Collaborative Research: 3D-Integrated Micro-photometer Chips: Unveiling the Impact of Beam Collimation, Chip Size, and Flexibility on Studying Functional Neural Dynamics

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

Understanding how the human brain enables us to sense, move, learn, and perceive is a fundamental goal of neuroscience. The brain is made of billions of neurons that communicate with one another through electrical and chemical signals. Neuroscientists rely on fluorescence detecting probes to monitor the activities of neurons using light. However, these probes can be bulky and rigid, causing bleeding and inflammation. Some probe light sources, such as micro-light emitting diodes (LEDs), produce light with a broad spectrum which diminishes the quality of measurements. This project will overcome these issues by developing probes that are much smaller in size, have a softness similar to the brain, and produce light with narrow spectra. The results of this research could enhance our understanding of brain functions and causes for neurological diseases such as Alzheimer’s and Parkinson’s diseases. Furthermore, the research team plans to develop educational materials, including a new course in bioelectronics with hands-on laboratory experience for students. This project proposes to elucidate the effects of beam collimation, compact chip size, and mechanical flexibility of implantable optoelectronic probes on the quality of in vivo deep-brain fluorescence recordings. This will be achieved by vertically integrating inorganic single-crystalline LED and photodiode films obtained via layer transfer technology, distributed Bragg reflectors, and absorption filters to obtain 3D-integrated micro-photometer chips that are less than 1000 times smaller in volume compared to conventional probes, enabling minimally invasive, long-term stable, and high-quality fluorescence recording in deep brain regions. This will improve the signal quality and stability and allow recording in delicate brain regions such as the hindbrain, that preclude the use of traditional bulky/rigid implants. The outcomes of this project will facilitate a fundamental understanding of the neural circuits in these brain regions and advance the knowledge of sensory information processing, complex behavior generation, and neurological disease progression mechanisms in the brain. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.