Crosslinked Nanoparticles

Lin YH, Sonaje K, Lin KM et al (2008) Multi-ion-crosslinked nanoparticles with pH-responsive characteristics for oral delivery of protein drugs. J Control Release 132 141-149... 

Chen, S., Two-dimensional crosslinked nanoparticle networks, Adv. Mater., 12, 186, 2000. 

Knedel is a Polish term for dumpling , and the shell crosslinked nanoparticles... 

Shenhar R, Jeoung E, Srivastava S, Norsten TB, Rotello VM. Crosslinked nanoparticle stripes and hexagonal networks obtained via selective patterning of block copolymer thin films. Adv Mater 2005 17 2206-2210. 

Enzymatic polymerizations have been established as a promising and versatile technique in the synthetic toolbox of polymer chemists. The applicability of this technique for homo- and copolymerizations has been known for some time. With the increasing number of reports on the synthesis of more complex structures like block copolymers, graft copolymers, chiral (co)polymers, and chiral crosslinked nanoparticles, its potential further increases. Although not a controlled polymerization technique itself, clever reaction design and integration with other polymerization techniques like controlled radical polymerization allows the procurement of well-defined polymer structures. Specific unique attributes of the enzyme can be applied... 

Fig. 4 (a) Micelles formation in non-selective solvent and core-crosslinked nanoparticles, (b) Chemical structures of the implied copolymers. Reprinted from de Luzuriaga et al. [37]. Copyright 2010, with permission from Elsevier... 

Yoshii, K., Yamashita, T., Machida, S., Horie, K., Itoh, M., Nishida, E, and Morino, S. (1999). Photo-probe study of siloxane polymers. 1. Local free volume of an MQ-type silicone resin containing crosslinked nanoparticles probed by photoisomerizaiion of azobenzene. J. Nonctyst. Sol. 246, 90-103. 

Fig. 8 Rhodamine B dye (RhB, red solution) diffusing across a membrane of crosslinked nanoparticles (dotted line). The bold arrows point to the interface in each tube. The two right-hand images represent a time frame of about 15 min. Subsequent addition of water to the RhB/water droplet replaces the CdSe/toluene solution leading to a RhB/water-water interface separated by the nanoparticle membrane. Reprinted with permission from Journal of the American Chemical Society [47]. Copyright (2003) American Chemical Society...

G. Schmid, M. Baumle, and N. Beyer, Ordered two-dimensional monolayers of AU53 clusters, Angew. Chem. Int. Ed. 39 181 (2000) S. Chen, Two-dimensional crosslinked nanoparticle networks, Ac v. Mater. 12 186 (2000) S. Sun, C.B. Murray, D. Weller, L. Folks, and A. Moser, Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science 287 1989 (2000) C.L. Bowes and G.A. Ozin, Self-assembling frameworks beyond microporous oxides, Adv. Mater. 8 13 (1996). 

Means of increasing the binding capacity include grafting, formation of composites, crosslinked nanoparticles with affinity, and double cryogel networks. 

Figure 4.5 Plot of reduced viscosity versus concentration for control copolymers ( , 150 kDa , 100 kDa) and their analogous crosslinked nanoparticles ( , 150 kDa A, 100 kDa) in THF. Both copolymers were prepared from starting polymers incorporating ca. 15 mol% NCO functional groups along the backbone.

This assembly chemistry is only limited by the preparation of an appropriate amphiphilic or hydrophobic diblock copolymer. With the structure and chemical composition of the resultant nanoparticles readily tunable using a wide range of block copolymers that are synthetically available. A broad range of polymers have been utilized as the core hydrophobic domain of shell-crosslinked nanoparticles and include styrene, isoprene, butadiene, caprolactone, poly (ethylene oxide), acrylates, methacrylate and acrylamides. Monomers that have been used to prepare the hydrophilic water-soluble domain include, among others, poly(ethylene glycol), acrylic acid, 4-vinylpyridine, (meth)acrylic acid, 2-dimethylaminoethyl methacrylate and Wisopropylacrylamide. 

This approach has recently been extended by the same group for the synthesis of noncovalently crosslinked nanoparticles, which can be formed reversibly upon application of external stimuli (Seo etal, 2008). This group have also recently reported the application of microwave crosslinking chemistries for the synthesis of collapsed and functionalized polymer... 

---