Synthesis of Photopolymerizable Hydrophilic Macromers and Evaluation of Their Applicability as Reactive Resin Components for the Fabrication of Three‐Dimensionally Structured Hydrogel Matrices by 2‐Photon‐Polymerization

Abstract

Two‐photon polymerization (2‐PP) is a promising new photolithographic technique to fabricate three‐dimensional (3D), micro‐ and nano‐structured tissue engineering scaffolds from photopolymerizable monomers. Although various photo resins are known for the use in 2‐PP, there is currently a need for photo‐curable monomers processable by 2‐PP to generate biocompatible 3D‐structured hydrogel materials for soft or cartilage tissue regeneration. In the present work hydrophilic methacrylate monomers and macromers based on synthetic poly(glycerine) and poly(ethylene glycol) urethanes as well as on the biopolymers dextran and hyaluronan is prepared. The photopolymerization behavior of these substances are investigated and formed hydrogel networks are studied with regard to their mechanical properties, cytocompatibility, and hydrolytic degradation. Based on these examinations simple 3D model structures are fabricated from these photo‐curable monomers and macromers by 2‐PP. It is shown that both the synthetic monomers and the dextran methacrylate macromer are efficient 2‐PP starting materials whereas the hyaluronan methacrylate can be used for 2‐PP only in combination with suitable water‐soluble co‐monomers. No cytotoxic effects are found in preliminary chondrocyte cultivation experiments on 2‐PP‐fabricated scaffolds but initial cell adhesion on the hydrophilic scaffold surfaces is rather low and has to be further improved to apply these structures in tissue engineering.

Drug Delivery From Poly(ethylene glycol) Diacrylate Scaffolds Produced by DLC Based Micro‐Stereolithography

“…In the research field of bone regeneration based on photopolymerized hydrogels groups show interesting scaffold specimens with high potential in regenerative medicine . Hydrogel scaffolds can easily be formed via photo‐initiated polymerization, as for instance shown for the preparation of PEGDA scaffolds by dynamic photomask micro‐stereolithography or two‐photon polymerization . Fairbanks et al demonstrate that human mesenchymal stem cells proliferate well on hydrogel structures .…”

Electron-beam generated porous dextran gels: Experimental and quantum chemical studies

“…As previously reported, hydrogels prepared from D-MA in a conventional radical polymerization initiated thermally (298 K, ammonium peroxodisulfate/ N,N,N',N'tetramethylethylene diamine or potassium peroxodisulfate/ triethanolamine) (Möller et al 2007) or photochemically (eosin Y/triethanolamine initiation system) (Berg et al 2011) were investigated in respect to their biodégradation behavior. It was found that thermal and photochemical polymerization under the given conditions results in hydrogels, which slowly degraded in simulated body fiuid (SBF) medium.…”

Optimized Photoinitiator for Fast Two‐Photon Absorption Polymerization of Polyester‐Macromers for Tissue Engineering

“…But, this can cause unknown changes in the material characteristics due to the enhanced concentration of incorporated PI. [11] Several donor-p-donor and donorp-acceptor-p-donor systems, [11,22,23] similar as various acetophenons [24][25][26] have been proven to be efficient PIs for TPP. [17,18] When it comes to the application of the generated constructs in biomedical applications, initiator migration issues have been considered.…”

“…[19,20] In principle, the migration can occur by set-off, by diffusion, and by gas-phase transport. [24,25,35] 2.1.1. For example, one route for acetophenone based PIs, like Irgacure 369 (IC369), is to generate their own scission products (type I), which are in this case small aromatic radicals that can react to potentially harmful side products.…”