Bioinspired 4D Printing Shape-Memory Polyurethane Rhinoplasty Prosthesis for Dynamic Aesthetic Adjustment

The disparity between the postoperative outcomes of rhinoplasty and the expected results frequently necessitates secondary or multiple surgeries as a compensatory measure, greatly diminishing patient satisfaction. However, there is renewed optimism for addressing these challenges through the innovative realm of Four-Dimensional (4D) printing. This groundbreaking technology enables three-dimensional objects with shape-memory properties to undergo predictable transformations under specific external stimuli. Consequently, implants crafted using 4D printing offer significant potential for dynamic adjustments. Inspired by worms in our research, we harnessed 4D printing to fabricate a Shape-Memory Polyurethane (SMPU) for use as a nasal augmentation prosthesis. The choice of SMPU was guided by its Glass Transition Temperature (Tg), which falls within the acceptable temperature range for the human body. This attribute allowed for temperature-responsive intraoperative self-deformation and postoperative remodeling. Our chosen animal model for experimentation was rabbits. Taking into account the anatomical structure of the rabbit nose, we designed and produced nasal augmentation prostheses with superior biocompatibility. These prostheses were then surgically implanted in a minimally invasive manner into the rabbit noses. Remarkably, they exhibited successful temperature-controlled in-surgery self-deformation according to the predetermined shape and non-invasive remodeling within a mere 9 days post-surgery. Subsequent histological evaluations confirmed the practical viability of these prostheses in a living organism. Our research findings posit that worm-inspired 4D-printed SMPU nasal prostheses hold significant promise for achieving dynamic aesthetic adjustments.