Color and Shape-Switchable Biocatalytic Liquid Crystal Elastomers Responsive to Multiple Classes of Biomolecules

The incorporation of enzymes into stimuli-responsive materials has the potential to sensitize their response to specific biomolecules, providing unique materials for applications such as coatings, smart textiles, drug delivery, or sensing. Among stimuli-responsive polymers, liquid crystal elastomers (LCEs) have emerged as a leading actuator platform due to their inherent programmability, realizing shape transformations and large strains upon exposure to stimuli. The immobilization of enzymes in LCEs presents an unprecedented opportunity to create polymers that undergo shape reconfigurations in response to specific biosignals. In this presentation, we will discuss the immobilization of the enzymes <i>Candida rugosa </i>lipase, glucose oxidase, and trypsin into acid-responsive LCEs. This imparted the LCEs with sensitivity to chemical signals that belong to different major classes of biomolecules, such as carbohydrates, lipids, or peptides. Enzyme-containing LCEs doped with methyl red readily switched color from yellow to red upon exposure to their enzymatic substrate. Multiple processing methods, such as twisted nematic patterning or 4D printing, were used to showcase the versatility of biocatalytic LCEs, which transformed from flat films or disks into curls or cones, respectively. Multiplexed responsiveness was demonstrated using a connected array of disks, each containing a different enzyme, highlighting the excellent chemical selectivity of enzymes. This work presents a novel platform of versatile bioresponsive color-switchable actuators that may have application in a wide range of biological fields.