title: Formation of Cucurbit[8]uril-Based Supramolecular Hydrogel Beads Using Droplet-Based Microfluidics.
abstract: Herein we describe the use of microdroplets as templates for the fabrication of uniform-sized supramolecular hydrogel beads, assembled by supramolecular cross-linking of functional biopolymers with the macrocyclic host molecule, cucurbit[8]uril (CB[8]). The microdroplets were formed containing diluted hydrogel precursors in solution, including the functional polymers and CB[8], in a microfluidic device. Subsequent evaporation of water from collected microdroplets concentrated the contents, driving the formation of the CB[8]-mediated host-guest ternary complex interactions and leading to the assembly of condensed three-dimensional polymeric scaffolds. Rehydration of the dried particles gave monodisperse hydrogel beads. Their equilibrium size was shown to be dependent on both the quantity of material loaded and the dimensions of the microfluidic flow focus. Fluorescein-labeled dextran was used to evaluate the efficacy of the hydrogel beads as a vector for controlled cargo release. Both passive, sustained release (hours) and triggered, fast release (minutes) of the FITC-dextran was observed, with the rate of sustained release dependent on the formulation. The kinetics of release was fitted to the Ritger-Peppas controlled release equation and shown to follow an anomalous (non-Fickian) transport mechanism.
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Appel
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Parker
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Oren A
authors.initials: OA
authors.lastname: Scherman
authors.affiliation: Department of Chemistry and ‡Melville Laboratory for Polymer Synthesis, Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Chris
authors.initials: C
authors.lastname: Abell
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry*; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils
chemical_list: D001952:Bridged-Ring Compounds; D020100:Hydrogels; D007093:Imidazoles; C507198:cucurbit(8)uril; D047028:Macrocyclic Compounds; D000099246:Cucurbit(n)urils