PEG-containing

Figure 18.1 A trifunctional reagent for studying protein interactions by mass spec. The bis-NHS ester arms crosslink interacting proteins, while the discrete PEG-containing biotin arm can be used to isolate or detect the conjugates using (strept)avidin reagents.

PEG contains no carboxylate groups in its native state, but can be modified to possess them by reaction with anhydride compounds. Either PEG or mPEG may be acylated with anhydrides... 

Johansson, G. (1992) Affinity partitioning in PEG-containing two-phase systems. In Poly(Ethylene Glycol) Chemistry Biotechnical and Biomedical Applications (J.M. Harris, ed.), pp. 73-84. Plenum, New York. 

PEGs also showed enhanced stability similar to that of ph-PEG. PEG containing hydroquinone substitutions showed a decrease in critical chain length but again not as drastically as the naph-PEG because the bulky hydrophobic group on the hydroquinone is in the middle of the chain while that of the 1-naphthol is on the end of the chain. Thus the effects of hydrophobic interactions have been shown to be a universal stabilizing factor in interpolymer complexation. 

PEG-grafted polystyrene is also well suited for reactions with highly reactive orga-nometallic reagents, provided that the support has been dried. PEG-containing polymers are generally more difficult to dry than pure polystyrene. Cross-linked PEG is stable towards Lewis acids, and can be used for SnCl4-mediated allylations of aldehydes with allyl silanes [21],... 

At present, attempts are being made to prolong the circulation time of poly(alkyl cyanomethacrylate) nanoparticles in the blood circulation by adsorbing PEG-coatings, for example using PEG containing nonionic surfactants such as poloxamers or poloxamines. 

In general, the modification of particulate carriers using amphipathic polyethylene glycol (PEG)-containing molecules results in a prolongation of their blood circulation time [57,58], A phosphatidylethanolamine derivative with polyethylene glycol (PEG-PE) is widely used to increase the plasma retention of particulate carriers such as liposomes [59-61], polystyrene microspheres [62], and nanospheres... 

Polyethylene glycols (PEG) have been intensively characterized by thermal analytic methods. The melting points of PEG increase with the molecular weight and decreases with the content of water as a result of eutectic formation. " Corrigan studied the different DSC peaks of PEG Once folded chain crystals and extended chain crystals are present in PEG 6000, which results in two DSC peaks. In PEG of higher molecular mass, only folded chain crystals are present. Lower molecular mass PEG contain only extended chain crystals. Craig reviewed the thermal studies of PEG, including properties in aqueous solutions. " " ... 

Figure 19.11. A redox-triggered PEG containing lipid (24) and its thiolytic cleavage.

Cationic polymers, such as poly(L-lysine) (PEL), polyethylenimine (PEI), chitosan, polyamidoamine (PAMAM) dendrimers, poly(2-dimethylamino) ethyl methacrylate, and polyphosphoesters, condense DNA to form compacted polyplexes. ° The size and the stability of polyplexes depend on the ratio of cations vs. anions, temperature, ionic strength, and the solvent. Stability of polyplexes can be enhanced by conjugating PEG to the polycations or by using PEG-containing block or graft polymers that form micelles. Small cationic peptides are also able to condense DNA, however, six-consecutive-cations is the minimal requirement to achieve this effectively. 

Aqueous NF played a crucial role in a continuous process that combines wet air oxidation, membrane separation, and biological treatment for the treatment of PEG containing wastewaters. In a first brief wet oxidation pretreatment, the polymers were degraded to a lower MW to increase the rate of the subsequent biodegradation of the permeate. The polymeric NF membrane proved resistant to the oxidative conditions created by excess oxidant still present in the oxidized process streams, even at 130°C. The integrated process thus showed a much higher treatment efficiency than any of the single optimized processes. 

Kempe and Barany [45] developed the CLEAR family, which is based on the copolymerization of branched PEG-containing cross-linkers such as trimethylol-propane ethoxylate triacrylate, which contain various ethylene oxide units, with amino-functionalized monomers such as allylamine or 2-aminoethylmethacrylate. These amino groups constitute the starting points for the solid-phase synthesis. The loadings of these solid supports are affected by the amount of functionalized monomer used for polymerization. Typical loadings are in the range... 

---