Polystyrene microspheres

Here, we have demonstrated that it is possible to arrange successfully polystyrene microspheres with a diameter of 20 nm on each island (P4VP domain) of a PS-b- P4VP block copolymer film using hydrogen bonds. A 50 nm-large microsphere was rarely adsorbed to the PS-b-P4VP film. Since the present technique does not require an... 

C Vervaet, PR Byron. Polystyrene microsphere spray standards based on CFC-free inhaler technology. J Aerosol Med 13 105-115, 2000. 

Table 8 Uptake of Polystyrene Microsphere (60 nm diameter) in Rat Organs Following IV Injection... 

A report of a particle-based FPIA<56) details improvement in the limit of detection by two orders of magnitude over a conventional FPIA format for rabbit IgG, to 10 ° M. Goat anti-rabbit capture antibody (binder) is immobilized on polystyrene microspheres or colloidal gold particles, and the sample competes with a fluorescein-labeled rabbit IgG probe. The observed increase in sensitivity is apparently due to the large increase in effective mass of the binding complex. The polarization range is rather limited, though, reportedly due to low concentrations of immobilized antibodies. 

Fig. 27. Fluorescence date of Benner et al. (1980) for polystyrene microspheres that show fluorescence enhancement compared with elastic scattering theory.

Benner et al. suspended in water relatively monodisperse polystyrene microspheres, which contained a fluorescent dye, and they recorded fluorescence spectra. The spheres had a nominal diameter of 9.92 /im (with a 2% standard deviation). Figure 27 presents one of their experimental fluorescence spectra (b) together with elastic scattering spectra computed for a diameter of 9.92 /an (a) and for 9.99 fim (c). The structure of the fluorescence sp>ectrum is not in agreement with the Mie theory computation for a 9.92/xm diameter sphere, but it is quite consistent with the result predicted for a 9.99/xm diameter sphere. 

Sulfonated 8 and biotinylated polymer 38-coated streptavidin-derivatized polystyrene microspheres were useful as a platform for the detection of DNA... 

Wilson JN, Wang Y, Lavigne JJ, Bunz UHF. A biosensing model system selective interaction of biotinylated PPEs with streptavidin-coated polystyrene microspheres. Chem Commun 2003 1626-1627. 

This equation contains two unknown parameters (b and 9), and if we know one of them, the other can be calculated from Mw and G(D). With this idea, it was found that the average density of the polystyrene microspheres made of a few uncrosslinked chains is slightly lower than that of bulk polystyrene or conventional polystyrene latex. 

While several explanations for the particle concentration effect have been presented, VanHoof and Andren (1990) suggested a kinetic explanation rather than a thermodynamic one. Equilibrium sorption is independent of particle size, but kinetics is not, with small particles reaching equilibrium faster. A solids concentration effect on 4-chlorobi-phenyl was observed in an aqueous suspension of polystyrene microspheres. The apparent inverse relationship of 4-chlorobiphenyl partitioning with particle concentration diminished with time, demonstrating that nonattainment of equilibrium results in the observed phenomenon. 

The interception by foliage of activity in rain has been studied experimentally by Hoffman et al. (1989). Polystyrene microspheres, of diameter 3, 9 and 25 pm were labelled with 141Ce, 95Nb and 85Sr respectively. Artificial rain, with the particles in suspension, was applied to plots of clover, fescue and mixed herbage, and the fractional interception of the activity by the foliage was measured. 

Black, A. Pritchard, J.N. (1984) A comparison of the regional deposition and short term clearance of tar particulate matter from cigarette smoke with that of 2.5 pm polystyrene microspheres. Journal of Aerosol Science, 15, 224-7. 

As an undergraduate, Jonathan Behrendt studied for a B.Sc. in Chemistry and Law from the University of Exeter, where he was awarded a 2.1 hons. degree in 2001. He went on to study for a Ph.D. in chemistry at University College London, with Dr. Helen Hailes. His Ph.D. research project focused on the use of polymeric supports for the synthesis of structurally defined oligomers and cyclic ethers. Having been awarded his Ph.D. in 2005, he is currently working on the synthesis and functionalization of polystyrene microspheres as cellular delivery vectors, in the research group of Dr. Andy Sutherland at Aston University. 

Enscore, D., Hopfenberg, H., and Stannett, V., Effect of particle size on the mechanism controlling n-hexane sorption in glassy polystyrene microspheres, Polymer, Vol. 18, No. 8, 1977, pp. 793-800. 

In general, the modification of particulate carriers using amphipathic polyethylene glycol (PEG)-containing molecules results in a prolongation of their blood circulation time [57,58], A phosphatidylethanolamine derivative with polyethylene glycol (PEG-PE) is widely used to increase the plasma retention of particulate carriers such as liposomes [59-61], polystyrene microspheres [62], and nanospheres... 

Polystyrene microspheres are deposited in a hexagonally ordered array... 

Subramania, G., Constanf K., Biswas, R. et al.. Visible frequency thin film photonic crystals from colloidal systems of nanocrystalline titania and polystyrene microspheres, J.Am. Ceram. Soc., 85, 1383, 2002. 

In addition to PEGylation, polyvinyl pyrolidone (PVP) nanoparticles modified with hydrophilic polaxa-mine have been reported to adsorb less protein than the unmodified particles, conventional liposomes, and stealth liposomes.Polystyrene microspheres coated with lecithin and particles coated with Pluronic were also observed to adsorb less protein and demonstrate a prolonged blood circulation time without adversely affecting the safety profile of the drug. 

Polymer microspheres with monodispersed distribution in size are much perferable for phagocytosis assays, because the size dominantly governs phagocytosis of the microspheres by M< ). In addition, the microspheres should be prepared without any surfactants to exclude the influence of the soap molecules adsorbed onto the surface, on phagocytosis of the microspheres. We have synthesized monodispersed polystyrene microspheres by soap-free emulsion polymerization of styrene at 70 °C for 30 hr using potassium persulfate as a initiator [14]. The widely different diameters of the... 

Table 2 summarizes the results of M<[) phagocytosis of cellulose microspheres whose surfaces were grafted with various protein molecules, together with the microspheres not grafted or modified by coulping with a -hexyl (Q) chain, as well as polystyrene microspheres. In addition, the effect of fetal calf serum (FCS) added to M<[) cultures... 

---