Posted on Mar 15, 2019, 6 p.m.
Engineers from the University of Toronto have built a set of magnetic tweezers that can position a nano-scale bead inside human cells in three dimension with unprecedented precision; nano-bots have been used to study properties of cancer and may point the way to enhanced diagnosis and treatment.
For two decades Professor Yu Sun and his team have been building robots which can manipulate individual cells, their inventions have ability to manipulate and measure individual cells; their latest study is taking the technology even further, as published in Science Robotics.
A robotic system has been created that can manipulate sub-cellular structures inside electron microscopes that requires freeze drying cells and cutting them into slices; to probe live cells, others have used techniques such as laser or acoustics. Optical tweezers/lasers to probe cells is a popular approach.
The team designed a system that uses 6 magnetic coils placed in different planes around the microscope coverslip seeded with live cancer cells; a magnetic iron bead about 700 nanometers in diameter is placed on the coverslip where cancer cells easily take it up inside their membranes. Once inside the team controls its position using real time feedback from confocal microscopy imaging; computer controlled algorithms are used to vary electrical current through each of the coils, shaping the magnetic field in the dimension and coaxing the bead into any desired position within the cell.
Studies on cell nuclei previously required extraction from cells; the team can measure cell nuclei in intact cells without need to break apart the cell membrane or cytoskeleton; were able to show the nucleus is not equally stiff in all direction; were able to measure how much stiffer it became when prodded repeatedly; and determine which cell protein(s) may play roles in controlling this response.
According to the team such knowledge may point the way to new methods of diagnosing cancer, and the research could go even further. “ Whole swarms of nano-bots could be used to starve a tumour by blocking blood vessels into the tumour, or directly destroy it via mechanical ablation; this could offer a method to treat cancers resistant to various therapies”
While still a long way from clinical deployment, this is exciting work, with many directions and implications. The team is in the process of early animal experiments, they are not in the Fantastic Voyage yet, but they have achieved unprecedented accuracy in position and force control needed to get there.
Materials provided by University of Toronto Faculty of Applied Science & Engineering.
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Wang, C. Ho, Y. Tsatskis, J. Law, Z. Zhang, M. Zhu, C. Dai, F. Wang, M. Tan, S. Hopyan, H. Mcneill, and Y. Sun. Intracellular manipulation and measurement with multipole magnetic tweezers. Science Robotics, 2019 DOI: 10.1126/scirobotics.aav6180