Mussel Protein Research Articles

Mussel-inspired Fluoro-Polydopamine Functionalization of Titanium Dioxide Nanowires for Polymer Nanocomposites with Significantly Enhanced Energy Storage Capability

High-dielectric-constant polymer nanocomposites are demonstrated to show great promise as energy storage materials. However, the large electrical mismatch and incompatibility between nanofillers and polymer matrix usually give rise to significantly reduced breakdown strength and weak energy storage capability. Therefore, rational selection and elaborate functionalization of nanofillers to optimize the performance of polymer nanocomposites are vital. Herein, inspired by adhesive proteins in mussels, a facile modification by fluoro-polydopamine is employed to reinforce the compatibility of TiO2 nanowires in the fluoropolymer matrix. The loading of 2.5 vol % f-DOPA@TiO2 NWs leads to an ultrahigh discharged energy density of 11.48 J cm−3 at 530 MV m−1, more than three times of commercial biaxial-oriented polypropylene (BOPP, 3.56 J cm−3 at 600 MV m−1). A gratifying high energy density of 9.12 J cm−3 has also been obtained with nanofiller loading as high as 15 vol % at 360 MV m−1, which is nearly double to that of pure P(VDF-HFP) (4.76 J cm−3 at 360 MV m−1). This splendid energy storage capability seems to rival or exceed most of previously reported nano-TiO2 based nanocomposites. The methods presented here provide deep insights into the design of polymer nanocomposites for energy storage applications.

Mussel glues rely on cation-aromatic attraction

Mussels and other sea creatures that live along rocky shores often rely on special biological glues to fasten their soft tissues to rocks. Scientists study the chemistry of these sticky proteins in hopes of producing new biomaterials, such as medical adhesives to attach muscle to bone during surgeries. A team at the University of California, Santa Barbara, now reports that the stickiness of these mussel adhesives is, in part, due to attractive interactions between aromatic and positively charged amino acids (Nat. Chem. 2017, DOI: 10.1038/nchem.2720). Previous studies of mussel proteins have found that 3,4-dihydroxyphenylalanine (Dopa) and cationic amino acids such as lysine are critical for the materials’ function, says Matthew A. Gebbie, who is the first author on the new paper and is now a postdoc at Stanford University. Gebbie and his UCSB colleagues, including Wei Wei, J. Herbert Waite, and Jacob N. Israelachvili, hypothesized that these two functional groups

Tuning underwater adhesion with cation-π interactions.

Cation-π interactions drive the self-assembly and cohesion of many biological molecules, including the adhesion proteins of several marine organisms. Although the origin of cation-π bonds in isolated pairs has been extensively studied, the energetics of cation-π-driven self-assembly in molecular films remains uncharted. Here we use nanoscale force measurements in combination with solid-state NMR spectroscopy to show that the cohesive properties of simple aromatic- and lysine-rich peptides rival those of the strong reversible intermolecular cohesion exhibited by adhesion proteins of marine mussel. In particular, we show that peptides incorporating the amino acid phenylalanine, a functional group that is conspicuously sparing in the sequences of mussel proteins, exhibit reversible adhesion interactions significantly exceeding that of analogous mussel-mimetic peptides. More broadly, we demonstrate that interfacial confinement fundamentally alters the energetics of cation-π-mediated assembly: an insight that should prove relevant for diverse areas, which range from rationalizing biological assembly to engineering peptide-based biomaterials.

A new targeted delivery approach by functionalizing drug nanocrystals through polydopamine coating

Tumor target specificity via chemotherapy is widely considered to be very effective on tumor treatment. For an ideal chemotherapeutic agent like Camptothecin (CPT) (CPT is the abbreviation for Camptothecin), improved therapeutic efficacy and high selectivity are equally important. Inspired by adhesive proteins in mussels, here we developed a novel tumor targeting peptide XQ1 grafted CPT nanocrystals with polydopamine coating as a spacer. In this study, CPT nanocrystals were coated by polymerization of dopamine that was induced by plasma-activated water under an acidic environment, and then the tumor targeting peptide was grafted onto polydopamine (PDA) (PDA is the abbreviation for polydopamine) coated CPT nanocrystals through catechol chemistry. The PDA layer had negligible effects on drug crystallinity and structure but resulted in drug nanocrystals with excellent dispersion properties, improved dissolution rate and drug stability by preventing water hydrolysis. More importantly, tumor targeting peptide XQ1 facilitated a rapid cross-membrane translocation of drug nanocrystals via receptor-mediated endocytosis, leading to efficient intracellular drug delivery. Moreover, this novel drug formulation demonstrated more potent anti-cancer activity against tumor cells in comparison with free CPT and naked CPT nanocrystals and exhibited high selectivity, all of which are attributed to the tumor target specificity property and inherent pH-dependent drug release behavior.

Integrating Mussel Chemistry into a Bio-Based Polymer to Create Degradable Adhesives

Adhesives releasing carcinogenic formaldehyde are almost everywhere in our homes and offices. Most of these glues are permanent, preventing disassembly and recycling of the components. New materials are thus needed to bond and debond without releasing reactive pollutants. In order to develop the next generation of advanced adhesives we have turned to biology for inspiration. The bonding chemistry of mussel proteins was combined with preformed poly(lactic acid), a bio-based polymer, by utilizing side reactions of Sn(oct)2, to create catechol-containing copolymers. Structure–function studies revealed that bulk adhesion was comparable to that of several petroleum-based commercial glues. Bonds could then be degraded in a controlled fashion, separating substrates gradually using mild hydrolysis conditions. These results show that biomimetic design principles can bring about the next generation of adhesive materials. Such new copolymers may help replace permanent materials with renewable and degradable adhesive...

Natural Actin and Tropomyosin from Molluscan Catch Muscle

In this work, the main proteins of thin filaments (actin and tropomyosin) were isolated from the catch muscle of the mussel Crenomytilus grayanus and the rabbit skeletal muscles. Rabbit actin and tropomyosin and mussel tropomyosin were isolated by traditional methods as opposed to natural mussel actin (isolation of the mussel actin from acetone powder is impossible). These proteins were used to reconstruct actin+tropomyosin complexes in nonhybrid and hybrid manner. A non-hybrid complex, reconstructed from rabbit actin and tropomyosin, has higher reduced viscosity than complex of mussel proteins where reduced viscosity was nearly indistinguishable from the intrinsic viscosity. ÐÂ’oth rabbit and mussel actin were purified by polymerization-repolymerization cycles followed by gel filtration chromatography. During purification, the viscosity of both actins increased, and the difference in viscosity between them decreased. Based on the SDS-electrophoresis, we did not find any of the other proteins in the chromatographic fractions, except actin. However, obtained chromatographic fractions have significant differences in viscosity and rate of polymerization. We believe that these properties caused by the presence of an ending factor” (such as β-actinin or Cap Z) in actin preparations. The data obtained indicate that isolation of “natural” actin is accompanied by a coextraction of an unknown or known ending factor in amounts that may be greater than those obtained from the acetone powder of rabbit skeletal muscles.

Sandcastle Worm-Inspired Blood-Resistant Bone Graft Binder Using a Sticky Mussel Protein for Augmented In Vivo Bone Regeneration.

Xenogenic bone substitutes are commonly used during orthopedic reconstructive procedures to assist bone regeneration. However, huge amounts of blood accompanied with massive bone loss usually increase the difficulty of placing the xenograft into the bony defect. Additionally, the lack of an organic matrix leads to a decrease in the mechanical strength of the bone-grafted site. For effective bone grafting, this study aims at developing a mussel adhesion-employed bone graft binder with great blood-resistance and enhanced mechanical properties. The distinguishing water (or blood) resistance of the binder originates from sandcastle worm-inspired complex coacervation using negatively charged hyaluronic acid (HA) and a positively charged recombinant mussel adhesive protein (rMAP) containing tyrosine residues. The rMAP/HA coacervate stabilizes the agglomerated bone graft in the presence of blood. Moreover, the rMAP/HA composite binder enhances the mechanical and hemostatic properties of the bone graft agglomerate. These outstanding features improve the osteoconductivity of the agglomerate and subsequently promote in vivo bone regeneration. Thus, the blood-resistant coacervated mussel protein glue is a promising binding material for effective bone grafting and can be successfully expanded to general bone tissue engineering.

Spoilage Profiles of Green-Lipped MusselPerna viridis

Spoilage profiles of green-lipped mussel (Perna viridis) were investigated by the determination of degree of hydrolysis (DH), sodium dodecyl sulfate polyacrylamide gel electrophoresis and microbiological analysis. Spoilage activities rose along with the increase of temperature and the maximal degree of hydrolyzation of mussel protein was 35% occurred after 24 h incubation at 55C. Bacteria boosted after 4 h incubation at 25 and 35C, but were suppressed at temperature higher than 45C. DH increased sharply within 4–8 h, and then its growth slowed down. Photobacterium, Vibrio and Shewanella were predominant bacteria propagated in spoilage. Practical Applications A clear understanding of spoilage would be needed in maintaining the quality of the seafood, developing methods to curb the process, preserving the delicate flavor and obtaining desired functional peptides. The objective of this study is to explore spoilage mechanism under different temperatures and investigate the bacteria involved. Elucidation of spoilage mechanism will shed light on preservation of green-lipped mussel meat and the functional study of its protein hydrolysate.

Mussel-inspired approach to constructing robust cobalt-embedded N-doped carbon nanosheet toward enhanced sulphate radical-based oxidation.

Heterogeneous sulphate radical based advanced oxidation processes (SR-AOPs) have lately been raised as a promising candidate for water treatment. Despite the progress made, either the stability or the performance of the current catalysts is still far from satisfactory for practical applications. Herein, using polydopamine-cobalt ion complex that inspired by mussel proteins as medium, we facilely fabricate a robust SR-AOPs catalyst with cobalt nanoparticles (NPs) embedded in nitrogen-doped reduced graphene oxide matrix (NRGO@Co). The NRGO scaffold with high porosity and surface area not only stabilizes the NPs but also greatly facilitates the accessibility and adsorption of substrates to the active sites. With the synergistic effect arising from the NRGO and Co NPs, the NRGO@Co hybrid catalyst exhibits enhanced catalytic activity for activation of peroxymonosulfate (PMS) to degrade organic pollutants in water. Furthermore, taking advantage of the favorable magnetic properties, the catalyst can be easily recycled and reused for at least 4 runs with negligible loss of activity. Coupled with systematic investigation in terms of influential factors, mineralization, and radicals identification, make the catalyst hold significant potential for application in remediation of organic pollutants in water.

A novel electrodeposition route for fabrication of the superhydrophobic surface with unique self-cleaning, mechanical abrasion and corrosion resistance properties

Inspired by the adhesive proteins in mussels, a novel electrodeposition route has been developed to create multifunctional zinc (Zn)/polydopamine (pDop)/n-dodecyl mercaptan (NDM) composite coatings on different substrates, where oxidative polymerization of dopamine was simultaneously integrated during electrodeposition process. Hierarchical cauliflower-like structure was obtained on the electrodeposited Zn/pDop coatings. After modification with NDM, the prepared Zn/pDop/NDM coatings on different substrates (steel, Al and Cu) possessed excellent superhydrophobicity, exhibiting a maximum water contact angle (WCA) of 167.6° and a sliding angle (SA) less than 1° on the steel substrate. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were employed to investigate the morphology and the chemical composition of the coatings. The mechanisms of electrodeposition process were discussed. The integrated electrodeposition and polymerization processes promised a synergistic effect on promoting the superhydrophobicity of coating. Results indicated that the dopamine greatly improved the mechanical abrasion resistance of the prepared superhydrophobic coatings. Additionally, these coatings demonstrated superior superhydrophobic stability, corrosion resistance and self-cleaning properties. It is believed that this novel and facile electrodeposition route for fabricating superhydrophobic coatings on various metallic materials will generate great impacts in practical applications.

Preparation of gluten free bread enriched with green mussel (Perna canaliculus) protein hydrolysates and characterization of peptides responsible for mussel flavour

Green mussel protein hydrolysates (GMPH) utilization for the enrichment of gluten-free bread followed by characterization of flavour peptides using chromatography and electronic nose techniques have been done. The degree of hydrolysis was carried out in each protease digest, and the higher degree of hydrolysis was observed in pepsin digestion. Gluten-free (GF) bread was formulated by using buckwheat flour (BWF), rice flour (RF) and chickpea flour (CPF) (70:20:10) and GMPH were added in the range of 0–20% in the GF bread for enrichment with GMPH. Radar plot of the electronic nose analysis showed that the sensors P30/2, T30/1 and T70/2 had a higher response to the GF bread and GMPH. Consequently, the peptide sequence was obtained manually by ESI-MS spectra of GMPH (KGYSSYICDK) and F-II (SSYCIVKICDK). Flavour quality was 97% discriminately comparable to the GMPH and F-II fractions. Mussel flavoured GF bread can be included in the celiac diet.

Fabrication of polydopamine-coated superhydrophobic fabrics for oil/water separation and self-cleaning

We report a fabric coating method inspired the superhydrophobic properties of lotus leaves and the strong adhesion of the adhesive proteins in mussels. Dopamine, which mimics the single units of the adhesive mussel proteins, was polymerized in an alkaline aqueous solution to coat the surface of fabrics. The versatile reactivity of polydopamine allows subsequent Ag deposition to form a lotus-leaf-like rough structure on the fabric surface. The composite fabric exhibited high water repellence after fluorination. Because dopamine can adhere to all kinds of materials, this method can be applied to many fabrics regardless of their properties and chemical compositions using a universal process. The modified fabrics exhibited excellent anti-wetting and self-cleaning properties with contact angles of >150° and sliding angles lower than 9°. The fabrics also efficiently separated oil from oil/water mixtures under various conditions. Our method is versatile and simple compared with other hydrophobic treatment methods, which usually only work on one type of fabric.

Identification and expression analysis on two forms bactericidal permeability-increasing protein (BPI)/lipopolysaccharide-binding protein (LBP) of Triangle mussel, Hyriopsis cumingii

Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are the numbers of the lipid transfer protein/lipopolysaccharide-binding protein family and play crucial roles in the innate immune response to Gram-negative bacteria. Two forms homolog of BPI/LBP, designed as HcBPI/LBP1 and HcBPI/LBP2, was cloned from the hemocyte cDNA of Hyriopsis cumingii. The complete cDNA of HcBPI/LBP1 included an open reading frame (ORF) of 1865 bp, and 3' and 5' untranslated regions (UTR's) of 139 bp and 220 bp, respectively. The ORF encoded a putative protein of 479 amino acids with predicted 22-aa hydrophobic signal peptide. HcBPI/LBP2 cDNA was 2204 bp, 3' and 5' UTR's of 183 bp and 464 bp, respectively. ORF encoded a polypeptide of 518 amino acids with a putative signal peptide of 22 amino acid residues. The deduced amino acid sequence contained an N-terminal BPI/LBP/CETP, link domain and a C-terminal BPI/LBP/CETP domain BPI1 with three functional regions that display LPS-binding activity. The amino acids sequence similarity of LBP1 and LBP2 was 50%. HcBPI/LBP1 and LBP2 transcripts could be detected in all normal tested tissues by quantitative real-time RT-PCR, including hepatopancreas, adductor muscle, mantle, gill and hemocytes, but the highest level of expression was in gills of HcBPI/LBP1 and in hepatopancreas of HcBPI/LBP2. The recombinant of HcBPI/LBPs showed a high affinity to LPS and can effectively kill Gram-negative bacteria.  Corresponding author: Tel.: +86-0791-83969530; fax: +86-0791-83969530. E-mail address: cgwen@ncu.edu.cn (CG, Wen)

High‐Throughput Topographic, Mechanical, and Biological Screening of Multilayer Films Containing Mussel‐Inspired Biopolymers

A high‐content screening method to characterize multifunctional multilayer films that combine mechanical adhesion and favorable biological response is reported. Distinct combinations of nanostructured films are produced using layer‐by‐layer methodology and their morphological, physicochemical, and biological properties are analyzed in a single microarray chip. Inspired by the composition of the adhesive proteins in mussels, thin films containing dopamine‐modified hyaluronic acid are studied. Flat biomimetic superhydrophobic patterned chips produced by a bench‐top methodology are used for the build‐up of arrays of multilayer films. The wettability contrasts imprinted onto the chips are allowed to produce individual, position controlled, multilayer films in the wettable regions. The flat configuration of the chip permits to perform a series of nondestructive measurements directly on the individual spots. In situ adhesion properties are directly measured in each spot, showing that nanostructured films richer in dopamine promote the adhesion. In vitro tests show an enhanced cell adhesion for the films with more catechol groups. The advantages presented by this platform include ability to control the uniformity and size of the multilayers films, its suitability to be used as a new low cost toolbox and for high‐content cellular screening, and capability for monitoring in situ a variety of distinct material properties.

Bio‐inspired synthesis of molecularly imprinted nanocomposite membrane for selective recognition and separation of artemisinin

ABSTRACTInspired from the highly bioadhesive performance of mussel protein, a simple, yet efficient synthetic method for efficiently imprinting of Artemisinin (Ars) was developed to prepare the bio‐inspired molecularly imprinted membranes (MIMs) via atom transfer radical polymerization (ATRP). In this work, attributed to the unique properties of polydopamine (pDA) modified layers and ATRP technology, the uniform recognition sites for efficiently selective extraction of the Ars with high stability could be obtained on the MIMs surfaces. In addition, the maximum adsorption capacity of the MIMs is 158.85 mg g−1 by the Langmuir isotherm model, which is remarkable higher than NIMs. Additionally, because of the formation of the uniform specific recognition cavities on membrane surfaces, the as‐prepared MIMs exhibited a rapid adsorption dynamics and well‐fitted for the pseudo‐second‐order rate equation, also, possessed an excellent per‐selectivity performance (βartemether/Ars values is 0.18) of template molecule, which clearly demonstrated the potential value of this method in the selective separation and purification of Ars. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43405.

Pitch-Based Carbon Fibre-Reinforced PEEK Composites: Optimization of Interphase Properties by Water-Based Treatments and Self-Assembly

This work addresses the challenging fibre-matrix compatibilization and interface adhesion improvement of poly(etheretherketone) (PEEK) composites reinforced with pitch-based carbon fibre. An innovative and environmentally friendly method, inspired both by supramolecular “layer-by-layer” (LBL) assembly and by the composition of adhesive proteins in mussels was designed to modify the carbon fibre surface and improve the composites transverse properties by supramolecular interactions. The results proved that few sensitive carbon surfaces can be selectively modified by stable polyelectrolyte complexes and catechol amine polymer partners dispersed in water in such a way that a sizing treatment can be applied by techniques as simple as immersion or spraying procedure. It was shown that the combination of these solutions self-organized to form thin deposits containing compatibilization and/or crystallization promoter partners, thought transcrystallinity, onto carbon surface. This approach is an innovative and environmentally-friendly method which improves fibre-matrix interface quality in terms of compatibilization, adhesion and mechanical properties.

New sources of bioinspiration: Adhesive proteins of freshwater mussels

New sources of bioinspiration: Adhesive proteins of freshwater mussels

Synergetic effect of 3,4-dihydroxy-l-phenylalanine-modified poly(lactic-co-glycolic acid) nanopatterned patch with fibroblast growth factor-2 for skin wound regeneration.

Nanoscale topography substrates have potential in guiding cell polarization and migration. Wound healing can be accelerated by nanotopographical substrates which provided appropriate direction to host cells around wound site. We fabricated biodegradable poly (lactic-co-glycolic acid) (PLGA) nanopatterned patch (nP-patch) using capillary force lithography method. Simple surface modification was applied using 3,4-dihydroxy-l-phenylalanine (LD), which has been reported as effective adhesion molecules with similar structure as mussel protein, to immobilize fibroblast growth factor-2 (FGF2) on PLGA patches. In present study, we hypothesized that nP-patch could be enhanced the cell migration in vitro by a guide of nanotopography and that nP-patch with soluble growth factor could accelerate skin wound healing in vivo. To investigate its nanotopographical effect on cell behavior, human dermal fibroblast (HDF) cells were cultured on nP-patch and flat PLGA patch (F-patch). The rate of surface coverage was measured on nP-patch with vertical or parallel orientation. The surface coverage rate was significantly enhanced by nP-patch with vertical orientation compared to the parallel orientation or the F-patch. We made a full thickness (Ø 18 mm) wound on the back of athymic mice and implanted PLGA patches with or without FGF2. FGF2-loaded nP-patch showed much faster wound closure in 21 days compared to others. Histological analysis showed that regenerated tissue had a similar structure as native skin. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 594-604, 2017.

Alteration of Gene Expression Profile in Kidney of Spontaneously Hypertensive Rats Treated with Protein Hydrolysate of Blue Mussel (Mytilus edulis) by DNA Microarray Analysis

Marine organisms are rich sources of bioactive components, which are often reported to have antihypertensive effects. However, the underlying mechanisms have yet to be fully identified. The aim of this study was to investigate the antihypertensive effect of enzymatic hydrolysis of blue mussel protein (HBMP) in rats. Peptides with in vitro ACE inhibitory activity were purified from HBMP by ultrafiltration, gel filtration chromatography and reversed-phase high performance liquid chromatography. And the amino acid sequences of isolated peptides were estimated to be Val-Trp, Leu-Gly-Trp, and Met-Val-Trp-Thr. To study its in vivo action, spontaneously hypertensive rats (SHRs) were orally administration with high- or low-dose of HBMP for 28 days. Major components of the renin-angiotensin (RAS) system in serum of SHRs from different groups were analyzed, and gene expression profiling were performed in the kidney of SHRs, using the Whole Rat Genome Oligonucleotide Microarray. Results indicated although genes involved in RAS system were not significantly altered, those related to blood coagulation system, cytokine and growth factor, and fatty acids metabolism were remarkablely changed. Several genes which were seldom reported to be implicated in pathogenesis of hypertension also showed significant expression alterations after oral administration of HBMP. These data provided valuable information for our understanding of the molecular mechanisms that underlie the potential antihypertensive activities of HBMP, and will contribute towards increased value-added utilization of blue mussel protein.

Investigation of amino acid structure of proteins of freshwater bivalve mussels from the genus anodonta of the northern Ukraine

Mussels of the genus Anodonta of the northern Ukraine are one of poorly caught, but promising objects of river fishery in food and technology terms. The reason of poor catch of freshwater mussels is the lack of industrial technologies for use in food processing. The main objective of the research of freshwater bivalve mussels of the genus Anodonta of the northern Ukraine is to make sure that they contain complete protein, all essential amino acids, and their balanced content. The data obtained were compared with the mussels of the genus Mytilus species Mytilus galloprovincialis and the ideal protein on the scale of FAO/WHO. For the first time, the physicochemical composition of freshwater bivalve mussels of the genus Anodonta of the northern Ukraine was defined. For proteins of two types of the samples, the amino acid structure of soft flesh was determined and the amino acid score of each essential amino acid, followed by their comparison was calculated. To reduce the error of the research, the methods of mathematical modeling and analysis of the results were used. The utility coefficient, potential biological value for mussels of the genus Anodonta and mussels of the genus Mytilus were determined. It was proved that the soft flesh of freshwater mussels of the genus Anodonta has a high nutritional and biological value by the content of protein and essential amino acids. Research of the total content of the flesh after completion of growing period that is 10 months in mussels of the genus Anodonta and Mytilus showed that freshwater mussels prevail over the marine analog by 3.2 times, due to the greater growing capacity and the presence of the foot in mussels of the genus Anodonta. Therefore, they are the best raw material for cultivation and use in food technology, and further researches are highly promising.