X-ray Phase Contrast Allows Three Dimensional, Quantitative Imaging of Hydrogel Implants

Area of Science:

• Biomaterials Science
• Medical Imaging
• Tissue Engineering

Background:

• Hydrogels are crucial biomaterials for tissue engineering and drug delivery but are challenging to image in vivo.
• Existing imaging modalities struggle to provide sufficient contrast for hydrogel structures within soft tissues.
• X-ray Phase Contrast (XPC) imaging offers enhanced contrast based on multiple X-ray properties, showing promise for biomedical applications.

Purpose of the Study:

• To investigate the utility of analyzer-based X-ray Phase Contrast (XPC) for three-dimensional imaging of hydrogel biomaterials.
• To assess the capability of XPC imaging to visualize hydrogel structures and associated soft tissue responses in a preclinical model.
• To compare the quantitative accuracy of XPC imaging with gold-standard histology for tissue infiltration measurements.

Main Methods:

• Synthesis of porous fibrin-loaded poly(ethylene glycol) hydrogels.
• Subcutaneous implantation of hydrogels in a rodent model.
• Explantation and three-dimensional imaging using analyzer-based XPC.
• Histological processing and staining for comparative analysis.

Main Results:

• XPC imaging successfully identified both the hydrogel structures and adjacent soft tissue features.
• Visualization of skeletal muscle and quantification of invading fibrovascular tissue were achieved.
• Measurements of invading tissue using XPC showed no significant difference compared to histology.

Conclusions:

• Analyzer-based XPC imaging is a viable technique for the three-dimensional assessment of hydrogel biomaterials in vivo.
• XPC provides accurate visualization and quantification of the host tissue response to implanted hydrogels.
• This imaging modality holds significant potential for advancing research in tissue engineering and drug delivery applications.