Fluorimetric detection of pathogenic bacteria using magnetic carbon dots

•Magnetic carbon dots with amine functionalization was newly proposed.•Magnetic separation and fluorometric detection of pathogenic bacteria achieved.•Achieved very low limit of detection of pathogenic bacteria using this technique.

A novel and facile approach of pathogenic bacteria detection, which utilizes fluorescent sensing and bacteria capture with Magnetic carbon dots (Mag-CDs), was proposed in this work. Magnetic nanoparticles were synthesized and then decorated with C-dots, and further functionalized with amine groups (chitosan). In this way, bacteria were strongly anchored on the hybrid material Mag-CDs for highly sensitive fluorescent detection. The Mag-CDs were characterized by UV–vis, FT-IR spectra, TEM images, XRD, and EDX. The characterizations validate the fabrication of amine-Mag-CDs and the promising applications of this material. Fluorescence spectroscope and MALDI-MS were used for the detection and identification of bacterial strains, respectively. The limit of detection for Staphylococcus aureus and Escherichia coli was found to be 3 × 102 and 3.5 × 102 cfu mL−1, respectively. With these encouraging results, it is expected that it would open revenues for promising applications of Mag-CDs nanomaterial.

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