,S-CDs) were prepared, and an independent sulfur source is selected to achieve the doping controllability. The influence of sulfur doping on the molecular fluorophore was systematically studied.The introduction of sulfur atoms may promote the formation of molecular fluorophore due to the increased nitrogen content in CDs. The addition surface states containing sulfur were produced, and S element exists as –SO_3, and –SO_4 groups.Appreciate ratio of nitrogen and sulfur sources can improve the fluorescence emission. The photoluminescence quantum yields(PLQY) is increased from 56.4% of the single N-doping CDs to 63.4% of double-doping CDs, which ascribes to the synergistic effect of molecular fluorophores and surface states. The sensitivity of fluorescence to p H response and various metal ions was also explored.     

Facile synthesis of fluorescent carbon dots from shrimp shells and using the carbon dots to detect chromium(VI)

It is important to develop methods to sensitively and selectively determine chromium(VI) because chromium(VI) plays crucial roles in pathological and physiological processes. We developed an easy-to-perform, low-cost, and efficient method for synthesizing carbon dots from shrimp shells by calcining the shells without using any chemical reagents. The as-prepared carbon dots exhibited excitation-dependent fluorescence, with excitation and emission maxima at 350 and 400?nm, respectively. The Carbon dots were found to be excellent fluorescent probes for detecting chromium(VI) using the fluorescence quenching effect. The Carbon dots allowed chromium(VI) to be determined with a high degree of sensitivity. The chromium(VI) detection limit was 0.1?µM, and the relationship between the chromium(VI) concentration and the response was linear up to a chromium(VI) concentration of 70?µM. The method for synthesizing carbon dots is novel and the carbon dots produced offer promise for monitoring chromium(VI) in environmental matrices.     

Synthesis of nanostructured polymer materials with different morphologies: Nanoporous ordered networks and hollow capsules

Nanostructured polymer materials with interesting morphological variation, which include three dimensionally interconnected uniform nanoporous network arrays (volume- and surface-templated ordered arrays) and hollow core spheres were synthesized by inducing different polymerization process of phenol and formaldehyde as a precursor over silica templates (ordered silica colloidal crystals or individual silica particles). The pore sizes of the resulting nanostructured polymer materials can be easily controlled by monitoring the sizes of silica spheres, while their morphologies were modulated by controlling the initiation sites of the acid-catalyzed condensation reaction of the same polymer precursor and by modifying silica templates.     

Green synthesis of fluorescent graphene quantum dots and its application in selective curcumin detection

Herein, we present a facile low-cost and eco-friendly approach for conversion of bamboo timber waste (Bf) derived cellulose nanocrystals (Bf-CNCs) into strong blue luminescent graphene quantum dots (Bf-GQDs) by hydrothermal route. The various properties of synthesized Bf-GQDs were investigated using different spectroscopic techniques. The probable mechanism of Bf-GQDs formation from Bf-CNCs and the effect of pH, particle size on the fluorescent properties of Bf-GQDs also executed. Furthermore, Bf-GQDs were used for the detection of curcumin in an aqueous environment which is the major prerequisite of the present study. The Bf-GQDs showed remarkable photoluminescence (PL) quenching kinetics toward the curcumin (LOD 30.0 nM L⁻¹) assessed by Stern-Volmer plot. The practicability of the method assessed using ginger rhizome juice, while the selectivity of the Bf-GQDs evaluated against different metal ions and different biochemicals. The proposed method will support to establish the strategies for the detection of biochemicals from the aqueous system.     

Ultrasound-assisted synthesis of PbS quantum dots stabilized by 1,2-benzenedimethanethiol and attachment to single-walled carbon nanotubes

Lead sulfide (PbS) quantum dots stabilized by 1,2-benzenedimethanethiol can be synthesized by mixing Pb(NO₃)₂ and Na₂S solutions in ethanol under ultrasound irradiation. The PbS quantum dots (2.7 and 3.6 nm in diameter) are characterized by their absorption and fluorescence spectra in the near infrared region and by other surface analytical techniques. With addition of single-walled carbon nanotubes (SWNT) to the system, this ultrasound-assisted procedure allows attachment of PbS nanoparticles to SWNT surface via π–π stacking, thus providing a simple one-pot method for preparation of SWNT–PbS nanoparticle composite materials. Using the ultrasound-assisted method for synthesizing silica composites containing PbS nanoparticles by a sol–gel process is also described.     

碳纤维天鹅绒阴极与化纤天鹅绒阴极的比较

研制了一种碳纤维天鹅绒阴极,并对碳纤维天鹅绒阴极和化纤天鹅绒阴极进行了初步的比较研究。比较结果表明:碳纤维天鹅绒阴极比化纤天鹅绒阴极启动稍慢。在相同的驱动电压条件下,碳纤维天鹅绒阴极产生的微波输出功率有可能优于化纤天鹅绒阴极。但是,由于纤维脱落导致碳纤维天鹅绒产生微波的性能显著下降。在高电压运行中,化纤天鹅绒的纤维尖端由于高温烧蚀而膨胀、弯曲,从而影响了其运行寿命;但碳纤维天鹅绒的纤维尖端在实验运行后没有出现因高温烧蚀而膨胀、弯曲的现象。因此,碳纤维天鹅绒阴极的运行寿命应优于化纤天鹅绒。     

碳纤维天鹅绒阴极与化纤天鹅绒阴极的比较

研制了一种碳纤维天鹅绒阴极,并对碳纤维天鹅绒阴极和化纤天鹅绒阴极进行了初步的比较研究。比较结果表明：碳纤维天鹅绒阴极比化纤天鹅绒阴极启动稍慢。在相同的驱动电压条件下,碳纤维天鹅绒阴极产生的微波输出功率有可能优于化纤天鹅绒阴极。但是,由于纤维脱落导致碳纤维天鹅绒产生微波的性能显著下降。在高电压运行中,化纤天鹅绒的纤维尖端由于高温烧蚀而膨胀、弯曲,从而影响了其运行寿命;但碳纤维天鹅绒的纤维尖端在实验运行后没有出现因高温烧蚀而膨胀、弯曲的现象。因此,碳纤维天鹅绒阴极的运行寿命应优于化纤天鹅绒。