  Cell-based biosensors constitute a fundamental tool in biotechnology, and
their relevance has greatly increased in recent years as a result of a surging
demand for reduced animal testing and for high-throughput and cost-effective in
vitro screening platforms dedicated to environmental and biomedical
diagnostics, drug development and toxicology. In this context,
electrochemical/electronic cell-based biosensors represent a promising class of
devices that enable long-term and real-time monitoring of cell physiology in a
non-invasive and label-free fashion, with a remarkable potential for process
automation and parallelization. Common limitations of this class of devices at
large include the need for substrate surface modification strategies to ensure
cell adhesion and immobilization, limited compatibility with complementary
optical cell-probing techniques, and need for frequency-dependent measurements,
which rely on elaborated equivalent electrical circuit models for data analysis
and interpretation. We hereby demonstrate the monitoring of cell adhesion and
detachment through the time-dependent variations in the quasi-static
characteristic current curves of a highly stable electrolyte-gated transistor,
based on an optically transparent network of printable polymer-wrapped
semiconducting carbon-nanotubes.
