A Scalable and Power Efficient Retinal Prosthesis with an Optically-Addressed Nanoengineered Electrode Array
May 2022
RESEARCH
Abraham Akinin, Jeremy M. Ford, Jiajia Wu, Chul Kim, Hiren D. Thacker, Patrick P. Mercier, and Gert Cauwenberghs.
Sight is integral to our ability to perceive and interact with the world. The visual system captures information in such detail that it encompasses almost the entire sensory input bandwidth of the brain. And yet, millions of patients are afflicted with blindness requiring assistive technologies and community accommodation. A growing number of these cases are caused by diseases that result neural degeneration of photoreceptor cells in the retina such as Age-related Macular Degeneration. Implantable prosthetics to electrically stimulate the retina and restore vision are an active area of academic research and commercialization efforts. Unfortunately, considerable efforts have not produced a significant quality of life enhancement parallel to the astounding results of cochlear implants to restore hearing. To get there, novel approaches are needed to overcome the field’s main challenges: limited resolution and obtrusive packaging.
New Opportunities of Soft Electronics in Biomedical Engineering
May 2022
RESEARCH
Kuanming Yao, Guangyao Zhao, Xinge Yu
Distinguished from conventional rigid electronics, soft electronics is becoming a novel platform for next-generation biomedical instrumentations. With advanced materials, mechanics, and structural design, soft electronics could be realized in thin, light-weighted formats and thus can be worn on or implanted in human body, and may excel in great stretchability and conformal attachment with skin or tissue, which ensures continuous and precise healthcare monitoring or therapies. Our group focuses on exploring the novel soft electronics for the applications in various fields of biomedical applications, including motion and mechanical sensing, wearable energy harvesting, dynamic temperature sensing, sweat sensing, and closed-loop human-machine interface.
Neural Fragility of EEG May Help Localize the Seizure Onset Zone
May 2022
RESEARCH
Adam Li, Chester Huynh, Zachary Fitzgerald, Iahn Cajigas, Damian Brusko, Jonathan Jagid, Angel Claudio, Andres Kanner, Jennifer Hopp, Stephanie Chen, Jennifer Haagensen, Emily Johnson, William Anderson, Nathan Crone, Sara Inati, Kareem Zaghloul, Juan Bulacio, Jorge Gonzalez-Martinez, and Sridevi V. Sarma
Over 3.4 million people in the US have epilepsy and 30% of these patients have drug-resistant epilepsy (DRE), where they do not respond to medication. DRE patients are burdened by epilepsy-related disabilities and frequently hospitalized constituting around $13 billion dollars annually spent for treating epilepsy patients in the USA. Successful surgical treatment necessitates complete elimination of the brain region(s) known as the seizure onset zone (SOZ). Between 30%-70% of patients continue to have seizures 6 months after treatment due to mislocalization of the SOZ. We developed neural fragility, an electroencephalogram (EEG) marker for the SOZ, and validated it in a retrospective study of 91 patients predicting surgical outcomes using neural fragility conditioned on the clinically labeled SOZ. Fragility predicted 43 out of the 47 surgical failures correctly and had an overall accuracy of 76%, compared to the clinical accuracy of 48% (successful outcomes). Neural fragility outperformed 20 other EEG features on the same set of cross-validation samples suggesting it as a potential EEG biomarker for the SOZ.
Wireless Miniature Freely-Floating Optogenetic Stimulation Implant
Communicated by Dr. Jun Wang
RESEARCH
December 2021
Linran Zhao, Wen Li, Maysam Ghovanloo, Yaoyao Jia
There is an increasing realization that the majority of brain functions relate to a large distributed network of neurons that are spread over different interconnected regions of the brain. Thus, neural recording and modulation of the future will require the ability to simultaneously interface with multiple neural sites distributed over a large brain area. Traditional methods for modulating neuronal function have relied on direct stimulation by tiny electrodes, which effectiveness is undermined by the limited spatial and temporal precision with which individual cells can be selectively targeted. The emergence of optogenetic stimulation provides distinct advantages over electrical stimulation, such as cell-type specificity, sub-millisecond temporal precision, and rapid reversibility. Optogenetic neuromodulation has the potential to revolutionize the study of how neurons operate as members of larger networks and may ultimately help patients suffering from neurological disorders. Hence, we aspire to design a distributed wireless neural interface framework to stimulate large-scale neuronal ensembles over large brain areas. The distributed framework includes an array of tiny, wireless, and highly efficient implants, each of which operates autonomously to stimulate neural activities.
Spherical Biomimetic Eyes with Nanowire Arrays: From design to application
Communicated by Dr. Yiwen Wang
RESEARCH
December 2021
Leilei Gu, Yucheng Ding, Zhiyong Fan
“To see is to believe”. High-performance imaging devices are essential in society, particularly in the current age of Artificial Intelligence (AI) +. The biological eyes have been polished by natural selection for millions of years and their function has been verified by the diverse environment. Learning from the masterpiece of nature is therefore a shortcut to improve our manmade systems. As one of the wisest creatures in nature, human eyes are advanced image sensing systems with superiorities such as high resolution, wide field-of-view (FoV), high energy efficiency, and strong accommodations. Their high performance originates from the combined effect of a vastly flexible optical system, high-density and sensitive photoreceptor arrays, and powerful neural networks from both retina and cortex. The human eyes have a spherical shape with a hemispherical retina. A hemispherical shape matches well with the Petzval surface, which is the theoretical focal plane of the spherical lens, leading to clear and sharp imaging. In regular cameras, to mitigate the mismatching in planar structure, a delicate lens array has to be inserted to gradually bend the focal plane into quasi-flat. In our cell phones, there are 10-16 lens. With a well-designed hemispherical image sensor, high-quality imaging with a simple structure can be achieved.
