Mussel Adhesion Mechanism Research Articles

Bioinspired Asymmetric-Adhesion Janus Hydrogel Patch Regulating by Zwitterionic Polymers for Wet Tissues Adhesion and Postoperative Adhesion Prevention.

Asymmetrically adhesive hydrogel patch with robust wet tissue adhesion simultaneously anti-postoperative adhesion is essential for clinical applications in internal soft-tissue repair and postoperative anti-adhesion. Herein, inspired by the lubricative role of serosa and the underwater adhesion mechanism of mussels, an asymmetrically adhesive hydrogel Janus patch is developed with adhesion layer (AL) and anti-adhesion layer (anti-AL) through an in situ step-by-step polymerization process in the mold. The AL exhibits excellent adhesion to internal soft-tissues. In contrast, the anti-AL demonstrated ultralow fouling property against protein and fibroblasts, which hinders the early and advanced stages of development of the adhesion. Moreover, the Janus patch simultaneously promotes tissue regeneration via ROS clearance capability of catechol moieties in the AL. Results from in vivo experiments with rabbits and rats demonstrate that the AL strongly adheres to traumatized tissue, while the anti-AL surface demonstrate efficacy in preventing of post-abdominal surgery adhesions in contrast to clinical patches. Considering the advantages in terms of therapeutic efficacy and off the shelf, the Janus patch developed in this work presents a promise for preventing postoperative adhesions and promoting regeneration of internal tissue defects.

Mussel-Inspired Injectable Adhesive Hydrogels for Biomedical Applications.

The impressive adhesive capacity of marine mussels has inspired various fascinating designs in biomedical fields. Mussel-inspired injectable adhesive hydrogels, as a type of promising mussel-inspired material, have attracted much attention due to their minimally invasive property and desirable functions provided by mussel-inspired components. In recent decades, various mussel-inspired injectable adhesive hydrogels have been designed and widely applied in numerous biomedical fields. The rational incorporation of mussel-inspired catechol groups endows the injectable hydrogels with the potential to exhibit many properties, including tissue adhesiveness and self-healing, antimicrobial, and antioxidant capabilities, broadening the applications of injectable hydrogels in biomedical fields. In this review, we first give a brief introduction to the adhesion mechanism of mussels and the characteristics of injectable hydrogels. Further, the typical design strategies of mussel-inspired injectable adhesive hydrogels are summarized. The methodologies for integrating catechol groups into polymers and the crosslinking methods of mussel-inspired hydrogels are discussed in this section. In addition, we systematically overview recent mussel-inspired injectable adhesive hydrogels for biomedical applications, with a focus on how the unique properties of these hydrogels benefit their applications in these fields. The challenges and perspectives of mussel-inspired injectable hydrogels are discussed in the last section. This review may provide new inspiration for the design of novel bioinspired injectable hydrogels and facilitate their application in various biomedical fields.

Mussel‐inspired stretchable, anti‐fatigue, self‐healing and biocompatible hydrogel adhesives

AbstractHydrogels can form physically or chemically interactions with tissues and are widely used in the design of bioadhesive material. Polydopamine (PDA)/polyacrylamide (PAM)‐based adhesion hydrogels have emerged as one of the hydrogel adhesive materials with great potential for development. However, this type of hydrogel has low mechanical and adhesion properties, which has certain limitations in practical applications. Herein, inspired by the mussel adhesion mechanism, we introduced PDA into PAM/3‐aminophenylboronic acid grafted sodium alginate (SA‐PBA) double network system prepared a series of adhesive hydrogels, PDA was crosslinked by dynamic boronic ester bonds with SA‐PBA. The experimental results established that the hydrogels have favorable adhesive, anti‐fatigue, stretchable, and self‐healing properties. Cytocompatibility assay and in vitro hemolysis assay also indicated that the multifunctional hydrogel has excellent cytocompatibility and hemocompatibility.

Ultra-stretchable, high conductive, fatigue resistance, and self-healing strain sensor based on mussel-inspired adhesive hydrogel for human motion monitoring

Conductive hydrogels have been widely applied in various electronics, such as artificial skin, flexible devices, and implantable bioelectronics. However, it is still a challenge to develop high-performance hydrogel with high conductivity without compromising the toughness, stretchability, self-healing, and adhesion properties. Herein, inspired by the mussel-adhesion mechanism, an adhesive hydrogel that simultaneously achieves high conductivity (27.0 S·m−1), ultra stretchability (strain > 3700%), and strong toughness (1930 kJ·m−3) was developed by incorporating polydopamine (PDA)/sodium caseinate (SC) cross-linked network into the poly(acrylamide-co-acrylic acid) (P(AM-co-AA))/Al3+ network. Due to the abundant metal coordination and hydrogen bonds in the network, the obtained hydrogel displayed rapid self-healing capability (healing efficiency, HE > 97%) and excellent fatigue resistance. Moreover, the introduction of PDA-SC cross-linked network endowed the hydrogels with robust adhesion (36.5 kPa for pigskin) and high conductivity. The conductive hydrogel was assembled into a strain sensor, which demonstrated prominent sensing performance with a wide detection range (∼2500%), high sensitivity (gauge factor (GF) of 23.7), fast response time and reliable repeatability. The hydrogel strain sensor can be attached on human body to distinguish and monitor both large and subtle movement signals. The developed conductive hydrogel strain sensor is expected to have promising applications in wearable devices, human–machine interaction, and electrical skin, and to extend for use in other portable and wearable energy related devices with multifunction.

Fully degradable, highly elastomeric and adhesive silk fibroin electronic skin for microdynamic pressure monitoring

Highly sensitive soft electronic devices with biocompatibility are essential for epidermis and implantable applications. Inspired by the mussel adhesion mechanism, we report a silk fibroin (SF) elastomer with good adhesion, which can adhere tightly to the skin and monitor tiny vibration signals of the human body in real time. A mussel-inspired redox environment is created in SF networks by doping polydopamine (PDA)-intercalated clay, which for the first time endows SF elastomers with strong adhesion to various materials. Moreover, the introduction of PDA-clay allows the SF network to reconfigure at the mesoscopic scale and controls its nucleation rate, thus reducing the modulus and improving the flexibility of the elastomer, satisfying the requirements of skin conformal, and greatly improving the device sensitivity. Considering the biodegradable and biocompatible features, this elastomer can find potential applications in epidermis or implantable health-monitoring devices, e.g., speech recognition and pulse diagnosis are demonstrated with the assistance of deep learning algorithms.

Mussel-inspired HA@TA-CS/SA biomimetic 3D printed scaffolds with antibacterial activity for bone repair.

Bacterial infection is a major challenge that could threaten the patient's life in repairing bone defects with implant materials. Developing functional scaffolds with an intelligent antibacterial function that can be used for bone repair is very important. We constructed a drug delivery (HA@TA-CS/SA) scaffold with curcumin-loaded dendritic mesoporous organic silica nanoparticles (DMON@Cur) via 3D printing for antibacterial bone repair. Inspired by the adhesion mechanism of mussels, the HA@TA-CS/SA scaffold of hydroxyapatite (HA) and chitosan (CS) is bridged by tannic acid (TA), which in turn binds sodium alginate (SA) using electrostatic interactions. The results showed that the HA@TA-CS/SA composite scaffold had better mechanical properties compared with recent literature data, reaching 68.09MPa. It displayed excellent degradation and mineralization capabilities with strong biocompatibility in vitro. Furthermore, the antibacterial test results indicated that the curcumin-loaded scaffold inhibited S.aureus and E.coli with 99.99% and 96.56% effectiveness, respectively. These findings show that 3D printed curcumin-loaded HA@TA-CS/SA scaffold has considerable promise for bone tissue engineering.

One-pot deposition of a multi-functional biomimetic coating for vascular stents

Implantation of vascular stents, with particular reference to drug-eluting stents (DESs), is considered the main tool in treating coronary artery diseases (CADs) and has saved millions of lives. However, the complications, in-stent thrombosis (IST) and in-stent restenosis (ISR), of DESs are a major risk for stenting failure because of thrombus and hyperplasia. Vascular endothelial cells (ECs) are capable of secreting extracellular matrix (ECM) and vasoactive substances to maintain and regulate the homeostasis of the vascular environment. Hence, conferring endothelial-like functions to vascular stents is an effective solution to improve their biocompatibility. In this work, we propose a simple preparation method for a multi-functional coating that can mimic ECs function with continuous generation of nitric oxide (NO), located in a hyaluronic acid platform. The coating was fabricated by a one-pot deposition of dopamine (DA), thiol-hyaluronic acid (HA-SH), and copper ions (Cu). Thiol-modified HA was efficiently incorporated by DA, which mimics the adhesion mechanism of mussels, via the “thiol-Michael addition” click reaction, along with the complexing Cu which can catalyze the endogenous S-nitrosothiols (RSNO) to continuous liberation nitric oxide (NO). Both in vitro and in vivo experiments showed that the biomimetic microenvironment which hyaluronic acid coating combined with NO-generation capability could remarkably improve the anticoagulant properties of the vascular stents and further accelerate the in-situ endothelialization process while inhibiting the intimal hyperplasia and regulating inflammation. In conclusion, this study shows a simple one-pot method for the construction of multi-functional coatings that mimic an endothelial-like environment, which might endow vascular stents with enhanced anti-coagulation and endothelialization capability to prevent IST and ISR.

Interfacial Molecular Lock: A Universal Strategy for Hydrogel Adhesion

Hydrogel adhesion is fundamental to a large number of established and emerging fields. The existing adhesion methods have some problems, such as the limited penetration ability of polymers in hydrogels, the interface hardening caused by in situ monomer polymerization, the secondary damage caused by covalent strong bonding during detachment, the need for complementary techniques to induce adhesion, and the complex and impractical operation. Inspired by the adhesion mechanism of mussels, we propose a universal strategy of interfacial molecular lock (IML) for hydrogel adhesion, which is simple to operate. IML is composed of organic (low-molecular-weight) molecules containing catechol groups, which are easy to penetrate into hydrogels. The principle of IML relies on the combination of a dynamic covalent bond, coordination bond, hydrogen bond, π–π interaction, and cation-π interaction. IML can adapt to interfacial chemistry of hydrogels on different substrates and achieve reversible adhesion without external regulation. The molecular micro-polymerization further enhances the stability and strength of hydrogel adhesion. IML is expected to expand hydrogel adhesion in various applications, especially tissue adhesives, wound sealants, wearable devices, and hydrogel-on-metal protection.

Adhesive hydrogel wrap loaded with Netrin-1-modified adipose-derived stem cells: An effective approach against periarterial inflammation after endovascular intervention.

Endovascular interventions, such as balloon dilation and stent implantation, are currently recommended as the primary treatment for patients with peripheral artery disease (PAD), greatly improving patient prognosis. However, the consequent lumen restenosis that occurs after endovascular interventions has become an important clinical problem. Inflammation has been proven to be crucial to postoperative restenosis. In previous studies we have identified that Netrin-1-modified adipose-derived stem cells (N-ADSCs) transplantation is an effective anti-inflammatory strategy to repair vascular damage. Nevertheless, it remained to be explored how one could constantly deliver N-ADSCs onto damaged arteries. Therefore, we developed an adhesive double network (DN) hydrogel wrap loaded with N-ADSCs for sustained perivascular delivery. Inspired by the adhesion mechanism of mussels, we developed an adhesive and tough polyacrylamide/calcium-alginate/reduced graphene oxide/polydopamine (PAM/CA/rGO/PDA) hydrogel. Dopamine was attached to graphene sheets and limitedly oxidized to generate free catechol groups. The hydrogel could wrap damaged arteries and induce anti-inflammatory effects through N-ADSCs. In vitro experiments demonstrated that N-ADSCs significantly promoted the M2 polarization of macrophages to anti-inflammatory phenotypes and reduced the expression of inflammatory factors. In vivo experiments in a rat carotid artery guidewire injury model showed that the adhesive hydrogel wrap loaded with N-ADSCs could significantly reduce arterial inflammation, inhibit intimal hyperplasia and improve re-endothelialization. Altogether, this newly developed N-ADSCs-loaded hydrogel wrap provides an effective slow-releasing system, which may be a promising way to prevent and treat restenosis after endovascular interventions.

Mussel-inspired polyurethane coating for bio-surface functionalization to enhance substrate adhesion and cell biocompatibility

Considerable implant materials are prone to cause a severe inflammatory reaction due to poor histocompatibility, which leads to various complications and implant failure. Surface coating modification of these implant materials is one of the most important techniques to settle this problem. However, fabricating a coating with both adequate adhesiveness and excellent biocompatibility remains a challenge. Inspired by the adhesion mechanism of mussels, a series of mussel-inspired polyurethanes (PU-LDAs) were synthysized through a step growth polymerization based on hexamethylene diisocyanate as a hard segment, polytetra-methylene-ether-glycol as a soft segment, lysine–dopamine (LDA) and butanediol as chain extenders with different mole ratios.The coatings of PU-LDAs were applied to various substrates, such as stainless steel, glass and PP using a facile one-step coating process. The introduction of 3,4-dihydroxyphenylalanine (DOPA) groups can greatly improve the adhesion ability of the coatings to the substrates demonstrated by a 180° peel test. The peel strength of the PU-LDA100 coating containing high LDA content was 76.3, 48.5 and 67.5 N/m, which was 106.2%, 246.4% and 192.2% higher than that of the PU-LDA00 coating without LDA on the surface of stainless steel, glass and PP, respectively. Meanwhile, this PU coating has a lower immune inflammatory response which provides a universal method for surface modification of implant materials. Moreover, the DOPA groups in PU-LDAs could combine with the amino and thiol groups on cell membrane surface, leading to the improvement of cell adhesion and growth. Therefore, it has great potential application in the field of biomedical implant materials for the clinic.

A tannin-functionalized soy protein-based adhesive hydrogel as a wound dressing

Bioinspired strategies for preparing multifunctional hydrogels have drawn attention. Among these hydrogels, the adhesive types have been extensively studied, However, most of them exhibit poor mechanical properties, short-term adhesion, and no antibacterial activity. Inspired by the mussel adhesion mechanism, an adhesive hydrogel made from tannic acid (TA), acrylamide (AM), and soy protein isolate (SPI) is presented in this study. The adhesive hydrogel showed a large tensile strain (932%), high tensile strength (45.8 kPa), high toughness (155.15 kJ·m−3), and ideal compressive properties owing to the formation of a hybrid double network (DN). This hydrogel exhibited satisfactory adhesion to various materials, including muscle tissue, metal, rubber, glass, plastic, and wood. The TA-PAM-SPI hydrogel also showed good antibacterial properties against Escherichia coli and Staphylococcus aureus, in addition to self-healing properties and biocompatibility. With these characteristics, the TA-PAM-SPI hydrogel was used as a wound dressing to accelerate wound healing and skin tissue regeneration. This study provides a convenient approach to preparing multifunctional hydrogels and promoting the application of SPI in biomedical materials.

Engineering Stem Cell Recruitment and Osteoinduction via Bioadhesive Molecular Mimics to Improve Osteoporotic Bone-Implant Integration.

For patients with osteoporosis, the therapeutic outcomes of osteoimplants are substantially affected by the impaired proliferation, migration, and osteogenic differentiation abilities of bone marrow mesenchymal stem cells (BMSCs). To improve bone-implant integration in osteoporotic condition, here we reported a one-step biomimetic surface strategy to introduce BMSC recruiting and osteoinductive abilities onto metallic osteoimplants. In our design, the bioadhesive molecular peptide mimic inspired by mussel foot proteins (Mfps) was used as molecular bridging for surface functionalization. Specifically, a BMSC-targeting peptide sequence (E7) and an osteogenic growth peptide (Y5) were grafted onto the titanium implant surfaces through a mussel adhesion mechanism. We found that a rational E7/Y5 feeding ratio could lead to an optimal dual functionalization capable of not only significantly improving the biocompatibility of the implant but also enabling it to recruit endogenous BMSCs for colonization, proliferation, and osteogenic differentiation. Mechanistically, the E7-assisted in situ recruitment of endogenous BMSCs as well as the enhanced interfacial osteogenesis and osteointegration was associated with activation of the C-X-C chemokine receptor type 4 (CXCR4) receptor on the cell surface and promotion of stromal cell-derived factor (SDF-1α) autocrine secretion. We anticipated that rational dual-functional surfaces through bioadhesive molecular mimics will provide a simple, effective, nonimmunogenic, and safe means to improve the clinical outcomes of intraosseous implants, especially under osteoporotic conditions.

An antibacterial biomimetic adhesive with strong adhesion in both dry and underwater situations.

Adhesives have attracted extensive attention in biomedical applications in recent years. However, the development of adhesives with strong adhesion in both dry and underwater conditions and antibacterial properties is still a challenge. Herein, a biomimetic adhesive (DP@TA/Gel) was developed based on the adhesion mechanism of mussel in water, from adhesion and solidification to avoiding excessive oxidization processes. DP@TA/Gel exhibited rapid strong nonspecific adhesiveness to diverse materials including wood (485 kPa) metal (507 kPa), plastic (74 kPa), and even fresh biological tissue (39 kPa) in dry conditions. Specially, owing to its biomimetic design, DP@TA/Gel could imitate the mussel adhesion mechanism underwater, endowing it with robust (38 kPa), highly repeatable (at least 15 times) and long-term (at least 120 h) stable adhesion even in underwater conditions. Remarkably, DP@TA/Gel also exhibited high adhesiveness in various water environments, including seawater, and a wide range of pH (3-11) and NaCl concentration (0.9-10%) solutions without any stimulus. In addition, DP@TA/Gel showed excellent biocompatibility and antibacterial properties. Thus, the DP@TA/Gel adhesive has appealing potential biomedical applications such as sutureless wound closure and as a tissue adhesive.

Rational integration of defense and repair synergy on PEEK osteoimplants via biomimetic peptide clicking strategy

Polyetheretherketone (PEEK) has been widely used as orthopedic and dental materials due to excellent mechanical and physicochemical tolerance. However, its biological inertness, poor osteoinduction, and weak antibacterial activity make the clinical applications in a dilemma. Inspired by the mussel adhesion mechanism, here we reported a biomimetic surface strategy for rational integration and optimization of anti-infectivity and osteo-inductivity onto PEEK surfaces using a mussel foot proteins (Mfps)-mimic peptide with clickable azido terminal. The peptide enables mussel-like adhesion on PEEK biomaterial surfaces, leaving azido groups for the further steps of biofunctionalizations. In this study, antimicrobial peptide (AMP) and osteogenic growth peptide (OGP) were bioorthogonally clicked on the azido-modified PEEK biomaterials to obtain a dual-effect of host defense and tissue repair. Since bioorthogonal clicking allows precise collocation between AMP and OGP through changing their feeding molar ratios, an optimal PEEK surface was finally obtained in this research, which could long-term inhibit bacterial growth, stabilize bone homeostasis and facilitate interfacial bone regeneration. In a word, this upgraded mussel surface strategy proposed in this study is promising for the surface bioengineering of inert medical implants, in particular, achieving rational integration of multiple biofunctions to match clinical requirements.

Mussel-Inspired Underwater Adhesives- from Adhesion Mechanisms to Engineering Applications: A Critical Review

Recent progress in the adhesion mechanism of mussels has led to great excitement in the field of adhesive materials. Although great progress has been made in the mussel adhesion mechanism and underwater adhesives, there are still many unknowns and challenges in this area. Thus, it is highly important to review the recent progress in mechanisms of mussel adhesion and mussel-inspired adhesives and predict trends for the future. In this review, we (1) summarize the research progress in fundamental interaction mechanisms in natural mussels; (2) discuss the application of the mussel interaction mechanism in the biomimetic mussel adhesive materials, from permanent/high-strength adhesives to temporary/smart adhesives; (3) briefly state the potential applications of the mussel-inspired adhesives in multiple fields, such as engineering applications, smart robotics and biomedicine; (4) summarize the future perspectives and unsolved challenges of mussel adhesion mechanisms and mussel-inspired adhesive materials. We envision that this review will provide an insightful perspective in understanding the mussel adhesion mechanism and directions to further explore, and promote the development of novel biomimetic mussel adhesive materials.

Surface bioengineering of diverse orthopaedic implants with optional functions via bioinspired molecular adhesion and bioorthogonal conjugations

In this work, we reported an upgraded mussel-inspired strategy for surface bioengineering of osteoimplants by combination of mussel adhesion and bioorthogonal click chemistry. The main idea of this strategy is a mussel-inspired synthetic peptide containing multiple 3,4-dihydroxy-L-phenylalanine (DOPA) units and a dibenzocyclooctyne (DBCO) terminal (DOPA-DBCO). According to the mussel adhesion mechanism, the DOPA-DBCO peptide could stably adhere onto a variety of material surface, leaving the residual DBCO groups on the surface. Then, the DBCO residues could be employed for a second-step bioorthogonal conjugation with azide-capping biomolecules through bioorthogonal click chemistry, finally leading to the biomodified surfaces. To demonstrate the generality of our strategy for surface biomodification of diversified orthopaedic materials including metallic and polymeric substrates, we here conceptually conjugated some typical azide-capping biomolecules on both metal and polymeric surfaces. The results definitely verified the feasibility for engineering of functional surfaces with some essential requirements of osteoimplants, for example, the ability to facilitate cell adhesion, suppress bacterial infection, and promote osteogenesis. In a word, this study indicated that our novel surface strategy would show broad applicability for diverse osteoimplants and in different biological scenarios. We can also image that the molecular specificity of bioorthogonal conjugation and the universality of mussel adhesion mechanism may jointly provide a versatile surface bioengineering method for a wider range of biomedical implants.

Mussel-Inspired Adhesive Double-Network Hydrogel for Intraoral Ultrasound Imaging.

Periodontal diseases could be diagnosed through intraoral ultrasound imaging with the advantages of simple operation procedures, low cost, and low safety risks. A couplant is normally placed between transducers and tissues for better ultrasound image quality. If applied intraorally, the couplants should possess good stability in water and robust mechanical properties, as well as strong adhesiveness to transducers and tissues. However, commercial couplants, such as Aquaflex (AF) cannot fulfill these requirements. In this work, inspired by the mussel adhesion mechanism, we reported a poly(vinyl alcohol)-polyacrylamide-polydopamine (PVA-PAM-PDA) hydrogel synthesized by incorporating PDA into the PAM-PVA double-network for intraoral ultrasound imaging. The hydrogel maintains good stability in water as well as exceptional mechanical properties and can adhere to different substrates (i.e., metal, glass, and porcine skin) without losing the original adhesion strength after multiple adhesion-strip cycles. Besides, when applied to porcine mandibular incisor imaging, the PVA-PAM-PDA hydrogel possesses good image quality for diagnosis as AF does. This work provides practical insights into the fabrication of multifunctional hydrogel-based interfaces between human tissues and medical devices for disease diagnosis applications.

Three-dimensional printing of a β-tricalcium phosphate scaffold with dual bioactivities for bone repair

β-Tricalcium phosphate (β-TCP) had been widely used in the field of bone defect repair because of its osteoconduction and osteoinduction properties. However, for critical-sized bone defects, β-TCP scaffolds need to be functionalised to enhance osteoinduction and antibacterial activity. In this study, we proposed a protocol for mimicking a mussel adhesion mechanism to immobilise bone morphoprotein 2 mimetic peptide (BMP2-MP) and Ornithodoros savignyi (OS) on a three-dimensionally printed β-TCP scaffold. BMP2-MP and the OS polypeptides containing the YKYKY tail were converted into 3,4‐dihydroxyphenylalanine (DOPA) molecules via hydroxylase. The surface morphology and phase composition of the different scaffolds were analysed via scanning electron microscopy and X-ray diffraction. In addition, the binding activity of BMP2-MP and OS containing the DOPA tail to the scaffold were evaluated. The antibacterial activity of the different scaffolds was studied in vitro by performing bacteriostatic experiments against Escherichia coli and Staphylococcus aureus. The osteoinduction capability of the different scaffolds was evaluated by detecting osteogenesis-associated genes via quantitative polymerase chain reaction and by determining alkaline phosphatase expression levels. Our results demonstrated that introduction of the DOPA tail enhanced the binding capability of BMP2-MP and OS with the β-TCP scaffold, thereby enhancing the antibacterial and osteoinduction capabilities of the scaffold. A scaffold with strong antibacterial and osteoinduction capability will have good application prospects in the field of critical-sized bone defect repair.

Mussel‐Inspired Hydrogels for Self‐Adhesive Bioelectronics

AbstractWearable and implantable bioelectronics are receiving a great deal of attention because they offer huge promise in personalized healthcare. Currently available bioelectronics generally rely on external aids to form an attachment to the human body, which leads to unstable performance in practical applications. Self‐adhesive bioelectronics are highly desirable for ameliorating these concerns by offering reliable and conformal contact with tissue, and stability and fidelity in the signal detection. However, achieving adequate and long‐term self‐adhesion to soft and wet biological tissues has been a daunting challenge. Recently, mussel‐inspired hydrogels have emerged as promising candidates for the design of self‐adhesive bioelectronics. In addition to self‐adhesiveness, the mussel‐inspired chemistry offers a unique pathway for integrating multiple functional properties to all‐in‐one bioelectronic devices, which have great implications for healthcare applications. In this report, the recent progress in the area of mussel‐inspired self‐adhesive bioelectronics is highlighted by specifically discussing: 1) adhesion mechanism of mussels, 2) mussel‐inspired hydrogels with long‐term and repeatable adhesion, 3) the recent advance in development of hydrogel bioelectronics by reconciling self‐adhesiveness and additional properties including conductivity, toughness, transparency, self‐healing, antibacterial properties, and tolerance to extreme environment, and 4) the challenges and prospects for the future design of the mussel‐inspired self‐adhesive bioelectronics.

Fabrication of high-performance composite nanofiltration membranes for dye wastewater treatment: mussel-inspired layer-by-layer self-assembly

Inspired by the mussel adhesion mechanism, plant polyphenol tannic acid (TA) with abundant catechol groups and hydrophilic Jeffamine (JA) containing amino groups were used in a layer-by-layer (LBL) process to fabricate composite nanofiltration (NF) membranes in this study. Alternately immersing a polyacrylonitrile substrate into individual TA and JA buffer solutions could readily construct a NF membrane selective layer without any pre-treatment to the substrate. The optimised membrane showed a high pure water permeance of 37 L m−2 h−1 bar−1 whilst maintaining rejections higher than 90% towards various dyes with molecular weights ranging from 269 to 1017 g mol−1. Particularly, the obtained membrane exhibited excellent anti-fouling and long-term performance attributed to the hydrophilic membrane surface and covalent bonds in the selective layer. The novel strategy inherited the advantages of a mussel-inspired dopamine material but overcame its disadvantages. The results disclosed in this study not only provide a novel strategy to prepare composite NF membranes, but also facilitate the mussel-inspired LBL design of advanced materials for environmental applications.