Surface-bound poly

Maeda M, Kumano A, TirteU DA. H -I- -Induced release of contents of phosphatidylcholine vesicles bearing surface-bound poly-electrolyte chains. J Am Chem Soc 1988 110 7455-7459. 

While this sensor employed only a model nucleic acid probe (poly(A)), it demonstrates the principle of detection of the complementary sequence, the analyte poly(U). Figure 7.9(a) shows that a frequency decrease of 600 Hz was observed following the hybridization step, Step 3, and that this decrease was not observed with a control sensor that did not possess surface-bound poly(A). The sensor exhibits a relatively small frequency change that is superimposed on a large initial resonance frequency (9 MHz), and so S/N is low in addition, difficulties associated with ex situ measurements at constant humidity preclude the use of this device for practical DNA or RNA detection. 

In this article, we will discuss the steric repulsion of plasma proteins, platelets, and bacteria by surface-bound poly(ethylene oxide) (PEO). PEO, a neutral hydrophilic polymer, has been used most widely for surface modification of biomaterials. 

Second, dopamine has been linked covalently to a poly(aryloxy-phosphazene) via a diazo-coupling technique (24). Experiments showed that rat pituitary cells in culture responded to the surface-bound dopamine in a similar manner to that found when the dopamine was free in solution. 

Baum et al. apphed RAFT polymerization to synthesize brushes of PS, PMMA, poly(Nd -dimethylacrylamide) (PDMA), and their copolymers on azo-initiator-bound sihcate surfaces [127]. 2-Phenylprop-2-yl dithiobenzoate was added as a free (unboimd) RAFT agent to control the graft polymerization. Because of a very low concentration of surface-bound initiator, a free... 

Fig. 21 A Schematics of albumin-bound poly(N-isopropylacrylamide) (PNIPAM)-grafted surface via albuminated DC iniferter. B Hypothetical action of temperature-dependent switching of protein desorption by squeezing out and mechanical motion...

Figure 3.20 Plots showing the activity of the enzyme, glucose-6-phosphate dehydrogenase as a function of time for (open circles) the free enzyme in solution and (black circles) the enzyme bound to the surface of poly[W.v(phcnoxy)phosphazene]. The polyphosphazene is an excellent surface substrate because of the stability of the polymer backbone to nitration and reduction, and the ease with which the hydrophobicity or hydrophilicity of the surface can be changed. From Allcock and Kwon, reference 191.

Qaddoumi et al. [65] studied the uptake of PLGA nanoparticles in rabbit conjunctival epithelial cell culture. The highest uptake by cultured conjunctival cells was achieved for the smallest particles (100 nm), compared to larger 800 nm and 10 pm particles. A study of the fate of the tiny 100-nm particles following 2 h of cultured cells exposure to a 0.5 mg/mL dose showed that 6% was internalized by conjunctival epithelial cells, 1.5% was surface-bound, whereas the remainder of the dose was found in the donor medium. In an in vivo rabbit eye study [66] on the uptake of poly(hexyl cyanoacrylate) nanoparticles, 6 h postinstillation into the conjunctival sac, it was found that the fraction that was internalized by conjunctival epithelial cells was only 1% of the dose reflecting in vivo precorneal elimination... 

Scheme 3. Idealized sketch of a gold surface modified with a multilayered assembly prepared by (a) alternate deposition of layers of poly(acryhc acid) and poly-L-lysine on a positively charged cystamine SAM (the multilayer assembly is stabilized by electrostatic interactions between adjacent layers, [136]) and by (b) covalent attachment of a layer of G4 poly(amidoamine) dendrimer to a 11-mercapto-l-undecanoic acid SAM after activation of the surface-bound cEirboxylic groups with pentafiuorophenol and EDC. The dendrimer monolayer is afterwards biotinylated by covalent binding of desthiobiotin amidocaproate (not shown) to assemble an overlayer of avidin by affinity interactions [133].

Some papers have appeared that deal with the use of electrodes whose surfaces are modified with materials suitable for the catalytic reduction of halogenated organic compounds. Kerr and coworkers [408] employed a platinum electrode coated with poly-/7-nitrostyrene for the catalytic reduction of l,2-dibromo-l,2-diphenylethane. Catalytic reduction of 1,2-dibromo-l,2-diphenylethane, 1,2-dibromophenylethane, and 1,2-dibromopropane has been achieved with an electrode coated with covalently immobilized cobalt(II) or copper(II) tetraphenylporphyrin [409]. Carbon electrodes modified with /nc50-tetra(/7-aminophenyl)porphyrinatoiron(III) can be used for the catalytic reduction of benzyl bromide, triphenylmethyl bromide, and hexachloroethane when the surface-bound porphyrin is in the Fe(T) state [410]. Metal phthalocyanine-containing films on pyrolytic graphite have been utilized for the catalytic reduction of P anj -1,2-dibromocyclohexane and trichloroacetic acid [411], and copper and nickel phthalocyanines adsorbed onto carbon promote the catalytic reduction of 1,2-dibromobutane, n-<7/ 5-l,2-dibromocyclohexane, and trichloroacetic acid in bicontinuous microemulsions [412]. When carbon electrodes coated with anodically polymerized films of nickel(Il) salen are cathodically polarized to generate nickel(I) sites, it is possible to carry out the catalytic reduction of iodoethane and 2-iodopropane [29] and the reductive intramolecular cyclizations of 1,3-dibromopropane and of 1,4-dibromo- and 1,4-diiodobutane [413]. A volume edited by Murray [414] contains a valuable set of review chapters by experts in the field of chemically modified electrodes. 

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