High-performance ferrite nanoparticles for magnetothermal neural excitation

Wireless and cell-specific manipulation of neural circuits may enable non-invasive treatment of the diseased brain. Existing neuromodulation methodologies lack cellular specificity and resolution (electrical deep brain stimulation (DBS)) or rely on transgenes (optogenetics), and require surgical implantation of conduits to deliver electromagnetic stimuli into the targeted deep brain structure. Using nanoscale materials with tunable properties, this thesis seeks to develop minimally invasive tools to facilitate wireless dissection of neural circuits and provide solutions beyond current surgical and pharmacological interventions to treat diseases. We rely on non-invasive alternating magnetic fields as a signaling modality to actuate magnetic nanoparticles to dissipate heat via hysteretic losses. The transduced thermal stimuli can then trigger the depolarization of heat-sensitized cells, leading to phasic excitation of neurons in arbitrarily deep brain structures. We first develop a general dynamic hysteresis model that can qualitatively predict loss power trends for ferrite nanoparticles of variable size and chemical composition in the presence of clinically relevant field frequencies and amplitudes. We then identify synthesis strategies to produce highly-crystalline magnetic nanoparticles with enhanced biomedical performance over previously described methods. With this optimized materials set, we demonstrate wireless control of neural circuits in vitro and in vivo by magnetothermal stimulation.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2016

Author dc:creator

• Chen, Ritchie

Advisor dc:contributor.advisor

• Polina Anikeeva.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/104182

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/104182