Prototype soft robots used to deliver drugs to the nervous system
Targeted drug delivery using tiny, tumbling soft robots can be achieved soon thanks to rotating magnetic fields. In a study carried out by several US research institutes and biotechnology companies, tiny robots were observed to perform better as drug delivery vehicles to neural tissue: when controlled using a magnetic field, specially developed MANiAC (magnetically aligned nanorods in alginate capsules) microbots moved with improved efficacy and even reduced the occurrence of side effects from off-target dosing.
As explained by Lamar Mair of Weinberg Medical Physics, a medical device company in the US, diseases of the central nervous system (CNS) are hard to treat. However, the MANiAC microbots can navigate the complex architecture of the CNS – they can move against fluid flow, climb slopes, and move about neural tissues, such as the spinal cord, and deposit their drug payload at precise locations.
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[Controlling the microbots using magnetic fields is a particularly promising method of drug delivery as they are not influenced by tissues and tend to be very safe.]
The research team behind MANiAC explained that each “millimeter-scale” microbot consists of a cluster of aligned magnetic nickel nanorods, encased within a soft spherical alginate shell. When subjected to a rotating magnetic field – which could be generated by an electromagnet located outside the patient’s body – the microbot tumbles/rolls in the direction of the rotation – by slowly moving the electromagnet, it’s possible to guide the MANiAC from one place to another.
In lab tests, the microbots were able to climb steep slopes and move upstream against a fluid flow similar to what they would experience in the CNS. The researchers were also able to manoeuvre and deposit dye-loaded MANiACs around the surface of rodent neural tissue with a fine degree of control.
“These results are very preliminary and highly experimental, but we think we have demonstrated strong evidence that small, soft, capsule-based microrobots have potential for controlled local delivery in neural diseases,” said Professor David Cappelleri, of Indiana’s Purdue University.
