Reversible pH- and Lipid-Sensitive Vesicles from Amphiphilic Norbornene-Derived Thiobarbiturate Homopolymers

Synthesis of a new molecular architecture, an amphiphilic, norbornene-derived thiobarbiturate homopolymer (NTBH), by ring-opening metathesis polymerization (ROMP) and its characterization is discussed. The newly designed hompolymer shows a self-assembled vesicle formation in aqueous solution. Dynamic light scattering and critical aggregation concentration studies confirm the aggregate formation in solution while atomic force microscopy and transmission electron microscopy of the dried sample on the silicon substrate further confirm the vesicular morphologies of these amphiphilic homopolymers. Encapsulation studies of hydrophilic doxorubicin and hydrophobic Nile red suggest the reversible nature of the NTBH vesicles. Dye release studies in acidic and lipophilic environment demonstrate the stimuli-responsive nature of the novel systems. The results demonstrate that these self-assembled NTBH vesicles have great scope in the field of medicine as they symbolize themselves as promising carriers for the stimuli-triggered intracellular delivery of hydrophobic drugs.