Adsorption of Poly(Ethylene Glycol) Amphiphiles to Form Coatings Which Inhibit Protein Adsorption

Malmsten, Martin; Alstine, James M. Van

doi:10.1006/jcis.1996.0064

Cited by 90 publications

(89 citation statements)

References 12 publications

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“…Therefore, the higher the surface density and chain length of PEG, the more desirable the exclusion of protein will become. In agreement with Jeon et al [78], Malmstrem et al [79] pointed that polymer surface density is the major contributing feature for efficient protein adsorption resistance. The Increase in conversion rate from ethylene oxide (EO 4 to EO 6 ) for an amphiphile enzyme stabilizer is in agreement with earlier findings that show longer E-O chains improve the enzymatic conversion yield up to EO 80 .…”

Section: Role Of Amphiphiles Propertiessupporting

confidence: 81%

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

2013

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Abstract:One of the concerns for economical production of ethanol from biomass is the large volume and high cost of the cellulolytic enzymes used to convert biomass into fermentable sugars. The presence of acetyl groups in hemicellulose and lignin in plant cell walls reduces accessibility of biomass to the enzymes and makes conversion a slow process. In addition to low enzyme accessibility, a rapid deactivation of cellulases during biomass hydrolysis can be another factor contributing to the low sugar recovery. As of now, the economical reduction in lignin content of the biomass is considered a bottleneck, and raises issues for several reasons. The presence of lignin in biomass reduces the swelling of cellulose fibrils and accessibility of enzyme to carbohydrate polymers. It also causes an irreversible adsorption of the cellulolytic enzymes that prevents effective enzyme activity and recycling. Amphiphiles, such as surfactants and proteins have been found to improve enzyme activity by several mechanisms of action that are not yet fully understood. Reduction in irreversible adsorption of enzyme to non-specific sites, reduction in viscosity of liquid and surface tension and consequently reduced contact of enzyme with air-liquid interface, and modifications in biomass chemical structure are some of the benefits derived from surface active molecules. Application of some of these amphiphiles could potentially reduce the capital and operating costs of bioethanol production by reducing fermentation time and the amount of enzyme used for saccharification of biomass. In this review article, the benefit of applying amphiphiles at various stages of ethanol production (i.e., OPEN ACCESSAppl. Sci. 2013, 3 397 pretreatment, hydrolysis and hydrolysis-fermentation) is reviewed and the proposed mechanisms of actions are described.

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Section: Role Of Amphiphiles Propertiessupporting

confidence: 81%

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

2013

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“…PEG had been widely used as a coating to generate biocompatible surfaces that are nonimmungenic, nonantigenic, and resist protein adsorption (Alcantar et al, 2000;Kingshott and Griesser, 1999;Malmsten and Van Alstine, 1996). The molecular basis of the protein repellant properties of PEG is reportedly attributed to a number of different interactions: steric repulsion due to the polymer chain, repulsion due to the presence of a hydration shell around the polymer chain, and/or electrostatic repulsion stemming from the polar monomeric units (Chapman et al, 2000;Harris and Zalipsky, 1997;Lee and Schaffer, 2003).…”

Section: Discussionmentioning

confidence: 99%

PEG conjugation moderately protects adeno-associated viral vectors against antibody neutralization

Lee

Maheshri

Kaspar³

et al. 2005

Biotechnol. Bioeng.

135

114

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AAV gene therapy vectors have significant clinical promise, but serum neutralization poses a challenge that must be overcome. We have examined the potential of conjugating the AAV surface with activated polyethylene glycol chains to protect the vector from neutralizing antibodies. Two key parameters were investigated: the polymer chain size and the PEG:lysine conjugation ratio. Transduction data revealed that the vector is fully infectious until a critical PEG conjugation reaction ratio was exceeded, and this critical level was found to vary with polymer chain size. At this key conjugation ratio, however, particles were moderately protected from serum neutralization, 2.3-fold over unmodified vector, demonstrating that there is a small window of PEGylation for which particles are still fully infective and benefit from antibody protection. TEM results and structural analysis indicate that the drop of infectivity as the PEG concentration is increased beyond the critical conjugation ratio may be due to a combination of steric interference with viral regions necessary for infection as well as reaction at important lysine residues. However, this first study analyzing the potential of PEG to protect AAV from serum neutralization shows that the approach has promise, which can be further enhanced if the locations of PEG attachment can be more finely controlled. ß

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“…There is considerable discussion regarding the protein ''rejecting'' properties of PEG and PEG-containing deriva-Materials tives, and different underlying mechanisms have been sugWater was first purified by a Milli-RO 10PLUS pretreatgested (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). It is becomming increasingly clear that the ment unit, including depth filtration, carbon adsorption and protein rejecting properties of PEG-containing molecules are decalcination preceeding reverse osmosis.…”

Section: Methodsmentioning

confidence: 99%