Abstract: Objective To prepare customized porous silicone orbital implants using embedded 3D printing and assess the effect of surface modification on the properties of the implants. Methods The transparency, fluidity and rheological properties of the supporting media were tested to determine the optimal printing parameters of silicone. The morphological changes of silicone after modification were analyzed by scanning electron microscopy, and the hydrophilicity and hydrophobicity of silicone surface were evaluated by measuring the water contact angle. The compression modulus of porous silicone was measured using compression test. Porcine aortic endothelial cells (PAOECs) were co-cultured with porous silicone scaffolds for 1, 3 and 5 days to test the biocompatibility of silicone. The local inflammatory response to subcutaneous porous silicone implants was evaluated in rats. Results The optimal printing parameters of silicone orbital implants were determined as the following: supporting medium 4% (mass ratio), printing pressure 1.0 bar and printing speed 6 mm/s. Scanning electron microscopy showed that the silicone surface was successfully modified with polydopamine and collagen, which significantly improved hydrophilicity of the silicone surface (P<0.05) without causing significant changes in the compression modulus (P>0.05). The modified porous silicone scaffold had no obvious cytotoxicity and obviously promoted adhesion and proliferation of PAOECs (P<0.05). In rats bearing the subcutaneous implants, no obvious inflammation was observed in the local tissue. Conclusion Poprous silicone orbital implants with uniform pores can be prepared using embedded 3D printing technology, and surface modification obviously improves hydrophilicity and biocompatibility of the silicone implants for potential clinical application.

Key words: orbital implant, embedded 3D printing, silicone, polydopamine, collagen