Surface with polyethylene glycol

Formulation strategies for stabilization of proteins commonly include additives such as other proteins (e.g., serum albumin), amino acids, and surfactants to minimize adsorption to surfaces. Modification of protein structure to enhance stability by genetic engineering may also be feasible, as well as chemical modification such as formation of a conjugate with polyethylene glycol. 

Several of these problems can be solved by polyplex modification with polyethylene glycol (PEG). PEGylation has been broadly explored for surface shielding ( stealthing ) of many liposomal and nanoparticulate carriers. In the case of cationic polymers, Plank et al. [62] demonstrated that complement activation can be reduced when the polymers are PEGylated. Such a modification can be... 

Northfelt DW, Martin FJ, Working P, Volberding PA, Russell J, Newman M, Amantea MA, Kaplan LD. Doxorubicin encapsulated in liposomes containing surface-bound polyethylene glycol pharmacokinetics, tumor localization, and safety in patients with AIDS-related Kaposi s sarcoma. J Clin Pharmacol 1996 36 55-63. 

Fig. 8 Concept of simultaneous microbe repulsion and biocide release of a specifically designed network. The network is composed of poly(2-hydroxyethylacrylate) crosslinked with polyethyleneimine and surface-grafted with polyethylene glycol. The polyethyleneimine junctions take up silver ions, which then form nanoparticles due to the template character of these nanocontainers. Reproduced and adapted from [90]...

An elegant example of the analysis of colloid surfaces containing covalently attached hydrophilic species has been provided by Brindley et al who studied the surface chemistry of polystyrene colloids with surface grafted polyethylene glycol groups [39]. These colloids were prepared by surfactant-free copolymerization of styrene with PEG using potassium persulphate as an initiator. The XPS analysis of these microparticles is shown in Fig. 11. 

Multiple inking is possible using microfluidic networks over the PDMS stamps.Papra, A. Bernard, A. Juncker, D. Larsen, N. B. Michel, B. Delamarche, E. Microfluidic Networks Made of Poly(Dimethylsiloxane), Si, and Au Coated With Polyethylene Glycol for Patterning Proteins Onto Surfaces. Langmuir 2001, 17, 4090-4095... 

It is important to point out that, unlike other enzyme systems where very significant deviations from classical behavior have been observed, the size of the KIEs and their temperature dependences are all seen to hover around the classical values in GO. In a very careful study, Seymour examined the impact of surface modification on the parameters describing H-transfer in GO. The impact of the surface modifier was assessed, by comparing H-transfer in proteins modified with polyethylene glycol to those modified by glycosylation [92]. 

About 150 lipid molecules were present per 1 of enzyme. It was used to esterify 1-phenylethanol with lauric acid in isooctane, giving 95% conversion in 2 h. A lipid-coated lipase has also been used to esterify lauric acid with glycerol in sc carbon dioxide with 90% conversion.98 Catalase with less than 5% of its surface amino groups modified by the nonionic surfactant 9.7 had a higher activity in 1,1,1-trichloroethane than when the enzyme was conjugated with polyethylene glycol.99... 

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