UV-Cured Antibacterial Hydrogels Based on PEG and Monodisperse Heterofunctional Bis-MPA Dendrimers

Patrik Stenström,Yanmiao Fan,Sandra García-Gallego,Daniel Hutchinson,Yuning Zhang,Michael Malkoch

doi:10.3390/molecules26082364

Patrik Stenström, Yanmiao Fan + Show 4 more

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https://doi.org/10.3390/molecules26082364

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Abstract

Bacterial infections are one of the major threats to human health due to the raising crisis of antibiotic resistance. Herein, second generation antibacterial heterofunctional dendrimers based on 2,2-bis(methylol)propionic acid were synthesized. The dendrimers possessed six alkenes and 12 ammonium end-groups per molecule and were used to fabricate antibacterial hydrogels together with dithiol-functional polyethylene glycol (mol wt of 2, 6 and 10 kDa) as crosslinkers via thiol-ene chemistry. The network formation can be completed within 10 s upon UV-irradiation as determined by the stabilization of the storage modulus in a rheometer. The hydrogels swelled in aqueous media and could be functionalized with the N-hydroxysuccinimide ester of the dye disperse red 13, which allowed for visually studying the degradation of the hydrogels through the hydrolysis of the ester bonds of the dendritic component. The maximum swelling ratio of the gels was recorded within 4–8 h and the swelling ratios increased with higher molecular weight of the polyethylene glycol crosslinker. The gel formed with 10 kDa polyethylene glycol crosslinker showed the highest swelling ratio of 40 and good mechanical properties, with a storage modulus of 8 kPa. In addition, the hydrogels exhibited good biocompatibility towards both human fibroblasts and mouse monocytes, while showing strong antibacterial activity against both gram-positive and gram-negative bacteria.

Highlights

Hydrogels are physically or chemically crosslinked networks that absorb water without dissolution due to their crosslinks, which prevent solubilization of their components
We presented the facile synthesis of a library of cationic amino/ammonium-functionalized bis(methylol)propionic acid (bis-MPA) dendrimers [23]
We presented the synthesis of AB2C-monomers based on bis-MPA, which enabled the facile synthesis of heterofunctional polyester dendrimers via a divergent growth approach [27]

Summary

Introduction

Hydrogels are physically or chemically crosslinked networks that absorb water without dissolution due to their crosslinks, which prevent solubilization of their components Their unique physiochemical properties have led to them having a wide range of applications in the field of biomedicine [1]. Hydrogel-based contact lenses are perhaps the most successfully commercialized example These soft contact lenses, introduced by Czech chemist Otto Wichterle in the early 1960s [2], are considered by most users to be significantly more comfortable than harder lenses based on e.g., poly(methyl methacrylate) (PMMA). Another example of commercialized hydrogels is the superabsorbent polymers used in hygiene products such as disposable diapers [3]. Such active and functional gels have been applied in the creation of self-healing hydrogels [3,4,5], antimicrobial wound dressings [6,7,8,9,10], hydrogels for drug-delivery [11,12,13] and in tissue engineering [14,15,16,17]

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