Simple and facile carbon dots based electrochemical biosensor for TNF-α targeting in cancer patient's sample

Highlights: • A cost-effective, high yield fluorescence carbon dots (CDs) were synthesized by microwave pyrolysis method. • These CDs were dispersed in poly methyl methacrylate (PMMA) matrix to fabricate the biosensing platform for the detection of TNF-α in cancer patient samples. • This fabricated immunosensor exhibited a wide dynamic range of 0.05–160 pg mL⁻¹ with a lower detection limit of 0.05 pg mL⁻¹ and sensitivity of 5.56 pg mL⁻¹ cm⁻². • This immunosensor showed a high correlation with the conventional technique, ELISA for early screening of cancer patient serum samples. Tumour Necrosis Factor (TNF-α) is a pro-inflammatory cytokine having key roles in cell death, differentiation, survival, proliferation, migration and is a modulator of immune system. Therefore, TNF-α is an ideal biomarker for several disease diagnosis including cancer. However, out of all the biomarkers of cancer, TNF-α) is less explored for cancer detection. Only a few reports are available of developing biosensors for TNF-α targeting in human serum samples. Also, Carbon Dots (CDs) remains less explored in biosensor application. In this regard, for the first time, a sensitive and low-cost electrochemical biosensor based on CDs has developed. CDs were synthesized by simple yet facile microwave pyrolysis. Poly methyl methacrylate (PMMA) was selected as the matrix to hold CDs to fabricate the biosensing platform. This novel CD-PMMA nanocomposite featuring excellent biocompatibility, exceptional electrocatalytic conductivity, and large surface area. CD-PMMA was applied as transducing material to efficiently conjugate antibodies specific towards TNF-α and fabricate electrochemical immunosensor for specific detection of TNF-α. The fabricated immunosensor was used for the detection of TNF-α within a wide dynamic range of 0.05–160 pg mL⁻¹ with a lower detection limit of 0.05 pg mL⁻¹ and sensitivity of 5.56 pg mL⁻¹ cm⁻². Furthermore, this CDs based immunosensor retains high sensitivity, selectivity, and stability. This immunosensor demonstrated a high correlation with the conventional technique, Enzyme-Linked Immunosorbent Assay for early screening of cancer patient serum samples.