Graphene foam field-effect transistor for ultra-sensitive label-free detection of ATP

As the major energy molecule of cells, adenosine triphosphate (ATP) regulates various biological processes and has been found to be closely related to many diseases. Therefore, ATP detection in trace amounts is very useful for understanding various biological processes, studying cellular events such as proliferation and apoptosis, and estimating contaminated degree of food and medical instrument. To date, the trace sensing ATP at picomolar level in biological systems is still a major challenge. Because of unique electrical and structural properties, graphene has attracted much attention in biosensing applications. Here, a sensitive and selective graphene foam field-effect transistor (GF-FET) biosensor for ATP detection is demonstrated. The lowest detection limit of the biosensors for analyzing ATP is down to 0.5 pM, which is one or several orders lower than the reported results. Moreover, the GF-FET biosensor show a good linear current response to ATP concentrations in a broad range from 0.5 pM to 50 mu M. The GF-FET sensor surface can be regenerated for many times and used for up to weeks without significant loss of functionality. Based on this sensing platform, label-free measurements of ATP concentrations in human serum as well as in cell lysate are demonstrated. The work may provide a novel platform to study ATP release and energy-regulated biological processes, suggesting a promising future for biosensing applications.