TY - JOUR
T1 - Radio-frequency response of single pores and artificial ion channels
AU - Kim, H. S.
AU - Ramachandran, S.
AU - Stava, E.
AU - Van Der Weide, D. W.
AU - Blick, R. H.
PY - 2011/9
Y1 - 2011/9
N2 - Intercellular communication relies on ion channels and pores in cell membranes. These protein-formed channels enable the exchange of ions and small molecules to electrically and/or chemically interact with the cells. Traditionally, recordings on single-ion channels and pores are performed in the dc regime, due to the extremely high impedance of these molecular junctions. This paper is intended as an introduction to radio-frequency (RF) recordings of single-molecule junctions in bilipid membranes. First, we demonstrate how early approaches to using microwave circuitry as readout devices for ion channel formation were realized. The second step will then focus on how to engineer microwave coupling into the high-impedance channel by making use of biocompatible micro-coaxial lines. We then demonstrate integration of an ultrabroadband microwave circuit for the direct sampling of single-hemolysin pores in a suspended bilipid membrane. Simultaneous direct current recordings reveal that we can monitor and correlate the RF transmission signal. This enables us to relate the open-close states of the direct current to the RF signal. Altogether, our experiments lay the ground for an RF-readout technique to perform real-time in vitro recordings of pores. The technique thus holds great promise for research and drug screening applications. The possible enhancement of sampling rates of single channels and pores by the large recording bandwidth will allow us to track the passage of single ions.
AB - Intercellular communication relies on ion channels and pores in cell membranes. These protein-formed channels enable the exchange of ions and small molecules to electrically and/or chemically interact with the cells. Traditionally, recordings on single-ion channels and pores are performed in the dc regime, due to the extremely high impedance of these molecular junctions. This paper is intended as an introduction to radio-frequency (RF) recordings of single-molecule junctions in bilipid membranes. First, we demonstrate how early approaches to using microwave circuitry as readout devices for ion channel formation were realized. The second step will then focus on how to engineer microwave coupling into the high-impedance channel by making use of biocompatible micro-coaxial lines. We then demonstrate integration of an ultrabroadband microwave circuit for the direct sampling of single-hemolysin pores in a suspended bilipid membrane. Simultaneous direct current recordings reveal that we can monitor and correlate the RF transmission signal. This enables us to relate the open-close states of the direct current to the RF signal. Altogether, our experiments lay the ground for an RF-readout technique to perform real-time in vitro recordings of pores. The technique thus holds great promise for research and drug screening applications. The possible enhancement of sampling rates of single channels and pores by the large recording bandwidth will allow us to track the passage of single ions.
UR - http://www.scopus.com/inward/record.url?scp=80053399807&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/13/9/093033
DO - 10.1088/1367-2630/13/9/093033
M3 - Article
AN - SCOPUS:80053399807
SN - 1367-2630
VL - 13
JO - New Journal of Physics
JF - New Journal of Physics
M1 - 093033
ER -