Magnetic Resonance Imaging for tracking cellular patterns obtained by Laser-Assisted Bioprinting

Olivia Kérourédan,Sylvain Miraux,Raphaël Devillard,Jean-Christophe Fricain,Emeline Julie Ribot

doi:10.1038/s41598-018-34226-9

Abstract

Recent advances in the field of Tissue Engineering allowed to control the three-dimensional organization of engineered constructs. Cell pattern imaging and in vivo follow-up remain a major hurdle in in situ bioprinting onto deep tissues. Magnetic Resonance Imaging (MRI) associated with Micron-sized superParamagnetic Iron Oxide (MPIO) particles constitutes a non-invasive method for tracking cells in vivo. To date, no studies have utilized Cellular MRI as a tool to follow cell patterns obtained via bioprinting technologies. Laser-Assisted Bioprinting (LAB) has been increasingly recognized as a new and exciting addition to the bioprinting’s arsenal, due to its rapidity, precision and ability to print viable cells. This non-contact technology has been successfully used in recent in vivo applications. The aim of this study was to assess the methodology of tracking MPIO-labeled stem cells using MRI after organizing them by Laser-Assisted Bioprinting. Optimal MPIO concentrations for tracking bioprinted cells were determined. Accuracy of printed patterns was compared using MRI and confocal microscopy. Cell densities within the patterns and MRI signals were correlated. MRI enabled to detect cell patterns after in situ bioprinting onto a mouse calvarial defect. Results demonstrate that MRI combined with MPIO cell labeling is a valuable technique to track bioprinted cells in vitro and in animal models.

Highlights

Recent advances in the field of Tissue Engineering allowed to control the three-dimensional organization of engineered constructs
In order to determine the optimal conditions to obtain sufficient Magnetic Resonance Imaging (MRI) signal intensity for tracking cell patterns in vitro, cells were incubated with different concentrations of Micronsized superParamagnetic Iron Oxide (MPIO) (1:1000, 1:500, 1:200, 1:100 from the stock solution containing 4.5 mg Fe/mL)
This paper reports the first MR images of laser-assisted bioprinted cells labeled with a contrast agent

Summary

Introduction

Recent advances in the field of Tissue Engineering allowed to control the three-dimensional organization of engineered constructs. Laser-Assisted Bioprinting (LAB) has been increasingly recognized as a new and exciting addition to the bioprinting’s arsenal, due to its rapidity, precision and ability to print viable cells This non-contact technology has been successfully used in recent in vivo applications. LAB has been successfully used to print a large variety of biological components such as hydrogels, DNA, peptides and live cells[6,7,8,9] This technology provides significant advantages such as rapidity, reproducibility, precision, high cell viability and density[4,5,10]. For the successful application of this technology it is crucial to track printed cells in vivo in a non-invasive manner, in order to check the quality of printed patterns immediately after the bioprinting process, to study their persistence and evolution over time, and to provide insight into cellular proliferation and migration dynamics[21]. No technology has been able to achieve this

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