Scalable Laser Printing of Three-Dimensional Living Tissue Constructs

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The rising success rate of transplants has resulted in a critical need for more tissues and organs. Approximately 95,000 people are on the waiting list for new organs in the US alone, and some die every day waiting for transplants. Organ printing provides a promising solution to the problem of organ donor shortage. This award supports fundamental research to generate knowledge that enables the scale up of a jet-based, orifice-free laser bioprinting technique for organ printing. Results from this research will enable the wider use of laser printing for the fabrication of living tissue constructs for implantation. In addition, this award will promote the development of bioprinting technologies for cell and organ printing and provide three-dimensional engineered tissues for cell behavior and pharmacokinetics studies.In this new laser bioprinting technique, an optical scanner will be incorporated into the laser beam delivery system to optically guide laser pulses to efficiently transfer bioinks of a ribbon instead of mechanically moving the ribbon. The objective of this research is to understand the effects of the interaction of laser pulses-induced adjacent fluid jets on the jettability and printability during optical scanner-enabled laser-induced forward transfer bioprinting. The jettability will be evaluated based on whether two adjacent well-defined jets can be formed during jet formation, and the printability will be assessed based on whether a well-defined line can be formed from well-defined jets. The formation of each laser-induced jet will be modeled using the existing homogenous nucleation-based phase explosion theory. The governing fluid continuity and Navier-Stokes equations for droplet formation under the jet interaction will be solved numerically using a finite element method with mixed interpolation for spatial discretization as well as an implicit finite difference method for time integration. In order to derive a reduced system of equations and boundary conditions containing the governing physics, a scale analysis of the governing equations and interfacial conditions will be performed. The scale analysis results will be used to validate the numerical simulation on the onset of instability (droplet formation) under the effects of two adjacent jets. The resulting knowledge of the interaction of adjacent jets will be used to predict the influences of printing conditions such as the scanning speed of optical scanner on the jettability and printability and further validated during the laser bioprinting of cellular tubes.