Microvascular oxygen quantification using two-photon microscopy


An instrument is demonstrated that is capable of three-dimensional (3D) vasculature imaging and $p_{O_2}$ quantification with high spatial resolution. The instrument combines two-photon (2P) microscopy with phosphorescence quenching to measure $p_{O_2}$. The instrument was demonstrated by performing depth-resolved microvascular $p_{O_2}$ measurements of rat cortical vessels down to 120µm below the surface. 2P excitation of porphyrin was confirmed, and measured $p_{O_2}$ values were consistent with previously published data for normoxic and hyperoxic conditions. The ability to perform 3D $p_{O_2}$ measurements using optical techniques will allow researchers to overcome existing limitations imposed by polarographic electrodes, magnetic resonance techniques, and surface-only $p_{O_2}$ measurement techniques.

Journal article
Optics Letters