Si Doped CoO Nanorods as Peroxidase Mimics for Colorimetric Sensing of Reduced Glutathione

Abstract

Si doped CoO nanorods (denoted as Si-CoO) were prepared by the hydrothermal method. The Si-CoO composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectra (XPS), etc. The results suggest that Si element uniformly distributed onto CoO nanorods with a diameter of 50–100 nm. The as-prepared Si-CoO nanocomposite possessed an excellent peroxidase-like activity as well as quickly catalyzed the colorless substrate 3,3,5,5-tetramethylbenzidine (TMB) to be oxidized into blue oxTMB by H2O2 only in 20 s, which was easily visually observed. The electron spin resonance (ESR) data confirms that superoxide radicals (•O2 –) play a key function in catalytic reaction. On the basis of the peroxidase biomimetic activity of Si-CoO, we constructed a new biosensor for detection of H2O2 and reduced glutathione (GSH) in the range of 1–100 uM with a limit of 0.22 and 0.45 uM, respectively.

A Covalent Black Phosphorus/Metal–Organic Framework Hetero‐nanostructure for High‐Performance Flexible Supercapacitors

“…Moreover,t he O1 ss pectrum (Figure 2i)c an be divided into two peaks,c orresponding to O-P (533.2 eV) and O-Co (531.5 eV) bonds. [50] This indicates that the Co 2+ in ZIF-67 are outstandingly bound with oxygen functional groups on E-BP,g enerating P-O-Co covalent bind. Figure 2j shows the Co 2p spectrum with doublet (two typical peaks) at the binding energies of 781.1 and 796.7 eV,r espectively, revealing the formation of Co À Ob ond in E-BP/ZIF-67 hybrids.…”

The Fabrication of Amino Acid Incorporated Nanoflowers with Intrinsic Peroxidase-like Activity and Its Application for Efficiently Determining Glutathione with TMB Radical Cation as Indicator

“…In this work, the presence of Cu 2+ ion and Cu + ion in the hybrid nanoflowers was confirmed by the XPS spectrum, and the ratio between Cu 2+ ion to Cu + ion is 1:0.374 ( Figure S2 in Supplementary Information). According to the published reports, several peroxidase mimics generate hydroxyl radical by decomposing H 2 O 2 to accomplish the conversion of TMB to TMB radical cation (oxidized TMB) relying on its peroxidase-like activity (Formula (3)) [ 40 , 41 , 55 ]. Therefore, the amino acid incorporated nanoflowers with intrinsic peroxidase-like activity were chosen as a peroxidase mimic to achieve the oxidation of TMB in this experiment.…”

“…The d -amino acid-incorporated nanoflowers were prepared as reported previously [ 40 ]. Briefly, amino acid powder (60 mg) was dissolved in 3 L of PBS solution (10 mM, pH 7.4), and then 20 mL of CuSO 4 solution (120 mM) was added into the above-mentioned mixture, followed by the incubation at room temperature for three days.…”

“…Therefore, numerous efforts have been devoted to solving these problems by developing novel enzyme mimics to replace the natural enzyme [ 36 ]. To our knowledge, several nanostructures, such as gold nanoclusters, Co 3 O 4 nanoparticles, gold nanoparticles, FeS 2 nanoparticles, or Si doped CoO nanorods possessing instinct peroxidase-like activity were fabricated to detect GSH owing to its greater resistance to adverse surroundings and cost-effectiveness [ 37 , 38 , 39 , 40 , 41 ]. The oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) catalyzed by the mimetic peroxidases can be suppressed by GSH, accompanied by a sharp decrease of the absorbance at 652 nm.…”

A fluorescent probe based on cucurbit[7]uril for the selective recognition of phenylalanine

“…2,3 As a consequence, the development of reliable methods for amino acid recognition and determination are of great significance in food testing, nutritional analysis, medical diagnostics, and for numerous other fields. [4][5][6][7][8][9] To date, many methods, including high performance liquid chromatography (HPLC), 10 gas chromatography (GC), 11 capillary electrophoresis (CE), 12 and optical techniques, 13,14 have been employed for the recognition and detection of the twenty natural amino acids. Among the optical techniques, the fluorescence approach is particular attractive given its excellent selectivity, fast response time, low detection limits, and the inexpensive instrumentation required 15 .…”