Selective and Sensitive ZnO Quantum Dots Based Fluorescent Biosensor for Detection of Cysteine

Area of Science:

• Materials Science
• Analytical Chemistry
• Biochemistry

Background:

• Cysteine is a crucial amino acid involved in various biological processes.
• Accurate detection of cysteine is vital for diagnosing and monitoring related health conditions.
• Development of sensitive and selective fluorescent probes is essential for cysteine quantification.

Purpose of the Study:

• To develop a novel and effective zinc oxide quantum dots (ZnO QDs)-based fluorescent probe.
• To utilize this probe for the sensitive and selective detection of cysteine in diverse sample matrices.
• To characterize the synthesized ZnO QDs and evaluate the performance of the developed fluorescent sensor.

Main Methods:

• Synthesis of a melamine-based fluorescent pre-probe via condensation reaction.
• Homogeneous dispersion of ZnO quantum dots (QDs) into the pre-probe solution.
• Characterization of ZnO QDs using X-ray diffraction (XRD), nano-particle size analyzer, and Field Emission Scanning Electron Microscopy (FE-SEM).
• Detection of cysteine in solutions like bovine serum albumin and tap water using the developed fluorescent probe.

Main Results:

• ZnO QDs were successfully synthesized and characterized, with sizes determined by Scherrer's equation and nano-particle size analysis.
• The developed fluorescent probe demonstrated high selectivity and sensitivity towards cysteine detection.
• The probe exhibited a significant Stokes shift of 236 nm.
• The limit of detection (LOD) and linear range for cysteine were determined as 0.642 μM and 0.1-600 μM, respectively.

Conclusions:

• A novel ZnO QDs-based fluorescent probe has been successfully developed for cysteine detection.
• The probe offers high sensitivity, selectivity, and a wide linear detection range.
• This ZnO QD fluorescent sensor presents a promising tool for L-cysteine analysis in various applications.