Structural and molecular interrogation of intact biological systems

Area of Science:

• Neuroscience
• Biotechnology
• Molecular Biology

Background:

• Understanding complex biological systems requires high-resolution data while maintaining a global perspective.
• Current methods often face limitations in preserving tissue integrity for comprehensive analysis.

Purpose of the Study:

• To introduce CLARITY, a novel method for rendering intact tissues optically transparent and permeable.
• To enable high-resolution, deep-tissue imaging and molecular analysis without sectioning.

Main Methods:

• CLARITY involves crosslinking intact tissue into a 3D hydrophilic polymer network, creating a nanoporous hydrogel.
• This process results in a stable, transparent, and macromolecule-permeable tissue construct.
• The method was applied to mouse brains for various imaging and molecular labeling techniques.

Main Results:

• Achieved intact-tissue imaging of long-range projections, local circuitry, cellular and subcellular structures in mouse brains.
• Demonstrated in situ hybridization, multi-round immunohistochemistry, and antibody labeling throughout intact adult mouse brains.
• Successfully applied CLARITY to non-sectioned human clinical samples from neuropsychiatric disease cases.

Conclusions:

• CLARITY provides a transformative approach for visualizing complex biological structures at high resolution.
• The method facilitates detailed molecular and structural analysis of intact tissues, including human samples.
• CLARITY offers a pathway for studying the structural and molecular basis of physiological functions and diseases.