Polymeric biomaterials inspired by marine mussel adhesive proteins

Enhancement of Mechanical, Thermal, and Barrier Behavior of Sustainable PECF Copolyester Nanocomposite Films Using Polydopamine-Functionalized MXene Fillers

The development of high-strength titanium carbide (Ti3C2Tx) MXene-PDA nanosheet-based sustainable poly(ethylene-co-1,4-cyclohexane dimethylene 2,5-furan dicarboxylic acid) (PECF) copolyester nanocomposites with superior tensile, thermal, and barrier properties is a promising avenue for advanced materials. However, achieving Ti3C2Tx MXene-based polyester nanocomposites that exhibit exceptional thermal conductivity, and enhanced mechanical and barrier properties remains a significant challenge. In this study, we employed self-assembly technology through layer-by-layer (LBL) coating to create highly saturated Ti3C2Tx MXene-PDA fillers that are uniformly dispersed and strongly bonded within the PECF matrix. This approach enabled the formation of dense nanocomposites with diverse functional properties. Specifically, MPP2 nanocomposites (0.3 wt %) demonstrated excellent mechanical performance, with a compressive tensile strength of 84 MPa and a modulus of 4.4 GPa, alongside remarkable O2, CO2, and H2O vapor barrier properties and superior thermal stability. Compared to pure PECF, the addition of Ti3C2Tx MXene-PDA at a loading of 0.3 wt % resulted in substantial improvements: a 30% increase in tensile strength, a 109% increase in modulus, and significantly enhanced barrier properties for O2 (27.3-times), CO2 (24.7-times), and H2O vapor (5.0-times). These findings highlight the potential of Ti3C2Tx MXene-PDA-reinforced PECF nanocomposites for high-performance applications, offering valuable insights for future materials development.

Clinically Oriented Oral Environment-Triggered Underwater Adhesives for Root Caries Treatment through Dentinal Tubule Occlusion and Remineralization

The application of silk fibroin (SF) hydrogels is often limited by their brittleness; on the other hand, increasing ductility can lead to insufficient strength of the hydrogel. These drawbacks make it difficult to apply to treat root surface caries, which are continuously exudated by crevicular fluid and have special locations and shapes. Herein, we design an underwater adhesive hydrogel with a fluid-solid spontaneous transition triggered by water for root caries treatment. Guanidine hydrochloride (GH), amorphous calcium phosphate nanoparticles (ACP), and tannic acid (TA) are applied to coassemble with SF to form an underwater adhesive hydrogel (STAG). GH as a hydrogen bond dissociator can break the hydrogen bonds between SF and TA and rapidly diffuse in a water environment, thus providing the system with high fluidity and regelation ability. Ca2+ of ACP can chelate with TA to enhance the cohesion of the hydrogel. Hydrogel containing ACP has stronger adhesion strength in lap-shear and tensile tests than hydrogel without ACP and also exhibits better properties in rheological tests. Even if stored in freeze-dried powder form for 90 days, the STAG fluid can be smoothly injected from the needle with only 0.8 N, completely filling the defective area of root caries and solidifying in situ. The formed restorative material can effectively promote tooth remineralization and seal the dentin tubules, which provides a feasible pathway for the treatment of root caries.

PDA/PMMA Blend Membrane Utilized for the Selective Adsorption and Separation of Heavy Metal Ions

The detrimental effects of heavy metal aqueous pollution are attracting people's attention increasingly. Membrane separation technology plays a pivotal role in the treatment of aqueous pollution due to its low energy consumption and excellent separation effect. Inspired by the strong adhesion of heavy metal ions by the dopamine in mussel protein, we have fabricated the 5 %, 10 %, 20 % and 30 % proportion of polydopamine (PDA)/Polymethyl methacrylate (PMMA) blend membranes with dopamine structure by solvent-induced phase conversion. I-V current, UV titration and transmission tests examined the membrane's selective adsorption and retention capabilities for Fe3+, Cu2+ and Cr3+. These experiments indicated the different selectivity for Fe3+ of four blend membranes with varying PDA/PMMA fractions. Based on Langmuir's adsorption theory, the 10 % blend membranes exhibited the most outstanding selective adsorption for Fe3+ with an LOD of 4.724×10-9 M. Moreover, the ability to retain Fe3+ is still close to 100 % after 48 h of transmission. This study manifested that the PDA/PMMA blend membrane is capable of adsorbing trace amounts of Fe3+ from water, thereby contributing to aqueous purification.

Advances in Mussel Adhesion Proteins and Mussel-Inspired Material Electrospun Nanofibers for Their Application in Wound Repair

Mussel refers to a marine organism with strong adhesive properties, and it secretes mussel adhesion protein (MAP). The most vital feature of MAP is the abundance of the 3,4-dihydroxyphenylalanine (DOPA) group and lysine, which have antimicrobial, anti-inflammatory, antioxidant, and cell adhesion-promoting properties and can accelerate wound healing. Polydopamine (PDA) is currently the most widely used mussel-inspired material characterized by good adhesion, biocompatibility, and biodegradability. It can mediate various interactions to form functional coatings on cell-material surfaces. Nanofibers based on MAP and mussel-inspired materials have been exerting a vital role in wound repair, while there is no comprehensive review presenting them. This Review introduces the structure of MAPs and their adhesion mechanisms and mussel-inspired materials. Second, it introduces the functionalized modification of MAPs and their inspired materials in electrospun nanofibers and application in wound repair. Finally, the future development direction and coping strategies of MAP and mussel-inspired materials are discussed. Moreover, this Review can offer novel strategies for the application of nanofibers in wound repair and bring about new breakthroughs and innovations in tissue engineering and regenerative medicine.

A mussel inspired polyvinyl alcohol/collagen/tannic acid bioadhesive for wet adhesion and hemostasis

Bioadhesives are useful in surgery for hemostasis, tissue sealing and wound healing. However, most bioadhesives have limitations such as weak adhesion in wet conditions, insufficient sealing and poor clotting performance. Inspired by the adhesion mechanism of marine mussels, a novel bioadhesive (PCT) was developed by simply combining polyvinyl alcohol (PVA), collagen (COL) and tannic acid (TA) together. The results showed that the adhesion, sealing and blood coagulation properties boosted with the increase of tannic acid content in PCT. The wet shear adhesion strength of PCT-5 (the weight ratio of PVA:COL:TA=1:1:5) was 60.8 ± 0.6 kPa, the burst pressure was 213.7 ± 0.7 mmHg, and the blood clotting index was 39.3% ± 0.6%, respectively. In rat heart hemostasis tests, PCT-5 stopped bleeding in 23.7 ± 3.2 s and reduced bleeding loss to 83.0 ± 19.1 mg, which outperformed the benchmarks of commercial gauze (53.3 ± 8.7 s and 483.0 ± 15.0 mg) and 3 M adhesive (Type No.1469SB, 35.3 ± 5.0 s and 264.0 ± 14.2 mg). The as-prepared bioadhesive could provide significant benefits for tissue sealing and hemorrhage control along its low cost and facile preparation process.

Dopamine modified layered double hydroxide membranes based on nanofibril architectures: Toward superior tellurium separation properties for water treatment

Two-dimensional (2D) membrane materials are widely employed for the accurate sieving of ionic contaminants and are of great importance for water reuse. However, 2D membrane materials often suffer from uneven thickness and surface defects, which severely limit their application prospects. Herein, a continuous 2D membrane (LCUM/D) was prepared using cellulose nanofibrils (CNFs) as the support backbone for the assembled layered double hydroxides (LDHs) and dopamine (DA) as the adhesive. The results demonstrated that LDHs could be uniformly distributed in the network structure of CNFs, and the defects on the membrane surface could be effectively compensated by DA. Simultaneously, the continuous LCUM/D showed excellent rejection (97.18%) and selectivity of ionic contaminants tellurium. Dopamine not only compensated for the surface defects of the 2D membrane and enhanced the rejection of tellurium, but also caused no significant loss of water permeance. Moreover, the LCUM/D exhibited stability, which facilitated its long-term application. In addition, the improved hydrophilicity allowed LCUM/D satisfactory anti-fouling properties. This study provides new dimensional insights into the fabrication of continuous 2D membranes for the removal of ionic contaminant and enhances their application prospects in wastewater treatment.

Multifunctional and Tunable Coacervate Powders to Enable Rapid Hemostasis and Promote Infected Wound Healing

Hemostatic powders provide an important treatment approach for time-sensitive hemorrhage control. Conventional hemostatic powders are challenged by the lack of tissue adhesiveness, insufficient hemostatic efficacy, limited infection control, and so forth. This study develops a hemostatic powder from tricomponent GTP coacervates consisting of gelatin, tannic acid (TA), and poly(vinyl alcohol) (PVA). The physical cross-linking by TA results in facile preparation, good storage stability, ease of application to wounds, and removal, which provide good potential for clinical translation. When rehydrated, the coacervate powders rapidly form a cohesive layer with interconnected microporous structure, competent flexibility, switchable wet adhesiveness, and antibacterial properties, which facilitate the hemostatic efficacy for treating irregular, noncompressible, or bacteria-infected wounds. Compared to commercial hemostats, GTP treatment results in significantly accelerated hemostasis in a liver puncture model (∼19 s, >30% reduction in the hemostatic time) and in a tail amputation model (∼38 s, >60% reduction in the hemostatic time). In the GTP coacervates, gelatin functioned as the biodegradable scaffold, while PVA introduced the flexible segments to enable shape-adaptability and interfacial interactions. Furthermore, TA contributed to the physical cross-linking, adhesiveness, and antibacterial performance of the coacervates. The study explores the tunability of GTP coacervate powders to enhance their hemostatic and wound healing performances.

Exploiting Polyelectrolyte Complexation for the Development of Adhesive and Bioactive Membranes Envisaging Guided Tissue Regeneration

Mussels secrete protein-based byssal threads to tether to rocks, ships, and other organisms underwater. The secreted marine mussel adhesive proteins (MAPs) contain the peculiar amino acid L-3,4-dihydroxyphenylalanine (DOPA), whose catechol group content contributes greatly to their outstanding adhesive properties. Inspired by such mussel bioadhesion, we demonstrate that catechol-modified polysaccharides can be used to obtain adhesive membranes using the compaction of polyelectrolyte complexes (CoPEC) method. It is a simple and versatile approach that uses polyelectrolyte complexes as building blocks that coalesce and dry as membrane constructs simply as a result of sedimentation and mild temperature. We used two natural and biocompatible polymers: chitosan (CHI) as a polycation and hyaluronic acid (HA) as a polyanion. The CoPEC technique also allowed the entrapment of ternary bioactive glass nanoparticles to stimulate mineralization. Moreover, combinations of these polymers modified with catechol groups were made to enhance the adhesive properties of the assembled membranes. Extensive physico-chemical characterization was performed to investigate the successful production of composite CoPEC membranes in terms of surface morphology, wettability, stability, mechanical performance, in vitro bioactivity, and cellular behavior. Considering the promising properties exhibited by the obtained membranes, new adhesives suitable for the regeneration of hard tissues can be envisaged.

Novel Trends in Hydrogel Development for Biomedical Applications: A Review

Nowadays, there are still numerous challenges for well-known biomedical applications, such as tissue engineering (TE), wound healing and controlled drug delivery, which must be faced and solved. Hydrogels have been proposed as excellent candidates for these applications, as they have promising properties for the mentioned applications, including biocompatibility, biodegradability, great absorption capacity and tunable mechanical properties. However, depending on the material or the manufacturing method, the resulting hydrogel may not be up to the specific task for which it is designed, thus there are different approaches proposed to enhance hydrogel performance for the requirements of the application in question. The main purpose of this review article was to summarize the most recent trends of hydrogel technology, going through the most used polymeric materials and the most popular hydrogel synthesis methods in recent years, including different strategies of enhancing hydrogels’ properties, such as cross-linking and the manufacture of composite hydrogels. In addition, the secondary objective of this review was to briefly discuss other novel applications of hydrogels that have been proposed in the past few years which have drawn a lot of attention.

Mussel-inspired triple bionic adsorbent: Facile preparation of layered double hydroxide@polydopamine@metal-polyphenol networks and their selective adsorption of dyes in single and binary systems

To effectively address the serious human health challenges and ecological damage caused by organic dyes in wastewater, we developed a novel bionic adsorbent (LDH@PDA@MPNs) for the selective adsorption and removal of malachite green (MG) and crystalline violet (CV). The adsorbent was prepared using a facile two-step method based on mussel-inspired chemistry and metal complexation. The physicochemical structure, surface morphology, and composition of the LDH@PDA@MPNs were characterized by scanning electron microscopy, Fourier-transform infrared spectrometry, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Adsorption of MG and CV with the LDH@PDA@MPNs was evaluated. Under optimal conditions, the maximum adsorption of MG and CV by the adsorbent was 89.608 and 40.481 mg/g, respectively. The adsorption kinetics showed that the experimental data were in good agreement with the pseudo-second-order kinetic model, and the equilibrium adsorption isotherm data fitted well with the Freundlich model. The thermodynamic results indicated that the adsorption of the dyes on LDH@PDA@MPNs was a spontaneous endothermic process. Importantly, the bionic adsorbent not only shows high removal efficiency by easy regeneration with low-cost reagents but also exhibits high selectivity for dyes in both single and binary systems. Therefore, LDH@PDA@MPNs have the potential to adsorb and remove dyes from complex wastewater solutions.