AN APPROACH FOR 3D MICROPRINTING OF SOFT ROBOTIC BIOPSY TOOLS AT 1 FRENCH LENGTH SCALES VIA <i>EX SITU</i> DIRECT LASER WRITING.

Abstract

The prevailing challenge in pediatric cardiac biopsy-a critical diagnostic tool for myocardial diseases-is the risk associated with its invasive nature and the difficulty in accessing intricate, small-sized vasculatures such as the left ventricle in children. Traditional instruments often fail to navigate these confined spaces effectively, compromising the diagnostic process. In response, here we introduced an innovative additive manufacturing (AM) strategy for creating dual-material soft-robotic biopsy tools suited for pediatric cardiac interventions. Our approach utilizes "<i>ex situ</i> Direct Laser Writing (<i>es</i>DLW)" for 3D microprinting both soft (IP-PDMS) and rigid (IP-Dip2) materials to realize a soft-robotic biopsy tool with 1 French (333 <i>μ</i>m) outer diameter (OD) and 1.5 mm height. Leveraging FSI simulations to optimize the materials and geometries, the final design favors a polynomial design with IP-PDMS for the soft actuator and IP-Dip2 for the rigid biopsy needle. Microfluidic pressurization tests affirmed the tool's precise actuation with a maximum deformation of 51% at 50kPa. Additionally, <i>ex vivo</i> tests on bovine heart tissue confirmed successful penetration without mechanical failures, proving the tool's efficacy. While future work will explore the structural integrity and functionality of the dual-material biopsy tools, these initial results establish a foundational technology for enhancing pediatric health interventions.