Magnetic powered microbots for thrombolysis
The removal of occlusive blood clots, for example in ischemic stroke, is treated with fibrinolytic enzymes like tissue plasminogen activator (tPA) or catheter based mechanical thrombectomy devices, or both. These approaches are limited in cases where the clot is not accessible to catheters or when transport of a fibrinolytic drug is slow (see schematic above). To address these shortcomings we have developed a magnetically powered microbot we call microwheels because they roll along surfaces like a wheel. Using rotating, lower powered (1-10 mT) rotating magnetic fields we can translate and steer microwheels along complex paths. We have immobilized tPA onto these microwheels to provide a combined biochemical and mechanical lysis strategy that is faster than tPA alone at therapeutic concentrations. The images on the right show microwheels ablating a fibrin clot; microwheels moving in a corkscrew motion (A) or straight line (B), compared to soluble tPA at a therapeutic concentration.
This project is in collaboration with David Marr and Ning Wu (Colorado School of Mines), Paco Herson (University of Colorado Anschutz Medical Campus), and Jordan Shavit (University of Michigan). It is funded by NIH awards R01NS102465 and NIH R21AI138214.
Related Publications
T.O. Tasci, P.S. Herson, K.B. Neeves, D.W.M. Marr. Surface-enabled propulsion and control of colloidal microwheels. Nature Communication, 7 (2016): 10225. DOI: 10.1038/ncomms10225.
T. Yang, T.O. Tasci, K.B. Neeves, N. Wu, D.W.M. Marr. Magnetic microlassos for reversible cargo capture, transport, and release. Langmuir, 33 (2017): 5932-5937. DOI: 10.1021/acs.langmuir.7b00357.
T.O. Tasci, D. Disharoon, R.M. Schoeman, K. Rana, P.S. Herson, D.W.M. Marr, K.B. Neeves. Enhanced fibrinolysis with magnetically powered colloidal microwheels. Small, 13 (2017): 1700954. DOI: 10.1002/smll.201700954
T. Yang, A. Tomaka, T.O. Tasci, K.B. Neeves, N. Wu, D.W.M. Marr. Microwheels on microroads: Enhanced translation on topographical surfaces. Science Robotics, 4 (2019): eaaw9525. DOI: 10.1126/scirobotics.aaw9525
D. Disharoon, K.B. Neeves, D.W.M. Marr. AC/DC magnetic fields for enhanced translation of colloidal microwheels. Langmuir, 35 (2019):3455-3460. DOI: 10.1021/acs.langmuir.8b04084
D. Disharoon, D.W.M. Marr, K.B. Neeves. Engineered micro- and nanoparticles for fibrinolysis. Journal of Thrombosis and Haemostasis, 17 (2019): 2004-2015. DOI: 10.1111/jth.14637
E.J. Roth, C.J. Zimmerman, D. Disharoon, T.O. Tasci, D.W.M. Marr, K.B. Neeves. An experimental design for the control and assembly of magnetic microwheels. Review of Scientific Instruments, 91 (2020): 093701. DOI: 10.1063/5.0010805