Bioprinting technique incorporating topographical guidance for stem cell alignment, precision deposition and promoting cardiomyocyte differentiation

Abstract

Event Abstract Back to Event Bioprinting technique incorporating topographical guidance for stem cell alignment, precision deposition and promoting cardiomyocyte differentiation Ramya Bhuthalingam1, Pei Qi Lim1, Scott A. Irvine1, Animesh Agrawal1, Priyadarshini S. Mhaisalkar1, An Jia2, Chee Kai Chua2 and Subbu S. Venkatraman1 1 Nanyang Technological University, School of Material Science & Engineering, Singapore 2 Nanyang Technological University, School of Mechanical & Aerospace Engineering, Singapore Introduction: Bioprinting is greatly aided by the use of automated robotic dispensing systems for the delivery of biomaterials and cells. The robotic dispensing systems allow precision control for placement and patterning down to 10s of µm. This precision can be exploited not only for dispensing but also for surface patterning. Surface patterning aids the orientation and differentiation of stem cells seeded onto the biomaterial[2]. In particular, the alignment of Mesenchymal stem cells (MSCs) within channels or grooves on the surface promotes differentiation towards a cardiomyocyte phenotype[1],[3]. There are many complex methods for the introduction of grooves into a polymer surface, which can be time consuming and lack the flexibility to create more complex patterns. We tested the robotic dispensing systems ability to create cell aligning surface channels following the multiple patterns programmed into the controlling CAD software. Furthermore, stem cells aligned to these grooves were examined for lineage commitment towards cardiomyocytes. Finally the dispensing system was assessed for the potential for delivering stem cells within a gelatin bioink directly to the surface grooves[4]. The precision delivery and capability of the cells to sense the grooves was observed. Method: Polystyrene films were patterned with grooves, etched using pre-programmed designs by a Janome 2300N pressure controlled robotic dispensing system. A sharpened stylus was fitted to the dispensing head, thus allowing surface etching. MSCs were seeded onto the surface and their ability to align along the grooves was judged. The lineage commitment of the stem cells was also assessed by FACS for cardiomyocyte markers. Subsequently, a 2% gelatin/DMEM bioink containing MSCs was loaded into the printing head and the bioink was delivered to the pre-etched grooves following the identical pattern used for etching. Results and Discussion: The sharpened stylus allowed etching of the polystyrene surface following preprogrammed coordinates. The MSCs seeded onto the surface orientated along the grooves with an elongated morphology. FACS demonstrated an increase in the cardiomyocyte gene marker GATA4 and a decrease in the stem cell marker CD29[5]. The robot dispenser system could deliver cells in based gelatin bioink directly to the channels by following identical programming coordinates used for etching. The bioink delivered cells could sense the grooves and become aligned.