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Journal of Materials Chemistry. B Jun 2021Flexible bioelectronics have promising applications in electronic skin, wearable devices, biomedical electronics, etc. Hydrogels have unique advantages for... (Review)
Review
Flexible bioelectronics have promising applications in electronic skin, wearable devices, biomedical electronics, etc. Hydrogels have unique advantages for bioelectronics due to their tissue-like mechanical properties and excellent biocompatibility. Particularly, conductive and tissue adhesive hydrogels can self-adhere to bio-tissues and have great potential in implantable wearable bioelectronics. This review focuses on the recent progress in tissue adhesive hydrogel bioelectronics, including the mechanism and preparation of tissue adhesive hydrogels, the fabrication strategies of conductive hydrogels, and tissue adhesive hydrogel bioelectronics and applications. Some perspectives on tissue adhesive hydrogel bioelectronics are provided at the end of the review.
Topics: Adhesives; Electric Conductivity; Hydrogels; Wearable Electronic Devices
PubMed: 33908586
DOI: 10.1039/d1tb00523e -
Journal of Materials Chemistry. B Nov 2021Hydrogels consisting of a three-dimensional hydrophilic network of biocompatible polymers have been widely used in tissue engineering. Owing to their tunable mechanical... (Review)
Review
Hydrogels consisting of a three-dimensional hydrophilic network of biocompatible polymers have been widely used in tissue engineering. Owing to their tunable mechanical properties, hydrogels have been applied in both hard and soft tissues. However, most hydrogels lack self-adhesive properties that enable integration with surrounding tissues, which may result in suture or low repair efficacy. Self-adhesive hydrogels (SAHs), an emerging class of hydrogels based on a combination of three-dimensional hydrophilic networks and self-adhesive properties, continue to garner increased attention in recent years. SAHs exhibit reliable and suitable adherence to tissues, and easily integrate into tissues to promote repair efficiency. SAHs are designed either by mimicking the adhesion mechanism of natural organisms, such as mussels and sandcastle worms, or by using supramolecular strategies. This review summarizes the design and processing strategies of SAHs, clarifies underlying adhesive mechanisms, and discusses their applications in tissue engineering, as well as future challenges.
Topics: Adhesives; Animals; Biocompatible Materials; Humans; Hydrogels; Tissue Engineering
PubMed: 34647120
DOI: 10.1039/d1tb01503f -
Biomaterials Nov 2018Designing wound dressing materials with outstanding therapeutic effects, self-healing, adhesiveness and suitable mechanical property has great practical significance in...
Designing wound dressing materials with outstanding therapeutic effects, self-healing, adhesiveness and suitable mechanical property has great practical significance in healthcare, especially for joints skin wound healing. Here, we designed a kind of self-healing injectable micelle/hydrogel composites with multi-functions as wound dressing for joint skin damage. By combining the dynamic Schiff base and copolymer micelle cross-linking in one system, a series of hydrogels were prepared by mixing quaternized chitosan (QCS) and benzaldehyde-terminated PluronicF127 (PF127-CHO) under physiological conditions. The inherent antibacterial property, pH-dependent biodegradation and release behavior were investigated to confirm multi-functions of wound dressing. The hydrogel dressings showed suitable stretchable and compressive property, comparable modulus with human skin, good adhesiveness and fast self-healing ability to bear deformation. The hydrogels exhibited efficient hemostatic performance and biocompatibility. Moreover, the curcumin loaded hydrogel showed good antioxidant ability and pH responsive release profiles. In vivo experiments indicated that curcumin loaded hydrogels significantly accelerated wound healing rate with higher granulation tissue thickness and collagen disposition and upregulated vascular endothelial growth factor (VEGF) in a full-thickness skin defect model. Taken together, the antibacterial adhesive hydrogels with self-healing and good mechanical property offer significant promise as dressing materials for joints skin wound healing.
Topics: Adhesiveness; Adhesives; Animals; Anti-Bacterial Agents; Antioxidants; Bandages, Hydrocolloid; Benzaldehydes; Biocompatible Materials; Chitosan; Cross-Linking Reagents; Curcumin; Drug Liberation; Female; Humans; Hydrogels; Injections; Joints; Mechanical Phenomena; Mice; Micelles; Poloxamer; Schiff Bases; Skin; Vascular Endothelial Growth Factor A; Wound Healing
PubMed: 30172244
DOI: 10.1016/j.biomaterials.2018.08.044 -
Nature Nov 2019Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals...
Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions. Although tissue adhesives have potential advantages over suturing or stapling, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.
Topics: Acrylic Resins; Adhesiveness; Adhesives; Animals; Chitosan; Cross-Linking Reagents; Desiccation; Gelatin; Heart; Hydrogels; Hydrogen Bonding; Lung; Mice; Prostheses and Implants; Rats; Static Electricity; Stomach; Swine; Time Factors; Water; Wearable Electronic Devices; Wettability
PubMed: 31666696
DOI: 10.1038/s41586-019-1710-5 -
The Journal of Experimental Biology Feb 2017Robust adhesion to wet, salt-encrusted, corroded and slimy surfaces has been an essential adaptation in the life histories of sessile marine organisms for hundreds of... (Review)
Review
Robust adhesion to wet, salt-encrusted, corroded and slimy surfaces has been an essential adaptation in the life histories of sessile marine organisms for hundreds of millions of years, but it remains a major impasse for technology. Mussel adhesion has served as one of many model systems providing a fundamental understanding of what is required for attachment to wet surfaces. Most polymer engineers have focused on the use of 3,4-dihydroxyphenyl-l-alanine (Dopa), a peculiar but abundant catecholic amino acid in mussel adhesive proteins. The premise of this Review is that although Dopa does have the potential for diverse cohesive and adhesive interactions, these will be difficult to achieve in synthetic homologs without a deeper knowledge of mussel biology; that is, how, at different length and time scales, mussels regulate the reactivity of their adhesive proteins. To deposit adhesive proteins onto target surfaces, the mussel foot creates an insulated reaction chamber with extreme reaction conditions such as low pH, low ionic strength and high reducing poise. These conditions enable adhesive proteins to undergo controlled fluid-fluid phase separation, surface adsorption and spreading, microstructure formation and, finally, solidification.
Topics: Adhesiveness; Adhesives; Amino Acid Sequence; Animals; Bivalvia; Dihydroxyphenylalanine; Hydrogen-Ion Concentration; Osmolar Concentration; Proteins; Tensile Strength; Wettability
PubMed: 28202646
DOI: 10.1242/jeb.134056 -
Advanced Science (Weinheim,... Apr 2022Adhesives have a long and illustrious history throughout human history. The development of synthetic polymers has highly improved adhesions in terms of their strength... (Review)
Review
Adhesives have a long and illustrious history throughout human history. The development of synthetic polymers has highly improved adhesions in terms of their strength and environmental tolerance. As soft robotics, flexible electronics, and intelligent gadgets become more prevalent, adhesives with changeable adhesion capabilities will become more necessary. These adhesives should be programmable and switchable, with the ability to respond to light, electromagnetic fields, thermal, and other stimuli. These requirements necessitate novel concepts in adhesion engineering and material science. Considerable studies have been carried out to develop a wide range of adhesives. This review focuses on stimuli-responsive material-based adhesives, outlining current research on switchable and controlled adhesives, including design and manufacturing techniques. Finally, the potential for smart adhesives in applications, and the development of future adhesive forms are critically suggested.
Topics: Adhesives; Electronics; Humans; Physical Phenomena; Polymers; Tissue Adhesions
PubMed: 35233988
DOI: 10.1002/advs.202200264 -
Integrative and Comparative Biology Oct 2020The adhesive toe pads of tree frogs have inspired the design of various so-called 'smooth' synthetic adhesives for wet environments. However, these adhesives do not... (Review)
Review
The adhesive toe pads of tree frogs have inspired the design of various so-called 'smooth' synthetic adhesives for wet environments. However, these adhesives do not reach the attachment performance of their biological models in terms of contact formation, maintenance of attachment, and detachment. In tree frogs, attachment is facilitated by an interconnected ensemble of superficial and internal morphological components, which together form a functional unit. To help bridging the gap between biological and bioinspired adhesives, in this review, we (1) provide an overview of the functional components of tree frog toe pads, (2) investigate which of these components (and attachment mechanisms implemented therein) have already been transferred into synthetic adhesives, and (3) highlight functional analogies between existing synthetic adhesives and tree frogs regarding the fundamental mechanisms of attachment. We found that most existing tree-frog-inspired adhesives mimic the micropatterned surface of the ventral epidermis of frog pads. Geometrical and material properties differ between these synthetic adhesives and their biological model, which indicates similarity in appearance rather than function. Important internal functional components such as fiber-reinforcement and muscle fibers for attachment control have not been considered in the design of tree-frog-inspired adhesives. Experimental work on tree-frog-inspired adhesives suggests that the micropatterning of adhesives with low-aspect-ratio pillars enables crack arresting and the drainage of interstitial liquids, which both facilitate the generation of van der Waals forces. Our analysis of experimental work on tree-frog-inspired adhesives indicates that interstitial liquids such as the mucus secreted by tree frogs play a role in detachment. Based on these findings, we provide suggestions for the future design of biomimetic adhesives. Specifically, we propose to implement internal fiber-reinforcements inspired by the fibrous structures in frog pads to create mechanically reinforced soft adhesives for high-load applications. Contractile components may stimulate the design of actuated synthetic adhesives with fine-tunable control of attachment strength. An integrative approach is needed for the design of tree-frog-inspired adhesives that are functionally analogous with their biological paradigm.
Topics: Adhesiveness; Adhesives; Animals; Anura; Biomimetics; Mucus
PubMed: 32413122
DOI: 10.1093/icb/icaa037 -
Chemistry (Weinheim An Der Bergstrasse,... Jan 2022Protein-based adhesives with their robust adhesion performance and excellent biocompatibility have been extensively explored over years. In particular, the unique... (Review)
Review
Protein-based adhesives with their robust adhesion performance and excellent biocompatibility have been extensively explored over years. In particular, the unique adhesion behaviours of mussel and sandcastle worm inspired the development of synthetic adhesives. However, the chemical synthesized adhesives often demonstrate weak underwater adhesion performance and poor biocompatibility/biodegradability, limiting their further biomedical applications. In sharp contrast, genetically engineering endows the protein-based adhesives the ability to maintain underwater adhesion property as well as biocompatibility/biodegradability. Herein, we outline recent advances in the design and development of protein-based adhesives by genetic engineering. We summarize the fabrication and adhesion performance of elastin-like polypeptide-based adhesives, followed by mussel foot protein (mfp) based adhesives and other sources protein-based adhesives, such as, spider silk spidroin and suckerin. In addition, the biomedical applications of these bioengineered protein-based adhesives are presented. Finally, we give a brief summary and perspective on the future development of bioengineered protein-based adhesives.
Topics: Adhesives; Animals; Bivalvia; Peptides
PubMed: 34622998
DOI: 10.1002/chem.202102902 -
Chemical Reviews Mar 2022Tissue engineering is a promising and revolutionary strategy to treat patients who suffer the loss or failure of an organ or tissue, with the aim to restore the... (Review)
Review
Tissue engineering is a promising and revolutionary strategy to treat patients who suffer the loss or failure of an organ or tissue, with the aim to restore the dysfunctional tissues and enhance life expectancy. Supramolecular adhesive hydrogels are emerging as appealing materials for tissue engineering applications owing to their favorable attributes such as tailorable structure, inherent flexibility, excellent biocompatibility, near-physiological environment, dynamic mechanical strength, and particularly attractive self-adhesiveness. In this review, the key design principles and various supramolecular strategies to construct adhesive hydrogels are comprehensively summarized. Thereafter, the recent research progress regarding their tissue engineering applications, including primarily dermal tissue repair, muscle tissue repair, bone tissue repair, neural tissue repair, vascular tissue repair, oral tissue repair, corneal tissue repair, cardiac tissue repair, fetal membrane repair, hepatic tissue repair, and gastric tissue repair, is systematically highlighted. Finally, the scientific challenges and the remaining opportunities are underlined to show a full picture of the supramolecular adhesive hydrogels. This review is expected to offer comparative views and critical insights to inspire more advanced studies on supramolecular adhesive hydrogels and pave the way for different fields even beyond tissue engineering applications.
Topics: Adhesives; Biocompatible Materials; Humans; Hydrogels; Tissue Engineering
PubMed: 35023737
DOI: 10.1021/acs.chemrev.1c00815 -
ACS Nano Sep 2023Early stage oxidative stress, inflammatory response, and infection after tendon surgery are highly associated with the subsequent peritendinous adhesion formation, which...
Early stage oxidative stress, inflammatory response, and infection after tendon surgery are highly associated with the subsequent peritendinous adhesion formation, which may diminish the quality and function of the repaired tendon. Although various anti-inflammatory and/or antibacterial grafts have been proposed to turn the scale, most of them suffer from the uncertainty of drug-induced adverse effects, low mechanical strength, and tissue adhesiveness. Here, inspired by the tendon anatomy and pathophysiology of adhesion development, an adhesive and robust dual-layer Janus patch is developed, whose inner layer facing the operated tendon is a multifunctional electrospun hydrogel patch (MEHP), encircled further by a poly-l-lactic acid (PLLA) fibrous outer layer facing the surrounding tissue. Specifically, MEHP is prepared by gelatin methacryloyl (GelMA) and zinc oxide (ZnO) nanoparticles, which are co-electrospun first and then treated by tannic acid (TA). The inner MEHP exhibits superior mechanical performance, adhesion strength, and outstanding antioxidation, anti-inflammation, and antibacterial properties, and it can adhere to the injury site offering a favorable microenvironment for tendon regeneration. Meanwhile, the outer PLLA acts as a physical barrier that prevents extrinsic cells and tissues from invading the defect site, reducing peritendinous adhesion formation. This work presents a proof-of-concept of a drug-free graft with anisotropic adhesive and biological functions to concert the healing phases of injured tendon by alleviating incipient inflammation and oxidative damage but supporting tissue regeneration and reducing tendon adhesion in the later phase of repair and remodeling. It is envisioned that this Janus patch could offer a promising strategy for safe and efficient tendon therapy.
Topics: Adhesives; Biomimetics; Anti-Inflammatory Agents; Anti-Bacterial Agents
PubMed: 37622841
DOI: 10.1021/acsnano.3c03556