Ultrasound imaging and actuation technologies play a critical role in modern medicine, however applications rely heavily on the use of gas-filled agents, such as microbubbles and gas vesicles, which enhance ultrasound contrast and facilitate mechanical effects in biological tissues. The demand for improved imaging resolution, deeper tissue penetration, and more precise therapeutic interventions has driven ongoing research into developing more effective and reliable ultrasound-responsive materials. As clinical and research applications expand, there is a growing need for agents that combine long-term stability, tunable functionality, and robust performance under physiological conditions. Current gas-based ultrasound agents are inherently unstable in aqueous environments, suffering from rapid gas leakage, destructive collapse under insonation, and limited compatibility with different gases. Their fragile structures require cold-chain storage, complicating logistics and increasing costs. Additionally, their relatively large size restricts tissue penetration and cellular-level targeting, while their short functional lifespans and low collapse thresholds limit their effectiveness in repeated or high-power ultrasound applications. These shortcomings underscore the urgent need for more stable, programmable, and versatile ultrasound-responsive materials.
This technology centers on the development of metal-organic framework (MOF) nanotransducers—nanoscale crystals with angstrom-scale hydrophobic pore channels capable of stably confining designer gases such as CO₂, N₂, O₂, or air. The hydrophobicity of the pore surfaces allow these nanotransducers to retain gases in aqueous environments for over two years at room temperature and up to 60°C, eliminating the need for cold-chain storage. When exposed to focused ultrasound, the confined gas bubbles within the MOF pores undergo restricted, nonlinear oscillation, generating strong, sustained acoustic emissions and controllable mechanical forces without destructive collapse. These nanotransducers are programmable and effective as both ultrasound imaging contrast agents and acoustic actuators for applications such as neuromodulation. What differentiates this technology is its combination of long-term gas stability, programmability, and robust acoustic performance at the nanoscale. Unlike conventional microbubbles and gas vesicles, MOF nanotransducers maintain gas retention and acoustic functionality over millions of insonation cycles and at elevated temperatures. The MOF structure provides exceptional mechanical and thermal resilience, deep tissue penetration, and cellular-level targeting, while the tunable pore chemistry enables encapsulation of a variety of gases.
Metal-organic framework nanocrystals (200-2500 nm) with hydrophobic angstrom-scale pores stably confine designer gases via surface tension. These robust structures retain gas in water for years, producing sustained, strong acoustic emissions and controllable mechanical forces under focused ultrasound through restricted nonlinear oscillation. They function as stable ultrasound imaging contrast agents and acoustic actuators.
U.S. Provisional application serial no. 63/910,117 filed on 11/03/2025