Pnipam-covered gold nanodots for reversible adsorption of biomolecules

Thermoresponsive polymer poly(N-isopropylacrylamide) (Pnipam) can undergo a phase transition from a hydrophilic, water-swollen state to a hydrophobic, collapsed state when heated above its lower critical solution temperature, around 32°C in water. A temperature-induced change in the hydration of Pnipam can render its surface adhesive or non-adhesive to biomolecules. The author thus exploited a hybrid plasmonic nanostructure including a lithographic gold nanodots array covered with Pnipam brushes for reversible adsorption of protein molecules. Microscopic and spectroscopic analysis – e.g. scanning electron microscope, force microscope and far-field extinction microspectroscopy – will be carried on prepared hybrid nanomaterial to characterize the morphology and the optical properties. This thermoresponsive hybrid nanostructure was demonstrated to be able to switch efficiently the adsorption/desorption of bovine serum albumin proteins, by convenient temperature stimuli. This work could provide an important step toward the use of thermosensitive plasmonic structures in biomedical and biological applications such as enzyme immobilization, cell sorting, protein adsorption and purification.