Three-Dimensional Printing of a Tyramine Hyaluronan Derivative with Double Gelation Mechanism for Independent Tuning of Shear Thinning and Postprinting Curing

Biofabrication via three-dimensional printing (3DP) is expanding our capabilities of producing tissue engineering constructs for regenerative medicine, personalized medicine, and engineered tissue models of disease and diagnostics. Hydrogel-based materials for extrusion-based printing have been introduced; nevertheless, it is still challenging to combine into a single biomaterial all the requirements of an ink. These inks need to flow for extrusion under low shear, yet have immediate shape retention after deposition, provide a biochemical environment similar to that of physiological extracellular matrix, and a curing mechanism avoiding cell damage. This work introduces a simple and versatile tyramine-modified hyaluronan material (HA-Tyr) for extrusion-based printing, featured by (i) single component yet two distinct cross-linking mechanisms, allowing (ii) shear-thinning tuning independently of the postprinting curing; (iii) no rheological additives or sacrificial components; (iv) curing with visible light for shape stability; (v) possibility to postfunctionalize; and (vi) preservation of hyaluronan structure owing to low modification degree. The ink is based on a hydroxyphenol hyaluronan derivative, where the shear thinning properties are determined by the enzymatic cross-linking, while the final shape fixation is achieved with visible light in the presence of Eosin Y as photosensitizer. The two cross-linking mechanisms are totally independent. A universal rheologically measurable parameter giving a quantitative measure of the “printability” was introduced and employed for identifying best printability range within the parameter space in a quantitative manner. 3DP constructs were postfunctionalized, and cell-laden constructs were produced. Due to its simplicity and versatility, HA-Tyr can be used for producing a wide variety of 3D printing constructs for tissue engineering applications

Tuning the Cell-Adhesive Properties of Two-Component Hybrid Hydrogels to Modulate Cancer Cell Behavior, Metastasis, and Death Pathways

This work presents a polysaccharide and protein-based two-component hybrid hydrogel integrating the cell-adhesive gelatin-tyramine (G-Tyr) and nonadhesive hyaluronic acid-tyramine (HA-Tyr) through enzyme-mediated oxidative coupling reaction. The resulting HA-Tyr/G-Tyr hydrogel reflects the precise chemical and mechanical features of the cancer extracellular matrix and is able to tune cancer cell adhesion upon switching the component ratio. The cells form quasi-spheroids on HA-Tyr rich hydrogels, while they tend to form an invasive monolayer culture on G-Tyr rich hydrogels. The metastatic genotype of colorectal adenocarcinoma cells (HT-29) increases on G-Tyr rich hydrogels which is driven by the material’s adhesive property, and additionally confirmed by the suppressed gene expressions of apoptosis and autophagy. On the other hand, HA-Tyr rich hydrogels lead the cells to necrotic death via oxidative stress in quasi-spheroids. This work demonstrates the ideality of HA-Tyr/G-Tyr to modulate cancer cell adhesion, which also has potential in preventing primary metastasis after onco-surgery, biomaterials-based cancer research, and drug testing