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Abstract: Surface imprinting and adopting a nano-sized physical form are two effective approaches to overcome the template transfer difficulty within molecularly imprinted polymers and in particular advantageous to the imprinting of macromolecular structures like proteins. The surface protein-imprinted nanoparticles based on these two strategies are attractive for biosensor development. We here demonstrate a facile way for imprinting protein over nanoparticle supports. It was achieved simply via radical induced graft copolymerization of low concentration monomers on the surface of vinyl modified silica nanoparticles dispersed in aqueous media with lysozyme as a model protein. With a total monomer concentration of 0.4wt%, less than tenth that employed conventionally, the possible gelation of the dispersion after polymerization was avoided and hence the unagglomerated imprinted particles could be readily collected. It was proved that thin polymer shells with imprinted sites had been formed over the support particles. In batch rebinding tests, the imprinted particles reached saturated adsorption within 5min and exhibited significant specific recognition toward the template protein. The presented approach may be a versatile way for the fabrication of surface protein-imprinted nanoparticles via rational design of the surface chemistry of the support particles and choice of functional monomers according to the properties of the print protein. [ABSTRACT FROM AUTHOR]

Abstract: A graft copolymerization of acrylamide with N,N′-methylenebisacrylamide on chitosan in aqueous medium was utilized in the synthesis of molecularly imprinted polymer (MIP) gels using bovine serum albumin (BSA) as a template. The effect of the amount of initiator and the molecular weight and amount of chitosan on BSA rebinding was investigated. It was found that the resultant MIP gels based on chitosan-g-polyacrylamide (CS-g-PAM) showed significantly higher imprinting efficiency than those only consisting of polyacrylamide (PAM), and also better than those composed of chitosan/PAM semi-interpenetrating polymer network (CS/PAM-s-IPN). The batchwise adsorption of BSA and some non-template proteins showed that the CS-g-PAM based MIP gels demonstrated a quite significant template binding capacity different from the non-imprinted polymer (NIP) gels, and an obvious binding specificity for BSA. The adsorption isotherms of BSA on the MIP gels were determined and well fitted by a Langmuir model with a maximum binding capacity of 39.49mg/g wet gels. The adsorption kinetics was analyzed by a linear driving force mass-transfer model. The MIP gels also showed much better stability in rebinding of the imprint molecules than those based on CS/PAM-s-IPN after three adsorption–regeneration cycles. [Copyright &y& Elsevier]

Poly(acrylic acid) (PAA)-grafted cellulose copolymer beads were synthesized and tested in vitro as an adsorbent for selective removal of low-density lipoprotein (LDL) from human plasma. The copolymers were prepared by graft copolymerization of acrylic acid (AA) onto porous cellulose beads using cerium ammonium nitrate (CAN) as an initiator. The effect of initiator concentration, monomer amount and reaction time on the grafting was examined, and it revealed that the extent of grafting could be controlled by setting the appropriate reaction conditions. In vitro batch-wise adsorption tests were conducted to evaluate the lipoprotein sorption properties of the resulted copolymer beads, and the effect of grafting conditions on the adsorption performance was investigated. It was shown that the binding capacities of the best adsorbent derived from the appropriate reaction conditions could reach 4.96 mg/g total cholesterol (TC) and 4.46 mg/g LDL cholesterol (LDL-C) from human plasma, respectively, without significantly affecting the contents of beneficial constitutes such as high-density lipoprotein (HDL) and total proteins (TP). The influences of plasma amount and adsorption period on the adsorption properties were also determined and analyzed. It appears that this kind of copolymer is worthy of being developed as an alternative LDL adsorbent. [ABSTRACT FROM AUTHOR]

Abstract: Porous chitosan beads bearing poly(acrylic acid) (PAA) were prepared, and then tested as hemoperfusion adsorbents for selective removal of low density lipoprotein (LDL) in plasma. Macroporous chitosan beads were formed through phase inversion technique and cross-linked with ethyleneglycol diglycidylether (EGDE). Heterogeneous graft copolymerization of acrylic acid (AA) onto the cross-linked beads was carried out with ammonium persulfate (APS) as an initiator. FTIR spectral analyses confirmed the successful grafting, and environmental scanning electronic microscopy (ESEM) observation showed the decrease of the pore size across the beads with increasing PAA grafting percentage. The effect of reaction conditions, such as temperature, time and the concentrations of the monomer and the initiator, on PAA grafting percentage and efficiency was investigated in detail. The results revealed that the amount of PAA contained in the resultant copolymer beads could be readily controlled by adjusting the reaction variables. The plasma lipoprotein sorption tests showed that the introduction of PAA onto the cross-linked chitosan beads could greatly improve both their LDL binding capacity and selectivity. The lipoprotein sorption performance exhibited direct dependence on the PAA grafting percentage. Therefore, the properly prepared PAA-grafted beads might have potential application in selective removal of LDL by hemoperfusion. [Copyright &y& Elsevier]

Chitosan beads carrying various amino acids (a total of 12 kinds) were synthesized through quite simple procedures for selective removal of low density lipoprotein (LDL). Macroporous chitosan beads were prepared by the phase-inversion method, to which the amino acids were then coupled respectively, via either ethyleneglycol diglycidylether (EGDE) or epichlorohydrin (ECH). Among the amino acids used, in vitro tests proved L-Trp to be the best ligand for binding LDL. The adsorbent, which was prepared by coupling L-Trp to the chitosan beads via EGDE, demonstrated satisfactory adsorption performance for selective removal of LDL in human plasma. [ABSTRACT FROM AUTHOR]

Reports on the synthesis of an adsorbent with good adsorption performance for binding low density lipoproteins (LDL) through a simple preparation procedure. Use of the phase-inversion technique to form macroporous chitosan beads; Coupling of tryptophan to the epoxy-activated beads; Satisfactory adsorption capacity and selectivity for LDL.

Surface protein imprinting over nano- or micron-sized substrates is an effective approach for improving the biomacromolecule mass transfer and rebinding capacity. For achieving high recognition performance, it is necessary to introduce certain functional groups onto the surface of the support materials which can interact with the template protein. Herein, we report a surface protein imprinting approach using a new kind of core–shell magnetic chitosan submicrospheres as the supports. The surface of these magnetic chitosan particles is tethered with uncross-linked chitosan chains, hence bearing plenty of amino and hydroxyl groups, where a large amount of functional ligands can be readily coupled for capturing of the protein template. With lysozyme as a model print protein, the magnetic supports were functionalized with maleic acid and then coated with imprinted polymer layers. The resulting imprinted microspheres show significantly selective rebinding for lysozyme. In particular, they exhibit a specific rebinding capacity about three times higher than achieved with our previous lysozyme-imprinted particles synthesized in similar way but with maleic acid modified silica nanoparticles as the supports. This can be attributed to the much higher template binding capacity to the modified magnetic chitosan submicrospheres. Also, the resultant imprinted particles can be easily collected by a magnet. Therefore, such kind of chitosan submicrospheres may be a versatile carrier for constructing high-capacity and magnetically recyclable surface protein-imprinted particles. [ABSTRACT FROM AUTHOR]

As artificial receptors for protein recognition, epitope-imprinted polymers combined with fluorescence sensing based on quantum dots (QDs) can be potentially used for biological analysis and disease diagnosis. However, the usual way for fabrication of QD sensors through unoriented epitope imprinting is confronted with the problems of disordered imprinting sites and low template utilization. In this context, a facile and efficient oriented epitope surface imprinting was put forward based on immobilization of the epitope templates via thiol-disulfide exchange reactions. With N-succinimidyl 3-(2-pyridyldithio)-propionate (SPDP) as a heterobifunctional reagent, cysteine-modified epitopes of cytochrome c were anchored on the surface of pyridyl disulfide functionalized silica nanoparticles sandwiching CdTe QDs. After surface imprinting via a sol-gel process, the epitope templates were removed from the surface-imprinted layers simply by reduction of the thiol-disulfide, affording oriented epitope-imprinted sites. By this method, the amount of epitope templates was only 1/20 of traditionally unoriented epitopes. The resulting sensors demonstrated significantly enhanced imprinting performance and high sensitivity, with the imprinting factor increasing from 2.6 to 3.9, and the limit of detection being 91 nM. Such epitope-oriented surface-imprinted method may offer a new design strategy for the construction of high-affinity protein recognition nanomaterials with fluorescence sensing. [Display omitted] • Oriented epitope-imprinted polymers combined with fluorescence sensing. • Grafted epitope surface imprinting by thiol–disulfide exchange reaction. • Significant reduction in epitope template usage for epitope-imprinted polymers. • Great increase in the imprinting factor of the protein imprinted polymers. • Significantly enhanced fluorescence detection of proteins in fluorescence sensors. [ABSTRACT FROM AUTHOR]

Fe3O4 nanoparticles, used as peroxidase mimetics, exhibit splendid future in the biomedical field. However, the functionalization on Fe3O4 nanoparticles always goes with the loss of superparamagnetism and decrease in peroxidase-activity. Here, we synthesized green polyethylene glycol (PEG)-functionalized magnetic/N-trimethyl chitosan (CS) hybrid nanoparticles (Fe3O4@PAA/TMC/PEG NPs) with improved water dispersibility, superparamagnetism, high saturation magnetization and well peroxidase-like activity. The functionalized coating was divided in two steps, one involved a cross-linked PEG/PAA/CS middle layer to protect the nanocrystal Fe3O4 from oxidization, the other was a hydrophilic PEG/TMC outer layer improving the water dispersion, biocompatibility, as well as supplying positive quaternary ammonium groups for a potential increase of cell binding efficiency. The structure, composition and morphology of Fe3O4@PAA/TMC/PEG NPs were characterized by TEM, FT-IR spectroscopy, DLS, zeta potential measurement, respectively. Thermal performance was characterized by TGA, and the peroxidase-like mimics activity was tested by TMB·2HCl colour development experiments. The magnetic property of the as-prepared hybrid nanoparticles was first confirmed by VSM, and then proved by the bacterial pathogens adsorption, especially at ultralow pathogen concentration. Particularly, with an external magnet, the Fe3O4@PAA/TMC/PEG NPs, combined cationic quaternary ammonium groups and peroxidise-mimetic catalytic activity, were tested for antibacterial effect by plating method. [ABSTRACT FROM AUTHOR]

High recognition selectivity has been the main object in developing protein-imprinted materials. Here, we demonstrate a novel strategy for the controlled synthesis of PEGylated surface protein-imprinted nanoparticles with reduced nonspecific binding, which is based on sequential two steps of surface-initiated reversible addition–fragmentation chain transfer aqueous precipitation polymerization (SI-RAFT APP). Click chemistry was employed to construct hydrophilic nanocores with both high-density RAFT chain transfer agents and template-capturing groups. Through the first-step SI-RAFT APP, protein-imprinted nanoshells were formed over the nanocores using lysozyme as a model template. By the second-step SI-RAFT APP, nonlinear PEG chains were grafted from the core–shell imprinted nanoparticles before the removal of the template. Both the thickness of the imprinted nanoshells and the length of the grafted chains could be readily controlled by the polymerization time. Thus the obtained PEGylated core–shell particles exhibited greatly improved template binding selectivity compared with the non-PEGylated controls, typically with the imprinting factor increasing from 2.1 to 9.1. Meanwhile, the PEGylation process did not impair but significantly enhance the protein binding capacity. The generality of the established approach was preliminarily proved by imprinting another template protein, bovine hemoglobin. This work represents the first example for the controlled synthesis and post-imprinting functionalization of surface protein-imprinted nanoparticles via SI-RAFT polymerization. [ABSTRACT FROM AUTHOR]

Abstract: Surface molecular imprinting over functionalized nanoparticles has proved to be an effective approach for construction of artificial nanomaterials for protein recognition. Herein, we report a strategy for synthesis of core–shell protein‐imprinted nanoparticles by the functionalization of nano‐cores with ionic liquids followed by aqueous precipitation polymerization to build thermo‐responsive imprinted polymer nano‐shells. The immobilized ionic liquids can form multiple interactions with the protein template. The polymerization process can produce thermo‐reversible physical crosslinks, which are advantageous to enhancing imprinting and facilitating template removal. With bovine hemoglobin as a model template, the imprinted nanoparticles showed temperature‐sensitivity in both dispersion behaviors and rebinding capacities. Compared with the ionic‐liquid‐modified core nanoparticles, the imprinted particles exhibited greatly increased selectivity and two orders of magnitude higher binding affinity for the template protein. The imprinted nanoparticles achieved relatively high imprinting factor up to 5.0 and specific rebinding capacity of 67.7 mg/g, respectively. These nanoparticles also demonstrated rapid rebinding kinetics and good reproducibility after five cycles of adsorption–regeneration. Therefore, the presented approach may be viable for the fabrication of high‐performance protein‐imprinted nanoparticles with temperature sensitivity. [ABSTRACT FROM AUTHOR]

The double-shelled hollow polymer microspheres with a carboxylic acid in the inner shell and palladium metallic nanocolloids in the outer shell were prepared as a bi-functional catalyst for a tandem reaction including deacetalization on-hydrogenation from benzaldehyde dimethyl acetate to benzyl alcohol. The double-shelled hollow poly(ethyleneglycol dimethacrylate- co -acrylic acid) (PAA) and poly(ethyleneglycol dimethacrylate- co - N -vinyl pyrrolidone) (PNVP) microspheres were synthesized by a two-stage refluxing precipitation copolymerization in presence of 3-(trimethoxysilyl) propyl methacrylate (MPS)-modified silica as seeds to get SiO 2 /P t -BA/SiO 2 /PNVP tetra-layer microspheres with the subsequent hydrolysis of t -butyl ester to acid group and selective removal of the silica inner core and the sandwiched third layer. The palladium nano-colloids in outer-shell were prepared by the in-situ ethanol reduction of Pd(II) after the coordination of palladium acetate with N -pyrrolidone (NVP) groups in presence of SiO 2 /P t -BA/SiO 2 /PNVP tetra-layer microspheres as stabilizers. [Display omitted] [ABSTRACT FROM AUTHOR]

Researches on protein molecularly imprinted polymers have been challenged by the difficulties in facilitating biomacromolecular transfer, in particular upon the template removal step, and enhancing their recognition performance. Addressing these issues, herein we report synthesis of core–shell structured surface protein-imprinted nanoparticles with reversible physical cross-links formed in the imprinted nanoshells. The imprinted layers over nanoparticle supports are fabricated via aqueous precipitation polymerization (PP) of di(ethylene glycol) methyl ether methacrylate (MEO 2 MA), a thermo-responsive monomer bearing no strong H-bond donor, and other functional and cross-linking monomers. During polymerization, physical cross-links together with chemical cross-links are in site produced within the imprinted shells based on hydrophobic association among the PMEO 2 MA, favoring formation of high-quality imprints. While cooled appropriately below the polymerization temperature, these physical cross-links can be dissociated rapidly, thus facilitating removal of the embedded template. For proof of this concept, lysozyme-imprinted nanoparticles were synthesized at 37 °C over the nanoparticles functionalized with carboxylic and vinyl groups. The template removal from the imprinted nanoparticles was readily achieved by washing with a dilute acidic detergent solution at 4 °C. As-prepared imprinted nanoparticles showed greatly higher imprinting factor and specific rebinding than obtained with the same recipe but by solution polymerization (SP). Moreover, such imprinted nanomaterials exhibited satisfactory rebinding selectivity, kinetics and reusability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface imprinting of proteins over carbon dots anchored SiO 2 nanoparticles. • Configuring sandwich-structured template pre-assemble. • Performing post-imprinting modification. • The imprinted nanoparticles showed significantly enhanced fluorescence response. Molecularly imprinted polymers combined with fluorescence sensing show potential application in biological analysis and diseases diagnosis. We illustrate a versatile strategy for synthesis of surface protein-imprinted nanoparticles via sandwich-structured template pre-assemble and post-imprinting modification (PIM) for enhanced fluorescence detection. Carbon dots anchored SiO 2 nanoparticles are surface modified with both disulfanylpropanoic acid and vinyl groups. By amide linkage to the carboxyl terminals, protein templates are immobilized to the nanoparticles, and subsequently allowed to bind with functional monomers via strong interactions such as metal coordination and enzyme–inhibitor association. The sandwiched protein templates are surface imprinted by free radical copolymerization with other monomers. The templates are then removed from the imprinted shells by reduction of the disulfide bonds. The derived thiol groups are used for PIM of the imprinted cavities with carboxyl groups capable of electrostatic interaction with the protein rebound. For proof of concept, human serum albumin (HSA) was firstly used as a model template for surface imprinting. It was shown that binding of a Cu2+-chelating monomer to the immobilized HSA and the subsequent PIM could elevate the imprinting factor from 1.6 to 4.1 and further to 7.6, respectively. The final imprinted nanoparticles exhibited a low limit of detection of 9.8 nM and satisfactory recoveries ranging from 98.1 to 102.0% for measuring HSA in diluted human serum samples. This strategy was further confirmed by using trypsin, a typical serine protease, as another protein template, with both the Cu2+-chelating monomer and an enzyme inhibitor monomer binding to the surface coupled template. [ABSTRACT FROM AUTHOR]

Molecular imprinting as a facile and promising separation technique has received considerable attention because of their high selectivity for target molecules. In this study, we imprinted lysozyme (Lys) on the surface of core–shell magnetic nanoparticles via surface imprinting. The magnetic supports were functionalized with maleic acid and then coated with imprinted polymer layers. The structure and morphology of the resulting magnetic imprinted nanoparticles were characterized by transmission electron microscopy, scanning electron microscope, dynamic light scatting, vibrating sample magnetometer, and thermogravimetric analysis. Binding experiments were carried out to evaluate the properties of magnetic molecularly imprinted polymers (magnetic MIPs) and magnetic non-molecularly imprinted polymers (magnetic NIPs). The protein adsorption results showed that the magnetic MIPs had significant specific recognition toward the template protein and could be easily separated from solution by an external magnetic field. Moreover, the MIPs exhibited fast kinetics for the rebinding of the target protein due to the thin-imprinted layer and showed good reusability by four adsorption–desorption cycles. Therefore, the surface imprinting approach combined with magnetic nanoparticles provided an easy and fast method for the specific recognition of Lys. [ABSTRACT FROM PUBLISHER]

Highly magnetic polymer submicrospheres with a hairy core–shell structure were facilely synthesized by combining distillation–precipitation polymerization (DPP) with subsequent surface-initiated atom transfer radical polymerization (SI-ATRP), and then investigated for protein adsorption. A robust polymer shell consisting of poly(divinylbenzene- co -chloromethylstyrene) (P(DVB- co -CMS)) was coated on superparamagnetic submicrometer-sized magnetite colloid nanocrystal clusters (MCNCs) via DPP. With the benzyl chloride groups on the shell as initiator, poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) hairs were grafted by SI-ATRP approach. The resulting hairy core–shell structured Fe 3 O 4 @ P(DVB- co -CMS)–PDMAEMA microspheres showed pH- and temperature-sensitivity, and high-magnetization. The composite microspheres were further investigated for adsorption of a typical acidic protein, i.e. bovine serum albumin (BSA). They exhibited a high binding capacity up to over 660 mg/g (corresponding to 158 DMAEMA monomer units cooperating for binding one BSA molecule) and could rapidly reach binding equilibrium within 5 min. Moreover, the adsorption of BSA was found to be remarkably dependent on the pH and salt concentration of the protein solutions, and the bound protein could be quantitatively desorbed by washing with a medium with lowered pH or raised salt concentration. [ABSTRACT FROM AUTHOR]

Abstract: Molecularly imprinted polymers against proteins are regarded as promising substitutes for natural antibodies, but have been frustrated with the problems including reduced interaction between functional monomers and protein template in the aqueous media required during their synthesis and restricted mass transfer across the resulting crosslinked polymer matrixes. For addressing these issues, herein we proposed a strategy for imprinting of a protein on the surface of nanoparticles using a metal chelating monomer. With lysozyme as a model protein template and Cu2+ chelating N-(4-vinyl)-benzyl iminodiacetic acid as the coordination monomer along with other monomers, protein imprinted polymer nanoshells were formed over vinyl-modified silica nanoparticles via surface polymerization in high-dilution monomer solution. The feed concentration of the crosslinking monomer was optimized toward achieving the best imprinting effect. Compared with the related imprinted materials reported previously, the resultant core–shell imprinted particles showed greatly faster binding kinetics, elevated rebinding capacity and selectivity. More importantly, noticeably high binding affinity was achieved with an estimated dissociation constant of 4.1×10−8 M which is comparable to that of conventional antibodies [Copyright &y& Elsevier]

Highlights: [•] Great improvement of the recently proposed method. [•] Facile tuning the imprinted layer thickness by varying crosslinking degrees. [•] Effectively maximizing the imprinting efficacy by varying crosslinking degrees. [•] Rather high imprinting factor and specific binding, and rapid binding kinetics. [Copyright &y& Elsevier]

Abstract: Submicron-sized superparamagnetic magnetite colloid nanocrystal clusters (MCNCs) composed of many interconnected tiny Fe3O4 nanoparticles provide a new avenue for constructing highly magnetic polymer submicrospheres for biotechnological and medical applications. Herein, a facile and efficient method is described for the synthesis of Fe3O4@poly(methacrylic acid) (PMAA) core–shell submicrospheres using the MCNCs modified with polymerizable vinyl groups as the submicronic cores. The controlled encapsulation of the MCNCs with PMAA shells was achieved via precipitation polymerization mediated by a reversible addition–fragmentation chain transfer (RAFT) agent. A variety of factors influencing the formation of PMAA layers were examined, such as the loading amounts of the magnetic seeds and monomers, polymerization time, and the MCNCs’ surface chemistry. Compared with previous approaches, much higher seed dosage could be employed in the polymerization system without leading to significant particle conglutination. The shell thickness was readily tailored via varying two synthesis parameters, that is, monomer dosage and reaction time. The resulting hybrid particles showed high saturation magnetization and pH responsiveness. Also, this method was successfully extended to coating other hydrophilic polymer shells over the MCNCs and hence may be a general way for the synthesis of magnetic polymer submicrospheres. [Copyright &y& Elsevier]

Abstract: Fe3O4@polydivinylbenzene (PDVB) submicrospheres were prepared via distillation–precipitation polymerization of DVB in the presence of submicron magnetite colloid nanocrystal clusters (MCNCs) as seeds. The surface of the MCNCs was modified with vinyl groups before PDVB encapsulation. The resulting Fe3O4@PDVB particles showed a well-defined core–shell structure, and the shell thickness could be readily controlled by the DVB dosage. A lowly cross-linked poly(methacrylic acid) (PMAA) layer could be further coated onto the highly cross-linked PDVB shell via a second-stage DPP process, suggesting the presence of residual vinyl groups on the surface of the Fe3O4@PDVB particles. The hybrid particles showed rather high magnetization and near superparamagnetism, hence capable of easy magnetic separation. [Copyright &y& Elsevier]

Molecularly imprinted polymers endowed with photo-luminescent properties have attracted wide research interest in many fields such as biological analysis and diseases diagnosis. Herein, we illustrate a versatile method for the construction of surface protein-imprinted nanoparticles based on metal coordination and anchored carbon dots (CDs) for enhanced fluorescence detection of the target protein. As the fluorescent nanosupports for surface imprinting, CDs-attached SiO 2 nanoparticles were synthesized via thiol–ene click chemistry. With histidine (His)-exposed protein as templates, imprinted nanoshells were formed over the nanosupports via copolymerization of a Cu2+-chelating monomer and an oligo (ethylene glycol) monomer, hence producing high-quality imprinted cavities because of both the relatively strong coordination and inhibited non-specific binding. Using lysozyme as a model His-exposed template, the imprinted nanoparticles showed fluorescence enhancement while binding the target protein, and exhibited significantly increased specific fluorescence response than the controls without the metal coordination. They achieved a high imprinting factor of 5.8 and a low limit of detection of 10.1 nM. Furthermore, such sensors were applied to determine lysozyme in diluted chicken egg-white samples with satisfactory recoveries at three spiking levels ranging from 97.9 to 101.4%. Human serum albumin was also used as another template protein for preliminary confirming the generality of the presented strategy. [Display omitted] • Synthesis of carbon dots anchored SiO 2 nanoparticles via thiol-ene click reaction. • Surface imprinting of proteins over these fluorescence nanocores. • Combining use of Cu2+-chelating and OEG monomers to enhance fluorescence detection. • Protein-imprinted nanoparticles showing "turn-on" fluorescence response. [ABSTRACT FROM AUTHOR]

Poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) homopolymers with low polydispersities were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization. The performances of two chain transfer agents, 2‐cyanoprop‐2‐yl dithiobenzoate and 4‐cyanopentanic acid dithiobenzoate (CPADB), were compared. It was found that the polymerization of 2‐(diethylamino) ethyl methylacrylate was under good control in the presence of CPADB with 4,4′‐azobis(4‐cyanopentanoic acid) (ACPA) as initiator in 1,4‐dioxane at 70 °C. The kinetic behaviors were investigated under different CPADB/ACPA molar ratios. A long polymerization inhibition period was observed at high [CPADB]/[ACPA] ratio. The influences of [CPADB]/[ACPA] ratio, monomer/[CPADB] ratio, and temperature were studied with respect to monomer conversion, molecular weight control, and polydispersity index (PDI). The PDI decreased from 1.21 to 1.12, as the CPADB/ACPA molar ratio changed from 2 to 10. The molecular weight of PDEAEMA could be controlled by monomer/CPADB molar ratio. The control over MW and PDI was improved as the temperature increased from 60 to 70 °C; however, an additional increase to 80 °C led to a loss of control. Using PDEAEMA macroRAFT agent, pH/thermo double‐responsive block copolymers of PDEAEMA and poly(N‐isopropylacrylamide) (PDEAEMA‐b‐PNIPAM) with narrow polydispersity (PDI, 1.24) were synthesized. The lower critical solution temperature of PDEAEMA‐b‐PNIPAM block copolymer depended on the environmental pH. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3294–3305, 2008 [ABSTRACT FROM AUTHOR]

Abstract: Well-defined poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) brushes with high density were synthesized on the surface of polystyrene latex by atom transfer radical polymerization (ATRP) using acetone/water as the solvent and CuCl/CuCl2/bpy as the catalyst. It was found that the polydispersity of PDMAEMA brushes decreased with the increasing external CuCl2 concentration. The polymer brushes showed their lower critical solution temperature (LCST) at 31 and 33°C under pH values of 10.0 and 8.0, respectively. Dynamic light scattering studies demonstrate that PDMAEMA brushes were pH- and salt-responsive. PDMAEMA domains were used as the nanoreactors to generate gold nanoparticles on the surface of colloid particles. TEM results indicate that monodispersed gold nanoparticles were obtained. These gold composite nanoparticles displayed effective catalytic activity in the reduction of 4-nitrophenol by NaBH4. [Copyright &y& Elsevier]

Abstract: Well-defined poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) brushes were synthesized on the surface of polystyrene latex particles by atom transfer radical polymerization (ATRP). It was found that the surface-initiated polymerization of DMAEMA catalyzed by CuCl/CuCl2/bpy was under good control in the solvent of acetone/water at ambient temperature (35 °C). High-density PDMAEMA brushes with low polydispersity (PDI 1.21) were obtained. TEM results demonstrate that the PDMAEMA-grafted particles have core–shell structure. Dynamic light scattering studies indicate that the particles with PDMAEMA brushes are both pH and temperature responsive. [Copyright &y& Elsevier]

By using the agar beads as the support, L-lysine as the ligand, three kinds of absorbents with different spacers for removal of endotoxin were prepared. The adsorption capacity of three adsorbents was compared. Among them, Ag3, with L-lysine ligand and hexamethylendiamine as the spacer, was the best in adsorption capacity and was selected for hemoperfusion on rabbits. The results showed the level of endotoxin in endotoxemia rabbit after hemoperfusion was near normal level. The clearance percentage of endotoxin was 73.6% [ABSTRACT FROM AUTHOR]

Epitope imprinting has proved to be an effective way for fabricating artificial receptors for protein recognition. Surface imprinting over sacrificial supports is particularly favorable for generating high-quality epitope-imprinted cavities, but obtaining nanomaterials by this way is still a challenge. Herein, we propose a method for the synthesis of oriented surface epitope-imprinted open-mouthed polymer nanocapsules (OM-MIP NCs) by sacrificing asymmetric template-modified Janus nanocores. Amine/aldehyde functionalized SiO 2 Janus nanoparticles were prepared via the molten-wax-in-water Pickering emulsion approach, an easy scale-up technique. Epitope templates and vinyl groups were coupled to the aldehyde-bearing major side, whereas polyethylene glycol (PEG) chains were grafted to the amine-modified side. Incomplete imprinted shells were then generated principally on the non-PEGylated side via aqueous precipitation polymerization, hence affording OM-MIP NCs after etching the SiO 2 nanocores. With a C-terminus nonapeptide of bovine serum albumin (BSA) chosen as a model epitope and polymerizable carbon dots added to the pre-polymerization solution, fluorescent OM-MIP NCs were synthesized for sensing of BSA. Such NCs reached maximal fluorescent response within 15 min, greatly faster than the closed imprinted NCs within 130 min, proving good accessibility of their inner-surface imprinted cavities thanks to the open mouths. Furthermore, they showed excellent target protein detection performance, with an imprinting factor of 7.8, a limit of detection of 43.8 nM and a linear range of 0.2–6 μM. The recoveries in bovine serum samples at four spiking levels ranged from 99.2 to 107.2%, with relative standard deviations of 1.2–5.9%. [Display omitted] • Surface imprinting over epitope and PEG asymmetrically modified Janus nanoparticles. • Etching the cores affording open-mouthed epitope-imprinted polymer nanocapsulates. • Oriented epitope-imprinted cavities inside the nanocapsulates were highly accessible. • The nanocapsulates showing satisfactory target protein recognition. [ABSTRACT FROM AUTHOR]

• Protein- resistant layers were grafted to protein-imprinted polydopamine coatings. • Great increase in the imprinting factor of the imprinted polymers. • No decrease in the specific binding capacity of the imprinted polymers. • Significant improvement of the stability of the imprinted polymers in acidic media. Mussel-inspired dopamine (DA) self-polymerization over a variety of substrates has become a simple but versatile approach for synthesis of surface protein-imprinted materials. However, relatively high nonspecific binding to the imprinted polydopamine (PDA) coatings has long been an open problem because of their multifunctionalities. We herein propose a facile strategy for reduction of the nonspecific adsorption by covering the imprinted PDA coatings with slightly crosslinked nonlinear poly(ethylene glycol) (PEG) layers via aqueous precipitation polymerization before template removal. Vinyl groups are introduced onto the PDA coatings via Cu2+ mediated metal coordination for facilitating surface polymerization. The Cu2+ and embedded template are removed after polymerization. For proof of hypothesis, the protein imprinted PDA coatings were formed with SiO 2 nanoparticles as representative nano-supports and lysozyme as a model protein template. Protein binding tests show that the grafted PEG layers with an optimized feed crosslinking degree can significantly enhance both recognition selectivity and specific binding capacity to the imprinted nanoparticles, typically with the imprinting factor increasing from 2.6 to 6.4. Also, the PEG layers can remarkably improve the stability of the PDA coatings in the acidic template removal solution. The presented strategy represents the first example for PEGylation of protein-imprinted PDA coatings, and may be extended for surface imprinting of other bio/organic molecules over other substrate materials. [ABSTRACT FROM AUTHOR]