An optical fluorescence quenching sensor based on functionally modified iron-doped carbon nanoparticles was designed for the selective and sensitive Cr(VI) ion detection. Multifunctional iron-doped carbon nanoparticles were enclosed in the scaffolds of a promising stable nanocarrier system called hyperbranched polyglycerol (HPG), which has been fluorescently modified with 1-pyrene butyric acid using the Steglich esterification procedure. The therapeutic and diagnostic capabilities were boosted when these nanoparticles were enclosed in the fluorescently modified dendritic structure, HPG. Iron-doped carbon nanoparticles coupled with fluorescently modified hyperbranched polyglycerol can be used as a sensor for metal ions and can then be used to successfully remove them from a sample. Moreover, the synthesised nanoparticles demonstrated promising antimicrobial efficacy against bacteria and fungi. These results are also discussed in detail.

Synthesis and characterization of iron-doped carbon nanoparticles encapsulated within functionally modified hyperbranched polyglycerol and study of their chromium (VI) ion sensing and antimicrobial applications
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials and methods
        2.2 Synthesis of iron-doped carbon nanoparticles (FeCNP-1)
        2.3 Synthesis of fluorescent hyperbranched polyglycerol-pyrene butyric acid conjugates (HPG-PBA)
        2.4 Synthesis of iron-doped carbon nanoparticles encapsulated within functionally modified hyperbranched polyglycerol (FeCNP-2)
        2.5 Detection of Cr(VI) by fluorescence sensing
        2.6 Antimicrobial study of pristine carbon nanoparticles, iron-doped carbon nanoparticles and iron-doped carbon nanoparticles encapsulated within functionally modified HPGPBA
            2.6.1 Disc diffusion method for antibacterial susceptibility studies
            2.6.2 Agar well diffusion method for antifungal studies
    3 Results and discussion
        3.1 Characterisation of pristine carbon nanoparticles, iron-doped carbon nanoparticles, and iron-doped carbon nanoparticles encapsulated within functionally modified hyperbranched polyglycerol
        3.2 Detection of Cr(VI) by fluorescence sensing
        3.3 Antimicrobial study of pristine carbon nanoparticles, iron-doped carbon nanoparticles, and iron-doped carbon nanoparticles encapsulated within functionally modified hyperbranched polyglycerol
    4 Conclusion
    References

• Nihita Linson(Department of Chemistry, St. Thomas College Palai, Mahatma Gandhi University, Kottayam, Kerala 686574, India)
• Jissy Jacob(Department of Chemistry, St. Thomas College Palai, Mahatma Gandhi University, Kottayam, Kerala 686574, India)
• Sunny Kuriakose(Department of Chemistry, St. Thomas College Palai, Mahatma Gandhi University, Kottayam, Kerala 686574, India)