Nanoparticles have emerged as promising therapeutic and diagnostic tools, due to their unique physicochemical properties. The specific core and surface chemistries, as well as nanoparticle size,all play critical roles in particle transport and interaction with biological tissue. Localized delivery of therapeutics from hydrogels is well established, but these systems generally release molecules with hydrodynamic radii less than ~5 nm. Here, model nanoparticles with diameters between 10-40 nm and biologically-relevant surface chemistries are analyzed for their release from well-characterized hydrogels. Functionalized gold nanoparticles or quantum dots were encapsulated in three-dimensional poly(ethylene glycol) (PEG) hydrogels with varying mesh size. Nanoparticle size, surface chemistry, and hydrogel mesh size all influenced the release of particles from the hydrogel matrix. Size influenced nanoparticle release as expected, with larger particles releasing more slowly. However, citrate-stabilized nanoparticles were not released from hydrogels, and negatively-charged carboxyl or positively-charged amine-functionalized nanoparticles were released from hydrogels at slower rates than neutrally charged PEGylated nanoparticles of the same size. To further investigate the distribution and transport of nanoparticles within the PEG hydrogel matrix, transmission electron microscopy was used to image embedded nanoparticles within hydrogel sections. The nanoparticle-hydrogel interactions observed in this work will aid in development of future localized delivery systems.
Citation: Journal of Nanoparticle Research
Pub Type: Journals
Hydrogel, gold nanoparticles, quantum dots, surface functionalization, drug delivery