NONINVASIVE TECHNOLOGIES

Our vital organs – our heart, brain, and liver – are protected by the skin, skull, and rib cage. But when the unexpected occurs and a man's liver is invaded by cancer or an elderly lady's memory begins to fade, these protective structures become problematic, preventing direct intervention. Our laboratory aims to generate the next generation of noninvasive microsurgical devices that would enable physicians to operate on vital organs without having to perform an incision. For patients, this implies not only accessible, pain-less, and infection-free techniques, but also therapeutic and diagnostic capabilities never achieved before. Our current focus is on three classes of devices:

A Noninvasive Capillary Permeabilisier for Drug Delivery

Molecular and Cellular Surgery

By using ultrasound and sonosensitive particles, we perform molecular and cellular surgery on structures, such as endothelial cells and capillaries. Using these techniques, we aim to safely and controllably deliver a wide range of therapeutic and diagnostic agents including molecules, genes, nanoparticles, and cells. This technology is being developed for a wide range of diseases including the treatment of cancer.

A Noninvasive Acoustic Micropump for Drug Enhancement

Fluid Micropumping

By using ultrasound alone, we can enhance the distribution of drugs through tissue microenvironments. We are developing methods to enhance the distribution of molecules and nanoparticles. This technology is being developed for a range of diseases that includes cancer.

A Noninvasive Acoustic Particle Palpator for Measuring Tissue Elasticity

Remote Palpation

Devices and methods are also being developed to push tissue and track its displacement and relaxation to determine stiffness. This elasticity imaging technique provides a quantitative measure of a property, which has been linked to the progression of several diseases. This technology is being developed for early detection of liver diseases, such as liver fibrosis and hepatocellular carcinoma.

 

HOW IT WORKS

Ultrasound applied outside of our body can travel through several layers of tissue and converge to a small tissue volume. This focal volume is where all the action happens and we're here to develop innovative ways to probe and modify tissue so that we can diagnose and treat diseases.

Focused Ultrasound

Sound has the unique property of traveling through materials, which is the reason you can often hear your neighbour through opaque walls. Higher sound frequencies attenuate through the wall more so than lower frequencies. This is why you can hear lower tones from sources such as subwoofers.

In biomedical acoustics, very high frequencies known as ultrasound (0.25 to 10 MHz) are focused through several layers of tissue to converge to a small focal volume. This limits ultrasound-induced effects to a confined area while not affecting the surrounding healthy tissue. Ultrasound has unique properties when compared to other kinds of energy (e.g., light, magnetism):

  • Noninvasive
  • Deep penetration (several centimetres)
  • Non-ionising
  • Localisation (safety below certain intensities has been established)

Ultrasonically Generated Forces --> Novel Bioeffects

The focus of our laboratory is to functionally alter or probe biological tissue in a way that (1) is safe and temporary and (2) controllable at the micron- and nano-scale. We do NOT research high-intensity focused ultrasound (HIFU) or lithotripsy, which both use ultrasound to destroy tissue. In fact, we use pulse sequences, which more closely resemble ultrasound imaging pulses, which have an established safety profile. By carefully designing ultrasonic pulse sequences, we generate a wide range of ultrasonic phenomena within the focal volume:

  • Pushing
  • Expansion
  • Contraction
  • Heating (mild levels)

Our laboratory has an in-depth understanding of how the physics and biology are interacting with each other. We have the necessary balance of engineering, physics, and biology. Thus our manipulation and probing techniques are not limited to the size of the focal volume, but can be refined down to molecular and cellular behaviours through compartmentalisation of the phenomena (e.g., vascular, interstitial, and cellular compartments) and the use of sono-sensitive nano- and micro-particles (e.g., expansion and contraction of a microbubble). We can produce a range of safe and reversible bioeffects:

  • Increased vascular permeability
  • Increased cell membrane permeability
  • Displacement of fluid
  • Displacement of tissue