Functionalizing Collagen with Vessel‐Penetrating Two‐Photon Phosphorescence Probes: A New In Vivo Strategy to Map Oxygen Concentration in Tumor Microenvironment and Tissue Ischemia... oleh Cheng‐Ham Wu, Kristina S. Kisel, Muthu Kumar Thangavel, Yi‐Ting Chen, Kai‐Hsin Chang, Ming‐Rung Tsai, Chia‐Yu Chu, Yu‐Fang Shen, Pei‐Chun Wu, Zhiming Zhang, Tzu‐Ming Liu, Janne Jänis, Elena V. Grachova, Julia R. Shakirova, Sergey P. Tunik, Igor O. Koshevoy, Pi‐Tai Chou