【作者】 唐晓丹；

【导师】 胡知之； 于洪梅；

【作者基本信息】 辽宁科技大学 ， 化学工程与技术， 2021， 博士

【摘要】 近年来,纳米科技的飞速发展已经引起了生物医药和分析研究人员的极大兴趣。碳点（Carbon Dots,CDs）作为碳纳米材料家族的一个新成员,因具备超高的生物相容性,优异的光致发光、优越的电子转移能力、低细胞毒性和多功能表面改性等优点,在细胞/细菌成像、生物/化学传感、光电器件、靶向药物传递、癌症/基因治疗和其他生物医学应用中表现出惊人的应用潜力。目前,碳点的制备还存在弊病,如制备复杂繁琐、合成条件苛刻及环境污染,使用价格低廉、绿色无毒的试剂或可再生生物质废弃物作碳源制备环境友好的碳点已成为环境可持续发展的必然趋势。同时,为了减少资源消耗和能源浪费,通过设定不同发光颜色或检测机制实现两种或以上目标物的同时检测,是科研人员一直努力的工作方向。另外,量子产率是评价碳点荧光性能的一个重要指标。杂原子掺杂能够导致碳点的带隙和能级发生改变,不仅使碳点的荧光量子产率得到有效提升,还可以使碳点的发光光谱红移,碳点在可见光区的光学性能能够使其拥有更大的生物学应用前景。为了解决上述问题,在本论文中,通过元素掺杂制备了多种环境友好的功能化荧光碳点,利用先进的技术分析手段对碳点的结构和形貌进行表征,开发了这些材料在离子或药物传感中的实际应用。论文主要由以下四部分构成:第一章:对碳点的分类、光学特性和传感机理进行了阐述。着重围绕碳点的应用进行详细的论述,包括传感和信息涉密安全等光学领域的应用,光/电催化剂、LED、太阳能电池、超级电容器和可充电电池等能源领域的应用以及在生物成像、光疗、药物/基因传输和纳米医学等生物医学领域的研究及应用。第二章:以廉价的酒石酸为碳源,尿素为氮源,采用一步无溶剂固相法,简便,快速地合成了环境友好的发射绿光的荧光碳点（NCDs）。基于NCDs与Hg²⁺之间的特定亲和力,导致NCDs聚集而发生荧光猝灭。当向NCDs-Hg²⁺体系中引入I^-时,由于HgI₂的结合常数远远高于NCDs与Hg²⁺的结合常数,基于“turn-off-on”机制,构建了NCDs-Hg²⁺荧光增强型传感器灵敏检测I^-的方法。线性范围为0.3-15μM,检出限为69.4nM,该方法已成功用于水样和尿样中I^-的定量测定。基于内滤效应（IFE）和静态猝灭的猝灭机制,构建了猝灭型荧光传感器测定姜黄素的方法。在0.1-20.0μM范围内,具备线性关系,有令人满意的检出限29.8nM,并成功应用于食品和环境水样中姜黄素的测定,回收率在95.7-104.8%之间。综上,开发了基于同一个NCDs的化学传感器,利用两种不同传感机制同时检测I^-和姜黄素的荧光方法,在环境水样,生物和食品中对碘和姜黄素的检测和监测具有极大的应用潜力。第三章:以廉价的柠檬酸为碳源,硫脲为掺杂剂,采用无溶剂添加的固相法,制备了荧光性能优异的氮、硫共掺杂荧光碳点。通过浓度调控机制分别制成高浓度G-NSCDs和低浓度B-NSCDs,实现了对利福平、桑色素和Al³⁺的高灵敏和高选择性的次序检测。基于光诱导电子转移和动态猝灭的协同作用,G-NSCDs猝灭型荧光传感器实现了对利福平的灵敏检测,线性范围0.2-20.0μM,最低检出限为56.6nM。由于B-NSCDs激发光谱与桑色素紫外吸收光谱的有效重叠,构筑了基于内滤效应和静态猝灭共同作用的“turn-off”型B-NSCDs荧光传感器,实现了对桑色素的专一识别。ΔF和桑色素浓度（0.2-30.0μM）呈现良好的线性关系,最低检出限为51.2nM。基于桑色素和Al³⁺强有力的螯合作用,在B-NSCDs-桑色素体系基础上,利用“turn-off-on”机制又构筑了一种选择好,灵敏度高的Al³⁺荧光探针。Al³⁺响应范围在0.1-2.0μM时,最低检出限为45.8nM。综上,基于浓度调控的多色荧光碳点,利用多模式探索了简便快速,选择性好,灵敏度高的同时检测利福平、桑色素和Al³⁺的荧光方法,在疾病诊断、水质检测和生物医学等领域表现出卓越的应用潜力。第四章:以厨房废弃物葡萄皮为有机碳源,通过尿素引入氮元素,采用简单、无污染的一步固相热解法合成量子产率15.3%且发射绿色荧光的葡萄皮碳点（PT-NCDs）。通过TEM、XRD、XPS、FTIR和PL等表征技术对PT-NCDs的粒径、结构、元素组成及表面官能团进行了深入的分析,并对黄芩苷的传感能力进行了评估。基于光诱导电子转移和动态猝灭机理,实现了对治疗肝病特效药物黄芩苷的灵敏检测。黄芩苷浓度在0.1-20.0μM时,ΔF与C_黄芩苷呈线性关系,检出限为43.8nM,并将该方法成功用于生物样品（尿样和血清）的检测。与文献中的分析方法进行对比,本文构建的荧光传感器便捷、高效,在临床诊疗、医药监测和环境分析中具有重要的现实意义。更多还原

【Abstract】 In recent years,the rapid development of nanotechnology has aroused great interest among the biomedicine and analytical researchers.As a new member of the carbon nanomaterials family,carbon dots（CDs）have the advantages of ultra-high biocompatibility,excellent photoluminescence,superior electron transfer ability,low cytotoxicity and multifunctional surface modification,which have shown amazing potential applications in cell/bacterial imaging,biological/chemical sensing,optoelectronic devices,targeted drug delivery,cancer/gene therapy and other biomedicine fields.At present,the preparation of carbon dots still has disadvantages,such as complicated and cumbersome preparation,harsh synthesis conditions and environmental pollution.The use of inexpensive,green and non-toxic reagents or renewable biomass wastes as carbon sources to prepare environmentally friendly CDs has become an inevitable trend of environmental sustainable development.Meanwhile,in order to reduce resource consumption and energy waste,the simultaneous detection of two or more targets by setting different luminous colors or detection mechanisms is the direction of scientific research.In addition,quantum yield is an important indicator for evaluating the fluorescence performance of CDs.Heteroatom doping can change the band gap and energy level of CDs,which can not only effectively improves the fluorescence quantum yield of CDs,but also redshift the emission spectrum of CDs.The optical performance of CDs in the visible light region can be improved which make it have greater biological application prospects.The optical properties of CDs in the visible light region can make it have greater biological application prospects.To solve the above problems,in this thesis,a variety of environmentally friendly functionalized fluorescent CDs were prepared by element doping,and the structure and morphology of CDs were characterized by advanced technical analysis methods.The practical applications of CDs in the field of ion and drug sensing were developed.This dissertation is mainly composed of the following four parts:Chapter 1:The classification,optical properties and sensing mechanism of CDs were described,which focused on the applications of CDs for detailed discussion,including the applications in optical fields such as sensing and information security,the applications in energy fields such as light/electrocatalysts,LEDs,solar cells,supercapacitors and rechargeable batteries,and the research and applications in biomedical fields such as bioimaging,phototherapy,drug/gene transfer and nanomedicine.Chapter 2:A facile,fast,and environmental-friendly route to construct nitrogen doped CDs（NCDs）with green emission was developed using a one-step solvent-free solid phase method with inexpensive tartaric acid as carbon source and urea nitrogen source.Based on the specific affinity between NCDs and Hg²⁺,which caused the aggregation of CDs and quenched the fluorescence.When I^-was added into the NCDs-Hg²⁺system,since the binding constant of Hg I₂was much higher than that of NCDs and Hg²⁺,a method for sensitive detection of I^-with NCDs-Hg²⁺fluorescence-enhanced sensor was studied based on the"turn-off-on"mechanism.The linear range was 0.3-15.0μM with the detection limit of 69.4nM.This method has been successfully used for the quantitative determination of I^-in water and urine samples.Meanwhile,a quenching fluorescence sensor was constructed to determine curcumin based on the internal filtration effect（IFE）and the static quenching,achieving a good linear range of 0.1–20μM with a satisfactory detection limit of 29.8nM,which has been successfully applied to the determination of curcumin in food and environmental water samples with the recovery rate between 95.7-104.8%.In the present work,two sensing mechanisms for the detection of I^-and curcumin were integrated into one NCDs-based chemosensor,which has an extremely high potential for the detection and monitoring of iodine and curcumin in environmental water,biology and food samples.Chapter 3:The nitrogen and sulfur co-doped fluorescent CDs with excellent fluorescence properties were constructed using a solvent-free solid-phase method with cheap tartaric acid as carbon source and thiourea as dopant.High-concentration G-NSCDs and low-concentration B-NSCDs were prepared respectively with the concentration control mechanism,which realizes the highly sensitive and selective sequential detection of rifampicin,morin and Al³⁺.Based on the synergistic effect of light-induced electron transfer and dynamic quenching,the G-NSCDs quenched fluorescence sensor realized the sensitive detection of rifampicin with a linear range of 0.2-20.0μM and a minimum detection limit of 56.6nM.Due to the effective overlap of the B-NSCDs excitation spectrum and the ultraviolet absorption spectrum of Morin,a"turn-off"B-NSCDs fluorescence sensor based on the combined action of the internal filtration effect and static quenching had been constructed to realize the specific identification of Morin.ΔF and morin concentration（0.2-30.0μM）showed a good linear relationship with the lowest detection limit of 51.2nM.Based on the strong chelation effect of Morin and Al³⁺,a well-selected and highly sensitive Al³⁺fluorescent probe had been constructed using a"turn-off-on"mechanism with B-NSCDs-Morin system.The Al³⁺response range was0.1-2.0μM with the lower detection limit of 45.8nM.In summary,a simple,rapid,selective,and highly sensitive fluorescent method for simultaneous detection of rifampicin,morin and Al³⁺was explored with multi-mode detection mechanism based on the concentration-regulated multi-color fluorescent CDs,which shows excellent application potential in disease diagnosis,water quality detection,and biomedicine fields.Chapter 4:A simple,non-polluting,and one-step solid-phase pyrolysis method to synthesize grape skin CDs（PT-NCDs）emitting green fluorescence with a quantum yield of 15.3%using kitchen waste grape skin as the organic carbon source and urea as dopant.The particle size,structure,element composition and surface functional groups of PT-NCDs had been analyzed deeply with the characterization techniques such as TEM,XRD,XPS,FTIR and PL.Meanwhile,the sensing ability of baicalin was also evaluated.The sensitive detection of baicalin was realized based on the light-induced electron transfer and dynamic quenching mechanism,which is a specific drug for treating liver diseases.A linear relationship betweenΔF and the concentration of baicalin was 0.1-20.0μM with the detection limit of 43.8nM.The fluorescence sensor has been successfully used for the detection of baicalin in biological samples（urine and serum）.Compared with the analysis methods in the literature,the constructed fluorescence sensor is convenient and efficient,which has important practical significance in clinical diagnosis and treatment,medical monitoring and environmental analysis.更多还原