DENDRITIC O2 SENSOR WITH TWO-PHOTON ABSORBING ANTENNA

描述（由申请人提供）：我们建议构建一个纳米级的氧分子传感器，它将利用双光子（2 P）吸收现象，允许在各种生物对象中进行高分辨率的O2测量，包括使用双光子激光扫描显微镜（2 P LSM）在体内脑神经元中进行氧成像。纳米传感器的设计将结合联合收割机的几个原则和元素，目前在纳米科学和纳米技术应用的审查。这些措施包括：双光子吸收（2 PA）;天线阵列，由耦合到相同功能核心的多个发色团组成;从天线到核心的定向分子内能量转移（ET）;核心功能的树枝状封装，以提供其保护和对其局部环境的控制。简而言之，1）用作激发能的末端受体的器件的中心组分将是多官能化的Pt或Pd卟啉，其三重态发射强，在近红外线中发生并且对O2敏感; 2）由于金属卟啉的2 P吸收截面很小，几个强的2 P吸收体将连接到核上，直接或连接到连接到卟啉的树枝状臂的末端，提供有效的2 P天线; 3）选择2 P发色团，使得它们的2 P吸收带在组织的近红外窗口中（例如700-900 nm），而它们的发射将与核心金属卟啉的吸收带最大重叠，确保有效的天线-发射器能量转移（ET）; 4）在天线耦合中未使用的核金属卟啉上的官能团将用于连接保护树枝化基元;这些将形成封装套、隔离芯与生物组分的相互作用、控制氧的扩散并使整个传感器可溶于水。除了是关键的2 P在体内氧成像，所提出的构建将是一个很好的模型化合物，研究三重态发射和氧猝灭在单分子水平。如果成功，这些实验将为新的研究开辟道路，从小分子扩散的蛋白质构象研究到单分子氧传感器的构建。

DESCRIPTION (provided by applicant): We propose to construct a nano-scale molecular sensor for oxygen, which will take advantage of the two-photon (2P) absorption phenomenon, permitting high-resolution O2 measurements in a variety of biological objects, including oxygen imaging in brain neurons in vivo, using two photon laser scanning microscopy (2P LSM). The design of the nano-sensor will combine several principles and elements, currently under scrutiny in nano-science and nano-technology applications. These will include: two-photon absorption (2PA); an antenna-array, consisting of multiple chromophors coupled to the same functional core; directional intramolecular energy transfer (ET) from the antenna to the core; dendritic encapsulation of the core function to provide its protection and control of its local environment. In brief, 1) the central component of the device, serving as the terminal acceptor of the excitation energy, will be a polyfunctionalized Pt or Pd porphyrin, whose triplet state emission is strong, occurs in the near infra-red and is sensitive to O2; 2) because 2PA cross sections of metalloporphyrins are small, several strong 2P absorbers will be linked to the core, either directly or to the termini of dendritic arms attached to the porphyrin, providing an efficient 2P antenna; 3) the 2P chromophors will be chosen in such a way that their 2P absorption bands will be in the near infra-red window of tissue (e.g. 700-900 nm), while their emission will be maximally overlapped with the absorption band(s) of the core metalloporphyrin, assuring efficient antenna ->remitter energy transfer (ET); 4) the functional groups on the core metalloporphyrin unused in the coupling of the antenna will be used for attaching the protecting dendrons; these will form an encapsulating jacket, isolating the core from interactions with biological components, controlling diffusion of oxygen and making the entire sensor water-soluble. In addition to being the key to 2P in vivo oxygen imaging, the proposed construct will be an excellent model compound to study triplet state emission and oxygen quenching at the single molecule level. If successful, these experiments will open avenues for novel research, which will span from the studies of protein conformations by small molecule diffusion to the construction of a single-molecule oxygen sensor.