Smart Poly(acrylic acid)/Poly(acrylamide) Microgels with Interpenetrating Polymer Network Structure

Microgels with precisely tuned properties are of great importance as drug delivery systems. Here, we report the synthesis of microgel particles (MGs) with an interpenetrating polymer network structure composed of poly(acrylic acid) (PAA) and polyacrylamide (PAAM) for their potential application as cationic drug carriers. The MG properties were investigated via several analytical techniques, such as Dynamic Light Scattering (DLS) and zeta potential (ZP) measurements, Diffusion Nuclear Magnetic Resonance (NMR) spectroscopy, Asymmetrical Flow Field-Flow Fractionation (AF4) and Transmission Electron Microscopy (TEM). The MGs show pH-dependent swelling behavior with a radius of ~100 nm at collapsed state (pH < 4.5) and swell up to ~450 nm (pH~7), while their ZP decreases from −5 to −40 mV, depending on their composition. The results of the conducted studies demonstrate the potential of synthesized microgels for drug delivery in the gastrointestinal tract.