CA19-9 and CEA carbon nanotube-based biosensors: a key for gastrointestinal cancers diagnosis

Abstract Colorectal and pancreatic cancers represent significant global health challenges, contributing to high morbidity and mortality rates, largely due to limitations in early-stage detection. While traditional diagnostic methods are often invasive and costly, biosensors utilizing carbon nanotubes (CNTs) offer a transformative approach for detecting key cancer biomarkers. This review discusses the potential of CNT-based biosensors for the detection of established cancer biomarkers, specifically carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), two critical biomarkers for gastrointestinal cancers. We analyze various sensor configurations, including electrochemical, optical, and piezoelectric platforms, which leverage the exceptional properties of CNTs – such as high surface area and electrical conductivity – to achieve superior analytical performance. Key findings from the reviewed literature demonstrate that these advanced biosensors can achieve ultra-low limits of detection, often in the picogram/mL (pg/mL) and even femtogram/mL (fg/mL) range, surpassing conventional immunoassays by orders of magnitude. Furthermore, the integration of CNTs with other nanomaterials such as gold nanoparticles and quantum dots, further enhances signal amplification and sensor sensitivity. Despite existing challenges in industrial-scale fabrication and clinical integration, CNT-based biosensors hold promise for developing non-invasive diagnostic tests that could significantly improve early detection and monitoring of gastrointestinal cancers, leading to better patient outcomes.