Lasers create biomimetic scaffolds for growing cells

July 14, 2011
Capillaries Tissue

Capillaries made of artificial, resilient polymer with a diameter of 20 µm (credit: Fraunhofer Institute for Laser Technology ILT)

Research scientists at the Fraunhofer Institute for Laser Technology ILT have succeeded in producing hybrid biomimetic matrices that can serve as a basis for scaffold and implant structures on which cells can grow effectively.

The researchers developed a process for producing biomimetic scaffolds that closely emulate endogenous (within the body) tissue. This process allows the fabrication of specialized model systems for the study of 3-D cell growth.

The scientists used dissolved proteins and polymers that were irradiated with laser light and cross-linked by photolytic processes. They deployed specially developed laser systems that — by means of ultra-short laser
pulses — triggered multiphoton processes that led to polymerization.

Polymer Structure

Test matrix consisting of a polymer support structure and a protein functional structure (credit: Fraunhofer Institute for Laser Technology ILT)

The key factors in the process were the extremely short pulse durations and the high laser-beam intensities. The short pulse duration led to almost no damage by heat to the material. Ultra-fast pulses in the megawatt range drove a massive amount of protons into the laser focus in an extremely short time, triggering a non-linear effect.

The molecules in the liquid absorbed several photons simultaneously, causing free radicals to form that triggered a chemical reaction between the surrounding molecules.

As a result of this process of multiphoton polymerization, solids formed from the liquid. Using CAD data, a computer controlled the position of the laser beam through a microscope with a precision of a few hundred nanometers, in such a way that micrometer-fine, stable volume elements of cross-linked material gradually formed.

The researchers were able to produce cell scaffolds with a resolution of approximately one micrometer from dissolved proteins and polymers.

The long-term aim is to also use the process to produce complete artificial tailor-made organs, the researchers said.