Cellulose-based electrochemical recognition of doxorubicin in human biofluid

Doxorubicin (DOX) remains a crucial medication in cancer treatment, providing effective therapeutic options for a range of malignancies. As such, it necessitates meticulous monitoring and the development of reliable detection methods in biological samples to optimize dosage and avoid toxic concentrations. In this research, three-electrode micro-scale sensors were fabricated on paper using pen-on-paper technology. Highly conductive silver ink was synthesized, loaded into a ball-pen, and then used to draw electrodes onto a cellulose substrate. Results demonstrated that the ink dried instantaneously at room temperature upon deposition on the cellulose surface. Moreover, the developed three-electrode sensor exhibited excellent thermal stability, maintaining functionality at temperatures as high as 150°C. Mechanical bending of the sensor had no impact on its electrical characteristics, and moisture absorption did not alter either the electrical conductivity or resistance of the electrodes. Following this, the sensor’s electrochemical performance was assessed for detecting DOX in human plasma samples. The micro-scale sensor achieved a wide linear detection range between 10 and 1000 nM, with a low quantification limit of 10 nM. This study underscores the promise of nanoink-based cellulose sensors as sensitive, affordable, and scalable solutions for biomedical diagnostics.