3D MICROPRINTING OF MULTI-ACTUATOR SOFT ROBOTS ONTO 3D-PRINTED MICROFLUIDIC DEVICES VIA EX SITU DIRECT LASER WRITING

Abstract

Soft robots have emerged as powerful alternatives to their rigid counterparts due to inherent advantages including safety for humanrobot interactions and adaptability for manipulating delicate objects.Despite recent developments for macroscale multi-actuator soft robots, manufacturing challenges have impeded the miniaturization of such systems due to difficulties in facilitating the macro-to-micro fluidic connections required for controlling soft robots with fluidic actuation schemes.To bypass these barriers, here we introduce a novel "ex situ Direct Laser Writing (esDLW)"-based hybrid strategy for additively manufacturing mesoscale 3D multi-actuator soft robotic systems directly atop externally accessible microfluidic devices.Specifically, we use two-photon esDLW to 3D microprint sophisticated mesoscale multi-actuator soft robotic systems directly on top of-and notably, fluidically sealed to-externally accessible "Digital Light Processing (DLP)"-based 3D-printed microfluidic devices.We interrogated the efficacy of this strategy by loading fluorescently labeled fluids into the esDLW-printed soft actuators as well as by performing cyclic burst-pressure experiments.Experimental results revealed uncompromised print-to-microdevice fluidic integrity both qualitatively from an absence of undesired leakage of the fluorescently labeled fluid and quantitatively for 100 cycles of pressure ramping up to 500 kPa inputs.In combination, these results suggest that the presented esDLW strategy holds promise as a pathway for scaling fluidically actuated soft robotic systems down to the mesoscale for emerging applications, such as for robot-assisted surgical interventions.