Highly sensitive detection of Campylobacter jejuni using a carbon dot-embedded nanoMIPs fluorescent sensor

• First carbon dot-embedded fluorescent nanoMIPs for Campylobacter jejuni. • Development of first CD-nanoMIP based fluorescent sensor for C. jejuni. • High specificity and sensitivity were achieved with epitope-mediated CD-nanoMIP receptors. • Successful application of the fluorescent sensor was shown in water sample analysis. • The established sensor platform can be used for detecting pathogenic bacteria. Campylobacter jejuni , a leading cause of gastroenteritis worldwide, poses significant detection challenges due to the labor-intensive and insufficiently sensitive current methods. Developing efficient, rapid diagnostics is vital for clinical and food industry applications; yet the vulnerability of biological elements in creating bacterial sensors remains a major obstacle. This study introduces an innovative fluorescence-based sensor employing fully synthetic carbon dot (CDs) functionalized molecularly imprinted polymer (CDs@nanoMIPs) receptors to detect this foodborne pathogenic bacterium. The CDs@nanoMIPs synthesis was accomplished using a solid-phase approach, with an immunodominant epitope of C. jejuni serving as a guiding template. During the polymerization process, nitrogen-doped CDs were synthesized in situ and incorporated into nanoMIPs as a fluorescent tag, constituting approximately 19 % of the composite. The synthesized nanomaterials were characterized by employing transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FT-IR), fluorescence microscopy, UV–Vis spectrophotometry, and fluorescence spectrometry. CDs@nanoMIPs demonstrated a notable blue fluorescence when excited at 350 nm, along with excellent photostability and a negative zeta potential. These nanostructured particles (59 nm) exhibited moderate polydispersity and a spherical morphology. The FT-IR spectrum deviated from that of conventional CDs, aligning more closely with the template epitope. When in contact with C. jejuni , CDs@nanoMIPs induced a significant increase in fluorescence intensity, enabling the efficient bacterial detection. This interaction showed exceptional affinity and sensitivity towards C. jejuni , featuring a linear range of 1 × 10 1 –1 × 10 8 CFU mL −1 (R 2 = 0.98) and a low detection limit of 4.6 CFU mL −1 . CDs@nanoMIPs-based C. jejuni sensors marked a novel approach to pathogen detection.