The spectrum of applications for biomaterials is expanding with new or enhanced features such as integrated optical functionality. The correlation between function and structure opens up new possibilities for the development of novel materials and methods for advanced applications.
Three-dimensional optical structures with specific functionality in terms of diffractive properties can be found in volume holograms. Among existing techniques for three-dimensional optical structuring, such as direct laser-writing or self-assembly, volume holography provides the unique possibility to create optical structures through the entire volume beyond a point-by-point, line-by-line or plane-by-plane fabrication, with high resolution and accuracy in a single step.
In tissue engineering and medical science, many applications become accessible through explicit control over molecular structure and mechanical properties, such as elasticity, cross-linking degree or surface morphology. In many cases, a given structure is linked to a certain functionality. Similarly optical structures with diffractive properties are linked with specific functionalities, such as to concentrate light into a focus.
The strategy to combine optical structuring of the volume and specific modification of the surface has the potential to result in the design of advanced biomedical implants. In particular, intra-ocular lenses (IOLs), implanted in place of the natural eye lens in ophthalmic surgery, open up the prospect of substantial improvement to enhance the approximation to the original function of the natural eye lens. Prospective IOLs could fulfill their function - i.e. to focus the light onto the retina - with an optically structured volume. As a result, the shape and surface of the IOL remain free and available for other purposes. Thus, subsequent surface modifications remain optional to achieve specific interaction with the biological environment.
Volume holographic techniques provide the opportunity to attach 3D optical structures with variable functionalities to a photosensitive material. In this sense, the integration of optical functionality into biomaterials appears desirable in line with the idea of a correlation between structure and function.