Self-Helical Fiber for Glucose-Responsive Artificial Muscle

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Robotics

Background:

• Helical structures offer advantages for artificial muscles due to their high movement potential.
• Conventional methods for creating helical fibers often require high temperatures, posing challenges for thermoset hydrogels prone to thermal degradation.
• Developing thermally stable, high-performance artificial muscle fibers remains a significant challenge.

Purpose of the Study:

• To develop a novel self-helical hydrogel fiber for artificial muscle applications without thermal processing.
• To create a glucose-responsive artificial muscle using a self-helical hydrogel fiber.
• To evaluate the actuation performance and potential applications of the developed hydrogel fiber.

Main Methods:

• Fabrication of a sheath-core fiber composed of a twisted nylon core and a hydrogel sheath.
• Induction of spontaneous helical transformation during swelling through balanced forces.
• Incorporation of phenylboronic acid for glucose responsiveness and controllable actuation.
• Characterization of tensile stroke, load-bearing capacity, and work density.

Main Results:

• The self-helical hydrogel fiber spontaneously formed a helical structure during swelling without thermal treatment.
• The helical fiber demonstrated a maximum tensile stroke of 2.3%, six times greater than nonhelical fibers.
• The artificial muscle exhibited tensile stroke with load, achieving a maximum work density of 130 kJ/m³.
• Reversible actuation was observed in response to changes in glucose concentration.

Conclusions:

• The self-helical hydrogel fiber represents a promising advancement in artificial muscle technology, overcoming thermal processing limitations.
• The glucose-responsive nature of the fiber opens avenues for applications in biosensing and targeted drug delivery.
• This novel material exhibits significant potential for developing advanced soft robotic systems and biomedical devices.