We conducted an in depth study to determine the actual three-dimensional structure of polymeric objects extracted from photopolymerized lipid / nanotube assemblies. The DLS, UV, TEM, SEC, SANS results led us to conclude that the nanotubes had a linear structure, countering the existing hypothesis that the objects would have a three-dimensional ring-shaped structure (published in Polymer Chemistry and Physics).
Furthermore, studies using of fluorescent probes allowed us to investigate the dynamic character of the objects using extinction of fluorescence experiments. Interestingly, the polymers maintained their capability to exchange fluorescence between particles even after polymerization.
However, in spite of this dynamic character, the polymerized arrangement possesses a defined geometry and is very stable. This was based on micelle migration in electrophoresis gels and the encapsulation / liberation of fluorescent probes.
Biological applications
We decided to evaluate the ability of these nano constructs in various chemical biology applications, such as probe delivery and targeting.
1) We showed that auto-arrangements polycationic nano constructs, with specific polar heads are capable of effective DNA transfection in mammalian cells. (Collaboration Dr Jean-Serge Remy, University of Strasbourg)
2) Polymerized lipidic micelles could be used as a multivalent platform to study the inhibition of the HIV trans infection by targeting the interaction DC-SIGN - Sugar. The chosen in vitro model mimics the trans infection of a healthy cell by an HIV infected cell. We have found that certain combinations of glycosylated micelles allow the very effective inhibition of this trans HIV infection. Although these results are still preliminary, they present a real and significant step forward in the development of an antiviral vaginal cream. (Collaboration Dr Evelyne Schaeffer).
3) In vivo studies of the micelles are in progress to explore their possible applications in medical imaging. The first results have shown that certain types of particles are able to trap Tc, a PET imaging tracer ( in collaboration with Dr David Brasse, Dr Jean-Serge Remy).
Photopolymerized lipidic constructs
