Today, applications for Grids emerge in various scientific fields, each with specific requirements. We present concept and architecture which enables biomedical experts to collaborate and share resources by encapsulating their knowledge and expertise as grid services, with (semi-)formally described semantics. Grid Services allow machine processing of the encapsulated knowledge, while their semantic description provides means for their automated discovery and interaction. This brings new possibilities of building biomedical systems offering machine-driven assistance to the biomedical experts.