title: Tailored Polymeric Membranes for Mycobacterium Smegmatis Porin A (MspA) Based Biosensors.
abstract: Nanopores based on protein channels inserted into lipid membranes have paved the way towards a wide-range of inexpensive biosensors, especially for DNA sequencing. A key obstacle in using these biological ion channels as nanodevices is the poor stability of lipid bilayer membranes. Amphiphilic block copolymer membranes have emerged as a robust alternative to lipid membranes. While previous efforts have shown feasibility, we demonstrate for the first time the effect of polymer composition on MspA protein functionality. We show that membrane-protein interaction depends on the hydrophobic-hydrophilic ratio (f-ratio) of the block copolymer. These effects are particularly pronounced in asymmetric protein pores like MspA compared to the cylindrical α-Hemolysin pore. A key effect of membrane-protein interaction is the increased 1/fαnoise. After first showing increases in 1/fαbehaviour arise from increased substate activity, the noise power spectral densityS(f)was used as a qualitative tool for understanding protein-membrane interactions in polymer membranes. Polymer compositions with f-ratios close to lipid membranes caused noise behaviour not observed in lipid membranes. However, by modifying the f-ratio using a modular synthetic approach, we were able to design a block copolymer exhibiting noise properties similar to a lipid membrane, albeit with better stability. Thus, by careful optimization, block copolymer membranes can emerge as a robust alternative for protein-pore based nano-biosensors.
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106.
authors.forename: Danielle
authors.initials: D
authors.lastname: Morton
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106.
authors.forename: Shahab
authors.initials: S
authors.lastname: Mortezaei
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106.
authors.forename: Sukru
authors.initials: S
authors.lastname: Yemenicioglu
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Isaacman
authors.affiliation: Department of Physics, University of Washington, Seattle, WA 98195.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Nova
authors.affiliation: Department of Physics, University of Washington, Seattle, WA 98195.
authors.forename: Jens H
authors.initials: JH
authors.lastname: Gundlach
authors.affiliation: Department of Electrical and Computer Engineering, University of California, Santa Barbara, CA, 93106.
authors.forename: Luke
authors.initials: L
authors.lastname: Theogarajan