Fabrication of an injectable acellular adipose matrix for soft tissue regeneration

The acellular adipose matrix (AAM) represents a promising source of biomaterial for applications in soft tissue regeneration. In this study, we aimed to prepare an injectable AAM to serve as a ready-to-use allograft. A fabrication procedure including harvesting, delipidating, and decellularizing was established. Accordingly, we proposed a mechanical disruption during delipidation and a final homogenization to produce the AAM powder in an injectable form. Our results demonstrated that mechanical disruption would enhance the efficiency of fat removal from the tissue and would significantly shorten the delipidation duration. A decellularization strategy composed of Tris–HCl and Sodium Dodecyl Sulfate was developed for adipose tissue. The evidence for a complete cellular remnant removal was shown through Hematoxylin and Eosin staining and DNA measurements. The AAM powder was prepared by mechanical disruption under reduced temperatures, which resulted in an AAM particle size in the range of 100 μm. In vitro cytotoxicity testing via extraction demonstrated that AAM had no toxicity on human adipose derived stem cells (hADSCs). Further experiments showed a positive support of the AAM extraction on the migration and proliferation of hADSCs, which indicated its role as a modulator for cell recruitment and proliferation during the tissue remodeling process. Subcutaneous injection of AAM presented a gradual degradation and integration with the surrounding tissues. In the following 8 week post-injection period, AAM supported the in vivo adipogenesis observed in the peripheral side along the implant. Overall, the results of this study demonstrated that the fabrication protocol for the acellular adipose matrix can be applied to injectable materials, which provide proper biocompatibility and potential applicability as off-the-shelf material for soft tissue regeneration.