Dendritic upconverting nanoparticles for multiphoton imaging and sensing

用于多光子成像和传感的树突上转换纳米颗粒

• 批准号: 8932692
• 负责人: SERGEI VINOGRADOV
• 金额: $ 35.72万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-24 至 2018-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8932692
• 关键词: Address; Angiography; Architecture; Back; Binding; Biocompatible; Biological; Biological Process; Blood flow; Brain; Cerebrovascular Circulation; Cerebrum; Coupled; Dendrimers; Detection; Dyes; Electric Stimulation; Energy Transfer; Evaluation; Fluorescence; Frequencies; Functional Magnetic Resonance Imaging; Goals; Health; Image; Imagery; Imaging Techniques; Ions; Lanthanoid Series Elements; Lasers; Ligands; Light; Measurement; Methods; Microscopic; Microscopy; Modification; Morphology; Mus; Neurosciences; Optics; Oxygen; Partial Pressure; Photons; Physiologic pulse; Physiological; Pilot Projects; Posterior Pituitary Gland; Problem Solving; Property; Radiation; Resolution; Risk; Rodent; Rodent Model; Route; Sampling; Scheme; Shapes; Signal Transduction; Solutions; Source; Stroke; Surface; Technology; Testing; Time; Tissues; Toxic effect; Variant; Vesicle; Visible Radiation; Water; absorption; base; bioimaging; blood rheology; carboxylate; chemical property; chromophore; cost; design; extracellular; feeding; imaging modality; imaging probe; in vivo; luminescence; macromolecule; nanoparticle; neurotransmitter release; prevent; ratiometric; research study; two-photon

DESCRIPTION (provided by applicant): In this project we address the need in probes for two-photon microscopy - the leading imaging technique for dynamic visualization and quantification of biological processes in vivo in 3D with micron-scale spatial resolution. We propose to develop a new class of multiphoton probes, termed dendritic UCNPs, which comprise lanthanide-based up converting nanoparticles (UCNPs) and dendritic ligands. The key advantage of UCNPs is their enormously high multiphoton absorption cross-sections, which exceed those of the most efficient multiphoton probes available today by several orders of magnitude. Recently, we demonstrated that due to this remarkable property, in vivo two-photon depth-resolved microscopic imaging with UCNPs can be accomplished using simple low-power continuous-wave (CW) infrared light sources, which is in contrast to conventional two-photon experiments requiring very expensive pulsed femtosecond lasers. This remarkable advantage comes on top of other benefits of UCNPs, which include record-high photo stability, zero background fluorescence (due to CW infrared excitation) and greatly diminished risk of photo damage. However, lack of robust methods of UCNP solubilization and functionalization has been a major obstacle preventing their inclusion into the toolkit of modern imaging methods. We propose to solve this problem by using dendritic macromolecules. Our key proposition is that modification of UCNP surfaces with hydrophilic shape-persistent dendrimers will make up an efficient and general route to soluble bio-compatible UCNPs, whose luminescence will be coupled to analyte detection via UCNP-to-dendrimer excitation energy transfer (EET). Our approach capitalizes on unique structural features of dendritic architecture, i.e. intrinsic polyvalency and pseudo- globular shape. Both "colorless" probes for morphologic angiographic two-photon imaging and dedicated probes for imaging of specific analytes (pH and Ca2+) will be developed. To test the probes we will perform: (a) angiographic imaging in vivo in rodent brain, determining changes in blood rheology upon functional stimulation; (b) simultaneous in vivo multiphoton imaging of alterations in tissue pH and partial pressure of oxygen (pO2) in stroke rodent models; d) imaging of extracellular Ca2+ flux in mouse neurohypophysis upon electrical stimulation. All these experiments will differ from conventional multiphoton imaging in that the cost of the excitation sources will be lower by ca 1000 fold. These applications will demonstrate the ability of the new probes to a) replace currently used expensive multiphoton setups; and b) go beyond and address questions and hypotheses in neuroscience for which no alternative solutions are currently available.

描述（由申请人提供）：在此项目中，我们解决了两光子显微镜的探针中的需求 - 用于动态可视化和定量体内生物学过程的领先成像技术，并以微米尺度的空间分辨率在3D中。我们建议开发一种新的多光子探针，称为树突UCNP，该探针包括基于灯笼的纳米颗粒（UCNPS）和树突状配体。 UCNP的关键优点是它们极高的多光子吸收横截面，超过了当今最有效的多光子探针的横截面。 Recently, we demonstrated that due to this remarkable property, in vivo two-photon depth-resolved microscopic imaging with UCNPs can be accomplished using simple low-power continuous-wave (CW) infrared light sources, which is in contrast to conventional two-photon experiments requiring very expensive pulsed femtosecond lasers.这种显着的优势取决于UCNP的其他好处，其中包括创纪录的照片稳定性，零背景荧光（由于CW红外激发）以及造成照片损害的风险大大降低。但是，缺乏UCNP溶解化和功能化的强大方法一直是一个主要障碍，无法将其纳入现代成像方法的工具包。我们建议通过使用树突大分子来解决这个问题。我们的关键主张是，用亲水性形状抗性树枝状聚合物对UCNP表面进行修饰将构成一种有效且一般的途径，以通过UCNP-TO-TO-DENDENDRIMER激发能量转移（EET）耦合到可溶性生物兼容的UCNP。我们的方法利用了树突结构的独特结构特征，即内在的多性价和伪球形。形态血管造影两光子成像的“无色”探针和用于特定分析物（pH和Ca2+）成像的专用探针都将开发。为了测试我们将执行的探针：（a）啮齿动物大脑中体内的血管造影成像，确定功能刺激时血流变学的变化； （b）同时在中风啮齿动物模型中的组织pH和氧气压力（PO2）变化的体内多光子成像； d）在电刺激时，小鼠神经触及旋转中细胞外Ca2+通量的成像。所有这些实验都将与常规多光子成像不同，因为激发源的成本将降低Ca 1000倍。这些应用程序将证明新探针对a）替换当前使用的昂贵多光子设置的能力； b）超越并解决了当前没有其他解决方案的神经科学中的问题和假设。