A label-free, non-dispruptive, and real-time analytical device to monitor the dynamic features of biomolecules and their interactions with neighboring molecules is an essential prerequisite for biochip- and diagonostic assays. To explore one of the central questions on the lipid-lipid interactions in the course of the liquid-ordered (lo) domain formation, called rafts, we developed a method of reconstituting continuous but spatially heterogeneous lipid membrane platforms with molayer-bilayer juntions (MBJs) that enable to form the lo domains in a spatiotemporally controlled manner. This allows us to detect the time-lapse dynamics of the lipid-lipid interactions during raft formation and resultant membrane phase changes together with the raft-associated receptor-ligand binding through the surface plasmon resonance (SPR). For cross-validation, using epifluorescence microscopy, we demonstrated the underlying mechanisms for raft formations that the infiltration of cholesterols into the sphingolipid-enriched domains plays a crucial roles in the membrane phase-separation. Our membrane platform, being capable of monitoring dynamic interactions among lipids and performing the systematic optical analysis, will unveil physiological roles of cholesterols in a variety of biological events.
Bibliographical noteFunding Information:
This work was supported in part by KIST intramural grants (# 2E29530 , # 2V07430 , and # 2E29475 ), the National Research Foundation , and BK 21 Plus Program funded by the Ministry of Education of Korea . N.J.W. and S.-H.O. acknowledge support from the Minnesota Partnership for Biotechnology and Medical Genomics.
- Lipid monolayer-bilayer junction
- Lipid raft
- Lipid-lipid interaction
- Optical sensors
- Surface plasmon resonance