Functionalized Monodisperse Particles with Chloromethyl Groups for the Covalent Coupling of Proteins

Sarobe, J.; Molina-Bolı́var, J.A.; Forcada, Jacqueline; Galisteo, F. Cabello; Hidalgo‐Álvarez, R.

doi:10.1021/ma9707143

Cited by 30 publications

(31 citation statements)

References 34 publications

(47 reference statements)

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“…We speculate that this difference is primarily due to electrostatic effects. The initial step of covalent attachment of lysozyme to nanoparticles involves its physical adsorption (Giacomelli et al, 2000;Molina-Bolivar and Galisteo-Gonzales, 2005;Sarobe et al, 1998;Suen and Morawetz, 1985). This adsorption is primarily determined by the interactions of the hydrophobic parts of lysozyme molecules with the hydrophobic surface of polystyrene latex.…”

Section: Resultsmentioning

confidence: 99%

Charge‐directed targeting of antimicrobial protein‐nanoparticle conjugates

Satishkumar

Vertegel

2008

Biotech & Bioengineering

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Use of antimicrobial enzymes covalently attached to nanoparticles is of great interest as an antibiotic-free approach to treat microbial infections. Intrinsic properties of nanoparticles can also be used to add functionality to their conjugates with biomolecules. Here, we show in a model system that nanoparticle charge can be used to enhance delivery and increase bactericidal activity of an antimicrobial enzyme, lysozyme. Hen egg lysozyme was covalently attached to two types of polystyrene latex nanoparticles: positively charged, containing aliphatic amine surface groups, and negatively charged, containing sulfate and chloromethyl surface groups. In the case of bacterial lysis assay with a Gram-positive bacteria Micrococcus lysodeikticus, activity of lysozyme conjugated to positively charged nanoparticles was approximately twice as large as that of free lysozyme, while lysozyme conjugated to negatively charged nanoparticles showed little detectable activity. At the same time, when assayed using a low-molecular weight oligosaccharide substrate, lysozyme attached to both positively and negatively charged nanoparticles showed slightly lower activity than free enzyme. A possible explanation of these results is that lysozyme attached to negatively charged nanoparticles cannot be effectively targeted to the bacteria because of the electrostatic Coulombic repulsion from the negatively charged bacterial cell walls, whereas lysozyme conjugated to positively charged nanoparticles was targeted better than free enzyme due to stronger electrostatic attraction to bacteria. Zeta potential measurements confirmed the validity of this hypothesis. Thus, nanoparticle charge is an important factor that can be used to control targeting and activity of protein-nanoparticle conjugates.

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Section: Resultsmentioning

confidence: 99%

Charge‐directed targeting of antimicrobial protein‐nanoparticle conjugates

Satishkumar

Vertegel

2008

Biotech & Bioengineering

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“…Functionalization of the surface with amino, epoxy and carboxyl groups allows the covalent attachment of target ligands such as proteins [1,6]. Contrary to passive adsorption, covalent immobilization provides a stable material-biomolecule conjugate and avoids nonspecific binding [27,28].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and functionalization of superparamagnetic poly- ɛ -caprolactone microparticles for the selective isolation of subpopulations of human adipose-derived stem cells

Balmayor

Pashkuleva

Frias

et al. 2011

J. R. Soc. Interface.

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There has been a growing interest in using biofunctionalized magnetic particles for cell isolation. This paper describes the synthesis and characterization of magnetite-polymer (Fe 3 O 4 -poly-1-caprolactone, magnetite-PCL) microparticles surface functionalized with amino and epoxy groups allowing easy covalent attachment of specific antibodies and subsequent ability to bind target cells. Particles with different sizes (4 -135 mm), spherical shape and superparamagnetic behaviour (magnetite content of about 13 wt%) were obtained. The functionalized microparticles presented high protein-binding capacity (coupling efficiency of 47% for epoxy-and 71% for amino-functionalized particles) with a low level of non-specific binding. We have further investigated the influence of initial protein concentration, pH, ionic strength, temperature and incubation time on the capacity of amino-functionalized particles to bind protein molecules. The results showed that maximum protein coupling is rapidly achieved ( 5 h) at pH 5.5 and low ionic strength (0.05 M NaCl). Furthermore, when cultured in direct contact with osteoblast-like cells (Saos-2) or human-derived adipose stem cells (ASCs), the amino-functionalized particles did not affect the proliferation and morphology of the cells. As a proof of principle for the application of magnetic microparticles for cell isolation, CD105 (endoglin) antibody was coupled to the magnetic particle surface to bind subpopulations of human ASCs expressing the CD105 antigen. The isolation of CD105þ ASCs from a heterogeneous cell population was confirmed by flow cytometry analysis. Given the demonstrated potential of functionalized magnetite-PCL microparticles for selective cell isolation, we expect that these particles may be further applied in immuno-magnetic cell separation owing to their versatility and ease of surface modification.

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“…Magnetic beads functionalized with chloromethyl groups are more important in applications such as magnetic separations, solid phase syntheses, immunodiagnostics, etc. Their chlorine groups are easily displaced by nucleophiles to produce anion exchange polymers, solid state synthesis (Merrifield) resins and electron beam negative resists [3][4][5][6]. Polystyrene particles functionalized with choloromethyl are produced by direct polymerization or copolymerization of commercial chloromethyl styrene via bulk, solution, emulsion, and suspension polymerization [7].…”

Section: Introductionmentioning

confidence: 99%