Click reactive microgels as a strategy towards chemically injectable hydrogels

Abstract

Doubly crosslinked microgels (DX microgels) are hydrogels constructed by covalently interlinked microgel particles, offering two levels of hierarchy within the network, the first one being the microgel and the second being the interlinked microgel network. Herein we describe an efficient approach for DX microgel synthesis via the ultrafast triazolinedione (TAD)-based click reaction. Cyclopentadienyl functional microgels were prepared by a conventional water in oil (W/O) suspension, free-radical copolymerization of poly (ethylene glycol) methyl ether methacrylate (M-n = 500 g mol(-1)) with glycidyl methacrylate and ethylene glycol dimethacrylate as crosslinkers. Microgel post-modification was subsequently achieved by reacting glycidyl functions with sodium cyclopentadienide (NaCp), resulting in Cp-functionalized microgels. Finally, the microgels were mixed with a bis-TAD functional crosslinker, resulting in crosslinking with adequate kinetics (minutes to seconds) to form a doubly crosslinked microgel network. Size distributions of swollen microgels before creation of the second network were followed by optical microscopy and particle size measurements. The efficient functionalization of the microgels with Cp units was demonstrated by a fluorescence labelling study. Dynamic rheology data showed the increase of mechanical properties from the microgels to the doubly crosslinked microgel network formed after addition of the TAD crosslinker. The current study thus highlights the efficiency of catalyst free modular ligation chemistry to synthesize DX microgels with a very fast gelation process from 5 minutes to 15 seconds depending on the crosslinker to Cp ratio, from 0.7 to 1 respectively

Galactose-functionalized injectable thermosensitive microgels for target specific uptake in hepatoma cells

“…As a class of soft materials, microgels have been applied in many fields due to their high-water content, 1,2 ideal chemical 3,4 and physical structure, 5,6 including drug delivery systems, 7,8 catalysts 9,10 and nanotechnology, 11,12 good mechanical properties 13 and good biocompatibility. 14,15 Moreover, the functions of microgels can be extended by modifying different molecules and groups on their surfaces, 16,17 such as enhancing wound healing, 18 enriching oxygen, 19 tissue regeneration, 20 target, 21 biosensing, 22 topical antifungal therapeutics, 23 etc.…”

Tandem Metathesis Polymerization-Induced Self-Assembly to Nanostructured Block Copolymer and the Controlled Triazolinedione Modification for Enhancing Dielectric Properties

“…1,2,4-Triazoline-3,5-dione (TAD) as a polar molecule has a high dipole moment and can effectively react with many different functional aryl and unsaturated aliphatic groups in seconds under mild conditions without the requirement of catalysts, irradiation, or other external stimulus. , The Diels–Alder and Alder–ene reactions based on TAD as one of the versatile click chemistry molecules have attracted more and more attention from engineering practice and academic field. − Despite the large number of reports on the modification of different nanostructures previously by using click chemistry, , the TAD-based click reaction is rarely used to modify self-assemblies, especially all-polymeric nanostructures. It is well-known that the conjugated dienes and enes are widely used for efficient postfunctionalization by virtue of the TAD click reaction. − For example, when the TAD molecule was reacted with the double bonds on the PNBE backbone, the glass transition temperature, molecular polarity, and mechanical properties of polymers were optimized, which drastically improve the dielectric properties and application potential of PNBE film in energy storage devices.…”

“…12,13 The Diels−Alder and Alder−ene reactions based on TAD as one of the versatile click chemistry molecules have attracted more and more attention from engineering practice and academic field. 14−18 Despite the large number of reports on the modification of different nanostructures previously by using click chemistry, 19,20 to modify self-assemblies, especially all-polymeric nanostructures. It is well-known that the conjugated dienes and enes are widely used for efficient postfunctionalization by virtue of the TAD click reaction.…”

Investigation of the Formation Process of PNIPAM-Based Ionic Microgels

“…Microgels as soft materials have been applied in many areas such as drug delivery systems, , catalysts, , and nanotechnology. , Owing to their wide applications, many types of microgels are prepared including polyacrylamide, , poly­( N -isopropylacrylamide) (PNIPAM), − and poly­(acrylic acid) microgels. , Among them, the most studied is PNIPAM-based microgels for their thermo-sensitivity. Generally, they are covalent bond cross-linked with the cross-linker N , N ′-methylenebisacrylamide (MBAA).…”