Affordable Light-Sheet Microscope Could Spur Biomedical Exploration

By broadening the availability of light-sheet fluorescence microscopy (LSFM) world-wide, a team at Juntendo University is helping to smooth the path to future discoveries in biomedicine.

Advancements in tissue clearing techniques have made LSFM systems an important tool for biomedical research. However, the complexity and high cost of these systems have put them out of the reach of many end-users in the biomedical field. Greater accessibility to tissue clearing techniques could help accelerate research in neuroscience, drug pathology, and other areas.

To make LSFM more accessible, the researchers developed desktop-equipped selective plane illumination microscopy (descSPIM), an LSFM system that is affordable and easy to install, assemble, and adapt to different tissue clearing protocols. The system can be openly sourced via a dedicated GitHub repository.

The researchers adopted a simple design and configuration for descSPIM. They eliminated the medium chamber, replacing it with a glass cuvette, and used a two-stage synchronization process during imaging to enhance ease of use and accommodate various sample sizes and clearing reagents.

Additionally, they streamlined the process for capturing optical data and converting the data to images. Simplifying this process significantly reduced image acquisition time, allowing routine 3D imaging of cleared samples to be accomplished in minutes. Despite its basic SPIM configuration, descSPIM enables efficient 3D imaging at 3.45 × 3.45 × 7-25 µm³ voxel resolutions.

The team also focused on reducing the cost of LSFM. The descSPIM system’s compact design comprises a minimal number of commercially available optical elements on a modest-sized breadboard. The approximate cost of the system is between $20,000 and $50,000.

“LSFM remains prohibitively expensive for many end users, despite advancements in tissue clearing technologies,” professor Etsuo A. Susaki said. “When I recognized this bottleneck, I wanted to develop an affordable and sufficiently performing light-sheet microscope to enhance accessibility in biomedical research.”

Due to its simple design, descSPIM can be installed in one day by a non-expert and operated by someone with minimal experience. The researchers provide a parts list and instructions for the microscope’s construction and use as part of their open-source initiative. The size and configuration of descSPIM make it suitable for personal use, and particularly valuable in regions where access to high-end systems is limited.

“When compared to commercially available light-sheet microscopes, our proposed DIY system is more than 10 times less expensive, and strongly supports the dissemination of the tissue clearing and 3D imaging technology,” professor Kohei Otomo said.

After the researchers optimized the design of the microscope for rapid imaging of cleared tissue samples, they verified descSPIM’s application as an imaging tool using animal studies.

They used descSPIM to image volumetric, whole-brain samples of transgenic mice. The system enabled visualization of neuronal structures and distributions with cellular resolution. In cancer cell line-derived xenograft models, descSPIM enabled 3D imaging of entire tumor masses, facilitating visualization of drug distribution within the tumor tissues.

The researchers also used descSPIM to generate 3D images of thick tumor sections stained with fluorescent dyes, mimicking standard hematoxylin-eosin staining. While the resolution for clinical pathology examination was relatively low, the team was able to demonstrate the potential of descSPIM for future diagnostic applications.

The open-source design of descSPIM increases the accessibility of LSFM for research and academic institutions. “Commercial microscopy systems are generally designed as black boxes, where the internal mechanism is unknown to the users,” Otomo said. “However, the accessible design and open-source nature of descSPIM represent a departure from this norm. Its user-friendly construction and open-sourced nature foster a collaborative environment conducive to the development of pioneering imaging technologies.”

The descSPIM system is currently being used by various institutions to visualize organs, including the brain, hypothalamus, stomach, and intestine in mice and rats, and to investigate cancer metastasis in the lung. These diverse applications underscore the versatility and effectiveness of descSPIM across different biological contexts.

The research was published in Nature Communications (www.doi.org/10.1038/s41467-024-49131-1).