Polymer brushes in solid-state nanopores form an impenetrable entropic barrier for proteins
Journal article, 2018
Polymer brushes are widely used to prevent the adsorption of proteins, but the mechanisms by which they operate have remained heavily debated for many decades. We show conclusive evidence that a polymer brush can be a remarkably strong kinetic barrier towards proteins by using poly(ethylene glycol) grafted to the sidewalls of pores in 30 nm thin gold films. Despite consisting of about 90% water, the free coils seal apertures up to 100 nm entirely with respect to serum protein translocation, as monitored label-free through the plasmonic activity of the nanopores. The conclusions are further supported by atomic force microscopy and fluorescence microscopy. A theoretical model indicates that the brush undergoes a morphology transition to a sealing state when the ratio between the extension and the radius of curvature is approximately 0.8. The brush-sealed pores represent a new type of ultrathin filter with potential applications in bioanalytical systems.
Author
Gustav Emilsson
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Kunli Xiong
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Yusuke Sakiyama
University of Basel
Bita Malekian
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Viktor Ahlberg Gagnér
University of Gothenburg
Rafael L. Schoch
University of Basel
Roderick Y H Lim
University of Basel
Andreas Dahlin
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Nanoscale
2040-3364 (ISSN) 2040-3372 (eISSN)
Vol. 10 10 4663-4669Subject Categories
Physical Chemistry
Biophysics
Theoretical Chemistry
DOI
10.1039/c7nr09432a