Direct Ink Writing of Enzyme-Containing Liquid Crystal Elastomers as Versatile Biomolecular-Responsive Actuators

Abstract

The combination of enzymes and chemically responsive smart materials presents considerable opportunities in anti-fouling, sensing or medicine. Among stimuli-responsive polymers, liquid crystal elastomers (LCEs) have emerged as a leading actuator platform due to their inherent programmability, realizing large shape transformations upon exposure to stimuli. Herein, three different hydrolytic enzymes are immobilized into acid-responsive LCEs, which impart the LCEs with sensitivity to three distinctive classes of biomolecules: lipids, carbohydrates, and peptides. Dye-doped biocatalytic LCEs readily switch their color and shape upon exposure to the appropriate substrate. Twisted nematic patterning and direct ink writing are used to showcase the versatility of shape changes the enzyme-containing LCEs may undergo. Multiplexed responsiveness is also demonstrated using a connected array of 3D printed disks, each containing a different enzyme, highlighting the excellent chemical selectivity of the LCEs. This work presents a novel platform of versatile bioresponsive color-switchable actuators that may have application in a wide range of fields.