Hydroxyl radical (OH radical) is the most harmful free radical amongst the Reactive Oxygen Species (ROS) responsible for numerous diseases of DNA damage like mutagenesis, carcinogenesis and ageing. Therefore, it is important to find a suitable scavenger for OH radical. In the present contribution, we aim to investigate the ability of pristine armchair-SWCNT and B/N/P-doped armchair-SWCNT to scavenge OH radicals using DFT calculations. The calculations reveal that the B/Pdoped armchair-SWCNTs can act as a better scavenger for OH radical compared to pristine armchair-SWCNT but N-doped armchair-SWCNT does not act as a better scavenger for OH radical compared to pristine armchair-SWCNT. Furthermore, the developed scavenger is examined in terms of large-scale availability, biocompatibility, conductivity, stability and reactivity. For both in vivo and in vitro studies, the work is found to useful for enhancing SWCNT as a free radical scavenger.

    Abstract
    1 Introduction
    2 Computational details
    3 Results and discussion
        3.1 Binding energies and structural properties of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
        3.2 Nature of bonding analysis by using natural population analysis (NPA) and Wiberg bond index (WBI) of binding of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT.
        3.3 Stability of bonding analysis by using Natural bond orbital (NBO) of binding of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
        3.4 Comparison by using Density of States (DOS) of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
        3.5 Orbital contribution analysis by using partial density of states (PDOS) of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
        3.6 Comparison by using molecular electrostatic potential surface (MEPS) of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
        3.7 Comparison by using frontier molecular orbital analysis (HOMO, LUMO) of an OH radical attached to pristine (5,5) armchair SWCNT and BNP-doped (5,5) armchair SWCNT
    4 Conclusion
    Acknowledgements 
    References

• Meenakshi Malakar(Department of Physics, Assam University)
• Pradeep Kumar Shukla(Department of Physics, Assam University)