Confining copper nanoclusters on exfoliation-free 2D boehmite nanosheets: Fabrication of ultra-sensitive sensing platform for α-glucosidase activity monitoring and natural anti-diabetes drug screening

Anchoring Cu Nanoclusters on Melamine–Formaldehyde Microspheres: A New Strategy for Triggering Aggregation-Induced Emission toward Specific Enzyme-Free Methyl Parathion Sensing

“…Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectroscopy (XPS) were determined to acquire the chemical composition of CuNCs, MF microspheres, and MF@CuNCs. As displayed in FTIR spectra of CuNCs (Figure B), the peak at 1650 cm –1 is ascribed to the stretching vibration of CO on glutathione (GSH) . As for MF microspheres, the broad band locating at 3400 cm –1 resulted from the superimposed stretching vibrations of imino (−NH 2 ) and hydroxyl (−OH) groups; the peaks at 2918 and 1359 cm –1 are related to C–H of methylene groups and C–N bonds; the doublet at 1556 and 1506 cm –1 is due to the stretching vibrations of CN bonds in the 1,3,5-triazine ring; and the signals at 1163 and 1014 cm –1 correspond to the vibrations of ether C–O bonds.…”

“…The synthesis of CuNCs and MF was referred to previously reported works. , To fabricate the fluorescent composite MF@CuNCs, 20 mg of MF was dispersed in 1 mL of ultrapure water. Then, 1 mL of CuNCs (16 mg mL –1 ) was mixed with MF solution (20 mg mL –1 ) uniformly.…”

“…As displayed in FTIR spectra of CuNCs (Figure 2B), the peak at 1650 cm −1 is ascribed to the stretching vibration of C�O on glutathione (GSH). 27 As for MF microspheres, the broad band locating at 3400 cm −1 resulted from the superimposed stretching vibrations of imino (−NH 2 ) and hydroxyl (−OH) groups; the peaks at 2918 and 1359 cm −1 are related to C−H of methylene groups and C−N bonds; the doublet at 1556 and 1506 cm −1 is due to the stretching vibrations of C�N bonds in the 1,3,5-triazine ring; As recorded in XPS spectra (panels A and B of Figure 3), the binding energies of C, N, O, S, and Cu elements can be detected in both CuNCs and MF@CuNCs, suggesting the successful preparation of MF@CuNCs. Notably, the peaks at 932.0 and 951.6 eV in the inset corresponding to the binding energies of Cu 2p 3/2 and 2p 1/2 are assigned to Cu(0), and no obvious signal appears at approximately 942 eV, illustrating the absence of Cu 2+ in CuNCs.…”

Construction of a copper nanocluster/MnO2 nanosheet-based fluorescent platform for butyrylcholinesterase activity detection and anti-Alzheimer's drug screening

“…43 In our previous work, glutathione-protected CuNCs were confined on the surface of boehmite nanosheets, permitting the sensitive detection of a-glucosidase activity and screening of natural anti-diabetes drugs. 44 Herein, a fluorescence sensing method for BChE monitoring and BChE inhibitor screening was developed by incorporating polyethyleneimine-protected CuNCs (PEI-CuNCs) with manganese dioxide (MnO 2 ) nanosheets. As shown in Scheme 1, PEI-CuNCs with positive charges can be easily adsorbed on the surface of negatively charged MnO 2 nanosheets, resulting in a significant decrease in the fluorescence emission of PEI-CuNCs through the inner filter effect (IFE) of MnO 2 nanosheets.…”

“…43 In our previous work, glutathione-protected CuNCs were confined on the surface of boehmite nanosheets, permitting the sensitive detection of α-glucosidase activity and screening of natural anti-diabetes drugs. 44…”