Multifunctional, green, and aqueous adhesive from grape seed protein and tannic acid

Adhesives were widely applied in biomedical devices, wound dressings, hemostatic sealing, etc. Current approaches depended on petroleum and complex surface modifications, leading to limited functionalities. Herein, an aqueous adhesive (GT-50–50), based on the grape seed protein (GSP), water, and tannic acid (TA) was reported to bond various substrates (wood, iron, plastics, etc.) both in water and air without chemical modifications, by the formation of multiple non-covalent interactions at the adhesive-substrate interface. Due to the rapid formation of readily accessible short-range forces, it could achieve rapid adhesion to the above substrates within 8 s. The combination of TA and GSP through intermolecular hydrogen bonds enhanced the cohesive energy of the adhesive. Meanwhile, strong interactions formed between the GT-50–50 adhesive and substrates, resulting in an adhesive strength of 545.4 kPa on wood. Using iron as the substrate, the adhesion strength underwater was 74.1 kPa after immersing in water for 24 h. Reversible interactions endowed repeatable adhesion. After 10 adhesion-detachment cycles, the GT-50–50 adhesive exhibited an average adhesion retention ratio of 81.3% on the above substrates. Due to the thermo-sensitivity of hydrogen bonds, on-demand debonding was realized by elevating the temperature to 60°C. With numerous advantages, the GT-50–50 adhesive was promising in biomedical fields, such as wound dressings, tissue repair, biomedical sensors, etc.