Three-dimensional frameworks where cells can settle and grow tissues and organs are desired in regenerative medicine. Material scientists of the University Würzburg have now developed new scaffolds with very special characteristics.
The requirements for these structures made of polymer fibers are high: as they are implanted in the human body they need to be fully degradable – not too fast, but not to slow either. Also, only specific cells are supposed to settle, connect, and grow. Other substances, such as proteins and cells from the blood, need to be kept away.
Researchers of the University of Würzburg have now presented a promising new technique to the public.
Extremely thin fibers grow in electric field
The production of extremely thin polymer fibers has been possible before but the researchers from Marburg have now developed a technique that enables the fabrication of these fibers in a single step.
Using the traditional technique, the so-called electrospinning, an electric field is applied to a liquid that creates thin “jets”. The formed fibers are extremely thin (up to 10 nanometers).
The researchers from Marburg have moved this technique a huge step forward. They developed a specific macromolecule, which – once put in the liquid – changes its surface drastically. This molecule changes the hydrophobic fibers into hydrophilic fibers. This conversion prevents the agglomeration of unwanted proteins onto the fiber surfaces, which is an unwanted effect in the medicine as it activates the immune system and disrupts the wound healing.
Scaffold for body’s own cells
On the other hand, several attachments are highly wanted: The body’s own cells are desired to attach to the fiber structures in order to connect to each other and form a compact matrix. This helps the body to close extensive injuries.
In the laboratory, scientists even work on methods that might enable the production of new tissues or even organs with the aid of the fibers. For this, they form three-dimensional structures in the required shape, where afterwards the desired cells, for example hepatocytes, can settle.
The advantages of these implants are obvious: As the organ can develop from the cells obtained directly from the patient himself, the body won’t reject the graft. An additional medical therapy is therefore not necessary anymore and the fibers degrade after a few months.
The newly developed technique allows a production of the fibers with a wide variety of characteristics in a much faster time. In the future, this might even allow the development of structures where complex tissues can grow.
New organs grow in the laboratory
"Depending on which cells are intended to attach to the fibers, the respective bioactive peptides are provided on the fiber surface," says Dr. Jurgen Groll. These peptides ensure that precisely the cells required in the respective case are attracted.
The method developed by Groll and his colleagues makes it possible to produce fibers and fiber structures in a much quicker way than before and to equip them with various characteristics. Groll is convinced that – with this method – it will become feasible in the near future to design structures in the laboratory that sustain the growth of complex tissues.
Illustration: Cell in growth in three dimensional tissue engineering scaffolds. –Groll Laboratory, University of Würzburg.
University of Würzburg News (12/13/10)
Research in Germany (12/17/10)
Abstract (Nature Materials; 2011 Jan;10(1):67-73)