Recent progress in microsystem technologies for creating small, integrated and reliable microelectronic devices and microtransducers in combination with biological sensing elements has raised the expectation to get a comprehensive insight into dynamic cellular metabolic events and subsequently a complete understanding of the metabolism of human biology. Such micro- and nanobiosensor tools in combination with appropriate microfluidics enable the simultaneous description and moreover monitoring of gene, protein expression and metabolic states in a biosystem. This knowledge will lead to new future therapies and pharmaceutical treatments. Furthermore, with such methods and microdevices a new direct combination of diagnostics and immediately starting therapy can be established which is called theranostic. There are a lot of challenging problems to be overcome to reach this goal: microsystems monitoring of physical parameters in biological systems is well established, whereas chemo- and biosensors are available for only a few parameters and mainly as in vitro devices. Gene arrays entered the research market but are up to now not in clinical practice. Protein arrays are in a developmental state with promising results, but far from a mature reproducible state. For getting insights into metabolic events intra- and extracellularly, some new and promising technologies are under research and will undoubtedly revolutionize systems biology but only in the longer run. As a conclusion, it can be stated that new methods stemming from microelectronics and biological technologies are now entering the world of chemical and biological analytics as well as clinics to offer clinicians new theranostic tools in the future.