Monodisperse silica nanoparticle suspension for developing latent blood fingermarks

Abstract

Traditional fingermark developing methods are unsuitable for developing and extracting latent blood fingermarks on dark surfaces at crime scene because of their ineffectiveness or tedious operation procedures. In the present work, an effective and simple method was developed to serve this purpose using a suspension of monodisperse silica nanoparticles (MSNs). A suspension of 0.1 g/mL of MSNs was prepared by dispersing MSNs ultrasonically into an ethanol solution containing 1.0% Tween 80 and then uniformly sprayed onto the latent blood fingermarks on black plastic bags. Approximately 20 s later, ethanol was sprayed to clean the superfluous developing liquid. After the ethanol had evaporated, the latent fingermarks became visible as a result of the photonic crystal effect produced by the MSNs that had adsorbed to the fingermark ridges. The developed fingermarks were then photographed using a digital camera under a white or monospectral light source, revealing fine ridges and clear fingermark details. This novel, simple and effective method uses the photonic crystal effect of MSNs to develop latent blood fingermarks without the need for surface functionalization and conjugation to dye or fluorescently label molecules. The method can detect latent blood fingermarks that have been retained on a black plastic bag surface for at least 30 d. Given the simplicity and effectiveness of the developed method, MSNs may be a useful alternative material for use in developing latent fingermarks. Further research on the topic is warranted.

Recent progress in the applications of silica-based nanoparticles

“…This method utilizes the photonic crystal effect of monodisperse silica nanoparticles to improve latent blood fingermarks kept on black plastic bags surfaces for at least 30 days without the requirement of surfaces to functionalize and conjugate the dye or fluorescently label the molecules. 116 It has been widely known that the biodegradability of conventional silica nanoparticles is limited. Hence, the progression of intrinsically biodegradable SNPs has great attention and has aroused extensive research interest during the last decade, and many strategies have been investigated to enhance the biodegradability.…”

The Role of Silica Nanoparticle in Fingerprint Visualization Studies

“…These; overview photos, photography of evidence, and close-up photos of evidence (see Figs. 1,2,3). In general view shots, the crime scene is shot from different angles.…”

“…There are chemicals used for chemical development. Amido contains chemicals such as Black, Purple acid, protein dyes [2].…”

“…Moret and colleagues created silicon oxide nanoparticles synthesized with the carboxyethylsilanetriol sodium salt and 3-triethoxycylyl propylsuccinic anhydride to detect fingerprints. By using these particles, the detectability of natural fingerprints has been demonstrated on various non-porous surfaces such as glass, plastic, and stainless steel [2].…”

Nanoparticles used for fingermark detection—A comprehensive review

“…It was found that NPs synthesized with a binary mixture of TEOS and PTEOS, and WA6 fluorophore used as an aqueous suspension on glass substrates gave clear, luminescence ridges with secondary-and tertiary-level details and high contrast. Meng et al used SiO 2 NPs to detect fingermarks in blood on black plastic (Meng et al, 2018). A suspension of the NPs was made by dispersing it in ethanol and surfactant, and it was used to spray on the fingermarks.…”