Oxygen-Deficient Fluorescent λ-MnO2 Nanosheets for Selective Detection of Chloramphenicol

Monitoring and detection of chloramphenicol (CAP) in an environment and in the body of living organisms are crucial, as CAP has potential toxicity and causes harmful diseases in human beings including gray baby syndrome, leukemia, bone marrow suppression, hypersensitivity, aplastic anemia, and neurotoxic reactions. Here, we prepared a fluorescence-based probe composed of oxygen-defected λ-MnO2 nanosheets and thereafter utilized it in the detection of CAP. A simple and economical approach of synthesis via coprecipitations followed by probe ultrasonication was utilized to prepare the nanosensor. The stable fluorescence of the nanosensor at an excitation wavelength of 300 nm (λex = 300) and an emission wavelength of 415 nm (λem = 415) was quenched by CAP through the synergistic effect of the inner filter effect (IFE) and electron transfer mechanisms. The nanosensor demonstrated a highly sensitive response toward CAP, within the linear range from 25 to 300 nM. The calculated limit of detection obtained for CAP was 0.57 nM. The sensor’s performance was assessed in a real-world sample (blood serum), yielding an R2 value of 0.99, demonstrating the significant potential of λ-MnO2 nanosheets in CAP sensing. The λ-MnO2 nanosheet fluorescence sensor is an innovative, label-free platform for generating artificial fluorescence, applicable in biological and environmental domains to replace the traditional expensive, time-consuming, and complicated nanosensors.