A method for three-dimensional single-cell chronic electrophysiology from developing brain organoids

Abstract

Human induced pluripotent stem cell-derived brain organoids have shown great potential for studies of human brain development and neurological disorders. However, quantifying the evolution and development of electrical functions in brain organoids is currently limited by measurement techniques that cannot provide long-term stable three-dimensional (3D) bioelectrical interfaces with brain organoids during development. Here, we report a cyborg brain organoid platform, in which 2D progenitor or stem cell sheets can fold "tissue-like" stretchable mesh nanoelectronics through organogenesis, distributing stretchable electrode arrays across 3D organoids. The tissue-wide integrated stretchable electrode arrays show no interruption to neuronal differentiation, adapt to the volume and morphological changes during organogenesis, and provide long-term stable electrical contacts with neurons within brain organoids during development. The seamless and non-invasive coupling of electrodes to neurons enables a 6-month continuous recording of the same brain organoids and captures the emergence of single-cell action potentials from early-stage brain organoid development.

Recent Advances in Brain Organoid Technology for Human Brain Research

“…Third, techniques that detect and analyze brain functions without disrupting the growth or function of organoids need to advance. The recent development of flexible electrodes opened up the possibility of continuously measuring neuronal activity during organoid development and growth. − However, the current flexible electrode system that envelopes the brain organoid cannot detect internal electrical signals in a whole-brain organoid. Development of a flexible electrode that is integrated inside the brain organoid will allow us to identify the functional maturity of the inner layer of the brain organoid in the development and investigate disease progress more precisely.…”

“…Serpentine-shaped, deformable, stretchable gold wires envelop the organoid so that neural activity can be measured continuously during development regardless of organoid size. Recently, stretchable mesh nanoelectronics has been integrated during organoid formation, a so-called cyborg organoid (Figure C­(iii)). , The stretchable mesh nanoelectronics integrated into the organoid can measure the electrical activity and growth of the organoid over its entire development process. The embedded mesh nanoelectronics does not significantly affect cell differentiation or neuronal activity of the brain organoid and enables researchers to observe organoid maturation over time.…”

Engineering Brain Organoids: Toward Mature Neural Circuitry with an Intact Cytoarchitecture

“…During the organoid genesis, electrodes could be evenly spaced across the entire organoid, and electrophysiological measurements could be conducted all the time in single-cell resolution. Cyborg brain organoids were implemented into the brain organoid system to enable long-term non-invasive recording of neuronal activities ( 149 ). These approaches are part of bioinspired flexible electronics, enabling the safe establishment of neural interfaces and chronic recording from the entire organoid ( 150 ).…”

Stretchable mesh microelectronics for the biointegration and stimulation of human neural organoids

“…Chronic electrophysiology is crucial for understanding their developmental stages, characterizing functional connections, and for monitoring effects of psychiatric drugs or other interventions. Several studies have employed mesh electrodes to interface with organoids, using either a mesh based on parylene -C 26 or SU-8 27 . While these materials are flexible at certain thicknesses, they are not intrinsically stretchable and are made with relatively high modulus materials-they are limited in their ability to adapt to an organoid that grows over time.…”