University of Pittsburgh researchers have developed a fin thruster on acoustic resonator (FTAR) for microswimming robots (sMRs). Using acoustic input to oscillate a diaphragm connected to fins on the surface of microrobots (MRs), it is possibly to selectively navigate MRs with speeds up to 0.6 m/s. This approach could overcome challenges relating to longevity and tunability which have to date hindered the development and clinical application of sMRs.
Using fins attached to a resonating encapsulated cavity and diaphragm FTARs have been developed. These FTARs can be attached to microrobots to form sMRs. FTARs can propel sMRs accurately around the body.
Description
The use of sMRs in healthcare is a growing area of research. With their potential ability to swim, either autonomously or under direction through the body to hard-to-reach spaces, they could provide targeted medical treatment or interventions. While success has been observed in laboratory settings, much work is needed to improve the ability of sMRs to successfully steer 2D and 3D navigations in complex vasculature. Previous navigational approaches including oscillating microbubbles have had limited success and there is a need for more reliable and accurate navigational methods for MRs. FTAR could lead to the development of sMRs that can reliably navigate through the body and eventually result in the use of sMRs in clinical settings.
Applications
• Localized drug delivery
• Biopsy
• Microsurgery
Advantages
Most sMRs have two main types of oscillating micro thrusters: microbubble and solid sharp edge. While microbubbles can propel MRs, this method has poor longevity due to oscillating microbubbles dissolving in the liquid medium. Sharp edges can also propel sMRs but suffers from relatively low tunability for frequency. Finding a suitable ultra flexible material to generate useful levels of propulsion has been challenging.
This novel approach overcomes the shortcomings of existing techniques. The FTAR uses an encapsulated cavity resonator increasing longevity and does not require ultra flexible material. The FTAR has good tunability with multi-direction steering possible through multi FTARs that can be selectively activated allowing remote controlled navigation.
Invention Readiness
The FTAR has been produced using polydimethylsiloxane and consists of a cavity (resonator), diaphragm and fins. The dimensions of the cavity have been optimized to maximize the oscillation amplitude. Acoustic input leads to oscillation of the diaphragm with vibrations transmitted to and amplified in the fins, propelling sMRs. Testing demonstrated sMRs with FTARs can navigate a T-junction microchannel. Travel at speeds of ~0.6 m/s (an order of magnitude faster than microbubble swimmers) and a propulsion force in the N range for over 100 minutes was observed. Fin length and cavity height impacts on swimming speed, and future work could improve speed and navigation of sMRs by optimizing these parameters.
IP Status
Patent Pending
