Self-assembled Polymeric Nanoparticles

These nanopartides are not dassifled as simple polymeric partides because of their ingredients and formation process. They have been developed very recently and can be considered as a new class of submicronic particles [46]. 

Particles are obtained by combining two polymers a polymer based on 8-CyD 

The extremely rapid fabrication method involves the mixing of two polymeric aqueous solutions. This direct method does not require any further purification. Neither organic solvents nor surfactants are required. The fabrication yield is above 95% and nanoparticle size ranges between 100 and 400 nm. Particles contain empty CyD moieties, which can entrap a variety of compounds depending on the stability constant of the resulting complex. Encapsulation is based on the same, simple, one-step procedure. 

These nanopartides could be used for any therapeutic administration route (ocular, oral, pulmonary, dermal, or intravenous). Another interesting possible application could be the selective extraction of specific compounds from an aqueous solution. 

Amphiphilic CyDs (Lollipop, Cup-and-ball, Medusa-like, Skirt-shaped, and Bouquet) have been synthesized by the grafting of various substituents to different faces of native CyDs [65]. (Syntheses of CyD derivatives are presented in Chapter 2). Among them. Medusa-like cyclodextrins and Skirt-shaped cyclodextrins have demonstrated their ability to form nanocapsules or nanospheres. 

---

Jung SW, Jeong Yl, Kim YH, Kim SH. Self-assembled polymeric nanoparticles of poly(ethylene glycol) grafted pullulan acetate as a novel drug carrier. Arch Pharmacal Res 2004 27(5) 562-569. Peppas NA. Devices based on intelligent biopolymers for oral protein delivery. Int J Pharm 2004 277(1-2) 11-17. 

Recently, many studies have focused on self-assembled biodegradable nanoparticles for biomedical and pharmaceutical applications. Nanoparticles fabricated by the self-assembly of amphiphilic block copolymers or hydrophobically modified polymers have been explored as drug carrier systems. In general, these amphiphilic copolymers consisting of hydrophilic and hydrophobic segments are capable of forming polymeric structures in aqueous solutions via hydrophobic interactions. These self-assembled nanoparticles are composed of an inner core of hydrophobic moieties and an outer shell of hydrophilic groups [35, 36]. 

B6dard MF, Braun D, Sukhorukov GB, et al. (2008) Toward self-assembly of nanoparticles on polymeric microsheUs near-lR release and permeability. ACS Nano 2 1807-1816... 

Polymer micelles in aqueous medium are typically obtained with hydrophobic-hydrophiKc, so-called amphiphilic, block and graft copolymers. Analogous to conventional low-molecular surfactants, and in a selective solvent of one of the blocks, such polymeric surfactants self-assemble into nanoparticles with well-defined sizes and structures. 

From this overview and from Hadjichristidis et al. [ 13] recently published book, it is evident that amphiphilic block and graft copolymers are an interesting class of polymeric surfactants. They are unique is that they self-assemble into nanoparticles with well-defined sizes and morphologies. 

The polymeric catalytic membrane is utilized for biphasic laminar flow synthesis. Uozumi and coworkers developed membrane-installed microflow devices, in which a self-assembled polymeric Pd nanoparticle membrane was installed, for several important chemical transformations. The polymer membrane was precipitated at the laminar interface between the two parallel flows (Scheme 7.5). There is no doubt that the vast interfacial surface of the catalytic membrane with substrates and reactants in the biphasic flows would improve the rate of chemical transformation. 

Drug delivery is an application that has been investigated using amphiphilic phosphazene polymeric materials. An example of this was provided using polyphosphazenes substituted with N,N-diisopropylethylenediamine, an amine functionalized MW2000 poly[ethylene glycol] (AMPEG), and 4-ethyl-aminobenzoate These polymers were found to self-assemble into nanoparticles and were seen to be effective in the delivery of doxorubicin. 

The self-assembling character of bilayer membranes is demonstrated by the formation of free-standing cast films from aqueous dispersions of synthetic bilayer membranes. The tendencies for association are sufficiently strong to allow the addition of guest molecules (nanoparticles, proteins, and various small molecules) to these films where the connective forces are secondary in nature and not primary. Synthetic polymer chemists have made use of these self-assembling tendencies to synthesize monolayer films. In particular, a monomer that contains both reactive groups and hydrophobic and hydrophilic areas is cast onto an appropriate template that self-assembles the monomer, holding it for subsequent polymerization. Thus, a bilayer structure is formed by... 

A new variation of interfacial polymerization was developed by Russell and Emrick in which functionalized nanoparticles or premade oligomers self-assemble at the interface of droplets, stabilizing them against coalescence. The functional groups are then crosslinked, forming permanent capsule shells around the droplets to make water-in-oil (Lin et al. 2003 Skaff et al. 2005) and oil-in-water (Breitenkamp and Emrick 2003 Glogowski et al. 2007) microcapsules with elastic membranes. 

---