In this study, we report a controlled one-pot green synthesis of multiwalled carbon nanotubes (MWCNTs) via pyrolysis of sustainable agriculture waste (chickpea peel) at 400 °C in aqueous medium. These MWCNTs demonstrated 7.0 nm diameter, 0.28 nm graphitic spacing with carbonyl, hydroxyl, and carboxylic acid functionality. The D band (presence of sp3 defects) and G band ( E2g mode of graphite) at 1350 cm−1 and 1580 cm−1 originated in Raman spectrum, respectively. The prepared MWCNTs showed blue fluorescence with 10% fluorescence quantum yield in aqueous medium. The MWCNTs showed triple exponential decay characteristics with an average fluorescence lifetime of 4.7 ns. The synthesized MWCNTs revealed a consistent fluorescence in the cytoplasm of 22RV1 human prostate carcinoma cell line without exerting any sign of cytotoxicity. The MWCNTs also exhibited remarkable cytocompatibility in human immortalized prostate epithelial RWPE1 cells.

    Abstract 
    Graphic abstract
    1 Introduction
    2 Experimental details
        2.1 Materials
        2.2 Instrumentation
        2.3 Preparation of multiwall carbon nanotubes from chickpea peel
        2.4 Sample preparation for in vitro cell imaging
        2.5 Cytotoxicity assay
    3 Characterization of chickpea peel-derived MWCNTs
        3.1 Morphological characterization
        3.2 Photophysical study
    4 Results and discussion
        4.1 Bioimaging application
    5 Conclusions
    Acknowledgements 
    References

• Vikram Singh(Department of Materials Science and Engineering, Indian Institute of Technology Kanpur)
• Shovon Chatterjee(Department of Chemistry, Indian Institute of Technology Kanpur)
• Mahendra Palecha(Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur)
• Pratik Sen(Department of Chemistry, Indian Institute of Technology Kanpur)
• Bushra Ateeq(Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur)
• Vivek Verma(Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Centre for Environmental Science and Engineering, Indian Institute of Technology Kanpur)