title: Active interfacial shear microrheology of aging protein films.
abstract: The magnetically driven rotation of 300 nm diameter rods shows the surface viscosity of albumin at an air-water interface increases from 10(-9) to 10(-5) N s/m over 2 h while the surface pressure saturates in minutes. The increase in surface viscosity is not accompanied by a corresponding increase in elasticity, suggesting that the protein film anneals with time, resulting in a more densely packed film leading to increased resistance to shear. The nanometer dimensions of the rods provide the same sensitivity as passive microrheology with an improved ability to measure more viscous films.
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93117, USA.
authors.forename: Prajnaparamita
authors.initials: P
authors.lastname: Dhar
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Cao
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Fischer
authors.forename: J A
authors.initials: JA
authors.lastname: Zasadzinski
mesh_terms: D000418:Albumins / Q000378:metabolism*; D008280:Magnetics; D043942:Nanotubes / Q000737:chemistry; D011312:Pressure; D012212:Rheology; D012996:Solutions; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014783:Viscosity
chemical_list: D000418:Albumins; D012996:Solutions