Redox-Responsive Self-Assembled Amphiphilic Nanosheets from Polyglycerol Sulfate–Lipoic Acid Copolymers for Targeted Cancer Drug Delivery

Targeted drug delivery systems that are stimuli-responsive offer great potential for enhancing the therapeutic activity of drugs, decreasing off-target effects, and improving bioavailability. This proof-of-concept study introduces an amphiphilic drug delivery system (DDS) capable of loading hydrophobic cargo. Elevated glutathione (GSH) levels, characteristic of certain types of cancer cells' microenvironment, degrade the nanostructures and release the cargo. Linear polyglycerol sulfate (LPGS), known for its excellent biocompatibility, is combined with lipoic acid (LA). LA facilitates the formation of cross-linked nanosheet amphiphiles sensitive to reductive conditions. Morphological changes are observed by scanning electron microscopy (SEM), cryogenic transmission electron microscopy (Cryo-TEM), and cryogenic electron tomography (Cryo-ET) upon UV irradiation (<i>h</i>ν), creating a stable aggregate for loading hydrophobic cargo and assembling into sheets at elevated concentrations. The resulting material displays controlled release of model dyes under increased levels of GSH, tunable by the polymer size and LPGS:LA acid ratios. This behavior enhances targeted therapy and reduced off-target effects. Further loading with paclitaxel and subsequent release, together with <i>in vitro</i> assays, demonstrates the system's compatibility with an anticancer drug.