Comparison of the Rheological Properties and Structure of Fat Derivatives Generated via Different Mechanical Processing Techniques: Coleman Fat, Nanofat, and Stromal Vascular Fraction-Gel

Importance: Coleman fat, nanofat, and stromal vascular fraction-gel (SVF-gel) are three widely used fat derivatives. However, their rheological properties and structure remain unknown. Objectives: To disclose the rheological properties and structure of three different fat derivatives. Design, Settings, and Participants: Fat tissues obtained from eight different donors were processed into three separate groups: Coleman fat, nanofat, and SVF-gel (n = 8); their viscoelastic properties and structure were determined. Intervention: Oscillation measurements were performed in the context of serrated 25-mm parallel-plate geometry with a 1.2-mm gap at 25°C. In addition, fat samples were fixed using a patented protocol and observed under scanning electron microscopy. Main Outcomes and Measures: Comparison of the viscoelastic properties, microstructure, and particle size. Results: At 0.77 Hz, the elastic modulus of SVF-gel, Coleman fat, and nanofat was 201.6 ± 0.74, 69.94 ± 15.61, and 34.89 ± 3.484 Pa, respectively; their viscosity was 44.06 ± 3.038, 15.37 ± 2.0380, and 7.516 ± 0.7250 mPa, respectively. The particle size of SVF-gel, Coleman fat, and nanofat was 106.0 ± 4.796, 86.93 ± 3.597, and 12.61 ± 7.603 μm, respectively. Conclusion and Relevance: Mechanical processing may impact graft efficacy. The characterization of the rheological properties and structure of different fat derivatives in this study may help surgeons select the better type of tissue for a given intervention; however, further studies are still required.