New class of self-assembling macromolecules: amphiphilic invertible polymers (AIPs), have been designed by combining hydrophobic and hydrophilic constituents distributed along the polymer backbone. AIPs form invertible polymeric micelles or self-arranged aggregates of micelles in response to tuning of the polymer concentration and environmental polarity. The resulting invertible self-assembled nanostructures are functional in both polar and non-polar environments, giving these micelles potentially broad use in many chemical and biochemical applications. AIP macromolecules based on polyethylene glycol (PEG) and aliphatic dicarboxylic acids (AIPs- I), as well on PEG and polytetrahydrofuran (AIPs-II), form micelles, and self-assemble in micellar aggregates inversely responding to the changing AIP concentration and solvent polarity (scheme below).
Our current research with AIPs-I and AIPs-II is divided into two areas:
– Mechanism of AIP macromolecules self-assembly and inversion in response to the changing solvent polarity. We are working on phase diagram for the AIP self-assembled aggregates using systematical NMR, EPR study, as well as and scattering techniques. Careful analysis should provide us with mechanism of the invertibility of the self-assembly by micellar interactions with biomembrane.
– Bio-and pharmaceutical applications. In collaboration with Dr.Maran’s group at Mayo Clinic, Rochester,MN, we are working on developing the AIP-based nanocarriers which allow specific interactions with cell membrane and, possibly, delivery of poorly soluble lipophilic drugs, peptides, proteins. The ability of AIP assemblies “to cross interface” between polar and non-polar medium is considered.