Enhanced Biofunctionalization of Gold Nanoparticles Using the ISOFURE Method

The unique chemical and physical properties of gold nanoparticles (GNPs) render them as effective carriers for various biomedical applications. During the multi-step functionalization of the particles for these applications, it is important to tailor the surface properties in order to avoid agglomeration issues associated with charge neutralization, hydrogen bonding, etc. Although various additives have been employed to reduce agglomeration (such as charge and steric stabilizers), these result in an overall decreased surface area available for therapeutic functionalization. Herein, a novel strategy of isolating, functionalizing, and subsequently releasing (ISOFURE) biofunctionalized nanoparticles using a polymer matrix is reported to solve such issues. Specifically, a biodegradable poly(β-amino ester) hydrogel composite was synthesized with GNPs entrapped in its matrix. GNPs were biotinylated within the hydrogel matrix, and the GNPs were bound with streptavidin upon release from the hydrogel matrix. GNPs were then conjugated with the model enzyme catalase that was pre-biotinylated. UVvisible spectroscopy and bioassaying confirmed enzymatic activity of catalase bound GNPs via the ISOFURE methodology. The ISOFURE methodology has been shown to be an effective method to enhance biomolecular loading without the need of external stabilizing reagents