title: Enhancement of Image Contrast, Stability, and SALDI-MS Detection Sensitivity for Latent Fingerprint Analysis by Tuning the Composition of Silver-Gold Nanoalloys.
abstract: Metal alloy nanoparticles (NPs) offer a new combination of unique physicochemical properties based on their pure counterparts, which can facilitate the development of novel analytical methods. Here, we demonstrated that Ag-Au alloy NPs could be utilized for optical and mass spectrometric imaging of latent fingerprints (LFPs) with improved image contrast, stability, and detection sensitivity. Upon deposition of Ag-Au alloy NPs (Ag:Au = 60:40 wt %), ridge regions of the LFP became amber colored, while the groove regions appeared purple-blue. The presence of Au in the Ag-Au alloy NPs suppressed aggregation behavior compared to pure AgNPs, thus improving the stability of the developed LFP images. In addition, the Ag component in the Ag-Au alloy NPs enhanced optical absorption efficiency compared to pure AuNPs, resulting in higher contrast LFP images. Moreover, varying the Ag-Au ratio could enable the tuning of the resulting surface plasmonic resonance absorption and hence affect image contrast. Furthermore, the Ag-Au alloy NPs assisted the surface-assisted laser desorption/ionization MS analysis of chemical and biochemical compounds in LFPs, with better detection sensitivity than either pure AgNPs or AuNPs.
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Cheng
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Siu-Leung
authors.initials: SL
authors.lastname: Chau
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Samuel Kin-Man
authors.initials: SK
authors.lastname: Lai
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Ho-Wai
authors.initials: HW
authors.lastname: Tang
authors.affiliation: Department of Chemistry, The University of Hong Kong , Pokfulam Road, Hong Kong SAR, People's Republic of China.
authors.forename: Kwan-Ming
authors.initials: KM
authors.lastname: Ng
keywords: SALDI-MS; image contrast; image stability; latent fingerprints; nanoalloys; silver−gold nanoparticles