The Recognition of Sweat Latent Fingerprints with Green-Emitting Carbon Dots.

Dan Zhao,Xincai Xiao,Wenting Ma

doi:10.3390/nano8080612

Dan Zhao, Xincai Xiao + Show 1 more

Open Access

https://doi.org/10.3390/nano8080612

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Abstract

The recognition of fingerprints has played an extremely important role in criminal investigations, due to its uniqueness. This paper reports on the recognition of sweat latent fingerprints using green-emitting, environment-friendly carbon dots prepared with DL-malic acid and ethylenediamine, and the exploration of impacting factors in the development process of fingerprints. The experiments showed that better fingerprint images could be obtained when the latent fingerprints are developed in green-emitting carbon dots with pH 9 for 30 min, at room temperature. The reported method was also effective for latent fingerprints on a variety of substrates, as well as for those water-immersed ones, where the developed fingerprint remained stable after long-term preservation. Furthermore, the fluorescent three-dimensional fingerprint image could provide direct and simple evidence on pressing habits. The objective of this paper was to present this method. The method may help to narrow the range of suspects during criminal investigations and in forensic science.

Highlights

The fingerprint of a human being, is influenced by heredity and environment, exhibits a property of uniqueness [1,2,3], and has already become important evidence in criminal investigations and convictions [2,4,5,6]
This paper reported on the development of latent sweat fingerprints with G-carbon dots (CDs) as the developing solution, which is prepared using DL-malic acid and ethylenediamine
The green-emissioned CDs (G-CDs) were synthesized via the hydrothermal method, from DL-malic acid with ethylenediamine

Summary

Introduction

The fingerprint of a human being, is influenced by heredity and environment, exhibits a property of uniqueness [1,2,3], and has already become important evidence in criminal investigations and convictions [2,4,5,6]. Xu et al [16] based on the N-L-Cys-capped Mn-doped ZnS QDs prepared by the modification of heavy metal-free Mn, realized the development of latent fingerprints on various objects. Some of the developing solution contained Cd element, harmful to its users and the environment, and some required complicated preparation processes with strict synthesis environments and surface modifications. These problems greatly limit their applications in practical criminal investigations

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