Graphene Quantum Dot Decorated Flexible Carbon Nanotube Transistors for Ultrasensitive Detection of Copper Ion

Copper ions (Cu
²⁺
), trace elements in the human body, play roles in enzyme composition and key metabolic activities, and are linked to various diseases including cancer, neurological disorders, and leukemia. Thus, rapid, specific and high-sensitivity quantification of Cu
²⁺
is essential for disease diagnosis, food safety and ecological environment. However, conventional copper detection methods, such as atomic absorption/emission spectroscopy, colorimetric, fluorometric assays, and mass spectrometry, face challenges due to their low sensitivity, low limit of detection, and significant costs. In this study, we developed intrinsically flexible carbon nanotube field-effect transistors, enhanced with graphene quantum dots (GQDs), for the ultrasensitive detection of Cu
²⁺
. These sensors demonstrate a detection limit of as low as 0.1 fM. Enhanced with GQDs, the sensors display high sensitivity, positioning them as potential tools for wearable, rapid, and ultrasensitive Cu
²⁺
detection.