Short polyethylene glycol chains densely bound to soft nanotube channels for inhibition of protein aggregation

Abstract

Two-step self-assembly of two different lipids and a short polyethylene glycol (PEG) unit selectively produced molecular monolayer nanotubes with 7–9 nm-diameter nanochannels densely functionalized with short PEG chains. Fluorescence spectroscopy and microscopy using an environmentally responsive probe suggested that the PEG chains in the nanochannel were dehydrated when the temperature was raised above 45–50 °C and rehydrated by cooling to 25 °C, whereas the PEG chains in the bulk solution showed no such dehydration/rehydration behavior in response to variations of temperature. Nanotube channels that became hydrophobic as a result of the dehydration of the interior PEG chains effectively suppressed aggregation of a thermally denatured protein under high temperature conditions. Regeneration of the hydrophilic nanochannels by rehydration of the interior PEG chains allowed the encapsulated protein to be quickly released to the bulk solution and simultaneously facilitated the refolding of the protein.