Research

As a discipline at the intersection of molecular biology and in vivo imaging, molecular imaging enables the visualization of the cellular function and the follow-up of the molecular processes in living organisms without perturbing them. The multiple potentialities of this field are applicable to the diagnosis and treatment monitoring of diseases such as cancer and neurological and cardiovascular diseases.

We have developed a multimodal molecular imaging system for eye applications with has integrated photoacoustic microscopy (PAM), optical coherence tomography (OCT), and fluorescence microscopy. The PAM employs a wavelength tunable pulsed laser, a galvanometer, a scan lens, an ophthalmic lens, and an ultrasound transducer. High speed imaging is achieved to visualize individual blood vessels of the eye. Using animal models of abnormal microvasculature and neovascularization coupled with molecular contrast agents, molecular imaging is achieved.

The interplay of neurons and blood vessels plays a critical role in innumerable diseases causing death and impairment, from stroke and aneurysms to macular degeneration and diabetic retinopathy. Current treatment of pathologic blood vessels in wet macular degeneration can involve frequent (often monthly) injections inside the eye. We have developed a novel, noninvasive therapy to selectively and permanently eliminate pathologic microvasculature called photo-mediated ultrasound therapy (PUT). PUT removes microvessels precisely and efficiently without damaging surrounding tissue. PUT is agent-free. PUT relies on cavitation in microvessels produced by concurrently applied short pulse duration laser and therapeutic ultrasound. Cavitation is produced via photospallation due to transient thermoelastic stress following short pulse duration laser and is driven by concurrent ultrasound. Therefore, the laser intensity required for PUT is an order of magnitude lower than conventional retinal laser ablation, thereby significantly reducing the risk of collateral tissue damage. PUT treatment has high precision and high selectivity due to the high endogenous optical contrast between hemoglobin and other tissues. We are develop PUT as a novel method to selectively treat pathologic microvasculature in retinal vascular diseases, such as wet macular degeneration, diabetic retinopathy, and retinal vein occlusions in addition to investigating other applications.