Gold Nanoparticles Based Technologies For Visualization Of Latent Fingerprint

Fingerprint has the characteristics of different people,relative stability and traces left by touching objects,which is one of the important basis for identification of personal identity.The discovery,appearance and identification of fingerprint are always the important direction of criminal scientific research.Latent fingerprint is the most common physical evidence at the scene of a case,and its manifestation method has always been the focus of criminal technology research.In the development of latent fingerprint display technology,the traditional latent fingerprint display technology shows the disadvantages of low display rate,small amount of information and low contrast,especially for difficult fingerprints,such as trace level fingerprints,old fingerprints,wet fingerprints and overlapping fingerprints,etc.With the development of modern science and technology and material science,new materials and new technologies have been combined and applied to latent fingerprint display,which not only overcomes the shortcomings of traditional display technology,but also has the advantages of green,relatively lossless,strong specificity,high selectivity and wide application range.As a new material,nanomaterials have been widely used in the study of latent fingerprint.Among them,gold nanoparticles,as the most stable nanomaterials,have become the key research object in latent fingerprint technology because of their obvious physical and chemical characteristics in micro morphology,optical properties and biocompatibility.In this paper,the biological characteristics of fingerprints,the research background and the basic principles of latent fingerprint display technology are summarized,the development trend of latent fingerprint display technology is discussed,In this paper,the principle,method,effect and scope of application of different latent fingerprint technologies based on gold nanoparticles are analyzed in detail,and the factors that affect the effect of latent fingerprint are discussed in detail,in order to provide research basis and reference for latent fingerprint technology.The main results are as follows: 1.The liquid deposition technology based on gold nanoparticles has the advantages of high sensitivity,wide application range and high display rate of old and wet fingerprints,but its operation steps are complex and the image contrast of latent fingerprints on the surface of dark background and multi-color background is poor;2.The biological analysis technology based on gold nanoparticles has the advantages of strong specificity,high resolution and multi information,but the accuracy of its appearance and the sensitivity of its detection ability are still uncertain;3.The spectrum and mass spectrum imaging technology based on gold nanoparticles has the advantages of relatively non-destructive and in-situ analysis,and can well show trace level fingerprints and well separate and show heterogenous overlapping fingerprints,but there are problems such as interference of other spectrum signals in the spectrum imaging;in addition,the technology also has the advantages of expensive instruments,low spatial resolution and imaging flexibility The sensitivity is relatively poor;4.Based on the gold nanoparticle,the goldnanoparticle display technology,vacuum metal deposition technology(VMD)and electrochemical technology all have the advantages of fast and high resolution;the gold nanoparticle display technology and VMD are mainly used for non porous surfaces,while the electrochemical technology is suitable for wet or conductive surfaces,but none of them can get the chemical information of fingerprint components from the latent fingerprint.