Rapid optical tissue clearing using poly(acrylamide-co-styrenesulfonate) hydrogels for three-dimensional imaging.

Area of Science:

• Biomaterials Science
• Optical Imaging
• Histology

Background:

• Optical tissue clearing enables 3D imaging of intact tissues.
• The CLARITY (clear lipid-exchanged acrylamide-hybridized rigid imaging/immunostaining/in situ-hybridization-compatible tissue-hydrogel) method uses polyacrylamide gels.
• Passive CLARITY methods require efficient hydrogel clearing agents.

Purpose of the Study:

• To develop and evaluate poly(acrylamide-co-styrenesulfonate) hydrogels for passive CLARITY.
• To optimize hydrogel composition for reduced clearing time and improved imaging.
• To demonstrate the utility of the new hydrogel for 3D fluorescence imaging of DNA.

Main Methods:

• Radical copolymerization of acrylamide (AAm) and sodium p-styrenesulfonate (SS) at varying ratios.
• Characterization of poly(AAm-co-SS) hydrogel properties (molecular weight, refractive index, swelling).
• Application of the hydrogels in passive CLARITY for tissue clearing and subsequent 3D fluorescence DNA staining.

Main Results:

• Copolymer composition and properties were controlled by monomer ratio.
• Increased SS content led to lower molecular weight, slightly higher refractive index, and increased swelling.
• Hydrogels with higher SS content reduced tissue clearing time.
• Successful 3D fluorescence imaging of DNA in cleared tissues was achieved.

Conclusions:

• Poly(AAm-co-SS) hydrogels enhance the passive CLARITY clearing process.
• The developed hydrogel is effective for 3D fluorescence imaging of DNA.
• This technique offers an improved approach for optical tissue clearing and bioimaging.