Researchers at MIT have developed an ultrathin neural implant to deliver small volumes of medicine to specific target structures deep in the brain. Precision delivery could make it possible to treat diseases that effect very specific brain circuits, without interfering with the normal function of the rest of the brain, researchers say. A study using implanted drug delivery systems in rodents illustrate the technology’s ability to remotely control behavior and the importance of volume in modulating brain regions. This is important progress in the development of new, more effective methods of drug delivery.
Although specific medicines to treat many neurologic and neuropsychiatric diseases can cross the blood-brain barrier, they diffuse to non-target areas of the brain”, says Khalil Ramadi, Postdoctoral Fellow at Massachusetts Institute of Technology (MIT). He is the lead author of a study published in Proceedings of the National Academy of Sciences. “We have developed chronic MiNDS (Miniaturized Neural Drug Delivery System) microprobes to enable reliable and targeted delivery of nanoliters of drugs with pinpoint accuracy to deep brain structures where causative pathology would be localized.” Khalil and his thesis advisor, Michael Cima, the David H. Koch Professor of Engineering within the Department of Materials Science and Engineering and the Koch Institute for Integrative Cancer Research, and associate dean of innovation in the School of Engineering, collaborated with Institute Professors Robert Langer and Ann Graybiel.
Many future applications
This technology modulates and monitors neuronal activity, with cell-type specificity, in brain microstructures (1 mm3). The results obtained in animal models included behavior modification while minimizing unwanted side effects. The technology may potentially assist in more accurate research of neurological disease progression in preclinical models. In the future, with this technique, we may turn off or on specific neurons and brain nodes and look for a response. At the same time, scientists may get unprecedented insights by sampling tiny volumes of the brain microstructures fluids under specific conditions. Eventually Ramadi and his colleagues aim to translate the technology to the clinic. “Having a working system of delivering drugs with specific biological activity in a target tissue or cells open the possibility of many applications. One such case is brain tumors (gliomas) where higher doses or bigger antibody molecules of a therapeutic agent are needed to be effective without unwanted systemic circulation and circumventing the blood-brain barrier”, concludes Ramadi.
Image Source: image is credited to Khalil Ramadi. MiNDS probes developed at MIT cause minimal injury to brain tissue. This image shows minimal tissue scarring (green and red stains) and healthy neuron growth (purple) surrounding an implant.
Original Research: Abstract for “Focal, remote-controlled, chronic chemical modulation of brain microstructures” by Khalil B. Ramadi, Canan Dagdeviren, Kevin C. Spencer, Pauline Joe, Max Cotler, Erin Rousseau, Carlos Nunez-Lopez, Ann M. Graybiel, Robert Langer, and Michael J. Cima in PNAS. Published June 25 2018.