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951.
We report a rapid and versatile procedure for the preparation of photoreactive polymers and light-induced immobilization of proteins onto such polymers. Photoreactive controlled-pore glass, silica gel, glass slide, and polystyrene microtiter plate are prepared in 40-60s by microwave irradiation of the respective amino polymers and 1-fluoro-2-nitro-4-azidobenzene. Azido group, now part of the polymer, yields highly reactive nitrene under ultraviolet (UV) light at 365 nm. Thus, when photoreactive polymer and horseradish peroxidase or glucose oxidase are exposed to UV light, the reactive nitrene immobilizes the protein molecules in 10 to 20 min through covalent bonding. As nitrene has a property of inserting into C-H bond, the method may find potential applications for immobilization of biomolecules irrespective of their functional groups. 相似文献
952.
Yu Hou Dongrong Xiao Yangguang Li Lin Xu Changwen Hu 《Inorganica chimica acta》2004,357(11):3155-3161
A novel metal-organic compound Zn2(btec)(pipz)(H2O) (1) (btec=1,2,4,5-benzenetetracarboxylate, pipz=piperazine ) has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, TG analysis, luminescent spectrum and single-crystal X-ray diffraction. The title compound exhibits a novel three-dimensional network, which consists of two-dimensional wave-like sheets linked by zinc metal centers and piperazine. Compound 1 provides the first coordination network structure constructed together by bridging piperazine and btec mixed ligand. The study of the physical properties of 1 demonstrates that it exhibits a fluorescent emission in solid state at room temperature. 相似文献
953.
A novel three-dimensional metal-organic coordination polymer, [Zn2(HBTC)2(H2O)3]n (1) (BTC=1,2,4-benzenetricarboxylate), has been prepared by aqueous solution reaction of Zn(NO3)2 · 6H2O and BTC at moderate temperature and characterized by IR, TGA and single-crystal X-ray diffraction analysis. The three-dimensional architecture of 1 not only possesses rectangular cavities but also has ordered one-dimensional straight channels. Furthermore, compound 1 shows intense photoluminescent property at room temperature. 相似文献
954.
Christina Scha¨ffer Norbert Mu¨ller Pravat K. Mandal Rudolf Christian Sonja Zayni Paul Messner 《Glycoconjugate journal》2000,17(10):681-690
The peptidoglycan, the secondary cell wall polymer (SCWP), and the surface layer (S-layer) glycoprotein are the major glycosylated cell wall components of Paenibacillus alvei
CCM 2051. In this report, the complete structure of the SCWP, its linkage to the peptidoglycan layer, and its physicochemical properties have been investigated. From the combined evidence of chemical and structural analyses together with one- and two-dimensional nuclear magnetic resonance spectroscopy, the following structure of the SCWP-peptidoglycan complex is proposed:[(Pyr4,6)--D-Manp
NAc-(14)--D-Glcp
NAc-(13)]ñ11-(Pyr4,6)--D-Manp
NAc-(14)--D-Glcp
NAc-(1O)-PO2-O-PO2-(O6)-MurNAc-Each disaccharide unit is substituted by 4,6-linked pyruvic acid residues. Under mild acidic conditions, up to 50% of them are lost, leaving non-substituted ManNAc residues. The anionic glycan chains constituting the SCWP are randomly linked via pyrophosphate groups to C-6 of muramic acid residues of the peptidoglycan layer. 31P NMR reveals two signals that, as a consequence of micelle formation, experience different line broadening. Therefore, their integral ratio deviates significantly from 1:1. By treatment with ethylenediaminetetraacetic acid, sodium dodecyl sulfate, and sonication immediately prior to NMR measurement, this ratio approaches unity. The reversibility of this behavior corroborates the presence of a pyrophosphate linker in this SCWP-peptidoglycan complex.In addition to the determination of the structure and linkage of the SCWP, a possible scenario for its biological function is discussed. 相似文献
955.
Using overlap elongation PCR, we created repetitive DNA libraries encoding the elastin VPGVG and collagen-like GERGDRGDP sequences. From these libraries we isolated two repetitive DNA sequences, Col-5 encoding [(GERGDRGDP)5GER], and Ela-16 encoding [(VPGVG)16VPG]. Both proteins were expressed as thioredoxin fusion proteins. The resulting recombinant extracellular matrix-like proteins had the expected properties (cell adhesive ability and thermally responsive structural change) of the functional motif sequence unit used. 相似文献
956.
Zeng YN Zheng N Osborne PG Li YZ Chang WB Wen MJ 《Journal of molecular recognition : JMR》2002,15(4):204-208
Polymer capable of specific binding to Cu(2+)-2, 2'-dipyridyl complex was prepared by molecular imprinting technology. The binding specificity of the polymer to the template (Cu(2+)-2, 2'-dipyridyl complex) was investigated by cyclic voltammetric scanning using the carbon paste electrode modified by polymer particles in phosphate buffer solution. Factors that influence rebinding of the imprinted polymer were explored. The results demonstrated that cyclic voltammetry was an efficient approach to explore interactions between template and imprinted polymers. 相似文献
957.
Mizuno Y Sotomaru Y Katsuzawa Y Kono T Meguro M Oshimura M Kawai J Tomaru Y Kiyosawa H Nikaido I Amanuma H Hayashizaki Y Okazaki Y 《Biochemical and biophysical research communications》2002,290(5):1499-1505
Genes differentially expressed between parthenogenetic and androgenetic embryos are candidates for the identification of imprinted genes, which are expressed specifically from the maternal or paternal allele. To search for genes differentially expressed between parthenogenetic and androgenetic embryos, we used the RIKEN full-length enriched mouse cDNA microarray. The 25 candidates obtained included 8 known imprinted genes (such as IgfII, Snrpn, and Neuronatin) and 3 new ones--Asb4 (ankyrin repeat and SOCS box-containing protein 4), Ata3 (amino acid transport system A3), and Decorin--which were confirmed by using normal diploid embryos from the reciprocal F1 crosses of B6 and JF1 mice. The 25 candidates also included genes that showed no imprinting-associated expression in normal diploid embryos. We describe a feasible high-throughput method of screening for novel imprinted genes by using the RIKEN cDNA microarray. 相似文献
958.
Immunoselection and adenoviral genetic modulation of human osteoprogenitors: in vivo bone formation on PLA scaffold 总被引:5,自引:0,他引:5
Howard D Partridge K Yang X Clarke NM Okubo Y Bessho K Howdle SM Shakesheff KM Oreffo RO 《Biochemical and biophysical research communications》2002,299(2):208-215
The aim of this study was to examine the potential of immunoselected genetically modified human osteoprogenitors to form bone in vivo on porous PLA scaffolds. Human osteoprogenitors from bone marrow were selected using the antibody STRO-1 utilising a magnetically activated cell separation system. The STRO-1(+) fraction isolated 7% of nucleated marrow cells and increased fibroblastic colony formation by 300% and alkaline phosphatase activity by 190% over unselected marrow cell cultures. To engineer bone tissue, STRO-1(+) culture-expanded cells were transduced with AxCAOBMP-2, an adenovirus carrying the human BMP-2 gene, injected into diffusion chambers containing porous PLA scaffolds, and implanted in vivo. After 11 weeks the presence of bone mineral was observed by X-ray analysis and confirmed for mineral by von Kossa, as well as bone matrix composition by Sirius red staining, birefringence, and type I collagen immunohistochemistry. Bone formation in vivo indicates the potential of using immunoselected progenitor cells and ex vivo gene transfer with biodegradable scaffolds, for the development of protocols for the treatment of a wide variety of musculo-skeletal disorders. 相似文献
959.
Background
Polycaprolactone (PCL) is a biodegradable polymer which is used in tissue engineering applications thanks to its many favorable characteristics. However, PCL surfaces are known as hydrophobic leading to a lack of favorable cell response. To overcome this problem, PCL surfaces will undergo a surface functionalization by grafting bioactive polymers bearing ionic groups.Objective
Our laboratory has demonstrated that the grafting of bioactive polymers onto biomaterials can improve cell and antibacterial response. The objective of this work is to functionalize PCL surfaces by the grafting of a bioactive polymer.Methods
The grafting of an ionic polymer poly(sodium styrene sulfonate) (polyNaSS), using UV irradiation on PCL surfaces was carried out in a two-steps reaction process. PCL surfaces were (1) chemically oxidized in order to allow the formation of (hydro)peroxide species. (2) Then immersed in a sodium styrene sulfonate (NaSS) solution and placed under UV irradiation to induce the decomposition of (hydro)peroxides to form radicals able to initiate the polymerization of the NaSS monomer. Various parameters, such as polymerization time, the effect of the surface activation, lamp power and monomer concentration were investigated in order to optimize the yield of polyNaSS grafting. The amount of polyNaSS grafted onto PCL surfaces was first determined by toluidine blue colorimetric method and characterized by contact angle measurement, Fourier-transform infrared spectra recorded in attenuated total reflection mode (ATR-FTIR), scanning electron microscopy with Oxford energy dispersive spectroscopy (SEM-EDS).Results
Various techniques showed that the grafting of ionic polymer polyNaSS bearing sulfonate groups was successful by using radicals from (hydro)peroxides able to initiate the radical polymerization of ionic monomers onto PCL surfaces.Conclusion
We developed a new approach of radical grafting which allows us to successfully graft bioactive polymer polyNaSS covalently to PCL surfaces using UV irradiation. 相似文献960.
Dual doped biocompatible multicolor luminescent carbon dots for bio labeling,UV‐active marker and fluorescent polymer composite
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Subhadip Mondal Uttam Kumar Ghorai Priti Prasanna Maity Sumita Choudhary Subhashis Gangopadhyay Santanu Dhara Susanta Banerjee Narayan Ch. Das 《Luminescence》2018,33(6):1136-1145
We report on metal–non‐metal doped carbon dots with very high photoluminescent properties in solution. Magnesium doping to tamarind extract associated with nitrogen‐doping is for the first time reported here which also produce very high quantum yield. Our aim is to develop such dual doped carbon dots which can also serve living cell imaging with easy permeation towards cells and show non‐cytotoxic attributes. More importantly, the chemical signatures of the carbon dots unveiled in this work can support their easy solubilization into water; even in sub‐ambient temperature. The cytotoxicity assay proves the almost negligible cytotoxic effect against human cell lines. Moreover, the use of carbon dots in UV‐active marker and polymer composites are also performed which gave clear distinguishable features of fluorescent nanoparticles. Hitherto, the carbon dots can be commercially prepared without adopting any rigorous methods and also can be used as non‐photo‐bleachable biomarkers of living cells. 相似文献