One‐Pot Hydrothermal Synthesis of Highly Fluorescent Polyethyleneimine‐capped Copper Nanoclusters for Specific Detection of Rifampicin

Abstract

Herein, a novel bright-green and highly fluorescent polyethyleneimine capped copper nanoclusters (CuNCs@PEI) has been hydrothermally synthesized, which is employed as a fluorescence probe to determine rifampicin. Under optimum synthetic conditions, the morphology, surface chemistry and optical features of resulting CuNCs@PEI are well characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, UV-Vis absorption spectra, transient and steady-state fluorescence. In comparison to previous reports, the new species with a larger diameter of approximately 3 nm exhibit higher fluorescence quantum yield (QY) up to nearly 10.7%, and demonstrate tolerability to extreme pH, high ionic strengths as well as long-term UV irradiation. These excellent optical properties ascribe to unique grain size and surface chemical features of products, which are further discussed in this work. In addition, we employed as-prepared CuNCs@PEI to detect rifampicin based on fluorescence quenching phenomenon. The fluorescence intensity of probe is linearly proportional to rifampicin over the concentration rage from 0 to 20 μM, where the limit of detection (LOD) is 50 nM. Besides, this probe can be also used to assay rifampicin in serum samples with satisfactory recoveries.

State of the Art on Developments of (Bio)Sensors and Analytical Methods for Rifamycin Antibiotics Determination

“…Only a few of them required sample dilution [ 127 , 129 , 133 ], while the methods using a reagent p-chloranil or Fe(III) [ 139 ] are not applicable for such types of analysis. Regarding luminescence-based methods ( Table 3 and Table 4 ), only one cannot be applied to RIF determination in blood samples [ 151 ]. Most of the others can be used as described, with a few exceptions [ 44 , 49 , 153 , 157 ], which require sample dilution.…”

“…It can be directly applied either in the case of fluorescent analytes, or the species of interest can be determined based on their ability to quench the fluorescence of a fluorophore, as is the case for rifamycins. The fluorescence of various nanomaterials linearly decreased with the addition of increasing RIF concentrations ( Figure 5 ) due to either a dynamic, as was the case for QDs [ 148 , 149 ], or static types of quenching, as in the situation of RIF interaction with HAS [ 30 , 92 , 150 ], with Cu NCs capped with PEI [ 151 ] or with FA [ 152 ]. When the UV-Vis spectrum of RIF, acting as a quencher, overlapped with the emission and/or excitation spectrum of the fluorophore, the inner filter effect (e.g., RIF interaction with N-P-CNDs [ 97 ], FA-Cu NCs [ 152 ], GSH-Cu NCs [ 153 ], UCCS NaYF 4 :Yb, Tm@SiO 2 [ 154 ]) or the fluorescence resonance energy transfer (when CDs were the fluorophore [ 155 ]) might represent the main quenching mechanism.…”

A magnetic molecular imprinting‐based fluorescence probe for sensitive and selective detection of 2,4‐D herbicide

“…In recent years, a great deal of attention has been paid to fluorescence methods in chemical/biological sensing applications due to their marked sensitivity for detecting metal ions, environmental monitoring, and biological systems. It can achieve direct detection without a separation step, which makes the experimental procedure simple and efficient [10,11]. Moreover, turn-on fluorescence strategies have gained increasing attention due to their ability to avoid interference from the environment compared with turn-off ones.…”