Development of an efficient sensing platform capable of continual monitoring of biomarkers is needed to assess the functionality of the in vitro organoids and to evaluate their biological responses toward pharmaceutical compounds or chemical species over extended periods of time. Here, a novel label‐free microfluidic electrochemical (EC) biosensor with a unique built‐in on‐chip regeneration capability for continual measurement of cell‐secreted soluble biomarkers from an organoid culture in a fully automated manner without attenuating the sensor sensitivity is reported. The microfluidic EC biosensors are integrated with a human liver‐on‐a‐chip platform for continual monitoring of the metabolic activity of the organoids by measuring the levels of secreted biomarkers for up to 7 d, where the metabolic activity of the organoids is altered by a systemically applied drug. The variations in the biomarker levels are successfully measured by the microfluidic regenerative EC biosensors and agree well with cellular viability and enzyme‐linked immunosorbent assay analyses, validating the accuracy of the unique sensing platform. It is believed that this versatile and robust microfluidic EC biosensor that is capable of automated and continual detection of soluble biomarkers will find widespread use for long‐term monitoring of human organoids during drug toxicity studies or efficacy assessments of in vitro platforms.

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A solution of poly (vinyl alcohol) (PVA) in water was electrospun into ultrafine nanofibers using a commercially available electrospinning set-up. Some major electrospinning parameters such as the concentration of polymer solution, flow rate, spinning voltage and distance between the needle tip and collection target were chosen to investigate its effect on the topological morphology as well as the average diameter of the electronspun PVA nanofibers using Atomic Force Microscopy (AFM). Diameters of the nanofibers obtained ranged from 150 nm to 900 nm. The diameters of electrospun nanofibers were most significantly affected by the concentration of polymer solution. While lower concentration always gave rise to the formation of discontinuous nanofibers with beads, an increasing concentration yielded smooth and uniform nanofibers with increasing diameters and beaded morphology was found disappearing. Keeping solution concentration constant at a higher value that yielded smooth nanofibers, an increase in the flow rate again changed the morphology from smooth to beaded morphology of nanofibers obtained. Spinning voltage did not show any specific trend of diameter change at a wider range (10 to 25 kV) selected in this study.

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