All interactions between materials, such as implant surfaces or biomedical devices, with their respective environments are controlled by the topography and the chemical composition of their surfaces. Examples for such surface-controlled properties are the adhesion between two materials, wetting, protein adsorption and cell adhesion.

We describe the generation of novel, micropatterned polymer coatings with tailor-made properties with high spatial resolution. It allows the covalent binding of the coatings to a broad spectrum of different substrates, ranging from inorganic materials (metal, glass) to even very inert polymers and biological matter. It is based on C,H insertion reactions (C,H insertion crosslinking, CHic). To this a prepolymer containing dormant groups is deposited on the material to be coated by standard techniques of coating application. Upon exposure to heat or light the dormant groups become activated in the final coating and generate permanent links between the polymer chains and to the surface. As the activation step only requires brief heating or short irradiation it does not require chemical laboratory conditions and can be used directly even under surgery conditions.

We show that this simple and easy-to-use strategy can be used to generate hydrogel surfaces, which are even more bioinert than than Teflon coatings, through a very general concept called “entropic shielding”. We use such surfaces in several medical applications: glaucoma treatment, the isolation of circulating tumor cells, the detection and quantification of cell-free DNA and a general strategy to generate biochips, especially DNA chips.

An example for the latter one is the generation of a sepsis-chip, which can detect 40 different organisms causing sepsis within two hours. The same strategy is used for the generation of HPV-tpying chips, Borriolosis and Mastitis chips. A second use case is the avoidance of scar formation in the eye during glaucoma treatment. A third example is the isolation of rare cells such as circulating tumor cells through bioaffinity filtration. To this filters are designed and generated with lithographically designed pores with very precis size control and where the inside of the pores is modified by antibodies. We demonstrate that we can isolate circulating tumor cells CTC at extremely low concentrations. We show that we are able to isolate 1 single CTC cell in 50 ml full blood within less than 1 minute.

Juergen Ruehe

Albert-Ludwigs-Universitat Freiburg

Appearances