Abstract
For the functional analysis of ion channel activity, an artificial lipid bilayer suspended over microwells was formed that ruptured giant unilamellar vesicles on a Si substrate. Ca 2+ ion indicators (fluo-4) were confined in the microwells by sealing the microwells with a lipid bilayer. An overhang formed at the microwells prevented the lipid membrane from falling into them and allowed the stable confinement of the fluorescent probes. The transport of Ca 2+ ions through the channels formed by α-hemolysin inserted in a lipid membrane was analyzed by employing the fluorescence intensity change of fluo-4 in the microwells. The microwell volume was very small (1-100fl), so a highly sensitive monitor could be realized. The detection limit is several tens of ions/s/μm 2, and this is much smaller than the ion current in a standard electrophysiological measurement. Smaller microwells will make it possible to mimic a local ion concentration change in the cells, although the signal to noise ratio must be further improved for the functional analysis of a single channel. We demonstrated that a microwell array with confined fluorescent probes sealed by a lipid bilayer could constitute a basic component of a highly sensitive biosensor array that works with functional membrane proteins. This array will allow us to realize high throughput and parallel testing devices.
Original language | English |
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Pages (from-to) | 445-450 |
Number of pages | 6 |
Journal | Biosensors and Bioelectronics |
Volume | 31 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2012 Jan 15 |
Externally published | Yes |
Keywords
- Artificial lipid bilayer
- Ion channels
- Microwell array
- Nano-biodevices
- Suspended lipid bilayer
ASJC Scopus subject areas
- Biotechnology
- Biophysics
- Biomedical Engineering
- Electrochemistry