Immunosensor Accuracy Improved by Coating Beads with Poly-2-[3-(Methacryloylamino)Propylammonio]Ethyl 3-Aminopropyl Phosphate

Poly-2-[3-(methacryloylamino)propylammonio]ethyl 3-aminopropyl phosphate (poly-3MAm3AP) is a polymer that contains phosphorylcholine groups that can attract water to form a water layer, and amino groups that can be used for the covalent attachment of receptors such as anti-LH (Luteinizing hormone) antibody and LH antigen. Poly-3MAm3AP was synthesized with the anticipation that it would aid the recognition of a large number of analytes and eliminate nonspecific adsorption. Poly-3MAm3AP was coated on beads and served as an antigen-antibody reaction interface. The specificity of this surface was evaluated using surface plasmon resonance (SPR) by comparing responses to specific anti-LH antibody and nonspecific anti-hemoglobin antibody.Poly-3MAm3AP did not adsorb nonspecific antibody due to the presence of free water associated with the phosphorylcholine moiety. An immunosensor system was fabricated by combining poly-3MAm3AP-coated beads containing immobilized anti-LH antibody with an optical detector. Poly-3MAm3AP not only reduced nonspecific adsorption, but also increased the amount of specific antibody-antigen interaction. These favorable characteristics are due to an increased amount of immobilized receptor and an increased amount of space for antigen-antibody interaction arising from electrostatic repulsion within the poly-3MAm3AP electrolyte.     

Removal of multi-metals from water using reusable pectin/cellulose microfibers composite beads

Pectin (Pec) and cellulose microfibers (CF) extracted from orange waste were combined to form composite beads with enhanced adsorption capacity. Such beads were extensively tested in the removal of multi-metal ions from water. A factorial design approach was conducted to establish the optimum conditions for adsorption of Cd(II), Cu(II), and Fe(II) on Pec-CF beads. Batch adsorption experiments revealed that removal efficiency of such metal ions falls in the range of 94–58% and it followed the order Fe(II) > Cu(II) > Cd(II). The maximum Cd(II), Cu(II) and Fe(II) adsorption capacities calculated from the Langmuir isotherm were 192.3, 88.5 and 98.0 mg/g, respectively. FTIR analysis suggests that the functional groups on Pec-CF beads (binding sites) favor the adsorption of such metal ions. Desorption and reuse experiments demonstrated the beads could be used for at least five consecutive adsorption/desorption cycles. Our finds suggest the Pec-CF beads can serve as an efficient adsorbent for the removal of multi-metal ions from wastewater.     

STRUCTURAL CHANGES AND RELEASE CHARACTERISTICS OF CROSSLINKED CHITOSAN BEADS IN RESPONSE TO SOLUTION pH

The present investigation describes a novel method for preparing beads based on crosslinked chitosan with glutaraldehyde interpenetrating glycine polymer network. Four type of beads, viz., CHI1 (composed of chitosan, glycine and glutaraldehyde); CHI2 (composed of chitosan and glutaraldehyde); CHI3 (composed of chitosan and glycine) and CHI4 (only chitosan) were prepared and their release characteristics were studied using thyamine hydrochloride (Thy-HCl) as a model drug. Structural changes during swelling of CHI1 beads in solutions of different pH were studied using IR and UV spectroscopy.     

湖北襄樊出土有色玻璃串饰的检测分析

运用X射线衍射(XRD)和X射线荧光光谱(XRF)等手段,对湖北襄樊一处时代在东汉末年至魏晋初年之间贵族墓出土的不同颜色玻璃珠串饰进行了物相和成分分析.结果表明,这些玻璃珠属于低铅的PbO-SiO2系统配方,各种助熔剂的含量都很低,且矿物原料比较纯,杂质含量低;古代玻璃中常见的铜、铁等致色元素含量很低,而铋的氧化物含量...     

微珠阵列逆反膜性能的改善

光学元件阵列作为逆向反射器,具有准相位共轭特性,微珠阵列作为其中一类,已广泛用于显示、配合目标和交通标志.从衍射效应看,远场条件下大微珠的逆反性能优于小微珠.本文提出并实现了用激光法制作玻璃微珠,并且,为提高逆向反射效率和性能,又提出并实现了大微珠和小微珠镶嵌的制膜技术.所制成的新膜,从原理上和实验效果上均优于目前市场上已有的同类产品.它对该类产品的性能改进提供了新的前景.     

A NOVEL APPROACH TO SYNTHESIZE CHITOSAN BEADS CROSSLINKED BY EPICHLOROHYDRIN

The present investigation describes a novel method for preparing spherical chitosan particles based on crosslinking with epichlorohydrin.Certain amount of pre-crosslinking agent was added to form chitosan gels by traditional inverse phase suspension polymerization.Then the gels were crosslinked by epichlorohydrin at basic condition to obtain chitosan beads.The effects of reaction conditions,such as crosslinking time,the amount of crosslinking agent and the NaOH concentration,on the physical properties of the chitosan beads were investigated.The beads were found to have more amino groups in the polymer chains than the beads crosslinked by glutaraldehyde.The capacity for copper ions in as high as 40mg/g,The beads have good mechanical strength and can be reused.     

A review of: “The Handbook of Environmental Chemistry”

by Otto Hutzinger, University of Amsterdam and 52 authors from 8 countries, Springer-Verlag Berlin     

Optimizing protein recovery yield from serum samples treated with beads technology

Proteomics studies are often complicated by the wide dynamic range of the biological fluids, in which few highly abundant proteins obscure the signal of low abundant ones. To overcome this problem, several techniques have been developed on the basis of "depletion principles," namely immuno-subtraction with specific antibodies against the most-abundant proteins. Unfortunately, the probability of codepletion is a noteworthy drawback associated with these strategies. The ProteoMiner (PM) technology is a novel approach, consisting of a combinatorial library of hexapeptide ligands coupled to beads, that allows the capture of all species present in a proteome, but at much reduced protein concentration differences, simultaneously enhancing the concentration of the most dilute species. In this study, we evaluated the compatibility of the PM kit's elution reagent with 2-DE analysis, comparing five different purification methods on serum samples eluted from the beads: the "ReadyPrep 2-D Clean-up kit" and precipitation with organic solvents, as acetone/methanol, TCA/acetone, ACN, and chloroform/methanol. Considering protein recovery yield (quantity) and 2-DE spot pattern (quality), precipitation with ACN offered the most promising approach, showing the best spot resolution in all regions of the pH gradient and the greatest number of protein spots visualized on 2-D gels.     

Automatic detecting and counting magnetic beads‐labeled target cells from a suspension in a microfluidic chip

A novel microfluidic method of continually detecting and counting beads‐labeled cells from a cell mixture without fluorescence labeling was presented in this paper. The detection system is composed of a microfluidic chip (with a permanent magnet inserted along the channel), a signal amplification circuit, and a LabView® based data acquisition device. The microfluidic chip can be functionally divided into separation zone and detection zone. By flowing the pre‐labeled sample solution, the target cells will be sequentially separated at the separation zone by the permanent magnet and detected and counted at the detection zone by a microfluidic resistive pulse sensor. Experiments of positive separation and detection of T‐lymphocytes and negative separation and detection of cancer cells from the whole blood samples were carried out to demonstrate the effectiveness of this method. The methodology of utilizing size difference between magnetic beads and cell‐magnetic beads complex for beads‐labeled cell detection is simple, automatic, and particularly suitable for beads‐based immunoassay without using fluorescence labeling.     

Molecularly imprinted beads by surface imprinting

Molecular imprinting is a state-of-the-art technique for imparting molecular recognition properties to a synthetic polymeric matrix. Conventionally, the technique is easily carried out using bulk imprinting, where molecularly imprinted polymers (MIPs) are prepared in large chunks and post-treatment processes like grinding and sieving are then required. However, this strategy tends to produce sharp-edged, irregular MIP bits with a limited scope of direct application. In addition, due to the creation of binding sites within the polymeric bulk, the issue of the hindrance of adsorbate diffusion (especially in the case of macromolecules) during template rebinding makes the MIPs prepared through this approach unsuitable for practical applications. Thus over the years, many efforts to address the limitations of conventional molecular imprinting techniques have resulted in new imprinting methodologies. Systems like suspension and precipitation polymerization, where MIPs with tunable morphologies can be prepared, have been developed. Additionally, strategies like surface imprinting have also been employed. Ultimately, both of these approaches have been combined to prepare regularly shaped surface-imprinted MIP beads. Such an approach incorporates the advantages of both methodologies at the same time. Given their desirable physical morphologies and favorable adsorption kinetics, MIPs prepared in this manner show significant promise for industrial applications. Therefore, they will be the main focus of this review.