Oxygen depleted hypoxic regions in the tumour are generally resistant to therapies1. Although nanocarriers have been used to deliver drugs, the targeting ratios have been very low. Here, we show that the magneto-aerotactic migration behaviour2 of magnetotactic bacteria3, Magnetococcus marinus strain MC-14, can be used to transport drug-loaded nanoliposomes into hypoxic regions of the tumour. In their natural environment, MC-1 cells, each containing a chain of magnetic iron-oxide nanocrystals5, tend to swim along local magnetic field lines and towards low oxygen concentrations6 based on a two-state aerotactic sensing system2. We show that when MC-1 cells bearing covalently bound drug-containing nanoliposomes were injected near the tumour in SCID Beige mice and magnetically guided, up to 55% of MC-1 cells penetrated into hypoxic regions of HCT116 colorectal xenografts. Approximately 70 drug-loaded nanoliposomes were attached to each MC-1 cell. Our results suggest that harnessing swarms of microorganisms exhibiting magneto-aerotactic behaviour can significantly improve the therapeutic index of various nanocarriers in tumour hypoxic regions.
In the 1995 Collision Avoidance and Automated Traffic Management Sensors Proceedings we presented a stereo vision based approach for detecting the relative location of other vehicles in highway driving. This system was able to track other vehicles which were within the stereo pair visual field of view. In addition, important camera position variables such as inclination angle and camera height were dynamically calculated from image data without the need for external sensors.In collaboration with industrial partners we have tested the algorithm on additional video information under a number of different driving situations. The affect of noise in the camera geometry estimate on the algorithm's performance was also examined. As a result of these tests and the additional requirement of real time performance, a number of modifications were made to the algorithm to increase both its reliability and computational efficiency. We present the results of the testing and well as the algorithmic changes here.
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