Design and development of porous pluronic-based scaffolds for tissue engineering

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Functionalized Pluronic® F127 derivatives used as scaffold material for liver tissue engineering

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Exploring the future of hydrogels in rapid prototyping: a review on current trends and limitations

The combined use of hydrogels and rapid prototyping techniques has been an exciting route in developing tissue engineering scaffolds for the past decade. Hydrogels tend to be an interesting starting material for soft, and lately even for hard, tissue regeneration. Their application enables the encapsulation of cells and therefore an increase of the seeding efficiency of the fabricated structures. Rapid prototyping techniques, on the other hand, have become an elegant tool for the production of scaffolds with the purpose of cell seeding and/or cell encapsulation. By means of rapid prototyping, one can design a fully interconnected 3-dimensional structure with predetermined dimensions and porosity. Despite this benefit, some of the rapid prototyping techniques are not or less suitable for the generation of hydrogel scaffolds. In this review, we therefore give an overview on the different rapid prototyping techniques suitable for the processing of hydrogel materials. A primary distinction is made between (1) laser-based, (2) nozzle-based and (3) printer-based systems. Special attention is given to current trends and limitations regarding the respective techniques. Each of these techniques is further discussed in terms of the different hydrogel materials used so far. One major drawback when working with hydrogels is the lack of mechanical strength. Therefore, maintaining and improving the mechanical integrity of the processed scaffolds has become a key issue regarding 3-dimensional hydrogel structures. This limitation can be overcome either during or after post-processing the scaffolds, depending on the applied technology and materials

Stability of Pluronic® F127 bismethacrylate hydrogels : reality or utopia?

Hydrogels are hydrophilic polymer networks which have the ability to absorb significant amounts of fluids from the surrounding environment. Therefore, these polymer materials can be interesting for various engineering applications including tissue engineering, drug release systems, self-healing concrete, etc. As a result, both stable as well as degradable absorbing polymers are required. In the present study, the long-term stability of cross linked end-group modified Pluronic (R) F127 (PEO-PPO-PEO tri-block copolymer) hydrogels, i.e. Pluronic (R) F127 bismethacrylate (F127 BMA) hydrogels constituting different polymer concentrations (25 and 30% w/w) and crosslinked by two types of photo-initiator (Irgacure (R) 2959 versus VA-086 (R)) were evaluated in various environmental conditions. Degradation was evaluated by determining the gel fraction of the materials stored either in inert atmosphere, air, water or phosphate buffered saline. In addition, the temperature of the surrounding environment was also varied to assess the effect of temperature on the degradation profile of the cross-linked hydrogels. The results indicate that the synthesized hydrogel degrades as a function of time, showing pronounced degradation upon storage in dry and wet conditions both at room temperature and at body temperature. The obtained results clearly and explicitly limit the application of these hydrogels for self-healing concrete. In the building industry, degradation is undesired as a stable polymer is required to achieve sealing and healing irrespective of the applied timeframe. However, (bio-)degradation can be particularly useful for several biomedical applications including drug delivery