Effect of reaction parameters on the dispersion polymerization of 1-vinyl-2-pyrrolidone

Horák, Daniel; Krystufek, Miloslav; Spěváček, Jiří

doi:10.1002/(sici)1099-0518(20000201)38:3<653::aid-pola29>3.0.co;2-p

Cited by 58 publications

(12 citation statements)

References 25 publications

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“…Light scattering measurements, shown in Figure 2(B), indicate that the diameter and size distribution of the γ‐Fe 2 O 3 ‐HAS∼rFVIIa nanoparticles are 116 ± 14 nm. The difference in the diameters measured by TEM and light scattering is due to the fact that the first method measures the dry diameter of the bioactive nanoparticles, while the second one measures the hydrodynamic diameter, which takes into account the surface adsorbed solvent molecules as well as the swelling of the particles by the solvent 42. The dry and hydrodynamic diameters of the “naked” γ‐Fe 2 O 3 nanoparticles are 15.0 ± 2.1 and 103 ± 26 nm, respectively.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of recombinant factor VIIa‐conjugated magnetic iron oxide nanoparticles for hemophilia treatment

Shafir

Galperin

Margel

2008

J Biomedical Materials Res

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Maghemite (gamma-Fe(2)O(3)) nanoparticles of 15.0 +/- 2.1 nm in diameter were prepared by nucleation, followed by controlled growth of magnetic iron oxide thin films onto gelatin nuclei. Functionalization of these magnetic nanoparticles with activated double bonds was accomplished by interacting divinyl sulfone with the gelatin coating of the gamma-Fe(2)O(3) nanoparticles. The activated double bonds were then used for covalent binding, via Michael addition reaction, of recombinant factor VIIa and human serum albumin to the surface of these nanoparticles. Recombinant factor VIIa was also physically bound to the magnetic nanoparticles by interacting this factor with the human serum albumin conjugated gamma-Fe(2)O(3) nanoparticles. The influence of factor VIIa concentration on the immobilization yield has been elucidated. Leakage of the bound factor VIIa into PBS containing 4% albumin was insignificant. The coagulant activity of the physically adsorbed recombinant factor VIIa was similar to that of the free one and was significantly better than that of the covalently bound. The blood half-life of free factor VIIa is short, about 2-3 h, because of digestion by proteolytic enzymes and inhibitory effects. Stabilization of factor VIIa against trypsin (a model proteolytic enzyme) and chloromethyl ketone-type inhibitor was accomplished by conjugation of the factor to the gamma-Fe(2)O(3) nanoparticles. This stabilization may extend the blood half-life of factor VIIa. Therefore, IV injection of factor VIIa conjugated gamma-Fe(2)O(3) nanoparticles instead of free factor may avoid the frequent dosing and reduce the cost of hemophilia treatment.

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Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of recombinant factor VIIa‐conjugated magnetic iron oxide nanoparticles for hemophilia treatment

Shafir

Galperin

Margel

2008

J Biomedical Materials Res

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“…The compositions of polymerization mixtures are summarized in Table I. As an initiator, 2,2′‐azobisisobutyronitrile (AIBN) at concentration 1 wt% relative to monomers was used, with the exception of VP polymerization, for which 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) was preferred 19. The thickness of the slab was adjusted with a 3‐mm‐thick silicon rubber spacer between the Teflon plates, which were covered with cellophane to facilitate removal of the slab after polymerization.…”

Section: Methodsmentioning

confidence: 99%

CD4+CD28− T cell expansion in granulomatosis with polyangiitis (Wegener's) is driven by latent cytomegalovirus infection and is associated with an increased risk of infection and mortality

Morgan

Pachnio

Begum

et al. 2011

Arthritis & Rheumatism

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Objective. Expanded populations of CD4؉ CD28؊ T cells with a cytotoxic phenotype have been repeatedly reported in patients with granulomatosis with polyangiitis (Wegener's) (GPA). In healthy individuals expansion of this T cell population follows cytomegalovirus (CMV) infection. We undertook this study to investigate whether CMV infection may be responsible for driving the expansion of CD4؉CD28؊ T cells in GPA patients and how this might relate to clinical features.Methods. Forty-eight GPA patients and 38 agematched healthy donors were included in the study. CMV-specific IgG in serum was detected by enzymelinked immunosorbent assay. Flow cytometric analysis was used to study T cell populations and phenotype. The presence of CMV in renal biopsy tissue from GPA patients was investigated by immunohistochemistry and polymerase chain reaction (PCR). Clinical information was obtained from patient records.Results. Populations of CD4؉CD28؊ T cells were only expanded in CMV-seropositive GPA patients and controls. In CMV-seropositive GPA patients we observed negative correlations between the percentages of CD4؉CD28؊ T cells and both the percentage of naive T cells and the glomerular filtration rate at presentation. There was a significant association between the percentage of CD4؉CD28؊ T cells and risk of infection and mortality. CMV could not be detected in renal tissue by PCR or immunohistochemistry. CMV seropositivity itself was not a risk factor for infection in a cohort of 182 patients with antineutrophil cytoplasmic antibody-associated vasculitis who had been recruited into clinical trials performed by the European Vasculitis Study Group.Conclusion. The expansion of CD4؉CD28؊ T cells in GPA patients is associated with CMV infection and leads to a reduction in the number of naive T cells in peripheral blood. Patients with expanded CD4؉CD28؊ T cells have significantly increased mortality and risk of infection.

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“…The hydrophilic nature of the particles probably creates hydrogen bonds with water molecules that significantly enlarge the diameter. 29,30 The FTIR spectrum of the monomer demonstrates absorption peaks at 3629 and 1402 cm À1 corresponding to vibration and stretching bands of the hydroxyl group, respectively; a broad absorption peak at 1690-1600 cm À1 corresponding to the double bond stretching band and the OH bending modes; 31 1507 cm À1 corresponding to the aromatic ring stretching band; 1252 cm À1 corresponding to the phosphorus-oxygen double bond stretching band (P¼ ¼O); 1174 and 1093 cm À1 corresponding to antisymmetric stretching bands of the phosphorus group (PO À 3 ); 970 and 918 cm À1 corresponding to symmetric stretching bands of the phosphorus group (PO À 3 ); 827 cm À1 corresponding to the vibration bend of the para-di-substitute aromatic ring; 742 cm À1 corresponding to the carbon-phosphorus stretching band and 632, 552, and 462 cm À1 corresponding to the phosphorus group bends (PO À 3 ). 32 The FTIR spectrum of the crosslinked PStBP particles demonstrates broad absorption peaks similar to those of the monomer, especially for the hydroxy groups at 3200-3600, 1600-1690, and 1400-1480 cm À1 , and for the phosphonate groups at 1250, 1179, 1010, and 573 cm À1 .…”

Section: Synthesis Of the Crosslinked Pstbp Microparticlesmentioning

confidence: 99%

Synthesis and characterization of hydroxy‐bisphosphonate micrometer‐sized particles by dispersion polymerization of a new styrylbisphosphonate monomer

Chen

Goldshtein

Margel

2013

J. Polym. Sci. A Polym. Chem.

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Bisphosphonates (BPs) are nonhydrolyzable pyrophosphate (P‐O‐P) analogs possessing two phosphonate groups linked to a single carbon (P‐C‐P). The hydroxy‐bisphosphonates (hydroxyBPs) are obtained when the hydroxy group is also linked to this bridging carbon. Their ability to form bidentate or tridentate chelates with calcium ions results in a high affinity to hydroxyapatite (HAP) in dentin, enamel and bones. In this study, we designed and prepared crosslinked poly(styrylbisphosphonate) (PStBP) micrometer‐sized particles by dispersion polymerization of the styrylbisphosphonate (StBP) and ethylene glycol dimethacrylate (EDMA) monomers. The new StBP monomer was synthesized in an efficient one‐pot synthesis using tris(trimethylsilyl)phosphite as the phosphorus source followed by methanolysis. The StBP monomer was successfully isolated and characterized as tri‐sodium salt. Polymerization of the StBP monomer was carried out in two steps: in situ conversion of the tri‐sodium StBP monomer back to its acid form, followed by radical dispersion polymerization in the presence of the crosslinker EDMA monomer. The resulting crosslinked PStBP micrometer‐sized particles retained the unique high affinity of the hydroxy‐bisphosphonate side groups to calcium ions and exhibited good adhesive properties to HAP. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

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Effect of reaction parameters on the dispersion polymerization of 1-vinyl-2-pyrrolidone

Cited by 58 publications

References 25 publications

Synthesis and characterization of recombinant factor VIIa‐conjugated magnetic iron oxide nanoparticles for hemophilia treatment

Synthesis and characterization of recombinant factor VIIa‐conjugated magnetic iron oxide nanoparticles for hemophilia treatment

CD4+CD28− T cell expansion in granulomatosis with polyangiitis (Wegener's) is driven by latent cytomegalovirus infection and is associated with an increased risk of infection and mortality

Synthesis and characterization of hydroxy‐bisphosphonate micrometer‐sized particles by dispersion polymerization of a new styrylbisphosphonate monomer

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