Polyamidoamine Dendrimer Microgels: Hierarchical Arrangement of Dendrimers into Micrometer Domains with Expanded Structural Features for Programmable Drug Delivery and Release


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.


Chemical and Biochemical Engineering


This work was supported, in part, by the National Institutes of Health (R01EY024072).

Keywords and Phrases

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

International Standard Serial Number (ISSN)

0024-9297; 1520-5835

Document Type

Article - Journal

Document Version


File Type





© 2018 American Chemical Society (ACS), All rights reserved.

Publication Date

14 Aug 2018