1. Biomedical Optical Imaging Laboratory, Departments of Medicine and Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
2. Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA.
3. Department of Medicine, Division of Gastroenterology, Hepatology, and Nutrition, University of Pittsburgh, Pittsburgh, PA 15213, USA.
4. Department of Pathology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
5. Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
6. University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA 15232, USA.