Thermo-Responsive Hydrogel-Based Soft Valves with Annular Actuation Calibration and Circumferential Gripping

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Current biomedical valves often use rigid, non-compliant materials, hindering integration with human tissues.
• There is a need for advanced valve materials that are flexible and responsive for improved therapeutic and assistive devices.

Purpose of the Study:

• To develop and evaluate novel, biologically-inspired, stimuli-responsive valves using hydrogel-based materials.
• To compare the performance of N-Isopropylacrylamide hydrogels-based valves (NPHV) and PAAm-alginate hydrogels-based valves (PAHV) for optimized valve action.

Main Methods:

• Fabrication of NPHV and PAHV using a simple one-pot method.
• Evaluation of valve performance, including annular actuation and flow rate changes, under varying temperature conditions.
• Assessment of PAHV as a soft, stretchable gripper with a high load-to-weight ratio.

Main Results:

• NPHV demonstrated superior annular actuation at 40 °C (1.93 mm displacement in 4 min) compared to PAHV (0.8 mm displacement in 30 min).
• PAHV showed a significant flow rate change (up to 20%) and 100% payload capacity at 100 °C.
• PAHV proved effective as a soft, stretchable circular gripper with a high load-to-weight ratio.

Conclusions:

• Stimuli-responsive hydrogel valves offer enhanced performance over traditional rigid valves for biomedical applications.
• The developed valves, particularly PAHV, show potential for diverse applications including soft robotics and assistive devices.
• The simple fabrication method allows for further optimization and transdisciplinary applications.