The development of magnetic micromanipulation systems, using electromagnets or permanent magnets, has enabled a multitude of applications for cellular and intracellular measurement and stimulation. Controlled by different configurations of magnetic field generation systems, magnetic particles and different types of microrobots have been actuated by an external magnetic field to exert forces/torques and perform mechanical measurements on the intracellular structures. Magnetically controlled particles and microrobots have also been controlled to apply mechanical stimulations, generate aggregations to trigger cell signaling pathways, and produce heat to cause cancer cell apoptosis for hyperthermia treatment.

This thesis presents a multi-pole magnetic tweezers system for micromanipulation involving sub-micrometer position control and picoNewton force control of a sub-micron magnetic bead inside a single cell for measurement on different locations (spatial) and different time points (temporal). The average positioning error was quantified to be 0.4 µm. The system is also capable of applying a force up to 60 pN with a resolution of 4 pN for a period of time longer than 30 mins. The system was applied for revealing nuclear mechanics in migrating cells, and intra-embryonic mechanical properties.

The thesis also presents magnetic micromanipulation as a tumour treatment approach for glioblastoma, the most common and aggressive brain cancer in adults. Transmission Electron Microscopy images and histology results showed that the glioblastoma cells are able to internalize the carbon nanotubes within the cytoplasm, endosome, and lysosome. Through controlling the torque generation on magnetic carbon nanotubes, the results showed that the magnetic treatment is able to induce cell death on petri dish, and extend the survival time of tumour mice significantly from median survival of 22 days to 26 days. The treatment relies on physically tearing cellular structures without suppressing a specific cancer cell growth as in chemotherapy drugs, potentially circumvent the chemotherapy-resistance and provide an alternative or combinatory treatment approach for glioblastoma.