Shaping biomimicry: A standardized protocol for soft materials bulk density measurement supporting tissue-like performance

Tissue density is a critical parameter influencing various biological functions, including protein folding and cellular signaling, making accurate measurements essential for advancing our understanding of tissue mechanics and pathology. This work provides a standard operating procedure (SOP) for assessing the bulk density of soft materials using a liquid pycnometer and an analytical balance, along with its validation to ensure precision and reliability. This methodology guarantees precise density evaluations and a rigorous step-by-step procedure for measurement uncertainty estimation. Moreover, the SOP aligns with ASTM F2150 -19 standard for biomaterials characterization, which endorses the use of ASTM D792 -20 for bulk density measurements, based on the principle of Archimedes. By employing this approach, the study aims to enhance the development of in vitro models for biomedical research, drug testing, and tissue engineering. The SOP allows for bulk density estimation with a relative expanded uncertainty of 3%. Furthermore, it was demonstrated that the material employed for the validation, fibrin gel, is comparable, with a 95% level of confidence, to breast fat, placenta, breast gland, eye (choroid), kidney, liver, heart muscle, pancreas, spleen, diaphragm, eye (ciliary body), muscle, and tongue. Shaping biomimicry: a standardized protocol for soft materials bulk density measurement supporting tissue-like performance.