A comparison of the rheologic properties of an adipose-derived extracellular matrix biomaterial, lipoaspirate, calcium hydroxylapatite, and cross-linked hyaluronic acid.

[IMPORTANCE] Acquired soft-tissue injury with resultant volume loss may cause significant deformity in size, shape, and body or facial contour. Current autologous fat transfer techniques have several limitations, including availability, donor site morbidity, and unpredictable rates of resorption. We present an extracellular matrix (ECM) biomaterial derived from human adipose tissue as an off-the-shelf alternative for soft-tissue volume restoration and compare clinically relevant rheologic properties.

[OBJECTIVES] To determine the rheologic properties of adipose-derived ECM and to compare it with lipoaspirate, calcium hydroxylapatite, and cross-linked hyaluronic acid.

[DESIGN, SETTING, AND PARTICIPANTS] Adipose-derived ECM (n = 4), lipoaspirate acquired from aesthetic liposuction (n = 4), calcium hydroxylapatite (n = 4), and cross-linked hyaluronic acid (n = 4) were obtained to determine the viscoelastic properties.

[INTERVENTIONS] Dynamic frequency oscillation measurements were conducted using a rheometer (ARES-G2; TA Instruments). All injections were performed using a 20-gauge needle, and all measurements were performed using serrated 25-mm parallel-plate geometry with a 1.0-mm gap at 37°C.

[MAIN OUTCOMES AND MEASURES] Oscillation measurements for storage modulus, a measure of the elastic properties, and complex viscosity were obtained over an angular frequency range of 0.01 to 100 rad/s.

[RESULTS] At 1 Hz, adipose-derived ECM had a mean (SD) storage modulus of 713.2 (42.9) Pa and a mean (SD) complex viscosity of 115.8 (6.9) Pa/s. Lipoaspirate had a mean (SD) storage modulus of 382.1 (66.8) Pa and a mean (SD) complex viscosity of 61.5 (10.7) Pa/s. Calcium hydroxylapatite had a mean (SD) storage modulus of 1122.1 (67.1) Pa and a mean (SD) complex viscosity of 207.2 (11.6) Pa/s. Cross-linked hyaluronic acid had a mean (SD) storage modulus of 63.9 (3.0) Pa and a mean (SD) complex viscosity of 10.9 (0.5) Pa/s.

[CONCLUSIONS AND RELEVANCE] Of the 4 materials tested, calcium hydroxylapatite has the highest mean storage modulus and mean complex viscosity, and hyaluronic acid has the lowest. The viscoelastic properties of adipose-derived ECM are most similar to those of lipoaspirate, suggesting that it may be an ideal candidate for soft-tissue reconstruction.