Photoresponsive hydrogels are an emerging class of stimuli-responsive materials that exhibit changes in physical or chemical properties in response to light. Previous investigations have leveraged photothermal mechanisms to achieve reversible changes in hydrogel friction, although few have focused on photochemical means. To date, the tribological properties of photoswitchable hydrogels (, friction and lubrication) have remained underexplored. In this work, we incorporated photoresponsive methoxy-spiropyran-methacrylate monomers (methoxy-SP-MA) into a hydrogel network to form a copolymerized system of poly(-isopropylacrylamide--2-acrylamido-2-methylpropane sulfonic acid--methoxy-spiropyran-methacrylate) (p(NIPAAm--AMPS--SP)). We demonstrated repeatable photoresponsive changes to swelling, friction, and stiffness over three light cycles. Our findings suggest that volume changes driven by the decreased hydrophilicity of the methoxy-SP-MA upon light irradiation are responsible for differences in the mechanical and tribological properties of our photoresponsive hydrogels. Our results could inform future designs of photoswitchable hydrogels for applications ranging from biomedical applications to soft robotics.
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Int J Biol Macromol
January 2025
School of Biomedical Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China. Electronic address:
Hydrogels with favorable biocompatibility are regarded as ideal biomedical materials. However, their poor mechanical and tribological properties limit their further clinical applications. Konjac glucomannan (KGM), a safe natural polysaccharide, has the potential to bridge this gap by regulating the mechanical and tribological properties of hydrogels.
View Article and Find Full Text PDFBiomed Mater
January 2025
School of Advanced Manufacturing, Nanchang University - Qianhu Campus, Nanchang, Jiangxi, China, Nanchang, --- Select One ---, 330031, CHINA.
The articular cartilage is characterized by its gradient hierarchical structure, which exhibits excellent lubrication and robust load-bearing properties. However, its inherent difficulty in self-repair after damage presents numerous formidable challenges for cartilage repair. Inspired by the unique structure of articular cartilage, a biomimetic bilayer hydrogel composed of PAM (polyacrylamide) and PAM/SA (sodium alginate) is prepared using a two-step in-situ swelling method.
View Article and Find Full Text PDFAdv Healthc Mater
January 2025
School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241, P. R. China.
Urinary catheters serve as critical medical devices in clinical practice. However, the currently used urinary catheters lack efficient antibacterial and lubricating properties, often leading to discomfort with patients and even severe urinary infections. Herein, a new strategy of supramolecular assembly and disassembly of chitosan (Cs) is developed that enables efficient antibacterial lubricous and biodegradable hydrogel urinary catheters.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun, 130022, P. R. China.
Dentin hypersensitivity (DH), marked by exposed dentinal tubules, presents as a sharp toothache triggered by stimuli and subsides when the stimuli are removed. To address the limitations of current commercial desensitizers in terms of acid resistance, friction resistance, and stability, a black phosphorus nanosheet-composited methacrylate gelatin hydrogel (GelMA/BP) is developed for DH treatment, leveraging the synergistic effects of photothermal therapy and biomineralization. Incorporating the BP nanosheet provided GelMA/BP with a stable photothermal response and the continuous release of phosphate anions, which blocked dentinal tubules by converting light energy into heat and initiating biomineralization.
View Article and Find Full Text PDFSci Rep
December 2024
Department of Chemistry, University of Washington, Box 351700, Seattle, Washington, 98195, USA.
Trigger valves are fundamental features in capillary-driven microfluidic systems that stop fluid at an abrupt geometric expansion and release fluid when there is flow in an orthogonal channel connected to the valve. The concept was originally demonstrated in closed-channel capillary circuits. We show here that trigger valves can be successfully implemented in open channels.
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