Optimization of the co-axial dispensing nozzle of a 3D bioprinter for the fabrication of tubular structures with micro-channel encapsulation

Abstract

The 3D bio-printing has been developed as an effective approach to artificially create tubular tissue structures, which have been frequently found in body and organ systems. China Agricultural University (CAU) has developed a laboratory 3D bio-printer that can create tubular structures with the encapsulation of microfluidic channel. In order to create a tubular structure with more effective micro-channel encapsulation for better nutrient delivery and chemical stimulation, this work presents a design optimization of co-axial dispensing nozzle of this 3D bio-printer. In this study, an experimentally validated two-phase flow computational fluid dynamics modeling tool based on ANSYS CFX has been developed to analyze the microfluidic domain of fluid channels inside the nozzle. The simulations on the extrusion and encapsulation process of bio-inks have been conducted. Based on the response surface method, the simulation work has established an equation to predict the volume fraction of the encapsulating layer against a variety of influencing factors including the size of extrusion nozzle, pneumatic pressure condition and the dynamic viscosity of the bio-ink. This equation has been used to recommend optimal solutions of printing parameters for the CAU bio-printer, which is expected to improve the quality of bio-printed tubular structure with an encapsulation.

Development of a piston-actuated 3D bio-printer with performance prediction system for the reliable printing of tubular structures

“…Gelatin is also easily degraded in the body, making it suitable for bioprinting [26]. Shaoping et al demonstrated that a mixture of alginate and gelatin solution can produce bio-ink with a wide range of viscosity, from almost 0-25 000 mPa.s, compared to pure alginate or gelatin solutions (0% gelatin or 0% alginate) [25]. Therefore, this study employed an alginate-gelatin solution to produce a highviscosity printing material for improved formability.…”

“…The outer shell fluid, which contains supporting material, and the inner core fluid, mixed with cells, merge at the exit end of the external needle, resulting in encapsulation. The core fluid, containing cells, is firmly wrapped by the shell layer fluid, resulting in microencapsulation [25]. This process is significant for improving cell viability and the performance of micro tubular structures.…”

Floating Ricobendazole Delivery Systems: A 3D Printing Method by Co-Extrusion of Sodium Alginate and Calcium Chloride

“…These differences were taken into consideration during the set-up of the print flow rates for alginate and crosslinking inks. According to the properties of both alginate and crosslinking inks [32], the flow rates were fixed at 50 µL/min and at 100 µL/min, respectively.…”

Accelerating Effects of Flow Behavior Index n on Breakup Dynamics for Droplet Evolution in Non-Newtonian Fluids

“…The experiment devices of two-phase flow in microchannel consisted of the fluid driving unit, the microchannel sample, and the observation unit (Figure 1). The microchannel sample was vertical and coaxial [19,20], in which the dispersed phase flowed in the inner tube with the NaAlg solution and the continuous phase flowed in the outer tube with Oil. The inner diameters of the outer tube and the inner tube, respectively, were 1 mm and 0.42 mm.…”

“…There were four group experiments with the different mass fraction of NaAlg solution (0.1 wt%, 0.5 wt%, 1.0 wt% and 1.5 wt%). The experiment parameters were in the The microchannel sample was vertical and coaxial [19,20], in which the dispersed phase flowed in the inner tube with the NaAlg solution and the continuous phase flowed in the outer tube with Oil. The inner diameters of the outer tube and the inner tube, respectively, were 1 mm and 0.42 mm.…”