It is challenging to combine fundamentally different enzymatic and immunochemical assays on a single biosensor microchip. This could, however, be useful for the rapid measurement of metabolites and protein biomarkers in microliter-sized biological samples. For example, the simultaneous point-of-care detection of the key diabetes biomarkers insulin and glucose has not yet been achieved.

Joseph Wang, University of California, San Diego, USA, and colleagues, have developed a single-chip insulin/glucose sensing platform. The platform aims to address the key challenges associated with the different surface chemistries and procedures involved in enzymatic and immunological assays.

The team immobilized the enzyme glucose oxidase (GOx) and insulin antibody bioreceptors on closely spaced gold electrodes (pictured). This device enables bioassays of microliter biological samples. Glucose in blood or saliva is detected within the first minute, followed by insulin detection after 20 minutes.

The coupling of enzymatic and immunoassays of multiple metabolites and protein biomarkers onto a single microchip opens up new possibilities for point-of-care screening and diagnosis of various diseases and disorders. The rapid and simultaneous measurement of insulin and glucose could have profound implications for the treatment of diabetes.

• Enzymatic/Immunoassay Dual-Biomarker Sensing Chip: Towards Decentralized Insulin/Glucose Detection,
  Eva Vargas, Hazhir Teymourian, Farshad Tehrani, Ece Eksin, Esther Sánchez-Tirado, Paul Warren, Arzum Erdem, Eyal Dassau, Joseph Wang,
  Angew. Chem. Int. Ed. 2019.
  https://doi.org/10.1002/anie.201902664