Tracking Cell-Based Therapeutics in the Body with Microbubbles
Cell-based therapies such as stem cells are gaining clinical popularity, but without a reliable way to track these cells once they enter the body, it has been difficult to validate and monitor these treatments. Efforts are underway to develop imaging strategies for tracking injected cells, including the use of radionuclides, MRI, and viral genetic barcoding, but safety concerns and complex instrumentation have limited their usefulness. By combining safe, noninvasive, ubiquitous ultrasound imaging with commercially-available microbubbles, researchers at the University of Pittsburgh have developed a robust, serial, non-invasive, in vivo assessment of stem cell fate after injection in humans. This technology could prove useful both in the context of clinical trials and for guiding clinical decision making.
Description
Microbubbles are polymer-based gas-filled spheres on the scale of a few micrometers in diameter. When incubated together with human stem cells, microbubbles move inside the cells and remain there. Experiments both in vitro and in vivo indicate that this process neither harms the cells nor alters the unique acoustic characteristics of the microbubbles. Following internalization, ultrasound microbubbles and their cellular hosts are easy to locate from their signature harmonic frequencies using ultrasound imaging. Unlike other cell tracking solutions that involve radiation or complex instrumentation, ultrasound is a portable, non-invasive technique with relatively simple instrumentation, so microbubble-based tracking allows safe, serial imaging of systemically injected stem cells at the patient’s bedside.Applications
• Tracking cell-based therapeutics such as stem cells for tissue regeneration and the treatment of various diseases such as Parkinson’s, diabetes, or Huntington’sAdvantages
• Microbubbles are biocompatible, biodegradable, and stable• Commercially-available microbubbles have already undergone extensive safety testing
• Acoustic activity and biodegradability of microbubbles is adjustable by charging the fabrication materials and parameters
• Ultrasound is non-invasive, portable, ubiquitous, and safe for serial administration