Solid-Solid Interface Adsorption of Proteins and Enzymes in Nanophase-Separated Amphiphilic Conetworks

Amphiphilic polymer conetworks (APCNs) are materials with a very large interface between their hydrophilic and hydrophobic phases due to their nanophase-sepd. morphologies. Proteins were found to enrich in APCNs by up to 2 orders of magnitude when incubated in aq. protein solns., raising the question of the driving force of protein uptake into APCNs. The loading of poly(2-hydroxyethyl acrylate)-linked by-poly(dimethylsiloxane) (PHEA-l-PDMS) with heme proteins (myoglobin, horseradish peroxidase, Hb) and lipases was studied under variation of parameters such as incubation time, pH, concn. of the protein soln., and conetwork compn. Adsorption of enzymes to the uncharged interface is the main reason for protein uptake, resulting in protein loading of up to 23 wt. %. Exptl. results were supported by computation of electrostatic potential maps of a lipase, indicating that hydrophobic patches are responsible for the adsorption to the interface. The findings underscore the potential of enzyme-loaded APCNs in biocatalysis and as sensors.