Due to their high precision and flexibility,laser processes are versatile tools for small-scale production of medical devices. Processing materials with lasers makes it possible to functionalize specific areas of the surfaces when preparing them for medical technology applications. At the Fraunhofer Institute for Laser Technology ILT, experts are developing various methods for use in biomedical engineering.
High brilliant fiber lasers can be used to drill or join polymer parts for catheters and microfluidic components without degradation and under sterile conditions. For dosing systems and miniaturized drug depots, short-pulse lasers can be used to create pores in the millimeter or even micrometer range. Soft and flexible materials such as polymers as well as brittle materials such as ceramics can be processed using this technique.
In addition, structuring and molding processes can be applied to produce components for minimally invasive surgical and diagnostic solutions based on fundamental biological principles, such as the sensory hairs of insects (bionics). This means threadlike structures that extend outwards can be producedwith a high aspect ratio by casting laser-generated molds. Targeted photochemical functionalization makes it possible for scientists to control both a surface’s wetting and cell adhesion properties.
The cells of our body require specific biological stimuli to form tissues. To influence and direct this cell growth, our experts are investigating mechanical, topographical and molecular cues in in vitro cell cultures that can be implemented at precise positions on synthetic surfaces using laser-based modifications. Micro and nano structures alter the substrates’ roughness and wetting properties, which, in turn, affect cell adhesion and proliferation. This approach generates guidance structures that foster targeted cell growth. In particular, nanogrooves, which are produced with interference structuring, can change the distribution of the cell’s focal adhesions and affect complex mechanisms such as cell proliferation and differentiation.
Another technique involves laser radiation for the selective photochemical functionalization of surfaces. The surfaces are activated by photo-oxidation, which generates anchor groups for covalent immobilization of biomolecules such as peptides, proteins and growth factors. This process also allows researchers to create gradients for certain bio-molecules in order to precisely control how the cells are integrated. In the same way, photoactivatable molecules, or photolinkers, can be used in radiated zones to selectively bond with polymer surfaces and be ready for further functionalization with bioactive compounds. One possible application of this technique is the development of a new kind of artificial implant for the abdominal wall. The implant is selectively modified with various growth factors so that it integrates well into the tissue without interfering with neighboring organs.
The group of photolinkers also includes photocleavable linkers: special anchor groups that decompose upon radiation with light of a certain wavelength. Molecules immobilized by one of these linkers can be released in a targeted way. How to control the time and location of the release of active ingredients – drug delivery – is the subject of intense research. For many areas of medicine, the development of bioactive medical devices represents a promising new form of treatment. One example is a photorelease system for tumor reduction, which uses selective laser radiation to release doses of chemotherapy drugs on demand from tailor-made polymer scaffolds.
Besides ablation and photochemical functionalization of implant surfaces, additive processes are another way to produce functional scaffolds for applications such as tissue regeneration. One promising approach here is to make personalized implants from artificial scaffolds, which are seeded in vitro with autologous cells. To that end, scientists at Fraunhofer ILT are developing laser polymerization processes for manufacturing scaffold structures and artificial vascular systems made from biocompatible and biodegradable polymers for subsequent cell seeding.
Fraunhofer Institute for Laser Technology ILT
