Planar plasmonic antennas resolve transient nanoscopic phase separation in biological lipid membranes
Nanoscopic domains (also known as lipid rafts) in living cell membranes have been postulated to play major roles in regulating a large variety of biological functions. However, the underlying basis for their formation remains under heavy debate because their typical sizes and characteristic times are below the resolution of standard microscopes.
In a recent ACS Nano publication entitled Transient Nanoscopic Phase Separation in Biological Lipid Membranes Resolved by Planar Plasmonic Antennas, we report on the application of in-plane plasmonic antenna arrays with different nanogap sizes in combination with fluorescence correlation spectroscopy (FCS) to assess the dynamic nanoscale organization of mimetic biological membranes. Our approach takes advantage of the highly enhanced and confined excitation light provided by dimer nano-antennas together with their outstanding planarity to investigate membrane regions as small as 10 nm in size with microsecond time resolution.
- We show the existence of transient nanoscopic domains in both liquid-order and liquid-disorder phases of mimetic biological membranes, featuring characteristic sizes of 10 nm with residence times between 30 µs and 150 µs
- Our planar optical antenna methodology provides nanoscale observation areas with microsecond time resolution and full biocompatibility. This constitutes a significant step forward in our ability to address native biological membranes with unprecedented spatiotemporal resolution.