Sensing of creatinine on chlorophyll–cysteine capped cadmium selenium quantum dots conjugate as a creatinine-triggered quenching probe

This work presents a chlorophyll-cysteine-capped cadmium selenide conjugate (Chl-Cys-CdSe) probe for the sensitive and selective detection of creatinine, a critical biomarker for renal dysfunction analysis. The study aims to address the need for precise and selective detection tools by enhancing the emission properties of cysteine-capped CdSe quantum dots through modification with chlorophyll. Characterization of material was conducted using fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and X-ray diffraction. The results revealed that the Chl-Cys-CdSe conjugate exhibited a hexagonal morphology with an average particle size of 7–8 nm. The sensing mechanism relies on the fluorescence quenching of the Chl-Cys-CdSe QDs, which is most pronounced at pH 8, corresponding to optimal interactions with creatinine. The color changes in the paper strips were captured under UV light and quantified using ImageJ software to measure RGB intensity. The detection limits were determined through paper-based analysis, fluorescent, and UV–Visible spectrometric techniques. These results highlight the probe sensitivity and selectivity for creatinine detection. The Chl-Cys-CdSe conjugate-based probe represents a promising advancement in the field of renal health monitoring, offering a versatile and robust detection system that integrates fluorescent and colorimetric methods with advanced imaging techniques. This approach holds significant potential for clinical diagnostics and real-time health monitoring. • Water-dispersed chlorophyll-cysteine-capped CdSe QDs were synthesized for creatinine detection. • Chlorophyll was used to enhance emission and sensing properties. • The sensing mechanism was based upon quenching of emission and absorbance intensity upon addition of the analyte. • Chl-cysteine-capped CdSe QDs conjugate immobilized on a paper strip, which interacts with serum creatinine by changing color. • Analysis of creatinine concentration using smartphone RGB imaging.