Universal Method for Covalent Attachment of Hydrogels to Diverse Polymeric Surfaces for Biomedical Applications

Hydrogels, renowned for their biocompatibility and capacity to mimic biological tissues, are integral to many biomedical applications, such as implantable devices and wound dressings. However, their poor mechanical strength and the challenge of achieving durable adhesion to polymeric surfaces have hindered their broader utility. Current methods of creating hybrid solid-hydrogel (HSH) structures often rely on complex chemical linkers, adding steps, cytotoxic risks, and scalability issues. Here, a novel, reagent-free method that covalently bonds hydrogels to polymeric substrates directly via reactive oxygen species (ROS) generated by an atmospheric pressure plasma jet (APPJ) is introduced. Through an evaporation-induced enhanced concentration (EIEC) approach, robust hydrogel layers are formed on ROS-functionalized surfaces, eliminating the need for silane-based linkers and achieving up to 60 kPa adhesion strength in wet conditions. This strategy offers robust hydrogel adhesion, reduces processing complexity, and preserves cytocompatibility, as demonstrated by the culture of human mesenchymal stem cells (hMSCs) and THP-1 derived macrophages with minimal immune response. Applicable across various hydrogels, such as gelatin methacryloyl (GelMA), chitosan, and polymeric substrates, including Teflon, polyethylene, and polycaprolactone (PCL), this dry process holds substantial promise for integration into advanced biomanufacturing systems, such as 3D bioprinters, unlocking new potentials in tissue engineering and biomedical device fabrication.