Following Nature’s Example in Neurotechnology

By: Bhavya Anoop, ChemE ‘27

Biomimicry, or the emulation of models in nature, has recently become a cornerstone of biomedical research within neurotechnology. Biomimicry has a few different levels, varying from mimicking natural forms and functions to natural processes or systems, the former being the most common approach in medical research [1]. Numerous novel and innovative solutions have been developed in the field by studying and utilizing natural patterns found in the world.

One fundamental principle of nature, for instance, is Murray’s law, which, in biophysical fluid dynamics, details the relationship between the radii of parent and daughter vessels. In context, the law describes the decreasing sizes of pores across different scales, which researchers recently analyzed in plant systems to guide studies in the performance of lithium-ion battery electrodes, which are essential to many neural devices and implants [2]. Using this law, researchers could also develop artificial nerves with pores fit for neuroprosthetics. This is just one example of how a basic underlying principle of nature has been harnessed by scientists to improve the performance of many neurological devices.

Beyond just serving as broad inspiration, biomimicry can provide precise design blueprints and ideas for engineers. This close mimicking of natural components has been seen prominently in neural electrodes, which are small devices that can detect electrical signals produced by neurons once inserted into the brain. This allows scientists to interface the brain more efficiently while also allowing for studies into neurological disorders, such as epilepsy and Alzheimer’s disease. Roberto Portillo-Lara in the Department of Bioengineering at Imperial College London notes that this adaptive biomimetic approach can bridge the gap between synthetic and biological systems, allowing for better implantable technologies [3]. 

A recent issue in this realm was the inability of such neural probes to distinguish between different tissue types during implantation in surgery. To address this deficiency, researchers began studying the blood-sucking process of mosquitos, as well as the structure of their mouthparts. When hunting blood, mosquitoes face similar issues in terms of uneven surface terrain and thick surface tissue. To combat this, their mothparts overtime evolved to be flexible and multilayered. These qualities were then mimicked in a neuroprobe system with high-sensitivity sensors and a flexible electrode array [4]. Additionally, based on the lower lip structure of mosquitos, a probe track was designed to stabilize implantation [5]. Not only does this biomimetic solve the issue of minimally invasive implantation, but it also inspires similar innovations in the future.

Another unexpected source of inspiration in biomedical engineering has recently been North American porcupines, which are known for their quills. These quills feature microscopic deployable barbs that enable easy, lighter penetration yet high tissue adhesion [6]. These porcupine quills are part of a large family of thin-walled conical shell structures found in nature, including plant stems, feather shafts, and hedgehog spines [7]. These structures, because of their unique combination of compression and bending, have been said to have great potential in many biomedical applications, allowing for lighter and more mechanically efficient innovations. One proposed mechanism following this structure was in the drug delivery field: an intestinal microneedle robot that would absorb intestinal fluids and inject drugs into the intestinal wall [8]. Adapting this technique to implanting electrodes and other devices in the brain is ongoing [6].

Following the structures and patterns in nature offers much more room for further inspiration and innovation. Whether analyzing the flexibility of gecko feet, stingers in wasps or simply studying water flow patterns, the answers to countless healthcare issues have been readily available since the beginning of time. Collaboration should occur not only between engineers, medical professionals, and scientists but also with nature itself. 

References

1. Zhang, G. (2012). Biomimicry in biomedical research. Organogenesis, 8(4), 101-102. https://doi.org/10.4161/org.23395 

2. Katiyar, N. K., Goel, G., Hawi, S. et al. (2021). Nature-inspired materials: Emerging trends and prospects. NPG Asia Mater 13, 56. https://doi.org/10.1038/s41427-021-00322-y 

3. Portillo-Lara, R., Goding, J. A., Green, R. A. (2021). Adaptive biomimicry: design of neural interfaces with enhanced biointegration. Current Opinion in Biotechnology, 72, 62-68. https://doi.org/10.1016/j.copbio.2021.10.004 

4. Zhou, Y., Yang, H., Wang, X. et al. (2023). A mosquito mouthpart-like bionic neural probe. Microsyst Nanoeng, 9(88). https://doi.org/10.1038/s41378-023-00565-5 

5. Shoffstall, A. J., Srinivasan, S., Willis, M. et al. (2018). A mosquito inspired strategy to implant microprobes into the brain. Sci Rep. 8 (122). https://doi.org/10.1038/s41598-017-18522-4  

6. Cho, W. K., Ankrum, J. A., Guo, D., Chester, S. A., Yang, S. Y., Kashyap, A., Campbell, G. A., Wood, R. J., Rijal, R. K., Karnik, R., Langer, R., & Karp, J. M. (2012). Microstructured barbs on the North American porcupine quill enable easy tissue penetration and difficult removal. Proceedings of the National Academy of Sciences of the United States of America, 109(52), 21289–21294. https://doi.org/10.1073/pnas.1216441109 

7. Torres, F. G., Troncoso, O. P., Diaz, J., Arce, D. (2014). Failure analysis of porcupine quills under axial compression reveals their mechanical response during buckling, Journal of the Mechanical Behavior of Biomedical Materials, 39, 111-118. https://doi.org/10.1016/j.jmbbm.2014.07.017  

8. Gao, X., Li, J., Li, J., Zhang, M., Xu, J. (2024). Pain-free oral delivery of biologic drugs using intestinal peristalsis-actuated microneedle robots. Science advances, 10(1). https://doi.org/10.1126/sciadv.adj7067