From Sniffer Dogs to Emerging Sniffer Devices for Airport Security: An Opportunity to Rethink Privacy Implications?

Dogs are known for their incredible ability to detect odours, extracting them from a ‘‘complex’’ environment and recognising them. This makes sniffer dogs precious assets in a broad variety of security applications. However, their use is subject to some intrinsic restrictions. Dogs can only be trained to a limited set of applications, get tired after a relatively short period, and thus require a high turnover. This has sparked a drive over the past decade to develop artificial sniffer devices—generally known as ‘‘chemical sniffers’’ or ‘‘electronic noses’’—able to complement and possibly replace dogs for some security applications. Such devices have been already deployed, or are intended to be deployed, at borders, airports and other critical installation security checkpoints. Similarly to dogs, they are adopted for detecting residual traces that indicate either the presence of, or recent contact with, substances like drugs and explosives. It goes without saying that, as with sniffer dogs, the use of artificial sniffer devices raises many sensitive issues. Adopting an ethical and legal perspective, the present paper discusses the privacy and data protection implications of the possible deployment of a hand-held body scanning sniffer for screening passengers at EU airport security checkpoints

MPA-capped CdSe QD/mercaptoethylamine-capped AuNP nanocomposite-based sensor for instant detection of trinitrotoluene

CdSe quantum dots capped with mercaptopropionic acid (CdSe@MPA QDs) were synthesized by chemical route method. The developed CdSe@MPA QDs were pH optimized for higher emission. Gold nanoparticles in aqueous dispersion medium were synthesized by using sodium citrate as reduction agent and capped with mercaptoethylamine (MEA). Further, AuNP-MEA nanoparticles were conjugated with CdSe@MPAQDs. The “as-synthesized” nanomaterials and their composites were characterized by different analytical techniques like TEM, DLS, FTIR, UV-Vis, and PL spectroscopy. Upon excitation at λex = 400 nm, CdSe@MPA QDs show emission at 540 nm (λem) leading in a good spectral overlap with absorption spectra of AuNPs (λmax = 521 nm). Trinitrotoluene (TNT), being an electron deficient species can easily bind with electron-rich amine group. The amine functionalized GNPs (AuNP@MEA) were used as quenchers for FRET between QDs and GNPs to detect TNT. Using this assay, TNT has been selectively detected up to 21.9 nmol L−1 (LOD). Schematic diagram showing TNT detection based on FRET between gold nanoparticles and quantum dots is also suggested