Building a Modified Replicating Rapid-Prototyping Printer (RepRap) for Extrusion BioPlotting of Cardiomyocytes atop Planar Microelectrode Arrays (MEAs)

Abstract

Event Abstract Back to Event Building a Modified Replicating Rapid-Prototyping Printer (RepRap) for Extrusion BioPlotting of Cardiomyocytes atop Planar Microelectrode Arrays (MEAs) Sandra Springer1*, Sarah Fremgen1 and Swaminathan Rajaraman1 1 University of Central Florida, United States Novelty/Progress Claim We built a modified Replicating Rapid-Prototyping (RepRap) printer (Tronxy P802m) for three-dimensional, movable cell printing for extrusion of cell-loaded bioink powered by piston force. Printing viable cells is a rapidly ascendant technology for applications such as the generation of biological parts (e.g. heart tissue or bone) and the precision plating of cells atop cell-based biosensors to increase the coupling between cells and microelectrodes for the detection of good electrophysiological signals. The most common approaches for bioplotting of cells is through laser or inkjet printing. Both these techniques are cost-prohibitive for this purpose, are not readily available in biological labs and cannot address the requirements of low resource settings. To address these issues, we custom built an inexpensive, extrusion 3D printer and applied it toward the bioplotting of bioinks with primary and human cell lines. Such a bioplotter ideal for low resource settings, increases the accessibility of 3D printing technology for innovative applications developers in this space. Background/State-of-the-Art 3D printing for cell testing, regenerative medicine and physiological/pathological modelling is still a nascent but rapidly advancing field. This type of cell printing technology has showed significant value in tissue engineering applications such as the printing of cardiac muscle patches for an increased recovery after ischemic myocardial injuries [1] or the printing of bone, tracheal splints, vascular grafts, multi-layered skin and cartilage [2]. Furthermore, inkjet-based bioplotters have been used for the precision plating of cells atop of Microelectrode Arrays (MEAs) [3]. These are precise and predesigned plating processes of cell-laden constructs for cell patterning in 3D structures by inkjet-based, laser–based or extrusion-based printers [2]. Due to the high cost, the accessibility to these technologies is limited and extensive research is required to adapt these techniques for specific applications. To increase the availability of cellular bioplotting and simplify usage, we developed a low cost system with modified extrusion-based printing that provided easy customizability, robustness and simplicity and is ideal for laboratories in low-resource settings. Description of the New Method We modified a RepRap printer by building a syringe pump system and connected it to the printer via a controller board operated by the host software (Repetier-Host). The syringe pump system consists of printed thermoplastic PLA (Poly Lactic Acid) and off the shelf motor/metal components. The complete, assembled cell printer system is depicted in Figure 1. Part A of the image shows an overview of the connected printer to the controlling computer, part B and C are close-up images of the syringe pump-needle system and of the needle-extruder unit respectively. This unit is schematically presented in part D of Figure 1. A prepared cell solution is printed in a semi-sterile environment by extruding warm bioink at 37 °C (HL-1 cells in culture media or 5 x 105 cells/ml iCell Cardiomyocytes (CMC) in a 3 % gelatin-culture media ink) via a tubing into the needle unit by extrusion through a 30G sterile flat needle atop the desired device/surface. The interaction between the printer head and the syringe pump enables a movement in all three axes (x-, y-, and z-axis) of the needle unit during the printing process. Experimental Results We have demonstrated that such a modified, “home grown” printer can print living cells (HL-1 cells) in culture media (Figure 2 A - C) in a droplet printing mode (covered surface area 2.81 mm2; radius of 946 µm). However, the cells collected in the centre (Figure 2 B and C), whereby the cell covered surface decreased to 0.29 mm2; radius of 304 µm), which is a reduction of 89.68 % from the initial value. Furthermore, the cells were printed, cultured and observed for seven days in vitro and showed healthy morphologies. Additionally, cell droplets of CMC with precise and predesigned positions were printed atop of 3D printed MEAs ([4]; 30µm x 30µm microelectrodes; 1mm pitch). A schematic image of the precision plating of cells atop a MEA is visualized in part D of Figure 2. Part G of the figure depicts an overview photograph after the printing process and part E and F transmitted light images (Olympus IX71) of accurately, printed droplets with sizes of 680 µm and 750 µm both in radius. We analysed N = 48 drops of the bioink immediately after printing and observed an averaged area of 2.45 mm2 ± 0.52 mm2 respectively with an average radius of 880 µm. Further we noticed an immediate movement of the cells to the centre similar to the reduction of the cell covered surface of printed HL-1 cells. The corresponding data is visualized in part H of Figure 2. Our printer is a rapidly designed and built prototype ideal for low resource settings and customized bioink printing for advanced MEAs. Figure 1 Figure 2 References Reference [1] Gao, L.; Kupfer, M. E.; Jung, J. P.; Yang, L.; Zhang, P.; Da Sie., Y. et al. (2017): Myocardial Tissue Engineering With Cells Derived From Human-Induced Pluripotent Stem Cells and a Native-Like, High-Resolution, 3-Dimensionally Printed Scaffold. In Circulation Research 120 (8), pp. 1318–1325. DOI: 10.1161/CIRCRESAHA.116.310277 [2] Murphy, S. V.; Atala, A. (2014): 3D bioprinting of tissues and organs. In Nature biotechnology 32 (8), pp. 773–785. DOI: 10.1038/nbt.2958 [3] Azim, N.; Sommerhage, F.; Aubin, M.; Hickman, J.; Rajaraman, S. (2017): Precision Plating of Electrogenic Cells on Microelectrodes Enhanced with Nano-Porous Platinum for Cell-Based Biosensing Application. In Meet. Abstr. (Meeting Abstracts) MA2017-01 (42), p. 1954. Available online at http://ma.ecsdl.org/content/MA2017-01/42/1954.short. [4] Kundu, A.; Ausaf, T.; Rajaraman, S. (2018): 3D Printing, Ink Casting and Micromachined Lamination (3D PICLμM). A Makerspace Approach to the Fabrication of Biological Microdevices. In Micromachines 9 (2), p. 85. DOI: 10.3390/mi9020085 Keywords: Cell printing, RepRap Printer, Microelectrode Array (MEA), bioinks, Bioplotting Conference: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays, Reutlingen, Germany, 4 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Neural Networks Citation: Springer S, Fremgen S and Rajaraman S (2019). Building a Modified Replicating Rapid-Prototyping Printer (RepRap) for Extrusion BioPlotting of Cardiomyocytes atop Planar Microelectrode Arrays (MEAs). Conference Abstract: MEA Meeting 2018 | 11th International Meeting on Substrate Integrated Microelectrode Arrays. doi: 10.3389/conf.fncel.2018.38.00065 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Mar 2018; Published Online: 17 Jan 2019. * Correspondence: Ms. Sandra Springer, University of Central Florida, Orlando, Florida, 3216, United States, sandra.m.springer@t-online.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers Sandra Springer Sarah Fremgen Swaminathan Rajaraman Google Sandra Springer Sarah Fremgen Swaminathan Rajaraman Google Scholar Sandra Springer Sarah Fremgen Swaminathan Rajaraman PubMed Sandra Springer Sarah Fremgen Swaminathan Rajaraman Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.