Sensitive label-free imaging of brain samples using FxClear-based tissue clearing technique

ADAPT-3D: Accelerated Deep Adaptable Processing of Tissue for 3-Dimensional Fluorescence Tissue Imaging for Research and Clinical Settings

Light sheet microscopy and preparative clearing methods that improve light penetration in 3D tissues have revolutionized imaging in biomedical research. While most clearing methods focus on removing molecules that scatter light, the methods generally involve immersing tissues in solutions that minimize refraction of light to enhance detection of fluorescent signal deeper into tissues. Here, we developed a new tissue preparative method called ADAPT-3D with broad applicability across species and tissue types. This method enables efficient antibody staining and detection of endogenous fluorophores and offers advantages in terms of speed at which tissue staining and clearing is achieved. In about 4 days from tissue harvest to imaging, human intestinal tissue could be Axed, decolored and delipidated to remove light-interfering substances and stained with antibodies for imaging. In the intact mouse skull and brain, involving an 8-day protocol from tissue harvest to completion of imaging, the aqueous and non-shrinking ADAPT-3D method allowed the specialized channels between skull and underlying tissue to be detected without meningeal tearing. Overall, ADAPT-3D provides a highly versatile preparative method for 3D fixed tissue imaging with superior time savings, sensitivity and preservation of tissue morphology compared with previously described methods.

From morphology to single-cell molecules: high-resolution 3D histology in biomedicine

High-resolution three-dimensional (3D) tissue analysis has emerged as a transformative innovation in the life sciences, providing detailed insights into the spatial organization and molecular composition of biological tissues. This review begins by tracing the historical milestones that have shaped the development of high-resolution 3D histology, highlighting key breakthroughs that have facilitated the advancement of current technologies. We then systematically categorize the various families of high-resolution 3D histology techniques, discussing their core principles, capabilities, and inherent limitations. These 3D histology techniques include microscopy imaging, tomographic approaches, single-cell and spatial omics, computational methods and 3D tissue reconstruction (e.g. 3D cultures and spheroids). Additionally, we explore a wide range of applications for single-cell 3D histology, demonstrating how single-cell and spatial technologies are being utilized in the fields such as oncology, cardiology, neuroscience, immunology, developmental biology and regenerative medicine. Despite the remarkable progress made in recent years, the field still faces significant challenges, including high barriers to entry, issues with data robustness, ambiguous best practices for experimental design, and a lack of standardization across methodologies. This review offers a thorough analysis of these challenges and presents recommendations to surmount them, with the overarching goal of nurturing ongoing innovation and broader integration of cellular 3D tissue analysis in both biology research and clinical practice.