Structure of algal-born phenolic polymeric adhesives

Adhesive materials extracted from the brown alga Fucus serratus are composed of phenolic polymer, alginate, and CaCl2. The phenolic polymer undergoes an oxidation reaction in the presence of bromoperoxidase, KI, and H2O2. The nanostructure of the adhesive was investigated using small angle X-ray scattering, light scattering, and cryo- transmission electron microscopy experiments. These have shown that the phenolic polymer undergoes self-assembly and forms flexible chain-like objects. Oxidation or adding alginate does not alter this structure. However, once calcium ions are added, a rigid network is formed. Presumably, this network is responsible for the cohesive strength of the glue.     

Novel biomimetic adhesives based on algae glue

Inspired by the remarkable adhesive capabilities to wet surfaces of the secretes of the brown alga Fucus serratus, novel glues have been designed and characterized. Formulations composed of phloroglucinol, alginate, and calcium ions are capable of adhering to a variety of surfaces. Rheological data show that the presence of phloroglucinol lowers the amount of Ca(2+) ions required for sol-gel transition, which indicates interactions between the alginate and the phloroglucinol. SAXS data support this claim. The phloroglucinol adhesive binds porcine tissues together with an adhesive strength of 17-25 kPa, which indicates appropriate mechanical properties for application as a soft tissue adhesive.     

The interaction between model biomaterial coatings and nylon microparticles as measured with a quartz crystal microbalance with dissipation monitoring

The interaction between cells and biomaterials has been mimicked using nylon microparticles as pseudo-cells and PLMA and PIBMA as biomaterial model acrylate polymers. The shift of fundamental resonance frequencies was negative for both polymers, indicating mass-coupling to the sensor surface. The shifts of the 3rd, 5th and 7th overtone frequencies were initially positive for both polymers, indicating a particle slip or wobbling on the surface. The QCM technique could discriminate between the two different polymers, showing increased interaction between microparticle and PLMA. The dissipation shift was positive for all overtones on both polymers, but again with faster and more prominent response for PLMA.     

磁场及反应条件对十二烷基苯磺酸掺杂聚苯胺聚合成膜速率的影响

在恒定磁场(0.6 T)条件下, 采用过硫酸铵(APS)为引发剂, 在乳液体系中合成了十二烷基苯磺酸(DBSA)掺杂的聚苯胺(PAn). 借助石英晶体微天平(QCM)实时监测苯胺(An)在金电极表面聚合成膜过程, 探讨了磁场、APS浓度、DBSA浓度及反应温度对DBSA掺杂聚苯胺聚合成膜速率的影响. 实验结果表明, PAn在金电极表面的成膜速率随磁场强度的增加而增大; 由反应物浓度与PAn成膜速率的关系, 得出相应的动力学反应级数; 由PAn膜的增长速率与温度的关系, 得到成膜过程的活化能为41.08 kJ/mol. 考察了PAn聚合过程的UV-Vis光谱, 并与QCM所得的结果进行了比较. 结果显示, 在相同时间内, 磁场环境下合成的PAn的吸收强度大于无磁环境下合成的PAn.     

FeCl_3/APS复合氧化剂对乳液法合成聚苯胺动力学行为的影响

采用石英晶体微天平(QCM)技术,探讨了以三氯化铁(FeCl3)和过硫酸铵(APS)为复合氧化剂,十二烷基苯磺酸(DBSA)为乳化剂和掺杂剂时,苯胺(An)的乳液聚合动力学行为;并通过对产物的循环伏安分析,初步优化了聚合反应条件.结果表明,An的乳液聚合反应对复合氧化剂、An以及DBSA分别为1,0.5和0.5级.各种条件下的循环伏安(CV)图都显示出PAn的三对氧化还原特征峰.当FeCl3与APS物质的量比为2∶1;氧化剂总量与苯胺的物质的量比为3∶1;DBSA浓度为0.05mol/L时,CV测试的峰电流和电导率最大.     

石英晶体微天平在手性识别中的应用

石英晶体微天平(QCM)是一类重要的质量型检测器,因具有灵敏度高、分析速度快、检测成本低等优点而具有极好的应用前景,现已广泛应用于环境监测、药物分析、食品质量控制等诸多领域。手性工程的崛起对简单、快速、在线的手性检测技术提出了挑战,QCM手性传感器就是其中一个重要的发展分支。该文简要介绍了QCM的典型实验装置和基本传感原理,详细综述了近年来QCM在手性识别领域的研究进展,包括以环糊精衍生物、分子印迹聚合物、氨基酸衍生物等为手性主体的QCM在手性识别中的应用,并对其今后的发展进行了展望。     

石英晶体微天平技术研究纳米TiO_2表面Cu(Ⅱ)吸附与光化学还原过程

环境中排放的重金属离子Cu!对水生和陆生生物有强的毒害性。饮用水中Cu!的浓度高于1.0mg·L-1时,将会导致人畜得血色沉着病和胃肠粘膜病[1]。Cu!无法进行生物降解,除去废水中Cu!的常见方法有离子交换、置换、化学沉淀等[2],然而这些方法需要消耗大量的化学试剂,成本高。近来,研     

The effect of cucurbit[n]uril on the solubility,morphology, and the photophysical properties of nonionic conjugated polymers in an aqueous medium

The effects of cucurbit[n]uril on the dissolution and the photophysical properties of nonionic conjugated polymers in water are described. For this purpose, a fluorine‐based polymer, namely, poly[9,9‐bis{6(N,N‐dimethylamino)hexyl}fluorene‐co‐2,5‐thienylene (PFT) was synthesized and characterized by spectroscopic techniques including 1D and 2D NMR, UV–vis, fluorescent spectroscopy, and matrix‐assisted laser desorption mass spectrometry (MALDI‐MS). For the first time, it was demonstrated that a nonionic conjugated polymer can be made soluble in water through an inclusion complex formation with CB8. The structure of the complex was elucidated by NMR experiments including ¹H and selective 1D‐NOESY. This complex emits green and is highly fluorescent with fluorescent quantum yield of 35%. In contrast, CB6 or water‐soluble CB7 although they are chemically identical to CB8 do not have any effect on the dissolution and photophysical properties of PFT. By preparing a protonated version of PFT, the optical properties of PFT in methanol, protonated PFT and PFT@CB8 in water have been studied and compared. It was also observed that the morphology of the polymer PFT was affected by the presence of CB8. Thus CB8‐assisted self‐assembly of polymer chains leads to vesicles formation; these structures were characterized by DLS, AFM, SEM, and TEM fluorescent optical microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

基于金纳米粒子的QCM实时检测DNA错配的研究

利用石英晶体微天平（QCM）技术,用双硫醇分子作为连接剂,将金纳米粒子固定于金电极表面,以人类p53基因片断为DNA探针,研究了其在QCM金电极表面的固定、杂交和错配,重点探讨了金纳米粒子修饰的DNA错配碱基个数和错配位点对杂交的影响。在实验条件下,金纳米粒子在QCM金电极表面的修饰使其灵敏度得到了明显提高;而且,错配碱基个数和错配碱基位点的差异都对杂交产生了不同程度的影响。     

Preparation of oligoamide‐ended poly(ethylene glycol) and hydrogen‐bonding‐assisted formation of aggregates and nanoscale fibers

An oligoamide‐ended poly(ethylene glycol) (PEG) with a PEG weight‐average molecular weight of 5000 (PEG‐5000‐oligoamide), with 3,5‐bis‐[2‐(5‐acetylamino‐2‐isobutoxy‐benzoylamino)‐acetylamino]‐benzoyl as the oligoamide, was synthesized. PEG‐5000‐oligoamide aggregated in chloroform or toluene via hydrogen‐bonding interactions among the oligoamide strands as a core and PEG, which was soluble in the solvents, as a shell. When a chloroform solution of PEG‐5000‐oligoamide at a concentration of approximately 0.06 g/L was cast onto a silicon wafer or a mica plate, rapid solvent evaporation induced its self reassembly as nanofibers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1119–1128, 2005     

Rapid Detection of Staphylococcal Enterotoxin B by Two-Dimensional Molecularly Imprinted Film-Coated Quartz Crystal Microbalance

We fabricated a two-dimensional (2D) molecularly imprinted sol-gel thin film-coated quartz crystal microbalance (QCM) for the rapid detection of staphylococcal enterotoxin B (SEB) by combining organosilanes and the template protein SEB on the surface of piezoelectric quartz crystal (PQC) Au-electrode by in-situ immobilization. The detection process was monitored by the QCM's frequency shift (Δf). The working range of this method was 1.0 × 10^?1–1.0 × 10³ µg/mL. The detection limit was 6.1 ng/mL, which was lower than that of the PQC immunosensor, and the detection period was within 0.5 h. The reproducibility of the imprinted film-coated QCM was satisfactory due to no significant statistical difference (P > 0.05) in the rapid detection of SEB between intra- and inter-batch. The selectivity of the imprinted sol-gel film showed that it could discriminate the template molecule from its analogues and other guest molecules. Compared with immunochip, the imprinted film-coated QCM is more advantageous in terms of simplicity, rapidity, low cost, and sensitivity. Moreover, in real sample analysis, the recoveries of this method were 89.4–106.63%, which can be considered a favorable and applicable method for the rapid determination of SEB in real samples.     

QCM和SAW传感器的原理及其在现场检测中的应用

压电化学传感器是一类重要的质量敏感型检测器,由于具有体积小、灵敏度高、响应时间快等优越性而具有极好的应用前景.本文介绍了体声波化学传感器(QCM)和表面声波化学传感器(SAW)的原理,概述了最近几年的应用情况及提高灵敏度的方法,并对其发展趋势进行了展望.     

Interaction of Plasma Proteins with Tri‐quaternary Ammonium Salt Cationic Surfactant Studied by QCM‐D

A tri‐quaternary ammonium salt cationic surfactant was synthesized. Its structure was confirmed by using Fourier‐transform infrared spectroscopy, ¹H nuclear magnetic resonance spectroscopy, and X‐ray photoelectron spectroscopy analyses. Three model surfaces, including Au‐CH₃, Au‐OH and Au‐COOH, were fabricated. Adsorptions of surfactant on the three model surfaces and subsequent plasma proteins adsorption were investigated by quartz crystal microbalance with dissipation (QCM‐D). The mass of surfactant on the Au‐COOH surface was the largest, followed by that on the Au‐CH₃ surface, and that on the Au‐OH surface. These results suggested that the main driving force of surfactant immobilization was electrostatic interaction followed by hydrophobic interaction. Based on the results obtained, we concluded that the protein mass adsorbed on Au‐CH₃‐ S , Au‐OH‐ S , and Au‐COOH‐ S surfaces depended on the protein size and orientation. The mass and thickness of S on the Au‐COOH surface is the largest and the protein adsorption capacity of Au‐COOH‐ S surface is inferior to that of Au‐CH₃‐ S . The Au‐COOH‐ S surface could inhibit lysozyme adsorption, maintain the adsorption balance of bovine serum albumin, and induce fibrinogen‐binding protein adsorption.     

Synthesis of water soluble, biodegradable, and electroactive polysaccharide crosslinker with aldehyde and carboxylic groups for biomedical applications

We report the synthesis and characterization of a polysaccharide crosslinker of tetraaniline grafting oxidized sodium alginate with large aldehyde and carboxylic groups. We demonstrate that this copolymer has the following properties: it is water soluble under any pH, biodegradable, electroactive, and noncytotoxic; it can self-assemble into nanoparticles with large active functional groups on the outer surface; it can crosslink materials with amino and aminoderivative groups like gelatin to form hydrogels, and thus the electroactivity is readily introduced to the materials. This copolymer has potential applications in biomedical fields such as tissue engineering, drug delivery, and nerve probes where electroactivity is required.     

Energy transfer from fluorene‐based conjugated polyelectrolytes to on‐chain and self‐assembled porphyrin units

A new water soluble fluorene‐based polyelectrolyte containing on‐chain porphyrin units has been synthesized via Suzuki coupling, for use in optoelectronic devices. The material consist of a random copolymer of poly{1,4‐phenylene‐[9,9‐bis(4‐phenoxy butylsulfonate)]fluorene‐2,7‐diyl} (PBS‐PFP) and a 5,15‐diphenylporphyrin (DPP). The energy transfer process between the PBS‐PFP units and the porphyrin has been investigated through steady state and time‐resolved measurements. The copolymer PBS‐PFP‐DPP displays two different emissions one located in the blue region of the spectra, corresponding to the fluorene part and another in the red due to fluorescent DPP units either formed directly or by exciton transfer. However, relatively inefficient energy transfer from the PFP to the on‐chain porphyrin units was observed. We compare this with a system involving an anionic blue light‐emitting donor PBS‐PFP and a anionic red light‐emitting energy acceptor meso‐tetrakisphenylporphyrinsulfonate (TPPS), self‐assembled by electrostatic attraction induced by Ca²⁺. Based on previous studies related to chain aggregation of the anionic copolymer PBS‐PFP, two different solvent media were chosen to further explore the possibilities of the self‐assembled system: dioxane–water and aqueous nonionic surfactant n‐dodecylpentaoxyethylene glycol ether (C₁₂E₅). In contrast, with the on‐chain PBS‐PFP‐DPP system the strong overlap of the 0‐0 emission peak of the PBS‐PFP and the Soret absorption band of the TPPS results in an efficient Förster transfer. This is strongly dependent on the solvent medium used. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

A review of monolithic multichannel quartz crystal microbalance: a review

Monolithic multichannel quartz crystal microbalance (MQCM) is an emerging technology for advanced sensing and measurement applications. In this report, a comprehensive review of MQCM technology is presented. Firstly, basic MQCM's design, simulation and characterization with emphasis on acoustic interference are described. Next, various MQCM schemes to minimize interference and enhance sensitivity of conventional MQCM devices based on modification of quartz substrate structure are digested. These include mesa, convex and x-axis inversion structures. Three important MQCM sensing platforms and their application areas are then discussed. These comprise MQCM as a static multichannel detector, series MQCM as a multichannel detector for the flow injection analysis and multi-frequency QCM for multi-sensitivity/multi-dynamic range detection. Finally, potential MQCM applications including electronic noses, bio-sensor arrays, and photocatatalytic measurement are illustrated and prospective MQCM applications including electronic tongues and electrochemical measurement are suggested.     

Water Content of Hydrated Polymer Brushes Measured by an In Situ Combination of a Quartz Crystal Microbalance with Dissipation Monitoring and Spectroscopic Ellipsometry

Poly(methacryloyloxy ethyltrimethylammonium chloride) (PMETAC), poly(sulfopropylmethacrylate potassium salt), or poly(N‐isopropyl acrylamide) (PNIPAM) brushes are synthesized by means of the atom transfer radical polymerization technique from gold surfaces coated with a monolayer of the initiator ω‐mercaptoundecyl bromo isobutyrate. The brush growth is followed in situ and in real time by the combination of quartz crystal microbalance with dissipation technique (QCM‐D) and spectroscopic ellipsometry in a single device. The combination of QCM‐D and ellipsometry allows for the simultaneous determination of both the acoustic mass, m_acous, comprising the mass of the polymer and the solvent, and the optical mass, m_opt, which corresponds to the polymer mass alone. Brush hydration is calculated from the difference between the values obtained for m_acous and m_opt for each polymer synthesized. Brush hydration is then used to quantify the percentage of water released in the brush during collapse; a 30–40% release of water for PMETAC and PSPM brushes in 1 M NaCl and 80% for PNIPAM brushes when the temperature is increased to values above the lower critical solution temperature is observed.     

Solvation characteristics of a model water‐soluble polymer

The model water‐soluble polymer poly(ethylene oxide) was used to investigate solvation characteristics in mixtures of d‐water (deuterated water) and d‐alcohols (deuterated alcohols). Three d‐alcohols have been used: d‐methanol, d‐ethanol, and d‐ethylene glycol. Small angle neutron scattering was used to monitor the solvation properties of poly(ethylene oxide) in the d‐solvent mixtures. Nonideal solvent mixing was observed throughout. Solvent mixtures were found to be more effective solvating agents than individual solvents. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3195–3199, 2006