Biological and chemical sensors for cancer diagnosis

The great challenge for sensor systems to be accepted as a relevant diagnostic and therapeutic tool for cancer detection is the ability to determine the presence of relevant biomarkers or biomarker patterns comparably to or even better than the traditional analytical systems. Biosensor and chemical sensor technologies are already used for several clinical applications such as blood glucose or blood gas measurements. However, up to now not many sensors have been developed for cancer-related tests because only a few of the biomarkers have shown clinical relevance and the performance of the sensor systems is not always satisfactory. New genomic and proteomic tools are used to detect new molecular signatures and identify which combinations of biomarkers may detect best the presence or risk of cancer or monitor cancer therapies. These molecular signatures include genetic and epigenetic signatures, changes in gene expressions, protein biomarker profiles and other metabolite profile changes. They provide new changes in using different sensor technologies for cancer detection especially when complex biomarker patterns have to be analyzed. To address requirements for this complex analysis, there have been recent efforts to develop sensor arrays and new solutions (e.g. lab on a chip) in which sampling, preparation, high-throughput analysis and reporting are integrated. The ability of parallelization, miniaturization and the degree of automation are the focus of new developments and will be supported by nanotechnology approaches. This review recaps some scientific considerations about cancer diagnosis and cancer-related biomarkers, relevant biosensor and chemical sensor technologies, their application as cancer sensors and consideration about future challenges.