Towards MRI-controlled ferromagnetic and MC-1 magnetotactic bacterial carriers for targeted therapies in arteriolocapillar networks stimulated by tumoral angiogenesis.

The delivery of a therapeutic agent through controlled carriers directly to the tumoral lesion can enhance treatment efficacy by reducing dosage while minimizing systemic circulation of toxic compounds through healthy tissues. As such, the induction of a feedback controlled steering force on ferromagnetic carriers from magnetic gradients generated by an upgraded clinical magnetic resonance imaging (MRI) system has been demonstrated by our group. But the gradient strengths required in some sections of the capillary network may be technologically very difficult to achieve for human due mainly to the size and cooling issues of additional gradient coils embedded in the MRI bore. As such, the use of MC-1 magnetotactic bacteria (MTB) pushing microbeads with a therapeutic agent may provide complementary means of propulsion in smaller capillaries. Based on preliminary experimental results, carriers and a new method combining the induction of force in a ferromagnetic material with the thrust provided by MTB for direct targeting to the tumor mass are proposed.