Biocompatible Lab-On-Substrate technology platform

Multiwell plates in combination with optical inspection equipment are standard tools for biological and biomedical applications e.g. cell-to-cell interaction studies for cancer treatment. Microtechnology based multiwell plates have the potential to monitor physiological cellular interactions at single cell level with a high throughput e.g. for immunotherapy of cancer or targeted drug delivery, where each patient would receive drugs that are known to be useful for his/her specific situation. A Lab-On-Substrate technology platform based on standard PCB technology has been developed for costeffective fabrication of biological and medical test devices. And as typical PCB laminates, mainly with copper as conductive material, are not biocompatible, a new material base has been identified and evaluated. The long and short time biocompatibility of promising materials including surface treatments have been studied in-vitro. Aluminum, polyimide and Pyralux have been selected as materials with focus on their bio- and process compatibility. A process flow consisting of lamination, Al structuring by wet etching, microwell and via formation by laser drilling and via metallization was developed based on standard PCB processes. These technologies allow a combination of large area and fine structuring for electrode and microwell realization. Furthermore, surface modifications of different materials by both chemicals such as thiols and fluorinated acrylates and plasma treatment were inspected by surface tension and wetting analysis to allow designing the hydrophilicity / hydrophobicity microfluidics networks required for the microwell device. A long-term stability at standard atmosphere conditions of at least one year of these coatings was also found. The technology was demonstrated with a dielectrophoresis enhanced microwell device for single cell handling and detection of cell-to-cell interaction as needed for the improvement of tumor therapy. In summary this paper describes the proof of concept using PCB manufacturing processes with biocompatible materials for the realization of an electrically enhanced microwell plate. Outcome of the technology developments is a Lab-On-Substrate technology platform for a variety of biomedical applications.