Lower Critical Solution Temperature-Driven Self-Coacervation of Nonionic Polyester Underwater Adhesives

Abstract

To enable attachment to underwater surfaces, aquatic fauna such as mussels and sandcastle worms utilize the advantages of coacervation to deliver concentrated protein-rich adhesive cocktails in an aqueous environment onto underwater surfaces. Recently, a mussel adhesive protein Mfp-3s, was shown to exhibit a coacervation-based adhesion mechanism. Current synthetic strategies to mimic Mfp-3s often involve complexation of oppositely charged polymers. Such complex coacervates are more sensitive to changes in pH and salt, thereby limiting their utility to narrow ranges of pH and ionic strength. In this study, by taking advantage of the lower critical solution temperature-driven coacervation, we have created mussel foot protein-inspired, tropoelastin-like, bioabsorbable, nonionic, self-coacervating polyesters for the delivery of photo-cross-linkable adhesives underwater and to overcome the challenges of adhesion in wet or underwater environments. We describe the rationale for their design and the underwater adhesive properties of these nonionic adhesives. Compared to previously reported coacervate adhesives, these "charge-free" polyesters coacervate in wide ranges of pH (3−12) and ionic strength (0−1 M NaCl) and rapidly (<300 s) adhere to substrates submerged underwater. The study introduces smart materials that mimic the self-coacervation and environmental stability of Mfp-3s and demonstrate the potential for biological adhesive applications where high water content, salts, and pH changes can be expected.

A New pH-Responsive Nano Micelle for Enhancing the Effect of a Hydrophobic Bactericidal Agent on Mature Streptococcus mutans Biofilm

“…It should be noted that the micelles in neutral environment are positively charged, which may contribute to the capability of micelles to coat tooth surface and promote bacterial adhesion by electrostatic adsorption. Previous studies found many factors, including energy, charge, composition, stiffness, and hydrophobicity of tooth surface ( Belas, 2014 ; Song et al, 2015 , 2017 ; Teschler et al, 2015 ), as well as size, charge, and ionic strength of micelles ( Paula and Koo, 2017 ; Narayanan et al, 2020 ; Li and Liu, 2021 ), can affect the binding between micelles and tooth surfaces. These binding-promoting properties of micelles should be further studied to improve their clinical application potential.…”

Blending poly(2‐ethyl‐2‐oxazoline) with hydrophobic polymers as a hybrid adhesive with enhancedwater‐resistantproperties

“…Especially, 30PVPh/ PEOX raises the adhesion strength to 0.57 MPa, exhibiting high adhesion strength in a wet environment compared with other wet adhesives in the literature (Figure 7h). [45][46][47][48][49][50][51] The less moisture absorption of 30PVPh/PEOX is believed to be the main reason for the adhesion strength in wet conditions.…”

Biocompatible Catechol‐Functionalized Cellulose‐Based Adhesives with Strong Water Resistance

“…Therefore, it is a big challenge to develop biocompatible water-resistant adhesives with strong adhesion strength in a wet environment for practical applications in the adhesion science and technology. [12][13][14][15][16][17] In nature, a myriad of living organisms, such as sandcastle worms and mussels, can secrete sticky mucus to adhere to different surface of substrate. [18,19] Especially, mussels could secrete mussel adhesion proteins (MAPs) to anchor many materials firmly in wet conditions.…”

“…Therefore, it is a big challenge to develop biocompatible water‐resistant adhesives with strong adhesion strength in a wet environment for practical applications in the adhesion science and technology. [ 12–17 ]…”