Label-free impedimetric biosensor based on lectin and polypyrrole film for the early detection of pancreatic cancer cells.

Pancreatic cancer is considered a global public health issue due to its non-specific or asymptomatic features in early stages, leading to late diagnosis and poor prognosis for patients. In this paper, a biosensor composed of polypyrrole, multi-walled carbon nanotubes (MWCNTs), and the lectins concanavalin A (ConA) and wheat germ agglutinin (WGA) acting as bioreceptors, was developed to detect and differentiate between highly invasive (MIA Paca-2) and less invasive (BXPC3) cancer cell lines. Atomic force microscopy studies revealed effective immobilization of the biosensor components and the identification of the cell lines. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were applied to evaluate the assembly of the sensor platform. Moreover, differential pulse voltammetry (DPV) and EIS were used to assess the bioactivity of the biosensor, revealing high sensitivity, showing promising limits of detection (LODs) for WGA sensor, with LODs of 3.54 cells/mL for MIA Paca-2 and 19.87 cells/mL for BXPC3, and for ConA sensor, 4.15 cells/mL, along with linear ranges of 6.03 cells/mL for all cell lines. Selective studies with interfering molecules have proved the efficiency of the proposed biosensor in the specific detection of the target analytes. The electrochemical response directly correlated with the number of cells on the sensing interface. The platform detected pancreatic cancer cells and distinguished between MIA Paca-2 and BXPC3 based on their glycan expression patterns, as reflected in their lectin binding profiles. The sensitivity, phenotypic resolution, and compatibility with miniaturization make this lectin-based interface a promising tool for early pancreatic cancer screening in point-of-care settings.