Speaker
Description
Here, we present two different applications of responsive hydrogel, which can be prepared by electrospinning or micropatterning processes. The first application is the use of responsive hydrogel for soft actuators. We fabricated a soft actuating system based on hydrogel-incorporated fibers by combining electrospinning and hydrogel lithography. Fibrous passive and active layers were stacked and connected together by a hydrogel micropattern coupling layer. The combination of stimuli-responsive PAA or PNIPAAm with a PCL-based passive layer caused the bending and unbending of the multilayered fibrous actuator when the pH or temperature was changed. The computational simulation was also performed and revealed that the bending characteristics of the actuator are determined by the size and mechanical properties of the active layer relative to those of the coupling layer.
The second application is the use of bioresponsive hydrogel for biosensing. we monitored the volume changes of bioresponsive hydrogels using the concept of moiré patterns. To generate a moiré pattern, a hydrogel grating with microgroove patterns was fabricated via replica molding, which was then overlaid with a reference grating with a different pitch size. Although the change in the pitch size of the hydrogel grating due to external stimuli was small, a much greater signal could be obtained when moiré signals were used. After the pH-responsiveness of the hydrogel was successfully monitored using a moiré pattern, quantitative detection of the target protein was performed using an antibody-incorporated hydrogel. Brain-derived neurotrophic factor and platelet-derived growth factor were selected as the model proteins, and our proposed system successfully detected both proteins at nanomolar levels. In both cases, the pitch size change of hydrogel grating was monitored much more sensitively using moiré patterns than through direct measurements. The changes in the moiré signals caused by target proteins were detected in ex-vivo environments using a custom-made intraocular lens incorporating the hydrogel grating, demonstrating the capability of the proposed system to detect various markers in intraocular aqueous humor, when implanted in the eye.
References
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| Keywords | Responsive hydrogel; Soft actuator; Biosensor; Moiré patterns |
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