Bio-Material Testing

The development of new medical devices and biomaterials always includes extensive and safe testing of the same. Biomaterials can consist of a wide variety of carrier materials and also contain cellular components (tissue engineering). Adverse reactions, such as material-related implant failure, must be ruled out. The biomaterials must therefore be tested both in terms of their functionality (e.g. mechanical strength, abrasion resistance) and their biointeraction (e.g. biocompatibility). Already established methods can only be applied to the novel products to a limited extent. This poses the challenge of developing and applying suitable test procedures in parallel with the products.

To ensure optimal testing, various aspects must be considered and individually adapted to the product to be tested. In the case of implants, for example, this includes the most complete monitoring possible, the investigation of interactions with tissue, cells, or the immune system, as well as infection assessment and biofilm formation. The test procedures must also be adapted to the development phases of the products. Thus in vitro other procedures are needed than in the in vivo testing. For example, differences in accessibility for imaging, manipulation, and measurement methods are critical.

An excellent possibility for characterization and evaluation in test procedures form optical imaging methods. Whether in vitro in cell cultures or in vivo an optical display can be used to check the functionality of new implants, for example. Vitality can also be assessed and, if necessary, an infection can be detected. For this purpose, it is essential to use existing imaging techniques individually, to further develop, or to explore new methods, in order to obtain an optimal representation. Among other things, this can enable non-invasive acquisition and tracking of the live response of cells and tissues. Thus, endpoint-based imaging forms can be replaced.

Various imaging techniques are available at NIFE for this purpose. These are continuously adapted, improved, expanded and supplemented. In addition to classical microscopy methods, various Laser-based Imaging Capabilities are applied and established. In combination with scanning systems, this can open up high-resolution imaging. This includes confocal and multiphoton microscopy. By using fluorescence-based imaging, cell types down to cell components can be individually visualized.

A wide variety of imaging setups are being developed. Through specific adaptations, new areas of application can always be opened up. Besides the Visualization of cells and tissues, this also involves manipulation . Thus, cells can be characterized by light-controlled manipulations and measurements (Bio-photonics, Heisterkamp/Torres, LUH Quantum Optics). The interactions can be described up to nanometer levels . In addition to single cells, cell assemblies such as organoids and tissues can be imaged at high resolution and examined using laser-based nanosurgery. (Bio-photonicsHeisterkamp/Kalies, LUH Quantum Optics). Such high-resolution systems are currently mainly used in basic research. Developing new imaging systems and transferring them to the clinic is therefore essential (Bio-photonics LZH, Ripken, Laser Center Hannover).

Left: Multi-photon microscopy allows laser beams to be focused optimally. This allows a sample to be examined in detail. Right: Organoids (miniorganes) enable a wide variety of new test methods, as well as major steps in basic research.

In addition, laser-based nanotechnologies can be used to replicate natural tissues, for example, so that these can be used as test systems (Laser-based Nano-Technology, Chichkov, LUH Quantum Optics). In addition to the development and validation of new test methods, the reliable availability of relevant samples (cells and tissues) is also crucial (Scaffold Engineering & The Cryotechnology, Glasmacher, LUH multiphase processes).

The development and application of new test methods thrives on intergroup exchange. This is demonstrated by strong networking within the aforementioned groups, but also beyond them in the entire NIFE. Only through this good cooperation can the established techniques be optimally exploited. Thus, development and use/application go hand in hand.