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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