【作者】 王鑫；

【导师】 韩晓军； 陈冠英；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2021， 博士

【摘要】 近红外稀土发光纳米晶是一类新型具有优异光学性能的无机纳米探针,在活体成像、光治疗、生物传感等领域具有广阔的应用前景。然而,这类纳米晶还存在近红外发光量子产率低、难以兼容治疗模态、荧光强度活体定量分析难等问题,严重限制其生物诊疗一体化应用潜力。针对这些问题,本论文基于低声子能量的六方相Na Ln F₄稀土纳米晶材料,从核壳结构调控角度出发构筑了三种高效发光的稀土基纳米探针,并利用这些探针实现了高对比度的光学成像、成像介导的光热治疗及氧化应激标记物的定量分析。本论文的主要研究内容如下:利用NaErF₄:Yb@Na Lu F₄纳米探针实现体内高对比度的光学成像。在808nm近红外光的激发下,探究了Er³⁺离子自敏化核壳结构纳米晶（Na YF₄:x%Er@Na Lu F₄）中Er³⁺离子浓度对近红外二区发光（1525 nm）的影响,确定该体系中最佳Er³⁺离子掺入浓度为100%,实现了强度最高的1525 nm发光。在此基础之上,在内核中掺入Yb³⁺离子并优化其掺入浓度,研究Yb³⁺离子对Er³⁺离子1525 nm荧光的增强作用,最终获得荧光亮度更高的NaErF₄:20%Yb@Na Lu F₄核壳结构纳米晶（量子效率11%）。而且,该纳米晶在808 nm近红外光的激发下能够穿透11 mm鸡肉组织。通过聚丙烯酸（Polyacrylic acid,PAA）修饰使有机相纳米晶转移到水相溶液中,并PAA包覆的NaErF₄:20%Yb@Na Lu F₄核壳结构纳米晶经尾静脉注入小鼠体内,实现了高对比度的颅部血管成像。构筑稀土-普鲁士蓝诊疗体系（NaErF₄@Na YF₄@NaNdF₄@普鲁士蓝）用于探究近红外光学成像介导的光热治疗（Photothermal therapy,PTT）。在980 nm的近红外光下,考察该诊疗剂内部稀土核壳/壳/壳结构纳米晶（NaErF₄@Na YF₄@NaNdF₄）在1525nm的发光性能,用于实现近红外二区光学成像。同时,在808 nm的近红外光激发下,探究普鲁士蓝对稀土纳米晶的光热增强作用,揭示了Nd³⁺离子自身的交叉弛豫及Nd³⁺离子与普鲁士蓝之间的交叉弛豫作用是诊疗剂发挥光热作用的主要原因。该诊疗剂具有优异的近红外光学吸收、光热转化性能（光热转化率为η=50.5%）,能够抑制80%以上的He La细胞增长。最终,在小鼠肿瘤模型中原位注射该诊疗剂,利用近红外二区成像介导光热治疗,可有效地抑制肿瘤增长（与对照组相比肿瘤体积减小了12倍以上）。此外,利用光学成像还能监测光热治疗的过程,并对治疗情况进行评估。通过稀土-普鲁士蓝荧光探针（Na YF₄@Na Yb F₄@Na Yb F₄:Tm@Na YF₄@普鲁士蓝）进行近红外荧光寿命成像实现生物体内标记物的定量分析及动态监测。首先探究稀土纳米晶（Na YF₄@Na Yb F₄@Na Yb F₄:Tm@Na YF₄）的上转换发射光谱与普鲁士蓝的吸收光谱的重叠情况,阐明探针内部的荧光能量共振转移作用抑制了其在800 nm的上转换荧光寿命。然后在不同浓度的氧化活性物质的作用下,考察该探针荧光寿命的恢复情况,并基于此构建用于检测内源性氧化应激标记物的标准曲线。同时引入染料Hcy5保护该荧光探针免受O₂·^–的干扰,提高该探针的选择性。最后结合近红外荧光寿命信号独立于组织穿透深度的特性,在小鼠肝中毒和脚部炎症模型中,利用该探针分别对ONOO^–和Cl O^–进行不同时间点的荧光寿命成像,实现对生物标记物的定量分析和监测。更多还原

【Abstract】 The near infrared（NIR）rare earth doped nanocrystals are a class of novel inorganic nanoprobes with unique optical property,which are widely used in vivo imaging,phototherapy and biosensing.However,these nanocrystals suffered from low quantum yield,lack of compatibility with therapeutic model and hardly in vivo quantitative analysis using luminescence intensiy,limiting their biological research on integration of diagnosis and treatment.To overcome these problems,three efficient rare earth doped nanoprobes were constructed by regulating core/shell structure,according to the Na Ln F₄ nanocrystals with a hexagonal crystallographic phase and low phonon energy state.These probes realized high-constast bioimaging,image-guided photothermal therapy and quantitative detection of the oxidative stress markers.The main research contents are summarized as follows:High contrast optical in vivo imaging was performed with NaErF₄:Yb@Na Lu F₄nanoprobes.Under 808 nm NIR laser irradiation,the effect of doping Er³⁺ions concentration in Na YF₄:x%Er@Na Lu F₄on 1525 nm NIR-Ⅱluminescence was investigated via varying the doping concentration of Er³⁺ions.The optimal doping concentration of Er³⁺ions in the system was determined to be 100%,and the high1525 nm luminescence intensity was obtained.On the basic of 100%Er³⁺ions doping,Yb³⁺ions were introduced and optimized its doping concentration for enhancing1525 nm luminescence of Er³⁺ions.As a result,the core-shell nanocrystals of NaErF₄:20%Yb@Na Lu F₄ can generate brighter luminescence intensity（quantum yield was 11%）,and successfully penetrated 11 mm chicken tissue under 808 nm excitation.Coating polyacrylic acid（PAA）,NaErF₄:20%Yb@Na Lu F₄ core-shell nanocrystals was transfered to water phase and injected intravenously for the high contrast optical imaging of blood vasculature in the mouse brain.Rare earth-prussian blue theranostic agents（NaErF₄@Na YF₄@NaNdF₄@Prussian blue）were constructed for NIR luminescence imaging guided photothermal therapy（PTT）.For 980 nm light excitation,the 1525 nm luminescence of Er³⁺ions from interior NaErF₄@Na YF₄@NaNdF₄ core/shell/shell nanocrystals was investigated for NIR-Ⅱimaging.Under 808 nm light excitation,the photothermal enhancement of prussian blue to rare earth nanocrystals was studied,and demonstrated that the cross-relaxation between Nd³⁺ions,and new cross-relaxation pathways between Nd³⁺ions and prussian blue were the main reson for PTT.These theranostic agents had excellent NIR optical absorption and photothermal transformation performance（photothermal conversion was 50.5%）,resulting in⁸0%death of He La cells.Finally,NIR-Ⅱluminescence imaging guided PTT was realized by injection of the rare earth-prussian blue theranostic agents in the mouse tumor model,and effectively surpressed the tumor（the tumor size shrunk 12-fold compared to the tumors without treatment）.In addation,luminescence imaging also monitored the PTT process and evaluated the therapy.In vivo quantitative analysis and dynamic monitoring the markers of oxidative stress were realized using the rare earth-prussian blue luminescent probes（Na YF₄@Na Yb F₄@Na Yb F₄:Tm@Na YF₄@Prussian blue）.The overlap between luminescence spectra of Na YF₄@Na Yb F₄@Na Yb F₄:Tm@Na YF₄ nanocrystals and absorption spectra of prussian blue was investigated for illustrating the luminescence resonance energy transfer effect,which resulted the suppression of 800 nm luminescence lifetime of Tm³⁺ions.In the presence of different concentrations of oxidative species,the lifetime recovery of the rare earth-prussian blue luminescent probes was analyzed,and used for constructing a standard curve of oxidative stress markers.To improve the selectivity,the hydrocyanine 5（Hcy5）,an activatble dye,was introdeced as a competitor to protect rare earth-prussian blue luminescent probes from O₂·^–.Combined with NIR luminescence lifetime is independent of tissue penetration depth,the prepared luminescent probes were applied for ONOO^–and Cl O^–lifetime imaging at different time points in the hepatotoxicity and inflammation model of mice,realizing quantitative measurement and monitor of biomarkers.更多还原