Emerging bioprinting technologies enable fabrication of constructs for tissue engineering with spatially controlled deposition of cells and biologically active factors to mimic the structural complexity of tissues.
Bioprinting also supports production of constructs with complex geometries, as might be encountered in oral and maxillofacial surgical reconstruction cases. While the technology presents tremendous potential for craniofacial tissue engineering applications, progress has been dampened by the complexity associated with the development of biomaterials to be used in extrusion-based bioprinting. A recent article by Kiyotake et al. sought to develop standardized characterization methods and target windows of printability to facilitate transition of bioink development from trial-and-error approaches to standardized quantitative measures. To this end, the authors applied three quantitative rheological tests in the characterization of hyaluronic acid-based bioink formulations; namely, yield stress, viscosity, and storage modulus recovery. Among the three metrics investigated, the authors conclude that yield stress was the most important for bioprinting applications, but they underscore that other considerations, such as potential effects of cell concentrations and sterilization methods, should be considered. Overall, the article marks a shift toward the establishment of standardized methods for bioink characterization and provides initial target values to guide development of biomaterials for bioprinting applications.
Development and quantitative characterization of the precursor rheology of hyaluronic acid hydrogels for bioprinting.
Kiyotake EA, Douglas AW, Thomas EE, Nimmo SL, Detamore MS. Acta Biomater. 2019;95:176-187.