Fluorescent-Tagged, pH- and Redox-Responsive Polymeric Nanocarrier for Site-Specific Gastrointestinal Delivery

Stimuli-responsive polymeric nanocarriers have emerged as a promising strategy for targeted and controlled drug delivery, addressing limitations such as premature drug release and low bioavailability. Developing systems that respond to multiple physiological triggers is crucial for improving therapeutic precision and reducing side effects. The present study introduces the development of a unique amphiphilic random copolymeric nanocarrier with pH- and redox-responsiveness for advanced drug delivery applications. The copolymer incorporates hydrophilic carboxylic acid groups, hydrophobic coumarin moieties, and disulfide linkages, enabling self-assembly into spherical aggregates with a coumarin-rich core and a hydrophilic surface. These aggregates exhibit a low critical micelle concentration (0.006 mg mL^-1), ensuring stability in dilute environments. Spherical nanocarriers remain stable under acidic conditions (∼pH 2.0) and disassemble at neutral to basic pH (∼pH 7.4), mimicking gastrointestinal conditions. This property allows site-specific, stimulus-triggered drug release, with high drug-loading efficiency. The stimuli-responsiveness of the nanocarrier not only enhances oral drug delivery but also offers a versatile platform for encapsulating a wide range of therapeutics and diagnostics. This multifunctional nanocarrier system opens new avenues for personalized medicine and advanced material technologies, highlighting its potential for broader translational and industrial applications.