Departmental Seminar (13/01/2016)

Droplet Interface Bilayers: From Parallel optical nanopore sequencing to label free imaging lipid nano domains
by Prof. Mark Wallace (University of Oxford)

Date: Wednesday 13th January 2016

Start Time: 3.00pm

End Time: 4.00pm

Location: Ramsay Lecture Theatre

Pore-forming proteins such as S.aureus alpha-hemolysin can be used to sense the nucleotide-specific blockade in ionic current from single-stranded DNA present within the pore. Commercialisation of these methods has significant potential to increase the throughput of genome sequencing to the point where it can become a routine medical procedure. However, there are practical limits to the required scaling for these methods to sequence an entire genome in a few minutes.To overcome these limits we use droplet-interface bilayers to enable parallel optical detection of 10000 measurements per mm^2, 3 ms temporal resolution, and sub-pA equivalent amplitude resolution.

Lipid rafts are sub-micron proteolipid domains responsible for membrane trafficking and signaling. Their small size and transient nature puts an understanding of their dynamics beyond the reach of existing techniques, leading to much contention as to their exact nature and role. We have exploited the differences in light scattering from lipid bilayer phases to achieve dynamic imaging of nanoscopic lipid domains without any labels. We resolve the diffusion of domains as small as 40 nm in radius and observe nanodomain formation, destruction and dynamic coalescence with a domain lifetime of 220 ± 60 ms. Domain dynamics on this timescale suggests an important role in modulating membrane protein function.