AVS 49th International Symposium
    Biomaterials Tuesday Sessions
       Session BI+SS-TuA

Invited Paper BI+SS-TuA5
Threading DNA Through a Nanopore: Applications for Analyte Detection

Tuesday, November 5, 2002, 3:20 pm, Room C-201

Session: Molecular Recognition Surfaces
Presenter: J.J. Kasianowicz, National Institute of Standards and Technology
Authors: J.J. Kasianowicz, National Institute of Standards and Technology
S.E. Henrickson, National Institute of Standards and Technology
B. Robertson, National Institute of Standards and Technology
H.H. Weetall, EPA
M. Misakian, National Institute of Standards and Technology
Correspondent: Click to Email
We recently demonstrated that single-stranded DNA (ssDNA) can be driven electrophoretically through a solitary Staphylococcus aureus alpha-hemolysin (alpha-HL) ion channel. In an effort to use this model system to understand DNA transport in biological systems, we show that the partitioning of ssDNA into the pore depends on the side to which the polymer is added and on the magnitude of the applied potential. Kramer’s reaction rate theory was used to estimate both the height of the energy barrier for polymer translocation and the integral number of charges on ssDNA that interact with the barrier. In a related research effort, we illustrate three experimental results that suggest the interaction between polymers and a single nanopore can be used to quantitate analyte concentration and type. First, the probability that ssDNA enters the alpha-HL channel is proportional to the polymer concentration. Second, analyte binding to sites on ssDNA predictably alters the ability of the polymer to thread through the pore. Third, different ssDNA homopolymers induce current blockade patterns that are characteristic of the nucleotide type. We compare this method to other channel-based detection schemes. Finally, we show that modified polynucleotides might prove useful as "molecular rulers" for probing the structure of nanopores.