Fig. 4: Performance of unfolded protein-based underwater glue.
From: Synthesis of robust underwater glues from common proteins via unfolding-aggregating strategy
a Schematic of the measurement of the underwater adhesive strength of unfolded BSA glue. All adhesion tests were performed in water. b The underwater adhesion strength from different protein-based glues. The corresponding average molecular weight (Mw) of the polypeptide chains contained in each protein is also noted. c The adhesion strength of unfolded BSA glue to glass sliders and the breaking strength of the solidified glue at various degrees of unfolding. The Rg was employed to quantify the unfolding degree of a protein. d The adhesion strength of unfolded BSA prepared with different stabilizers. e The adhesion strength of unfolded BSA glue applied to bond a variety of materials. f Photograph of unfolded BSA-bonded glass slides lifting a 25 kg weight (with a bonding area of 1 cm2). g The adhesion strength of the glue to bond glass fabricated from the crude protein-containing mixture (reductant: TCEP, stabilizer: urea). h Comparison between unfolded BSA glue and mussel byssus bonding to glass sliders and their alkali resistance. Inset photographs showing a mussel (34 g) hanging on glass slides by four byssal threads (left) and a weight (20 g) hanging on glass slices by a string bonded to unfolded BSA (right). i Long-term bonding stability of unfolded BSA glue in water. j Comparison of adhesion strength of the unfolded BSA glue with commercial glues in water. k Comparison of the adhesion strength (lap shear strength) of unfolded BSA glue and those from previous reports3,13,41,58,59,60,61,62,63,64,65,66,67. Only the underwater glues were considered, of which all the steps of the adhesion process were performed underwater. (USPI urushiol grafted soy protein isolate, DOPA polydopamine, PVP polyvinyl pyrrolidone, PVA polyvinyl alcohol). All data in (b–e, g–j) are mean ± S.D. n = 3 independent samples per group.
