High-performance separation of nanoparticles with ultrathin porous nanocrystalline silicon membranes.
Porous nanocrystalline silicon (pnc-Si) is a 15 nm thin free-standing membrane material with applications in small-scale separations, biosensors, cell culture, and lab-on-a-chip devices. Pnc-Si has already been shown to exhibit high permeability to diffusing species and selectivity based on molecular size or charge. In this report, we characterize properties of pnc-Si in pressurized flows. We compare results to long-standing theories for transport through short pores using actual pore distributions obtained directly from electron micrographs. The measured water permeability is in agreement with theory over a wide range of pore sizes and porosities and orders of magnitude higher than those exhibited by commercial ultrafiltration and experimental carbon nanotube membranes. We also show that pnc-Si membranes can be used in dead-end filtration to fractionate gold nanoparticles and protein size ladders with better than 5 nm resolution, insignificant sample loss, and little dilution of the filtrate. These performance characteristics, combined with scalable manufacturing, make pnc-Si filtration a straightforward solution to many nanoparticle and biological separation problems.
Department of Biomedical Engineering, University of Rochester, Rochester, New York 14627, United States.
Thomas R
TR
Gaborski
Jessica L
JL
Snyder
Christopher C
CC
Striemer
David Z
DZ
Fang
Michael
M
Hoffman
Philippe M
PM
Fauchet
James L
JL
McGrath
D005591:Chemical Fractionation / Q000379:methods*; D005374:Filtration; D008567:Membranes, Artificial; D055616:Microtechnology; D053758:Nanoparticles / Q000737:chemistry; D010539:Permeability; D016062:Porosity; D012825:Silicon / Q000737:chemistry*
D008567:Membranes, Artificial; D012825:Silicon