3D Printed Waveguides Enable Precise Optogenetic Stimulation of Brain Organoids with High Spatial Resolution

Optogenetics, a technique enabling precise control of cellular activity with light, holds immense promise for understanding and treating disease. Giorgio Scordo, Kostas Kanellopulos, and Surangrat Thongkorn, alongside colleagues including Evgeniy Shkondin, have developed a novel 3D printed light delivery system designed to enhance optogenetic stimulation of brain organoids. The team leverages the precision of projection microstereolithography to fabricate miniature waveguides, and meticulously characterises the optical properties of the printing resin to maximise light transmission efficiency. Through design optimisation and initial testing with modified cells, the researchers demonstrate functional light delivery capable of inducing dopamine release with a 2. 8% efficiency, establishing a strong foundation for customisable optogenetic tools and paving the way for more sophisticated disease modelling and therapeutic strategies.

Microfabrication and Characterization of Nanoscale Devices

This research details the fabrication and characterization of micro- and nanoscale optical and electromechanical devices. Scientists meticulously crafted these devices using cleanroom techniques, focusing on precise control over materials and processes. Researchers employed a range of characterization techniques to assess the fabricated structures, including spectroscopic ellipsometry, optical microscopy, and electrical measurements, ensuring the quality and reproducibility of the devices. A key aspect of the research involves creating optical cavities using a nanograss template, followed by deposition of SU-8 resist and conversion to glassy carbon through high-temperature pyrolysis.

Metal contacts were then added to complete the optical structures. Simultaneously, scientists fabricated two-dimensional electromechanical sensors using similar cleanroom protocols. The team utilized spectroscopic ellipsometry to measure film thicknesses and refractive indices, while Dektak profilometry and four-point probe measurements assessed surface topography and electrical resistance. Scanning electron microscopy verified the pattern quality and cleanliness of the fabricated devices. This work demonstrates a high level of expertise in nanofabrication and material science, highlighting the importance of characterizing fabricated devices to verify their performance. These advancements have potential applications in optical sensors, electromechanical systems, and photonics, paving the way for innovative technologies in these fields.
D Printing for Brain Organoid Optogenetics

Scientists have pioneered a new method for stimulating brain organoids using light, employing a custom-designed 3D printed light delivery system. The team utilized projection microstereolithography to create these intricate structures, carefully characterizing an acrylate-based resin to ensure efficient light transmission. Researchers measured the resin’s refractive index and absorption properties to optimize the design and maximize light delivery to the organoids. Finite element method simulations were then employed to refine the 3D printed design, ensuring precise light propagation and targeted stimulation.

The selected resin exhibited a refractive index suitable for light confinement and minimal absorption, demonstrating its potential for optogenetic applications. Rigorous testing with optogenetically modified cells confirmed the functionality of the 3D printed waveguide, successfully inducing dopamine release with a stimulation efficiency of 2. 8%. This result validates the approach for customizable optogenetic applications, offering a precise and efficient method for stimulating complex brain organoid models. This innovative use of 3D printing and careful material selection addresses limitations of traditional methods in volumetric tissue environments, opening new avenues for advanced brain research.
D Printed Waveguides Enable Optogenetic Stimulation

Researchers have developed a novel three-dimensional light delivery system for optogenetic stimulation, utilizing 3D printing to fabricate customized waveguides. The team employed projection microstereolithography to create these intricate structures, carefully characterizing an acrylate-based resin to ensure efficient light transmission. Measurements revealed a refractive index suitable for light confinement and a low absorption coefficient, confirming its potential for delivering light to target cells. Finite element method simulations were then employed to optimize the 3D printed design, ensuring precise control over light propagation.

Subsequent tests with optogenetically modified cells demonstrated light-induced dopamine release with a stimulation efficiency of 2. 8%, confirming the functionality of the 3D printed waveguide. This innovative system addresses limitations of existing methods, such as restricted light penetration and proximity constraints in volumetric models like spheroids and organoids. The research demonstrates the potential of this technology to advance customizable optogenetic applications, offering precise spatial control and efficient light delivery for stimulating complex biological models.
D Printing Enables Functional Optostimulation

This research demonstrates the feasibility of fabricating complex, three-dimensional light delivery systems using 3D printing for optogenetic applications. Scientists successfully created waveguides from a specialized resin, optimizing their geometry and characterizing the resin’s optical properties to maximize light transmission. Initial tests using cells modified to respond to light confirmed that the 3D-printed waveguides could effectively deliver light, inducing dopamine release and demonstrating functional optostimulation. The study establishes a proof of concept, showing that 3D-printed structures can transmit sufficient light intensity for optogenetic stimulation. While acknowledging that the current system is not a fully developed tool, this work represents an important first step towards integrating 3D-printed waveguides into complex, three-dimensional organoid models. Future research will focus on reducing optical losses and further refining the waveguide design, paving the way for more detailed investigations into disease mechanisms and the development of potential therapeutic strategies.