Non-toxic luminescent Au Nanoclusters@Montmorillonite nanocomposites powders for latent fingerprint development

Abstract

Non-toxic Au nanoclusters@montmorillonite (AuNCs@MMT) nanocomposites with strong red fluorescence are prepared by a microwave (MW)-assisted synthesis method and immobilize Au NCs into sodium MMT clay matrix via electrostatic interaction. Due to the immobilization of Au NCs in the layered structure of the MMT clay matrix, the formative AuNCs@MMT nanocomposites show high emission, stable chemical features and less toxicity. The obtained Au NCs and AuNCs@MMT nanopowders were characterized by using UV-visible absorption spectroscopy, fluorescence spectroscopy, infrared spectroscopy, TEM/HRTEM, SEM and XRD etc. to depict their sizes, microstructures and optical features.Due to their environmentally friendly preparation, time-saving procedure, user-friendly operation, low cost, efficient UV-visible radiation-dependent photoluminescence and good affinity with finger residues, the as-synthesized AuNCs@MMT nanopowders are employed as a alternative florescent developing reagent for enhancing latent fingerprints deposited on various object surfaces (such as glass, porcelain enamel, stainless steel, painted metal, plastic products, weighing papers etc.) for individual identification. As results, the enhanced fingerprints with clear patterns and satisfactory ridge details were obtained by using as-prepared AuNCs@MMT nanopowders. At the same time, intensively red fluorescence as well as good contrast without background staining of developed prints demonstrated great advantages for surfaces with multicolour. Because of their good sensitivity, non-toxicity and strong resistance to background interference, the as-prepared fluorescent nanocomposites are an actual alternative to conventional powdering reagents, which may find potential application in forensic detection.

Interpol review of fingermarks and other body impressions 2016–2019

“…All the articles below refer to the application of micron-sized particles. Preliminary/Pilot studies : Several kinds of compounds were proposed to detect fingermarks on non-porous substrates through powder dusting: ABC dry fire extinguisher powder [ 354 ], Fuller’s earth [ 355 ], anthracene and naphthalene [ 356 ], BaTiO 3 :Dy 3+ microspheres [ 357 ], chitosan-tripolyphosphate microparticles [ 358 ], La 2 (MoO 4 ) 3 :Eu 3+ microcrystals [ 359 ], phenyl-doped graphitic carbon nitride [ 360 ], bis(salicylidene)cyclohexyl-1,2-diamino zinc(II) complex [ 361 ], functionalized montmorillonite [ 362 , 363 ], carbon dot@TiO 2 core-shell composite [ 288 ], household powders such as gram flour, coriander, cumin or black pepper [ 364 ], Ca 4 (PO 4 ) 2 O:Eu 2+ phosphors [ 365 ], Eu(Phen) 2 complex intercalated clay hybrids [ 366 ], AIE-based magnetic powder doped with tetraphenylethene derivatives [ 367 ], pyrene [ 368 ], silica microparticles coated with phenanthro imidazole derivative [ 369 ], europium (III) coordination polymer [ 370 ], Yb 3+ /Er 3+ co-doped ceramics presenting upconversion properties [ 371 ], cationic dye – diatomite composite [ 372 ], benzazole-doped silica microparticles [ 373 ], Yb 3+ /Er 3+ /Tm 3+ doped fluorides presenting upconversion properties [ 374 ], porous graphitic carbon nitride [ 375 ], YBO 3 :Eu 3+ /Tb 3+ phosphors [ 376 ], Mg 2 TiO 4 :Mn 4+ phosphor [ 377 ], carbazolyl-based phosphor [ 378 ], and AIE-based imidazole derivatives [ 379 ]. It should be emphasized that several of these studies are conducted with an extremely low number of donors leaving fresh, sebum-rich fingermarks.…”

Carbohydrate biopolymers, lignin based adsorbents for removal of heavy metals (Cd2+, Pb2+, Zn2+) from wastewater, regeneration and reuse for spent adsorbents including latent fingerprint detection: A review

“…Nanomaterials such as magnetic nanoparticles, semiconductor quantum dots and their composites, metals and their oxide nanoclusters, and carbon dots have been greatly attractive in latent fingerprint detection because of their good magnetic properties, sole dependency on size photoluminescence with stable emission, high quantum yield and good biocompatibility [ 113 ].…”

One‐Step Synthesis of Solid‐State Photoluminescent Carbon Nanodots from Grains for Latent Fingerprint Detection

“…Since 19th century, fingerprints have been used as one of the most important means for criminal investigations and many studies have focused on the development of fingerprint detection techniques. [1] Among the emerging strategies, the use of luminescent nanoparticles, especially rare earth fluorescent nanomaterials, [2][3][4] gold nanoparticles [5,6] and quantum dots, [7,8] was regarded as the most notable one in the field. [9] It was found that small powder particles adhere better on fingermark residue and then the detected residue are easily observed in virtue of the fluorescent properties of nanomaterials.…”