Sponges Based on Polydimethylsiloxane as Pulmonary Phantoms for Diffuse Optics

Diagnostic testing is evolving towards multimodal and hybrid approaches, which require accurate and dynamic phantoms for objective performance assessment. In particular, pulmonary phantoms, critical for evaluating deep penetration optical techniques, pose significant challenges due to the complex structure and dynamic properties of the lung. Existing phantoms often fail to replicate the unique characteristics of the lung, limiting their effectiveness in testing new diagnostic and therapeutic tools. We propose a novel approach to create pulmonary phantoms that more accurately mimic the composition and ultrastructure of the lung. By combining elastomers and hydrogels, we aim to replicate extracellular and cellular components while maintaining a gas-porous network. This bottom-up approach holds the potential to revolutionize pulmonary phantom development and the assessment of relevant multimodal protocols. Our method involves integrating water-in-oil emulsions of agarose hydrogel in PDMS and PDMS-based sponges. The resulting material offers a versatile platform for incorporating various contrast mechanisms and simulating the dynamic behavior of the lung. We are currently investigating the optical, acoustic, CT, and MRI properties of the phantom and its relevance for assessing deeppenetrating optical techniques.