No abstract

An in-situ reduction method has been reported to prepare gold nanoparticles (GNPs) of 40–110 nm by using the green reducing agents of proteins, which are activated by H2O2 and the superoxide anion (). The protein of collagen turns HAuCl4 to the aqueous Au(I) ainions, which are further reduced by other proteins to be highly monodispersed and spherical GNPs of different sizes. The GNPs reduced by different proteins are found to be with the exposed {100} facets, the distinctive UV-vis absorption spectra and various colors (See Fig. 1). By means of extracting the color responses, such as red, green and blue (RGB) alterations, an in-situ reduction method-based multidimensional sensing platform is fabricated in the process of GNPs synthesis. Without further modification of GNPs, nine common proteins are found to be well detected and discriminated at different concentrations. Moreover, this sensing platform also demonstrates great potentials in qualitative and semiquantitative analysis on the individuals of these proteins with high sensitivity. Furthermore, the validation of this multidimensional sensing platform has been carried out by analysis on the spiked proteins in human urine and the target proteins in complex matrix (e.g. lysozyme in human tear).

No abstract

In this study, the interaction between gas molecules, including HO, N, CO, NO, NO and NO, and a WSe monolayer containing an Se vacancy (denoted as V) has been theoretically studied. Theoretical results show that HO and N molecules are highly prone to be physisorbed on the V surface. The presence of the Se vacancy can significantly enhance the sensing ability of the WSe monolayer toward HO and N molecules. In contrast, CO and NO molecules highly prefer to be molecularly chemisorbed on the V surface with the non-oxygen atom occupying the Se vacancy site. Furthermore, the exposed O atoms of the molecularly chemisorbed CO or NO can react with additional CO or NO molecules, to produce C-doped or N-doped WSe monolayers. The calculated energies suggest that the filling of the CO or NO molecule and the removal of the exposed O atom are both energetically and dynamically favorable. Electronic structure calculations show that the WSe monolayers are p-doped by the CO and NO molecules, as well as the C and N atoms. However, only the NO molecule and N atom doped WSe monolayers exhibit significantly improved electronic structures compared with V. The NO and NO molecules will dissociate directly to form an O-doped WSe monolayer, for which the defect levels due to the Se vacancy can be completely removed. The calculated energies suggest that although the dissociation processes for NO and NO molecules are highly exothermic, the NO dissociation may need to operate at an elevated temperature compared with room temperature, due to its large energy barrier of ∼1 eV.