Optically and biologically active mussel protein-coated double-walled carbon nanotubes

A method of dispersing strongly bundled double-walled carbon nanotubes (DWNTs) via a homogeneous coating of mussel protein in an aqueous solution is presented. Optical activity, mechanical strength, as well as electrical conductivity coming from the nanotubes and the versatile biological activity from the mussel protein make mussel-coated DWNTs promising as a multifunctional scaffold and for anti-fouling materials.     

Electrodialysis Desalination and Reverse Osmosis Concentration of an Industrial Mussel Cooking Juice: Process Impact on Pollution Reduction and on Aroma Quality

ABSTRACT: An industrial mussel cooking juice was treated by a 3-step process to produce a natural aroma concentrate and a cleaned water stream. The juice was centrifuged before being desalinated by electrodialysis and then concentrated by reverse osmosis. As a result of this combined process, most of the physicochemical properties of the reverse osmosis permeate were reduced below the discharge standards. The concentrate was examined by a trained sensory panel (triangular tests, sensory profiles) and by gas chromatography/mass spectrometry. The sensory profile of the concentrate was shown as slightly different from the unprocessed mussel cooking juice one. Nevertheless, the concentration process preserved the native characteristic aroma of the cooked mussel, of interest to human or pet food industries.     

海洋生物及其粘附机理——微生物、小型海藻、巨型海藻、贻贝

主要介绍海洋生物中微生物、小型海藻、巨型海藻、贻贝等的粘附机理 ,这对于应用于外科和牙科领域的仿生胶粘剂及海洋防污涂层的研制有着重要的意义     

Mussel‐Inspired Contact‐Active Antibacterial Hydrogel with High Cell Affinity,Toughness, and Recoverability

Antibacterial hydrogel has received extensive attention in soft tissue repair, especially preventing infections those associated with impaired wound healing. However, it is challenging in developing an inherent antibacterial hydrogel integrating with excellent cell affinity and superior mechanical properties. Inspired by the mussel adhesion chemistry, a contact‐active antibacterial hydrogel is proposed by copolymerization of methacrylamide dopamine (MADA) and 2‐(dimethylamino)ethyl methacrylate and forming an interpenetrated network with quaternized chitosan. The reactive catechol groups of MADA endow the hydrogel with contact intensified bactericidal activity, because it increases the exposure of bacterial cells to the positively charged groups of the hydrogel and strengthens the bactericidal effect. MADA also maintains the good adhesion of fibroblasts to the hydrogel. Moreover, the hybrid chemical and physical cross‐links inner the hydrogel network makes the hydrogel strong and tough with good recoverability. In vitro and in vivo tests demonstrate that this tough and contact‐active antibacterial hydrogel is a promising material to fulfill the dual functions of promoting tissue regeneration and preventing bacterial infection for wound‐healing applications.     

仿生胶粘剂研究发展前景诱人

常用的合成胶粘剂在满足粘接要求、方便日常生活的同时,也带来了对健康和环境有害的污染成分。海洋贻贝粘附蛋白超强的防水粘附作用使其能够牢固地粘附在各种基材表面,具有良好的生物相容性、生物降解性和无毒性,为新型胶粘剂的研究提供了思路。本文简要介绍仿贻贝粘附蛋白胶粘剂的研究进展,概述仿生粘附在胶粘剂研究、新产品开发及解决某些难题方面的普遍作用及良好效果。     

Facile Fabrication of Robust Ice‐Phobic Polyurethane Sponges

Bio‐inspired superhydrophobicity is a promising anti‐icing (or deicing) strategy, but a superhydrophobic surface may lose its anti‐icing capability once the deposited water freezes. Herein, it is shown that ice can be readily and repeatedly removed from the surface of superhydrophobic polyurethane sponges via a simple mechanical squeezing process. The sponges are fabricated through a mussel‐inspired process and subsequent deposition of Ag nanoparticles. The resulting sponges are able to shed off the ice layers formed on their surfaces up to 90 times, exhibiting robust icephobic properties among the reported superhydrophobic surfaces. The mechanism for the excellent icephobicity is investigated by a highly sensitive microelectrobalance and a fluorescent labeling method. It is revealed that the icephobicity is attributed to low ice adhesion of the superhydrophobic sponges, as well as mechanical durability of their surface textures. The present findings provide a facile strategy to fabricate robust icephobic surfaces for various technological applications.     

Mussel‐Inspired Immobilization of Catalysts for Microchemical Applications

Immobilization of photocatalytic TiO₂ nanoparticles inside PDMS‐based microreactors was successfully attempted by sequential mussel‐inspired surface engineering of microchannels by using CA‐PVP and commercially available TiO₂ nanoparticles, respectively. TiO₂‐immobilized microreactors accomplished continuous photocatalytic degradation of MB for up to 30 days without releasing TiO₂ nanoparticles from the surface of the microchannels, confirming the robustness of TiO₂‐immobilization in photocatalysis media. Regeneration of microreactors with diminished photocatalytic activities was also possible with simple strong acid treatment, enabling efficient cleaning of used microreactors.     

Peptide Length and Dopa Determine Iron‐Mediated Cohesion of Mussel Foot Proteins

Mussel adhesion to mineral surfaces is widely attributed to 3,4‐dihydroxyphenylalanine (Dopa) functionalities in the mussel foot proteins (mfps). Several mfps, however, show a broad range (30%–100%) of tyrosine (Tyr) to Dopa conversion suggesting that Dopa is not the only desirable outcome for adhesion. Here, a partial recombinant construct of mussel foot protein‐1 (rmfp‐1) and short decapeptide dimers with and without Dopa are used and both their cohesive and adhesive properties on mica are assessed using a surface forces apparatus. Our results demonstrate that at low pH, both the unmodified and Dopa‐containing rmfp‐1s show similar energies for adhesion to mica and self–self‐interaction. Cohesion between two Dopa‐containing rmfp‐1 surfaces can be doubled by Fe³⁺ chelation, but remains unchanged with unmodified rmfp‐1. At the same low pH, the Dopa‐modified short decapeptide dimer did not show any change in cohesive interactions even with Fe³⁺. The results suggest that the most probable intermolecular interactions are those arising from electrostatic (i.e., cation–π) and hydrophobic interactions. It is also shown that Dopa in a peptide sequence does not by itself mediate Fe³⁺ bridging interactions between peptide films: peptide length is a crucial enabling factor.     

贻贝煮汁酶解液美拉德反应条件优化及其产物氨基酸组成分析

为提高对贻贝副产物的利用,以木瓜蛋白酶水解贻贝煮汁得到的酶解液为原料,经联合脱腥后进行美拉德反应,以感官评价及褐变程度为指标,研究影响贻贝煮汁酶解液美拉德反应呈味效果的各因素,并通过单因素试验及响应面试验设计优化工艺条件,以获得氨基酸态氮含量高且色泽风味好的产物。结果表明：响应面优化的美拉德反应最佳工艺条件为还原糖添加量3.3%、氨基酸添加量3.1%、加热时间55 min、初始pH 8.0,经高效液相色谱测定,贻贝煮汁液和美拉德反应产物中均检测出17 种氨基酸,在最优条件下的美拉德反应产物中,总氨基酸及必需氨基酸含量与煮汁液相比,分别增加了315.91%和428.84%。可见,经美拉德反应后的产物在营养和风味上均优于贻贝煮汁液,是研制新型贻贝调味品的理想原料。     

Long-term trends of Lake Michigan benthos with emphasis on the southern basin

Lake Michigan benthic macrofauna have been studied for almost a century, allowing for a unique analysis of long-term changes in community structure. We examined changes in abundances of three major taxonomic groups of benthic macroinvertebrates (Diporeia, Oligochaeta, and Sphaeriidae) in southern Lake Michigan from 1931 to 2015 and identified the most likely causes for these changes. Abundances of all three groups increased during 1931–1980 with the bulk of these increases occurring in nearshore (≤50 m) waters and coincident with increased loading of phosphorus (P) and subsequent increased primary production. Abundances of all three taxa declined during 1980–2000 again mostly in nearshore waters and coincident with decreased P loading. The quagga mussel (Dreissena rostriformis bugensis) invasion was associated with a further decline in phytoplankton primary production during 2000–2015. Both Diporeia and Sphaeriidae declined in abundance during that time, with Diporeia exhibiting the more pronounced decrease of the two groups. In contrast, Oligochaeta increased in abundance during 2000–2015. The quagga mussel has become, by far, the most abundant benthic macroinvertebrate species in terms of density and biomass. Overall, the primary driver of changes in the abundances of the three major taxa during this 85-year period appeared to be changes in phytoplankton primary production due to changing P loadings and, later in the time series, Dreissena filtering. The dreissenid mussels invasions coincided with a rapid decline of Diporeia abundance, but the mechanism of this negative effect remains unidentified. In contrast, Oligochaeta likely benefited from the quagga mussel invasion, perhaps via quagga-generated food supply.