Online and in situ analysis of organs-on-a-chip

Organ-on-a-chip technology is used to study biological processes that involve multiple cell types and temporal changes like, homeostasis, metabolism and responses to chemical triggers. Main benefits of organ-on-a-chip systems include: improved mimicking of the in vivo situation, easy manipulation of the microenvironment and low reagent consumption. Exploiting the unique dynamic aspects of organ-on-a-chip technology, such as liquid flow, automated online measurement of parameters by sensors or online coupling to analytical equipment becomes feasible. Apart from the challenge to detect drug uptake and chemical changes in real-time with high resolution at the microscale, the biggest challenge, is detection of the analyte of interest in cell culture medium, as this contains high amounts of salts, sugars and proteins required by the living cells. In this review online and in situ analytical techniques integrated with organ-on-a-chip devices are discussed with special emphasis on maintaining the biological relevance, achieving analytical compatibility, system integration and final applicability.