Sub-femtomolar vertical graphene field effect immunosensor for detection of lung tumor markers.

Area of Science:

• Biomedical Engineering
• Materials Science
• Oncology

Background:

• Lung cancer remains a leading cause of cancer-related mortality globally.
• Early detection of lung tumor markers is crucial for effective treatment and improved patient outcomes.
• Current diagnostic methods require sensitive and accurate tools for timely intervention.

Purpose of the Study:

• To develop a highly sensitive immunosensor for the quantitative detection of key lung tumor markers.
• To utilize a graphene/C60 heterojunction in a vertical field-effect transistor (VGFET) for enhanced sensing capabilities.
• To evaluate the sensor's performance against established clinical methods for lung cancer diagnosis.

Main Methods:

• Fabrication of a VGFET immunosensor using a graphene/C60 heterojunction.
• Immobilization of antibodies for specific capture of target lung tumor markers: carcinoembryonic antigen (CEA), cytokeratin 19 fragment (Cyfra21-1), and neuron-specific enolase (NSE).
• Integration of mesoporous silica nanospheres (MSNs) for signal amplification and enhanced detection sensitivity.

Main Results:

• The VGFET immunosensor achieved sensitive detection ranges for standard antigens from 1 pg/ml to 100 ng/ml.
• Initial limits of detection (LODs) were 5.6 amol/ml for CEA, 33.3 amol/ml for Cyfra21-1, and 12.8 amol/ml for NSE.
• With MSN amplification, LODs improved to 100 fg/ml (0.56 amol/ml for CEA), demonstrating superior sensitivity at extremely low concentrations.
• Sensor performance showed high consistency with clinically used immunoassays for serum samples.

Conclusions:

• The developed graphene/C60 VGFET immunosensor offers a sensitive and accurate platform for detecting multiple lung tumor markers.
• The incorporation of MSNs significantly enhances the sensing efficiency, enabling detection at ultra-low concentrations.
• This technology holds promise for improving early lung cancer diagnosis and patient management.