Three-dimensional scaffolding is an emerging research area in biomedical and tissue engineering. Scaffolds provide the possibility of growing tissues in a controlled environment, with desired characteristics and properties towards a specific application. Here we report a new method to 3D print biodegradable and biocompatible complex scaffolds with controlled porosity using Polyglycerol Sebacate Acrylate (PGSA). PGSA is essentially an acrylated form of PGS using photoinitiator to become a photocurable resin suitable for liquid crystal display (LCD) 3D printing. PGSA was selected because its rheological and crosslinking behavior (and hence its mechanical properties) can be controlled by changes in curing time, temperature, and pressure. This material has been proven cytocompatible, and capable of replicating tissue shapes according to detailed computer-aided designs.
We use a modified LCD 3D printer (X-cube, RobotDigg) consisting of a vat of photocurable resin that is suspended above an LCD screen. Using a UV-LED light source, the object is build layer-by-layer until the model is completed. It differs from traditional 3D printing in that the whole layer is cured together, making this a much faster process. The resin needs to be not only photocurable, but also have optimal rheological property for control of 3D printing parameters. Here, we developed a modified PGSA suitable for printing complex scaffolds. The material prepolymer viscosity was characterized using Rheometer (TA Instruments, USA). Additionally, the degree of cross-linkage under a UV-light source was characterized using FTIR - Fourier Transform Infrared Spectroscopy (PerkinElmer, USA) and differential Scanning Calorimetry (DSC) 8500 (Perkin Elmer, USA). Tensile and compression tests (MTS Insight, USA) were conducted on the build sample to determine its mechanical properties. Lastly, biocompatibility tests were performed on the cell-seeded scaffold to validate its cell adhesion, cell proliferation, and cell viability.
The LCD 3D printing is simple, fast and can provide excellent resolution due to small pixel sizes of the LCD screen. Therefore, combining LCD 3D printing and PGSA is a very promising tool for biomedical applications by allowing complex biocompatible, elastomeric tissue scaffolds that can be highly customized without modifying the manufacturing process.