Bio-enhanced polyrhodanine/graphene Oxide/Fe₃O₄ nanocomposite with kombucha solvent supernatant as ultra-sensitive biosensor for detection of doxorubicin hydrochloride in biological fluids

Cardiotoxicity and other side effects of current antineoplastic agents with narrow therapeutic windows, such as doxorubicin hydrochloride (DOX), have increased the need for advanced real-time monitoring approaches to control their dosage and minimize common side effects. In this study, we reinforced the biocompatible and electrosensitive polymeric structure of polyrhodanine with iron(II,III) oxide (Fe₃O₄) and coated graphene oxide (GO) with Fe₃O₄ (GO-Fe₃O₄) nanoparticles. The resulting hybrid polymeric platform was bio-enhanced by extraction of kombucha solvent supernatant and used as a highly sensitive biosensor with enhanced electroactive C[dbnd]N⁺ functional groups for real-time detection of DOX in the human blood plasma sample. The developed platform was well characterized by performing different analyses, and its applicability was evaluated using an electrochemical approach. The results showed the superior sensitivity (167.62 μA μM⁻¹ cm⁻²), low detection limit (DL, 0.008 μM), and quantification limit (QL, 0.056 μM) of the proposed biosensor. The biosensor detected DOX in the biological fluid with optimal accuracy (>99%), highlighting the ideal performance of the fabricated polymeric biosensor.