Iron chelating polypropylene films: Manipulating photoinitiated graft polymerization to tailor chelating activity

Transition metals, especially iron, enhance the oxidative degradation of lipids. Nonmigratory metal chelating active packaging can inhibit lipid oxidation and meet consumer demand for ‘cleaner' labels. Recently, the development of iron chelating films prepared by photoinitiated graft polymerization of acrylic acid on polypropylene (PP‐g‐PAA) was reported. The objective of this study was to tailor the chelating activity of PP‐g‐PAA by manipulating graft conditions. Carboxylic acids graft density and PAA graft thickness increased with graft time and acrylic acid concentration, with carboxylic acids density of up to 143 ± 32 nmol cm^?2, PAA graft thickness of ～6–18 μm, and ligand (carboxylic acid) to metal (Fe²⁺) binding ratio of ～4–5. Reducing photoinitiator graft density decreased this ratio to ～2–2.5, suggesting that graft chain density influences chelating activity. This work demonstrates the ability to tailor chelating activity of PP‐g‐PAA with potential applications in active packaging, chelation therapy, and water purification. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39948.     

羟基磷灰石涂层的生物仿生法研究进展

羟基磷灰石的生物复合涂层具有很高的外科应用价值.制备羟基磷灰石复合材料的方法有很多种,其中仿生法模仿了自然界生理磷灰石的矿化机制,在类似于人体组织内环境条件的水溶液中自然沉积出磷灰石层.仿生法具有许多其它方法无可比拟的优越性.本文对近年来文献报道中出现的生物仿生法进行了综述,阐述了各种仿生法中包括对基体进行预处理使其表面官能团化,再将基体在模拟体液中浸泡从而使磷灰石自然沉积的模拟生物矿化的4个阶段的工艺过程及其仿生机理.     

UV grafting process for synthetic drag reduction of biomimetic riblet surfaces

Skin–friction drag accounts for a large portion of resistance encountered by water‐based vehicles, such as ships and submarines. Developing drag reduction methods to improve drag reduction performance has drawn worldwide attention recently. UV‐induced polymerization has been investigated as a way to graft the drag reduction agent PAM on to a PVC substrate with a biomimetic riblet surface. The effects of AM concentration and irradiation time on the grafting rate were explored to determine optimal grafting parameters. UV grafting polymerization was clarified by comparing the peak absorption variation of the infrared spectrum before and after grafting. The PAM thin film grafted on riblet surface was measured approximately 10 µm in thickness. A rotating disk apparatus was built to measure the synthetic drag reduction performance. The drag reduction rate of the grafted PAM riblet surface was tested at approximately 14%, higher than the 6% of the traditional riblet surface. Moreover, the excellent drag reduction performance of grafted PDMS riblet surface lasted for 12 days. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42303.     

仿生物矿化制备硅纳米材料

利用正硅酸乙酯和人工合成的多肽,在比较温和的条件下快速合成了硅纳米材料,并研究了制备过程中的多种因素对产物形貌的影响,研究发现:在pH值=8.0的磷酸盐缓冲液中,当R5肽的浓度为10 mg/mL,正硅酸乙酯的浓度0.1mol/L,反应15min时,可得到规则的球状颗粒。X射线能谱分析证明产物为硅和多肽的复合物。     

Fabrication of anisotropic nanocomposite hydrogels by magnetic field-induced orientation for mimicking cardiac tissue

The ordered structure of biological tissues is a precondition for the development of high performance in these tissues. Hydrogels with anisotropic structures provide a good starting point for studying their biomimetic applications. In this work, a hydrogel that mimics the endogenous anisotropic structure of heart tissue was reported. The gel consists of acrylamide (AM) and 2-Acrylamide-2-methylpro panesulfonic acid (AMPS) as gel monomers, α-ketoglutaric acid as photoinitiator, and modified magnetic nanoparticles (Fe₃O₄-R_S) as crosslinking agent. Thus, AM, AMPS and Fe₃O₄-Rs was called AAF for short. In the system, the orientation of Fe₃O₄-Rs was arranged by an external magnetic field. Under ultraviolet (UV) irradiation, the precursor solution was polymerized in situ to form an AAF hydrogel. The structure, pore distribution, rheological properties, mechanical performance, swelling property, and biocompatibility of the prepared anisotropic AAF hydrogel were studied in this paper. Results showed that the mechanical performance of the AAF hydrogels was remarkably enhanced in comparison with the isotropic ones. The tensile strength of AAF hydrogel could reached 184 kPa in the direction of the parallel Orientation of Fe₃O₄-Rs, and 80 kPa in the direction of the vertical Orientation of Fe₃O₄-Rs under 25% strain (no magnetic field was applied during all test). Moreover, the anisotropic tensile ratio of AAF hydrogel also reached 2.3. The strength and modulus of anisotropic hydrogels were similar to cardiac tissue (anisotropic tensile ratio was 2.5), which has great potential for application in cardiac tissue engineering.     

仿生合成法制备二氧化硅的研究进展

目前,纳米材料领域研究的焦点是纳米二氧化硅的研究,而传统的化学方法制备二氧化硅需要严格控制反应的条件,试剂污染比较严重,资源的损耗较大,反应的时间也比较长;然而,自然界中的一些植物,在常温常压及近中性pH下,就能形成比较精美的硅纳米材料,这些有趣的现象使人们日益关注仿生硅化的研究。文章就二氧化硅的仿生合成进行简要评述。     

壳聚糖模板诱导梭状纳米羟基磷灰石的仿生合成

依据生物矿化的原理,在6%的双氧水溶液中以壳聚糖为模板仿生合成纳米羟基磷灰石。用X-射线衍射仪(XRD)和傅立叶红外变换光谱(FTIR)对纳米羟基磷灰石的结构和组成进行表征,通过透射电镜(TEM)观察纳米羟基磷灰石的形貌。结果表明,壳聚糖模板改变了羟基磷灰石的形貌,合成得到宽约为7~8 nm,长约30~40 nm的梭状纳米羟基磷灰石。     

Biomimetic Multienzyme Complexes Based on Nanoscale Platforms

Inspired by the widely present multienzyme complexes in nature that enable highly cooperative catalytic mechanisms, we designed a biomimetic dual‐functionalized nanoparticle‐based platform for colocalizing multiple enzymes. The use of nanoscale materials together with a novel sequential colocalization approach with two model enzymes [glucose oxidase (GOX) and horseradish peroxidase] resulted in a 100% increase in the overall conversion rate compared to the equivalent amount of free enzymes in solution and a physical mixture of individual immobilized enzymes on nanoparticles. GOX is an important enzyme used in glucose biosensors for diagnostics. Colocalizing GOX with peroxidase allows for colorimetric visualization of the peroxide formed that enables monitoring glucose levels in solution. This platform can be readily applicable to other multienzyme systems as well. © 2012 American Institute of Chemical Engineers AIChE J, 59: 355–360, 2013     

Development of Core-Shell Nanoparticle Drug Delivery Systems Based on Biomimetic Mineralization

Among various drug-delivery systems, core-shell nanoparticles have many advantages. Inspired by nature, biomimetic synthesis has emerged as a new strategy for making core-shell nanoparticles in recent years. Biomimetic mineralization is the process by which living organisms produce minerals based on biomolecule templating that leads to the formation of hierarchically structured organic–inorganic materials. In this minireview, we mainly focus on the synthesis of core-shell nanoparticle drug-delivery systems by biomimetic mineralization. We review various biomimetic mineralization methods for fabricating core-shell nanoparticles including silica-based, calcium-based and other nanoparticles, and their applications in drug delivery. We also summarize strategies for drug loading in the biomolecule-mineralized core-shell NPs. Current challenges and future directions are also discussed.     

贝壳结构及陶瓷的仿生研究

介绍了贝壳结构及其断裂方式,综述了仿贝壳结构的层状陶瓷的研究发展,认为层状陶瓷在结构设计、层与层之间的热应力匹配、界面结合强度等方面都有待进一步的研究.     

仿生合成技术及其应用研究

90年代以来,出现了一种模仿生物矿化中无机物在有机物调制下形成过程的新合成方法－仿生合成,利用仿生合成技术制备的纳米微粒,薄膜,多孔材料等物质具有特殊的物理和化学性能,潜在着广阔的应用前景,这使得无机材料的仿生合成技术已成为材料化学研究的前沿和热点。     

仿生表面改性技术研究进展

从结构仿生和功能仿生两个方面对仿生表面改性技术进行了综述,对分子印迹技术、模拟生物酶催化、仿细胞膜结构改性、智能高分子凝胶及生物传感器进行了介绍,并对仿生表面改性技术的发展趋势进行了展望。     

仿生合成在无机粉体制备技术中的应用

无机粉体以其优异的性能被广泛应用各个领域。本文概要介绍了仿生合成方法在无机粉体制备技术中的应用及其发展现状。仿生合成具有的诸多优点,使无机材料的仿生合成技术成为无机材料化学的研究前沿和热点。     

通过仿生法在纯镁表面制备羟基磷灰石涂层的研究

在纯镁表面自组装单分子层,用CaCl2和K2HPO4溶液对其进行预钙化处理,将处理过的纯镁试样浸泡于钙磷饱和溶液,仿生沉积得到羟基磷灰石涂层。利用X射线衍射和扫描电子显微镜对形成的涂层进行表征。试验结果表明,6天后即在镁基体表面得到了均匀致密、以羟基磷灰石（HA）为主晶相的羽毛状涂层。     

Biomimetic Polymer Nanostructures by Injection Molding

The nanometer scale topography of self‐assembling structural protein complexes in animals is believed to induce favorable cell responses. An important example of such nanostructured biological complexes is fibrillar collagen that possesses a cross‐striation structure with a periodicity of 69 nm and a peak‐to‐valley distance of 4–6 nm. Bovine collagen type I was assembled into fibrillar structures in vitro and sedimented onto solid supports. Their structural motif was transferred into a nickel replica by physical vapor deposition of a small‐grained metal layer followed by galvanic plating. The resulting inverted nickel structure was found to faithfully present most of the micrometer and nanometer scale topography of the biological original. This nickel replica was used as a die for the injection molding of a range of different thermoplastic polymers. Total injection molding cycle times were in the range of 30–45 seconds. One of the polymer materials investigated, polyethylene, displayed poor replication of the biological nanotopographical motif. However, the majority of the polymers showed very high replication fidelity as witnessed by their ability to replicate the cross‐striation features of less than 5 nm height difference. The latter group of materials includes poly(propylene), poly(methyl methacrylate), poly(L ‐lactic acid), polycaprolactone, and a copolymer of cyclic and linear olefins (COC). This work suggests that the current limiting factor for the injection molding of nanometer scale topography in thermoplastic polymers lies with the grain size of the initial metal coating of the mold rather than the polymers themselves.

     

功能性碳酸钙材料的仿生合成及表征

根据生物矿化机理,利用碳化法,选用实验室自制的硬脂酸钠作为改性剂,原位合成出功能性梭形碳酸钙材料。产品的改性效果通过活化度、吸油值、接触角等性能测定。同时通过透射电子显微镜（TEM）和X射线衍射（XRD）等测试手段对产品结构和形貌进行表征,并对反应机理进行了初步探讨。实验结果表明,当硬脂酸钠用量达到2.0％（占碳酸钙理论值）时,产品活化度可达到99.9％,接触角为121.62°,从而为仿生矿化制备新材料提供了理论依据和合成手段。     

模拟生物矿化制备球形碳酸钙粒子及表征

模拟生物矿化原理,以磷酸酯(DDP)作为有机质,采用碳化法制备了具有球形CaCO3粒子。通过场发射扫描电子显微镜(FESEM)、X射线衍射仪(XRD)、傅立叶红外光谱仪(FT-IR)、热重(TGA)及活化指数等检测手段对所得CaCO3粒子的形貌、晶型及性能进行了表征。     

Assessment of the ability of poly(l‐lysine)–poly(ethylene glycol) (PLL–PEG) hydrogels to support the growth of U87‐MG and F98 glioma tumor cells

Biomaterials that provide 3D‐like in vitro cell survival and proliferation are increasingly used to mimic the extracellular microenvironment in the context of a better understanding of tumorigenesis. In this study, a simple, affordable and fast technique to fabricate hydrogel matrices composed of poly(ethylene glycol) (PEG) and poly(l ‐lysine) (PLL) (as cell‐adhesive factor) were used to provide in vitro glioma cell growth. After UV photopolymerization of a precursor solution containing PEG‐diacrylate and easily obtainable PLL‐acrylate derivatives, F98 and U87‐MG cells (rat and human glioblastoma cell lines, respectively) were grown on top of different substrates that consist of combinations of PEG/PLL hydrogels and spontaneously formed cell aggregates of homogeneous sizes. Depending on the cell type, PEG and PLL concentrations, the cell aggregates patterns were different. The optimal combination to obtain cell survival and proliferation for both cell lines was determined as 3% PEG (w/v) and 0.001% PLL (w/v). This technique was also used to assess the efficacy of temozolomide and should be adaptable to other cancer cell lines to follow pseudo‐tumor growth in vitro. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46287.     

Biomimetic phospholipid polymers for suppressing adsorption of saliva proteins on dental hydroxyapatite substrate

To prevent infectious diseases induced by the adhesion of microorganisms and their metabolic products to dental implants, saliva protein adsorption, which induces the plaque deposition to the intraoral substrates should be inhibited. We used a water-soluble 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer to modify the surface of hydroxyapatite (HAp) substrate, the main component of dental implant surface. The MPC polymer containing a catechol group at the terminal of polymer chain and amino groups in the side chain was synthesized by mimicking the mussel adhesive protein. The MPC polymer containing 2% of the primary amino groups showed effective adhesion to the HAp substrate. Mucin, the dental plaque protein, adsorbs on the HAp surface; however, the MPC polymer modification could reduce this adsorption amount by more than 98% compared to the original HAp substrate surface. Thus, the treatment of the MPC polymer has potential to reduce oral infection due to plaque deposition.     

仿生防污涂层材料在船舶防污上的应用

综述了无毒无污染新型仿生防污涂层材料的概念和开发现状,介绍了仿生防污涂层材料的防污机理和各种新型高分子仿生防污涂层技术的发展概况,并展望了仿生防污涂层材料的发展方向。