Highly sensitive and real-time detection of sialic acid using a solution-gated graphene transistor functionalized with carbon quantum dots

•A new type of the SGGT has been designed fabricated for detection of sialic acid.•The CQDs are modified on the gate electrode as the recognition probes.•The sensitivity of the sensor can reach 10−19 M.•The sensor can realize the real-time monitor of sialic acid.•The sensor can realize the detection in the simulated serum samples.