Transparent Low Molecular Weight Poly(Ethylene Glycol) Diacrylate-Based Hydrogels as Film Media for Photoswitchable Drugs.

Théophile Pelras,Tom Scherzer,Sarah Glass,Christian Elsner,Bernd Abel,Agnes Schulze

doi:10.3390/polym9120639

Théophile Pelras, Tom Scherzer + Show 4 more

Open Access

https://doi.org/10.3390/polym9120639

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Abstract

Hydrogels have shown a great potential as materials for drug delivery systems thanks to their usually excellent bio-compatibility and their ability to trap water-soluble organic molecules in a porous network. In this study, poly(ethylene glycol)-based hydrogels containing a model dye were synthesized by ultraviolet (UV-A) photopolymerization of low-molecular weight macro-monomers and the material properties (dye release ability, transparency, morphology, and polymerization kinetics) were studied. Real-time infrared measurements revealed that the photopolymerization of the materials was strongly limited when the dye was added to the uncured formulation. Consequently, the procedure was adapted to allow for the formation of sufficiently cured gels that are able to capture and later on to release dye molecules in phosphate-buffered saline solution within a few hours. Due to the transparency of the materials in the 400–800 nm range, the hydrogels are suitable for the loading and excitation of photoactive molecules. These can be uptaken by and released from the polymer matrix. Therefore, such materials may find applications as cheap and tailored materials in photodynamic therapy (i.e., light-induced treatment of skin infections by bacteria, fungi, and viruses using photoactive drugs).

Highlights

Hydrogels can be defined as three-dimensional networks made of hydrophilic polymer chains that are able to retain a large amount of water or biological fluids in their swollen state [1,2,3,4]
The aim of this work was to demonstrate the formation of inexpensive, easy-to-make, transparent hydrogel materials that are demonstrate the formation of inexpensive, easy-to-make, transparent hydrogel materials that are capable of of releasing releasing absorbed absorbed large large organic organic molecules, molecules, like, like, for for instance, instance, tetrapyrrole-like tetrapyrrole-like structures, structures, capable which are commonly used in photodynamic therapy
The situation becomes more complicated if electron-rich molecules are are present in in the reaction mixture, because they can absorb a significant amount of photons in the absorption the reaction mixture, because they can absorb a significant amount of photons in the absorption rangeofofthe thephotoinitiator

Summary

Introduction

Hydrogels can be defined as three-dimensional networks made of hydrophilic polymer chains that are able to retain a large amount of water or biological fluids in their swollen state [1,2,3,4] Such networks can be either chemically (i.e., via covalent bonds) or physically (i.e., via entanglements, hydrogen bonds, crystallites, or van der Waals interactions) crosslinked, depending on the desired properties [2,4]. Hydrogels offer great potential as supporting materials for medical treatments, including among others contact lenses [6], artificial bones and cartilages [7], tissue engineering [8], cellular immobilization [9], separation of molecules and cells [10], in situ drug delivery materials [11], and bandages [12] In this context, transparent hydrogels that are able to release photoactive molecules into the skin may be very. These ROS are known to be cytotoxic and have been used in cancer therapy since the

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