Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements
Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements
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DOI：
10.1152/japplphysiol.01399.2003
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发表时间：
2004-11-01
影响因子：
3.3
通讯作者：
Ince, C
中科院分区：
文献类型：
--
作者：
Mik, EG;van Leeuwen, TG;Ince, C
本研究描述了使用双光子激发磷光寿命测量定量氧测定在体内。由于非线性双光子效应，将Pd-卟啉的激发波长从可见光加倍到红外允许更深的组织穿透以及更精确和受限的激发体积选择。通过使用来自1,064 nm Q开关激光器的聚焦激光束，提供10 mJ的10 ns脉冲，白蛋白结合的Pd-卟啉被有效地激发，并且观察到磷光的氧依赖性衰减。进行磷光寿命与氧张力的体外校准。得到的校准常数为k（q）= 356托（-1）。s（-1）（猝灭常数）和τ（0）= 550 μ s（在零氧条件下的寿命）。磷光强度显示出对激发强度的平方依赖性，这对于双光子激发是典型的。通过大鼠肾脏皮质的逐步PO（2）测量显示了双光子激发磷光寿命测量的体内演示。它的结论是，定量氧测量，在体外和体内，使用双光子激发氧依赖的磷光猝灭。双光子激发的使用有可能导致磷光寿命技术的新应用，例如。例如，在一个实施例中，以高空间分辨率对组织进行无创氧气扫描。据我们所知，这是第一个报告中，双光子激发被用于设置的氧依赖的磷光寿命测量猝灭。
This study describes the use of two-photon excitation phosphorescence lifetime measurements for quantitative oxygen determination in vivo. Doubling the excitation wavelength of Pd-porphyrin from visible light to the infrared allows for deeper tissue penetration and a more precise and confined selection of the excitation volume due to the nonlinear two-photon effect. By using a focused laser beam from a 1,064-nm Q-switched laser, providing 10-ns pulses of 10 mJ, albumin-bound Pd-porphyrin was effectively excited and oxygen-dependent decay of phosphorescence was observed. In vitro calibration of phosphorescence lifetime vs. oxygen tension was performed. The obtained calibration constants were k(q) = 356 Torr(-1) . s(-1) (quenching constant) and tau(0) = 550 mus (lifetime at zero-oxygen conditions) at 37 degreesC. The phosphorescence intensity showed a squared dependency to the excitation intensity, typical for two-photon excitation. In vivo demonstration of two-photon excitation phosphorescence lifetime measurements is shown by step-wise PO(2) measurements through the cortex of rat kidney. It is concluded that quantitative oxygen measurements can be made, both in vitro and in vivo, using two-photon excitation oxygen-dependent quenching of phosphorescence. The use of two-photon excitation has the potential to lead to new applications of the phosphorescence lifetime technique, e. g., noninvasive oxygen scanning in tissue at high spatial resolution. To our knowledge, this is the first report in which two-photon excitation is used in the setting of oxygen-dependent quenching of phosphorescence lifetime measurements.