Water‐Triggered Hyperbranched Polymer Universal Adhesives: From Strong Underwater Adhesion to Rapid Sealing Hemostasis

Abstract

is greatly decreased or even eliminated. For instance, the widely used cyanoacrylate adhesives exhibit strong adhesion in air, but when applied in water environment, they are hardened quickly to form a layer of stiff plastics, eventually resulting in the loss of adhesion. [9] The commercially available epoxy resins [10] and polyurethanes [11] are reported to demonstrate strong underwater adhesion, but long time of curing is usually required. Recently, host-guest chemistry strategy was reportedly employed to prepare underwater adhesives; however, the substrate surface needs to be modified in advance. [5,12] In addition, electrostatic and hydrophobic interactions were also proved to contribute to enhanced underwater adhesion, but the adhesion strength was relatively poor. [13,14] In nature, many organisms, such as mussels, barnacles, and castle worms, have evolved an unparalleled mechanism to perfectly tackle the underwater adhesion problem. [15][16][17] The finding of universality of catechol chemistry for wet adhesion has provided a valuable biomimetic source to develop diverse adhesives for use in aqueous environments. However, several problems, such as the complexity of administration, release of harmful organic solvents, [18,19] long-term curing, [2] need for oxidant addition, [20,21] and low adhesion strength, [18,22] may hamper the actual applications of these bioinspired adhesives. Although numerous dopamine-based adhesives have been reported and shown to bond various material surfaces, strong adhesion in water and particularly blood environment, remains nonexistent so far.Increasing studies on bioadhesives secreted by molluscs and insects have suggested that liquid coacervation plays a critical role in achieving underwater adhesion. [13] In this process, phase separation and concurrently increased hydrophobicity induced by coacervation can dispel the hydrated water on the interface, leading to much enhanced interaction of adhesive groups with the adherent and thus stable underwater adhesion. Up to date, several complex coacervate adhesives with linear structure have been reported, but the occurrence of those coacervations in water needs external triggers, such as temperature, [13] pH, [20,23] and iron strength. [24] Compared to linear counterparts, hyperbranched polymer (HBP) has a unique highly branched Despite recent advance in bioinspired adhesives, achieving strong adhesion and sealing hemostasis in aqueous and blood environments is challenging. A hyperbranched polymer (HBP) with a hydrophobic backbone and hydrophilic adhesive catechol side branches is designed and synthesized based on Michael addition reaction of multi-vinyl monomers with dopamine.It is demonstrated that upon contacting water, the hydrophobic chains selfaggregate to form coacervates quickly, displacing water molecules on the adherent surface to trigger increased exposure of catechol groups and thus rapidly strong adhesion to diverse materials from low surface energy to high energy in various environments, such as deionized water, sea ...

Polymeric Hydrogel Systems as Emerging Biomaterial Platforms to Enable Hemostasis and Wound Healing

“…The authors of the study proposed this interesting hemostatic system as first aid in emergency situations. [163] As mentioned earlier, in addition to using dopamine to impart efficient adhesiveness to hydrogels, another strategy to engineer adhesive hydrogels is to use TA, which is rich in catechol and pyrogallol groups, and, interestingly, it can act as both chemical crosslinker and catechol group provider. However, it has been argued that like dopamine-based adhesive hydrogels, their adhesive strength still needs to be improved.…”

Recent Advances in Complex Coacervation Design from Macromolecular Assemblies and Emerging Applications

“…Besides, Cui et al. [ 130 ] prepared a hyperbranched polymer from dopamine, pentaerythritol tetraacrylate and poly(ethylene glycol) diacrylate by Michael addition reaction. The polymer is in liquid state at room temperature, and self‐aggregates into gum‐like coacervate upon contacting water.…”

“…Reproduced with permission. [ 130 ] Copyright 2019, Wiley‐VCH. b) Instant underwater adhesion performance of CEIC.…”

Ultra-fast self-gelling powder mediate robust wet adhesion to promote healing of gastrointestinal perforations

“…Adhesive hydrogels that can strongly adhere to wet tissues have been widely used in wound dressings, [1][2][3][4][5] hemostatic agents, [6][7][8][9][10] wearable devices, [11][12][13] drug delivery systems, 14,15 and tissue engineering, [16][17][18][19][20][21] owing to their strong adhesion, excellent biocompatibility, good permeability, high deformability, and tunable mechanical properties. Two main hydrogel design strategies have been adopted to achieve adhesion on wet tissues: adhering prefabricated adhesive hydrogels [22][23][24][25][26][27][28][29] on wet tissues and forming adhesive hydrogels on wet tissues in situ from precursor solutions.…”

“…6,[33][34][35][36][37] Cui et al reported a hyperbranched polymer adhesive containing a hydrophobic backbone and hydrophilic side branches with catechol groups. 6 Upon contacting water, the hydrophobic chains self-aggregate to form coacervates, which displace the interfacial water and promote catechol group exposure, leading to tight contact and strong adhesion between the adhesives and tissues. Yuk et al prepared a dried double-sided tape by dehydrating hydrogels containing carboxylic acid and N-hydrosuccinimide ester groups.…”