Polymeric nanoparticles

Fig. 30 Types of nanocarriers for drug delivery, (a) Polymeric nanoparticles polymeric nanoparticles in which drugs are conjugated to or encapsulated in polymers, (b) Polymeric micelles amphiphilic block copolymers that form nanosized core-shell structures in aqueous solution. The hydrophobic core region serves as a reservoir for hydrophobic drugs, whereas hydrophilic shell region stabilizes the hydrophobic core and renders the polymer water-soluble.

The reaction described in this example is carried out in miniemulsion.Miniemulsions are dispersions of critically stabilized oil droplets with a size between 50 and 500 nm prepared by shearing a system containing oil, water,a surfactant and a hydrophobe. In contrast to the classical emulsion polymerization (see 5ect. 2.2.4.2), here the polymerization starts and proceeds directly within the preformed micellar "nanoreactors" (= monomer droplets).This means that the droplets have to become the primary locus of the nucleation of the polymer reaction. With the concept of "nanoreactors" one can take advantage of a potential thermodynamic control for the design of nanoparticles. Polymerizations in such miniemulsions, when carefully prepared, result in latex particles which have about the same size as the initial droplets.The polymerization of miniemulsions extends the possibilities of the widely applied emulsion polymerization and provides advantages with respect to copolymerization reactions of monomers with different polarity, incorporation of hydrophobic materials, or with respect to the stability of the formed latexes. 

Nanoparticles Polymeric Various natural polymers, Monomer... 

Polymeric Nanoparticles. Polymeric nanoparticles are nanoscale aggregates of biocompatible or biodegradable polymers. The size of nanoparticles varies from 10 to 1000 nm, and obviously, particles with a size smaller than 200 nm are preferable for tumor-targeted drug delivery. 

Fig. 5 Hydrogel-coated gold nanoparticles prepared by surfactant-free emulsion polymerization. After coating oleic acids on the gold nanoparticle, polymerization was carried out in the presence of A-isopropylacrylamide, acrylic acid, and ammonium persulfate (initiator). The size of resulting nanoparticles was in the range of 100-230 nm. (Modified from Ref l)...

W. Silverio Neto, A.T. Jensen, G.R. Ferreira, L.F. Valadares, R. Gambetta, S.G. Belem, F. Machado, A survey on synthesis processes of structured materials for hiomedical applications iron-based magnetic nanoparticles, polymeric materials and polymerization processes. Current Pharmaceutical Design 21 (2015) 5336-5358. 

Fig. 2.1.2 AFM image of styrene nanoparticles polymerized in ether and deposited onto an aluminum pan. The left pane shows the particles in a height mode, while the right pane is the timpli-tude phase image of the surface (V.R. Tirumala personal communication)...

Multifunctional biotinylated and streptavidin-coated polyurethane-urea nanoparticles have also been engineered from OAV nano-emulsions." " In these studies, biotin or streptavidin reacts with diisocyanate at the droplet interface and are successfully attached to the nanoparticle polymeric matrices. These nanoparticles exhibit diameters around 110-140mn (biotin nanoparticles) and 70-74nm (streptavidin nanoparticles). In addition, streptavidin-coated polyurethane-urea nanoparticles were functionalized with biotin anti-VCAM-1 and anti-ICAM-1 antibodies for specific targeting. Both nanoparticulate systems showed no cytotoxicity in healthy endothelial cells and therefore good biocompatibility properties. Figure 7.1 shows a schema of the synthesis of different polyurethane nanoparticles obtained from 0/W nano-emulsions by interfacial polymerization and images obtained by transmission electron microscopy. 

M.W. (2012) Local drug delivery strategies for cancer treatment gels, nanoparticles, polymeric films, rods, and wafer. Journal of Controlled Release, 159, 14-26. 

Keywords Pluorescence correlation spectroscopy Pluorescence microscopy Pluorescent probes Polymer solutions Polymer gels Polymer nanoparticles Polymeric micellar systems Translational diffusion... 

Gao et al prepared thermo-sensitive hybrid microcapsules by inverse Pickering suspension polymerization. Hydrophilic Si02 nanoparticles were surface modified by dimethyldichlorosilane to be hydrophobic and then dispersed in -hexane. Monomer A -isopropylacrylamide (NIPAm) and initiators were dissolved in water, which was later mixed with -hexane to form a Pickering inverse suspension stabilized with the modified Si02 nanoparticles. Polymerization was carried out at 60 or 0 °C using various initiators to form different structures of microcapsules. 

---