polymeric nanoparticles with dual responsive interlayers

Stimuli-responsive nanoparticles play a crucial role in many applications where on-demand effects are desirable, including drug delivery systems. Boronic acid-based systems are of particular interest for their ability to hydrogen bond intra/intermolecularly, but also to bind with diol/catechol moieties as a dynamic covalent (DC) interaction in a pH-dependent manner. Boronic acids, therefore, have great potential to be embedded in polymeric constructs as interlayers in order to perform programmed responsive operations triggered by pH and oxidative stress. We developed linear and bottlebrush amphiphiles with boronic acid blocks as interlayers. Nanoparticles from linear polymers were utilized to study hydrogen bonding effects on controlled release of a model hydrophobic solute. Nanoparticles from bottlebrushes were studied in the context of interlayer crosslinking effects with diol-containing crosslinkers in a stimuli-responsive manner. We discuss the effects of the self-assembly method (e.g., rapid nanoprecipitation vs. direct dissolution) on the physicochemical properties of the resulting nanoparticles. In addition, we studied the mixing process with stabilizers and evaluated the programmed responsiveness of nanoparticles under different pH and oxidative conditions to evaluate solute release kinetics. In summary, boronic acid-based nanoparticles hold great potential for pH and oxidative stress-responsive systems for environmentally-triggered release applications.