Recent advances in ultrasound have produced exquisite images of the anatomy, vessel architecture and functional blood flow properties of tissue. However, physicians still rely on invasive biopsy to assess the underlying cellular phenotype of tissue. To address this gap, researchers have sought to develop the “ultrasound molecular imaging” mode, in which targeted microbubbles can bind to molecular biomarkers through ligand-receptor interactions, and the signal from bound microbubbles can be used to image biomarker expression. The idea is to overlay a color map of biomarker expression onto the anatomical ultrasound image, in a similar manner to PET/CT. So far, ultrasound molecular imaging has achieved some success in phase 1 human clinical trials. However, ultrasound molecular imaging still has limited sensitivity and specificity, which hampers further capital investment and translation to the clinic.
My research group has sought to improve the sensitivity and specificity of ultrasound molecular imaging through the advent of cloaked-ligand microbubbles that are activated in situ by acoustic radiation force produced by an ultrasound transducer. My talk will detail our efforts to design, engineer and employ this technology. I will highlight our discovery that sub-populations of microbubbles can be selectively activated by matching the frequency of the radiation-force pulse to their resonance frequency. Finally, I will propose a new multi-color ultrasound molecular imaging mode for imaging multiple biomarkers in a single ultrasound imaging session.
Mark Borden is Inaugural Director of Biomedical Engineering and Professor of Mechanical Engineering at the University of Colorado, Boulder. He received the B.S. in Chemical Engineering from the University of Arizona in 1999 and the Ph.D. in Chemical Engineering from the University of California Davis in 2003. He then worked as a postdoctoral researcher in Biomedical Engineering at UC Davis and visiting scientist in Radiology at the Arizona Cancer Center. He was appointed Assistant Professor of Chemical Engineering at Columbia University in 2007 before moving to CU Boulder in 2010. He currently serves as a technical program committee member of the IEEE International Ultrasonics Symposium and the European Ultrasound Contrast Symposium. His honors include an NSF CAREER Award, James D. Watson Investigator Award and multiple department awards.