A comparative study of radiation tolerance between dECM hydrogel-adipose composite biomaterials and traditional breast implants

Postmastectomy breast reconstruction is limited by radiotherapy-induced tissue damage, as silicone implants are prone to capsular contracture, and autologous adipose grafts are limited by resorption and necrosis. In this study, two biomaterials were developed: an injectable decellularized omentum hydrogel-adipose composite (Adipose-dECM) using decellularized omentum hydrogel (dECM) bioactivity for tissue integration and an alginate-reinforced dECM hydrogel (Alg-dECM) for mechanical resilience. O-dECM, Adipose-dECM, Adipose, Alg-dECM, and Silicone were compared in a subcutaneous evaluation in female SD rats (n = 30). Half of the rats underwent radiotherapy (28 Gy) on day 16. The recorded outcomes included small-amplitude oscillatory shear rheology, scanning electron microscopy (porosity), enzymatic mass retention (collagenase), fibrous capsule thickness, inflammatory cell density, the ratio of type I to type III Collagen, and angiogenesis. Adipose-dECM showed early postradiotherapy volume retention, although the results were not statistically significant. However, long-term retention decreased to 30.75% on day 50. Compared with the Other implants, Adipose-dECM had the lowest inflammatory infiltration and reduced Collagen I deposition, although its capsular thickness was similar. Enhanced angiogenesis was detected in Adipose-dECM, with significantly greater CD31+ areas in the peri-implant tissue (1.31% vs 0.10%, p < 0.0001) and septa (0.60% vs 0.07%, p < 0.0001). After radiotherapy, the CD31 level remained elevated in peri-implant regions (0.84% vs 0.34%, p = 0.0010) and septa (0.29% vs 0.06%, p = 0.0003). Adipose-dECM enhanced radiation tolerance through anti-inflammatory modulation and angiogenesis. Nevertheless, its long-term volumetric stability was substantially inferior to that of silicone, indicating the need for material-level strategies to slow degradation while preserving bioactivity. Adipose-dECM therefore shows promise as a radiation-compatible bioactive scaffold for breast reconstruction but requires further optimization for durable clinical translation.