ABSTRACT
Direct ink writing via single or multihead extrusion is used to synthesize layer-by-layer (LbL) meshes comprising renewable polysaccharides. The best mechanical performance (683 ± 63 MPa modulus and 2.5 ± 0.4 MPa tensile strength) is observed for 3D printed structures with full infill density, given the role of electrostatic complexation between the oppositely charged components (chitosan and cellulose nanofibrils). The LbL structures develop an unexpectedly high wet stability that undergoes gradual weight loss at neutral and slightly acidic pH. The excellent biocompatibility and noncytotoxicity toward human monocyte/macrophages and controllable shrinkage upon solvent exchange make the cellular meshes appropriate for use as biomedical implants.
ABSTRACT
Owing to its purity and exceptional mechanical performance, bacterial nanocellulose (BNC) is well suited for tissue engineering applications. BNC assembles as a network that features similarities with the extracellular matrix (ECM) while exhibiting excellent integrity in the wet state, suitable for suturing and sterilization. The development of complex 3D forms is shown by taking advantage of the aerobic process involved in the biogenesis of BNC at the air/culture medium interphase. Hence, solid supports are used to guide the formation of BNC biofilms that easily form auxetic structures. Such biomaterials are demonstrated as implantable meshes with prescribed opening size and infill density. The measured mechanical strength is easily adjustable (48-456 MPa tensile strength) while ensuring shape stability (>87% shape retention after 100 burst loading/unloading cycles). We further study the cytotoxicity, monocyte/macrophage pro-inflammatory activation, and phenotype to demonstrate the prospective use of BNC as supportive implants with long-term comfort and minimal biomaterial fatigue.