Measurement of pO2 and pH in Living Breast Tumor Models with Three- Dimensional Resolution by Multiphoton Microscopy during Combined Therapy with Herceptin

摘要

Multiphoton laser scanning microscopy (MPLSM) has proved to be an important tool in cancer research providing insight into morphologic changes in tumor vasculature, extracellular matrix components and gene expression. However, there is a lack of techniques utilizing multiphoton microscopy to study functional physiologic parameters that are important in tumor development and response to therapy. This report details the development of methods to quantify pO2 and pH in vivo with high three-dimensional resolution and significant depth penetration (up to 400 micrometers) with MPLSM. The technique of phosphorescence quenching microscopy (PQM) was adapted to a multiphoton microscope to permit pO2 measurements using the Pd-porphyrin dendrimer, OxyphorR2 as the oxygen reporter. Measurements of pH were completed using MPLSM and a novel semiconductor nanocrystal (NC)-based reversible, ratiometric pH biosensor exploiting resonance energy transfer from the nanocrystal to a pH sensitive dye.