Dual Stimuli-Responsive Phenylboronic Acid-Containing Framboidal Nanoparticles by One-Step Aqueous Dispersion Polymerization

Phenylboronic acid-containing nanomaterials have found applications in various fields including biomedical engineering due to their unique stimuli-responsive characteristics. Contrary to the many reports on spherical nanoparticles, we are interested in nanostructures with different morphology which could potentially exhibit additional morphology-related effects. Here, phenylboronic acid-containing nanoparticles (PBANPs) in the size range of 80-250 nm in diameter were synthesized via aqueous dispersion polymerization of N-acryloyl-3-aminophenylboronic acid (PBAAM) using methoxy poly(ethylene glycol) acrylamide (PEGAM) as a polymerizable dispersant and N,N′-methylenebis(acrylamide) (MBAM) as a cross-linker. Microscopic analysis revealed that PBANPs were clusters, composed of smaller primary nanoparticles of ∼20 nm in diameter, possessing a framboidal morphology. The size of the PBANPs was significantly affected by the concentrations of PBAAM and PEGAM. Furthermore, PBANPs showed reversible swelling behavior in response to the changes in pH and fructose concentration. PBANPs could be used for fructose detection by the PBA-Alizarin Red S displacement assay. The unique framboidal morphology together with the characteristic properties of phenylboronic acid groups may be useful in biosensing applications. (Chemical Equation Presented).