Lei Lou

Dual-mode protein detection based on Fe3O4-Au hybrid nanoparticles

AbstractA facile method of synthesizing Fe3O4-Au hybrid nanoparticles is reported utilizing the multifunctional nature of polyethyleneimine (PEI). An abundance of 5 nm gold nanoparticles were attached to 50 nm Fe3O4 nanoparticles via the covalent binding between the -NH2 groups of the PEI and Au nanoparticles, as well as the electrostatic interaction between the negatively charged citrate-coated Au nanoparticles and the positively charged PEI-coated Fe3O4 nanoparticles. The as-prepared Fe3O4-Au hybrid nanoparticles, which combine the merits of magnetic materials and gold, were successfully employed for the first time in the dual-mode detection of carcinoembryonic antigen (CEA) via electrochemical and surface-enhanced Raman scattering (SERS) methods. Both methods make clever use of Fe3O4-Au nanoparticles and can accurately verify the presence of antigens. In particular, the electrochemical immunosensor detection displays a wide linear range (0.01–10 ng/mL) of response with a low detection limit (10 pg/mL), while the SERS method responds to even lower antigen concentrations with a wider detection range. The Fe3O4-Au hybrid nanoparticles therefore exhibit great potential for biomedical applications.

Fabrication of ZnO photonic amorphous diamond nanostructure from parrot feathers for modulated photoluminescence properties

A ZnO photonic amorphous diamond nanostructure was successfully synthesised using a feather barb of the Rosy-Faced Lovebird as supporting template via a facile sol-gel process. Different from ordered structures, an isotropic PBG around 500 nm was evidenced from reflectance spectra and an optical metallurgical microscopy image, which overlaps with the visible emission peak of ZnO. As a result, the inhibition of visible emission inside the PBG and the enhancement of UV emission at the PBG edges have both been observed, which is independent from the incident angle. Moreover, the rapid thermal annealing can also help improve the crystallinity of ZnO and raise the UV/visible emission ratio without affecting the structure. These results can be very useful for the study of the modification of the optical emission properties of ZnO and other semiconductor materials as well as research on ZnO random lasing.

A novel L-Lactate sensor based on enzyme electrode modified with ZnO nanoparticles and multiwall carbon nanotubes

A highly sensitive and stable L-Lactate sensor based on the synergic action of multi-wall carbon nanotube (MWCNTs) and ZnO nanoparticles has been developed. The unique sandwich-like layer structure (PDDA/LOD/ZnO/MWCNTs) provides a favorable microenvironment to keep the bioactivity of LOD and prevent enzyme molecule leakage. Therefore, the proposed L-Lactate biosensor exhibited good analytical performances including high sensitivity and selectivity with satisfactory stability to amperometric determination of L-Lactate. The results indicated that the proposed PDDA/LOD/ZnO/MWCNTs film was an attractive matrix for the immobilization of LOD enzymes to fabricate biosensors.