| AVS 55th International Symposium & Exhibition | |
| Biomaterial Interfaces | Thursday Sessions |
| Session BI+NC-ThM |
| Session: | Engineering Biointerfaces |
| Presenter: | S. Svedhem, Chalmers University of Technology, Sweden |
| Authors: | S. Svedhem, Chalmers University of Technology, Sweden A. Kunze, Chalmers University of Technology, Sweden H. Ekstrand, Chalmers University of Technology, Sweden P. Sjövall, SP Technical Research Institute of Sweden R. Frost, Chalmers University of Technology, Sweden M. Edvardsson, Chalmers University of Technology, Sweden B. Kasemo, Chalmers University of Technology, Sweden |
| Correspondent: | Click to Email |
Engineering of surface-supported lipid membrane model systems is currently a very active field of research. The present contribution will focus on two recent examples from our group in this area; (i) Lipid exchange between liposomes and supported lipid membranes of opposite charge, and (ii) The action of lipases on supported lipid membrane structures. These examples cover different kinds of supported lipid structures; both (planar) supported lipid bilayers and (intact) supported liposomes, as well as different kinds of biomolecular interactions associated with them. Key experimental techniques used to follow processes at these interfaces are the quartz crystal microbalance with dissipation monitoring (QCM-D), optical reflectometry, surface plasmon resonance (SPR), fluorescence microscopy, atomic force microscopy (AFM) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). Our first examples deals with lipid exchange/transfer between lipid membranes, which is important for many biological functions, but which has also the potential for in situ engineering of supported membranes. To learn more about how the dynamics of such processes can be studied, we have investigated the interaction of positively and negatively charged lipid vesicles with supported lipid bilayers (SLBs) of opposite charge. In particular, it was possible to follow the different steps during such modification processes both by QCM-D and TOF-SIMS, the latter allowing direct estimation of the fraction of different lipids in the membrane. These results have also implications for studies of how nanoparticles interact with membranes. The second example covers how lipases (PLA2 and PLD) act on membranes, and in particular how lag phases for such interactions can be monitored by QCM-D. Depending on the type of lipase under study, either dissolution or membrane morphology changes were observed. In conclusion, the combination of surface-supported lipid membranes and surface-sensitive analytical techniques allows for detailed studies of processes of relevance for biological membranes. In particular, the molecular composition can be controlled, and morphological changes of the membrane structure can be induced and visualized