Effects of printing conditions on cell distribution within microspheres during inkjet-based bioprinting

Heqi Xu,Jazzmin Casillas,Changxue Xu

doi:10.1063/1.5116371

Abstract

Inkjet-based bioprinting have been widely employed in a variety of applications in tissue engineering and drug screening and delivery. The typical bioink used in inkjet bioprinting consists of biological materials and living cells. During inkjet bioprinting, the cell-laden bioink is ejected out from the inkjet dispenser to form microspheres with cells encapsulated. The cell distribution within microspheres is defined as the distribution of cell number within the microspheres. The paper focuses on the effects of polymer concentration, excitation voltage, and cell concentration on the cell distribution within microspheres during inkjet printing of cell-laden bioink. The normal distribution has been utilized to fit the experimental results to obtain the mean and standard deviation of the distribution. It is found that the cell distribution within the microspheres increases with the increase of the cell concentration, sodium alginate concentration, and the excitation voltage.

Highlights

AND BACKGROUNDAdditive manufacturing, known as three-dimensional (3D) printing, was first presented in 19861 when photocrosslinkable polymers were utilized to successfully fabricate 3D structures based on a layer-by-layer manner
The continuous inkjet printing (CIJ) printing is limited by the risk of contamination that occurs during ink recirculation, and the thermal DOD printing may cause damage or death of living cells
This study investigates the effects of the printing variables on the post-printing cell distribution within the microspheres during inkjet printing of cell-laden bioink

Summary

Introduction

AND BACKGROUNDAdditive manufacturing, known as three-dimensional (3D) printing, was first presented in 19861 when photocrosslinkable polymers were utilized to successfully fabricate 3D structures based on a layer-by-layer manner. 3D bioprinting has been gaining more and more attention in a variety of tissue engineering and regenerative medicine applications.3,4 3D bioprinting utilizes different advanced manufacturing technologies to fabricate 3D functional tissues and organs layer by layer using bioink containing biological materials, additives, and living cells. Three main bioprinting techniques are widely used including inkjet-based, microextrusion-based, and laser-assisted bioprinting.14–16 Among these three bioprinting techniques, inkjetbased bioprinting is favored in this study because of the high cell viability and resolution, precise controllability, easy scale-up potential, high printing speed, to name a few. In a thermal DOD printer, a microheater element vaporizes a small pocket of the fluid; the formation and collapse of the vapor bubble generates an acoustic pressure pulse which ejects the fluid out from the inkjet dispenser. Thence, piezoelectric DOD printing is favored in this study due to good controllability and high cell viability

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