Dr. Sigalit Meker Presents: Patterned Lipid Bilayers on Titanium Dioxide
Dr. Sigalit Meker was enjoying her family vacation on sunny Sentosa Beach when she got the email: “Hi Sigi. What have you been working on this month? The group wants you to share your work when you get back.”
Alas, life is work, and work is life - at ETS.
Dr. Meker arrived early and eager to share her research this morning. Outfitted in a clean pink blouse and matching pink coffee cup, Dr. Meker smiled as she introduced us to a new concept: “Patterned Lipid Bilayers on Titanium Dioxide.”
Dr. Meker first refreshed our newest members with the concept lipid bilayer fabrication at the molecular level. Typical Quartz-Crystal Microbalance with Dissipation (QCM-D) substrates such as silicon dioxide and titanium dioxide, she explained, repel negatively charged lipids in low-ionic strength solvents. By “playing with” solution pH and ionic salt concentration, however, we can control vesicle adsorption and rupture.
But what if want to make bilayers that are more than just “homogenous lipid sandwiches”? What if we want negatively charged lipid bilayer compositions – which are difficult to form, due to static repulsion from solid substrates -- that are also recyclable, patternable, and that can remain stable until use even without solvent? This is where patterned DOCP lipid bilayers shine.
Dr. Meker showed us how she deposited the negatively charged lipid, DOCP, onto a titanium dioxide solid substrate via covalent bonding with both conventional inkjet printer and stamping techniques. The resulting intricate patterns resembled grids and even star-shapes.
The technique is not perfect, but it’s a start with promising potential: because the bottom layer is affixed to the substrate, the upper leaflet can be "peeled off" through ethanol washing and subsequently replaced with other lipid types, resulting in asymmetric bilayers that are air-stable and that can be formed in desired patterns.
The implications are impressive. Not only does this method allow for a potentially patterned lipid layer that is air-stable until use, but it also opens avenues for patternable bilayers with flexible composition for use in more diverse sensing applications. Future work on this idea will require confirming the individual lipid leaflet compositions, for example, by adding specific antibodies. While ETS has long specialized in creating supported lipid bilayers on solid supports, Dr. Meker’s research is poised to take us into a new direction.