Poly silica ormosils

Fig. 1 Chemical structures of the polymers commonly used for preparation of beads poly (styrene-co-maleic acid) (=PS-MA) poly(methyl methacrylate-co-methacrylic acid) (=PMMA-MA) poly(acrylonitrile-co-acrylic acid) (=PAN-AA) polyvinylchloride (=PVC) polysulfone (=PSulf) ethylcellulose (=EC) cellulose acetate (=CAc) polyacrylamide (=PAAm) poly(sty-rene-Wocfc-vinylpyrrolidone) (=PS-PVP) and Organically modified silica (=Ormosil). PS-MA is commercially available as an anhydride and negative charges on the bead surface are generated during preparation of the beads...

PEBBLEs are water-soluble nanoparticles based on biologically inert matrices of cross-linked polymers, typically poly(acrylamide), poly(decylmethacrylate), silica, or organically modified silicates (ORMOSILs), which encapsulate a fluorescent chemo-sensor and, often, a reference dye. These matrices have been used to make sensors for pH, metal ions, as well as for some nonionic species. The small size of the PEBBLE sensors (from 20 to 600 nm) enables their noninvasive insertion into a living cell, minimizing physical interference. The semipermeable and transparent nature of the matrix allows the analyte to interact with the indicator dye that reports the interaction via a change in the emitted fluorescence. Moreover, when compared to naked chemosensors, nanoparticles can protect the indicator from chemical interferences and minimize its toxicity. Another important feature of PEBBLEs, particularly valuable in intracellular sensing applications, is that the polymer matrix creates a separate... 

Figure 25-2. Microstructure of an organically modified silicate (Ormosil). Poly (dimethyl siloxane) chains combine silica blocks derived from hydrolysis of an alkoxysilane, Si(OR)4.

The production of polyacrylamide nanoparticles is based on a water-in-oil (W/0) microemulsion technique 40). The silica nanoparticles are prepared by a modified Stober method (75). The ormosil nanoplatform is prepared by a two-step method based on sol-gel process 24,41). The poly decylmethacrylate nanoplatform is prepared by emulsion polymerization 27,42). Encapsulation of drugs or nanocrystals into nanoparticles was made by adding these components to the reaction mixture at the beginning of, or during, the synthesis. Covalent... 

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