We report on the fabrication of micrometer-sized dendrimer hydrogels (µDHs) using the water-in-oil (w/o) inverse microemulsion method coupled with the highly efficient aza-Michael addition. EDA core polyamidoamine (PAMAM) dendrimer G5 (10 wt %) and poly(ethylene glycol) diacrylate (PEG-DA, Mn = 575 g/mol) (the molar ratio of amine/acrylate = 1/1) were dissolved in the water phase and added to hexane in the presence of surfactants span 80/tween 80 (5/1, w/w) (volume ratio of hexane to surfactants: 70:1) to form w/o microemulsions, in which PAMAM G5 cross-links with PEG-DA via the aza-Michael addition reaction. The resulting microgels are within 3-5 µm with relatively narrow size distribution. µDHs are pH-responsive degradable. They show good cytocompatibility and do not cause acute toxicity in vivo. Furthermore, they can realize a high loading of the hydrophobic drug CPT and enter the cells in the form of particles. The CPT and CPT/dendrimer complex can be slowly released following the zero-order release kinetics. Taken together, µDHs possessing hierarchically ordered dendrimers in micrometer domains represent a new class of microparticles with expanded structural features for programmable drug delivery and release.
- Addition reactions,
- Dendrimers,
- Gels,
- Hexane,
- Inverse problems,
- Manganese removal (water treatment),
- Microemulsions,
- Micrometers,
- Polyethylene glycols,
- Surface active agents,
- Targeted drug delivery, Aza-Michael addition,
- Drug delivery and release,
- Inverse micro emulsion,
- Narrow size distributions,
- Polyamidoamine dendrimers,
- Polyethylene glycol diacrylate,
- Structural feature,
- W/o microemulsions, Controlled drug delivery
Available at: http://works.bepress.com/hu-yang/54/
This work was supported, in part, by the National Institutes of Health (R01EY024072).