title: Capture and release of proteins on the nanoscale by stimuli-responsive elastin-like polypeptide "switches".
abstract: This article describes the fabrication and characterization of stimulus-responsive elastin-like polypeptide (ELP) nanostructures grafted onto omega-substituted thiolates that were patterned onto gold surfaces by dip-pen nanolithography (DPN). In response to external stimuli such as changes in temperature or ionic strength, ELPs undergo a switchable and reversible, hydrophilic-hydrophobic phase transition at a lower critical solution temperature (LCST). We exploited this phase transition behavior to reversibly immobilize a thioredoxin-ELP (Trx-ELP) fusion protein onto the ELP nanopattern above the LCST. Subsequent binding of an anti-thioredoxin monoclonal antibody (anti-Trx) to the surface-captured thioredoxin showed the presentation of the immobilized protein in a sterically accessible orientation in the nanoarray. We also showed that the resulting Trx-ELP/anti-Trx complex formed above the LCST could be reversibly dissociated below the LCST. These results demonstrate the intriguing potential of ELP nanostructures as generic, reversible, biomolecular switches for on-chip capture and release of a small number (order 100-200) of protein molecules in integrated, nanoscale bioanalytical devices. We also investigated the molecular mechanism underlying this switch by measuring the height changes that accompany the binding and desorption steps and by adhesion force spectroscopy using atomic force microscopy.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708-0281, USA.
authors.forename: Jinho
authors.initials: J
authors.lastname: Hyun
authors.forename: Woo-Kyung
authors.initials: WK
authors.lastname: Lee
authors.forename: Nidhi
authors.initials: N
authors.lastname: Nath
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Chilkoti
authors.forename: Stefan
authors.initials: S
authors.lastname: Zauscher
mesh_terms: D004549:Elastin / Q000737:chemistry / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D036103:Nanotechnology / Q000379:methods*; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D040081:Protein Array Analysis; D011485:Protein Binding; D012965:Sodium Chloride / Q000494:pharmacology; D000267:Tissue Adhesions
chemical_list: D010455:Peptides; D012965:Sodium Chloride; D004549:Elastin