Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Observation that children`s fingerprints disappear from surfaces more quickly than adults`, initiated a study to characterize the chemical components in fingerprints. Samples were obtained from about 50 individuals ranging in age from 3 to 64 by extracting chemicals from the fingertips using rubbing alcohol. Using combined gas chromatography/mass spectrometry, a wide range of compounds were identified. Samples from children contained higher levels of relatively volatile free fatty acids, while those from adults had higher levels of less volatile long chain esters of fatty acids. These esters are thought to originate from sebaceous glands located on the face and levels of these compounds increase substantially after puberty. Also, other compounds were observed that could be used to develop improved methods for fingerprint detection at a crime scene. Further, observation of specific compounds raises the possibility of being able to identify personal traits (gender, habits, diseases, etc. ) via analysis of components in fingerprints and/or skin. <s> BIB001 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The purpose of this project was to determine if there was a difference in the longevity of the latent fingerprints of children vs adults. It is generally believed that a subject’s age does not affect the evaporation rates of fingerprints. However, based upon a recent criminal investigation of child abduction, it was hypothesized that children’s latent fingerprints do not last as long as those of adults. Participation in this study was voluntary and informed consent obtained. A total of 97 subjects pressed their fingers on glass slides and their latent fingerprints were lifted one, three, five and seven days later. A comparison was then made between the longevity of the prints of children vs adults. Almost all of the adult prints were still present on day seven. Of the children’s prints, 20 percent were unclear on day three; 54 percent were unclear on day five; and 76 percent were unclear on day seven. This has implications for law enforcement and forensic science in that time may become a critical variable in criminal investigations requiring the lifting of latent fingerprints of children. <s> BIB002 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The work described in this report was focused on generating increased knowledge of fingerprint chemistry, particularly the composition of a latent fingerprint at the time it is deposited, and the chemical changes in lipid components that occur over time. Fingerprints from five male donors (aged 25-34 years) were collected and aged under controlled conditions. The prints were then sampled at set intervals, solvent extracted with dichloromethane, co-derivatized with MSTFA and analyzed by gas chromatography-mass spectrometry (GC-MS). It was shown that there was loss of squalene from prints stored in the light or in the dark. Loss was more rapid in the light, with squalene in prints from some donors not detected after 9 days storage. For these same donors, squalene was still detected after 33 days storage in the dark, but at much lower levels than in fresh prints. For saturated fatty acids (tetradecanoic, palmitic and stearic acid) there was a trend towards an increase in levels of these substances during storage (up to about 20 days) followed by a decrease back to original levels or below. This was the case for samples stored in the light or in the dark. For palmitoleic acid, a similar trend was seen. For oleic acid, this trend was seen for samples stored in the dark. For samples stored in the light the general trend was a decrease in level over the storage period (up to 33 days). <s> BIB003 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Latent fingerprint residue is a complex mixture of organic and inorganic compounds. A full understanding of the composition of this mixture and how it changes after deposition is lacking. Three solvent systems were compared for the simultaneous extraction and derivatization with ethyl chloroformate of selected amino and fatty acids from a nonporous substrate (Mylar for subsequent analysis by gas chromatography-mass spectrometry. A solvent system comprised of sodium hydroxide, ethanol, and pyridine was found to be the most effective. This method was applied to the analysis of latent fingerprint residue deposited on Mylar and preliminary data are presented. Twelve amino acids (e.g., serine, glycine, and aspartic acid) and 10 fatty acids (e.g., tetradecanoic, hexadecanoic, and octadecanoic acids) were identified. The potential application of this method to further the understanding of latent fingerprint chemistry has been demonstrated. <s> BIB004 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> An analysis of latent fingermark residues by Sodium-Dodecyl-Sulfate PolyAcrylamide Gel Electrophoresis (SDS-PAGE) followed by silver staining allowed the detection of different proteins, from which two major bands, corresponding to proteins of 56 and 64 kDa molecular weight, could be identified. Two other bands, corresponding to proteins of 52 and 48 kDa were also visualizable along with some other weaker bands of lower molecular weights. In order to identify these proteins, three antibodies directed against human proteins were tested on western blots of fingermarks residues: anti-keratin 1 and 10 (K1/10), anti-cathepsin-D (Cat.D) and anti-dermcidin (Derm.). The corresponding antigens are known to be present in the stratum corneum of desquamating stratified epithelium (K1/10, Cat.D) and/or in eccrine sweat (Cat.D, Derm.). The two major bands were identified as consistent with keratin 1 and 10. The pro-form and the active form of the cathepsin-D have also been identified from two other bands. Dermcidin could not be detected in the western blot. In addition, these antibodies have been tested on latent fingermarks left on polyvinylidene fluoride (PVDF) membrane, as well as on whitened and non-whitened paper. The detection of fingermarks was successful with all three antibodies. <s> BIB005 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Time-of-flight secondary ion mass spectrometry was applied in forensic research for characterization, visualization and analysis of fingerprints left after the fingers were contaminated by traces of drugs: amphetamine (AF), methamphetamine (MA) and methylenedioxymethamphetamine (MDMA; ecstasy). Experimental work was carried out using four kinds of bases (steel, aluminium, brass and glass) on which fingerprints were imprinted. The results of our preliminary studies have demonstrated that the ToF-SIMS technique can be a powerful tool in chemical investigations of fingerprints and detection of traces of substances, which do not exist in natural skin extraction, but can be found at the crime scene. <s> BIB006 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The application of powders to fingerprints has long been established as an effective and reliable method for developing latent fingerprints. Fingerprints developed in situ at a crime scene routinely undergo lifting with specialist tapes and are then stored in evidence bags to allow secure transit and also to preserve the chain of evidence. In a previous study we have shown that exogenous material within a fingerprint can be detected using Raman spectroscopy following development with powders and lifting with adhesive tapes. Other reports have detailed the use of Raman spectroscopy to the detection of drugs of abuse in latent fingerprints including cyanoacrylate-fumed fingerprints. This study involves the application of Raman spectroscopy for the analysis of drugs of abuse in latent fingerprints for fingerprints that had been treated with powders and also subsequently lifted with adhesive tapes. Samples of seized ecstasy, cocaine, ketamine and amphetamine were supplied by East Sussex Police and by the TICTAC unit at St. Georges Hospital Tooting. Contaminated fingerprints were deposited on clean glass slides. The application of aluminium or iron based powders to contaminated fingerprints did not interfere with the Raman spectra obtained for the contaminants. Contaminated fingerprints developed with powders and then lifted with lifting tapes were also examined. The combination of these two techniques did not interfere with the successful analysis. The lifting process was repeated using hinge lifters. As the hinge lifters exhibited strong Raman bands the spectroscopic analysis was more complex and an increase in the number of exposures to the detector allowed for improved clarification. Spectral subtraction was performed to remove peaks due to the hinge lifters using OMNIC software. Raman spectra of developed and lifted fingerprints recorded through evidence bags were obtained and it was found that the detection process was not compromised. Although the application of powders did not interfere with the detection process the time taken to locate the contaminant was increased due to the physical presence of more material within the fingerprint. <s> BIB007 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Exposure to light or heat, or simply a dearth of fingerprint material, renders some latent fingerprints undetectable using conventional methods. We begin to address such elusive fingerprints using detection targeting photo- and thermally stable fingerprint constituents: surface-enhanced Raman spectroscopy (SERS). SERS can give descriptive vibrational spectra of amino acids, among other robust fingerprint constituents, and good sensitivity can be attained by improving metal-dielectric nanoparticle substrates. With SERS chemical imaging, vibrational bands' intensities recreate a visual of fingerprint topography. The impact of nanoparticle synthesis route, dispersal methodology-deposition solvent, and laser wavelength are discussed, as are data from enhanced vibrational spectra of fingerprint components. SERS and Raman chemical images of fingerprints and realistic contaminants are shown. To our knowledge, this represents the first SERS imaging of fingerprints. In conclusion, this work progresses toward the ultimate goal of vibrationally detecting latent prints that would otherwise remain undetected using traditional development methods. <s> BIB008 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The enhancement of latent fingerprints, both at the crime scene and in the laboratory using an array of chemical, physical and optical techniques, permits their use for identification. Despite the plethora of techniques available, there are occasions when latent fingerprints are not successfully enhanced. An understanding of latent fingerprint chemistry and behaviour will aid the improvement of current techniques and the development of novel ones. In this study the amino acid and fatty acid content of 'real' latent fingerprints collected on a non-porous surface was analysed by gas chromatography-mass spectrometry. Squalene was also quantified in addition. Hexadecanoic acid, octadecanoic acid and cis-9-octadecenoic acid were the most abundant fatty acids in all samples. There was, however, wide variation in the relative amounts of each fatty acid in each sample. It was clearly demonstrated that touching sebum-rich areas of the face immediately prior to fingerprint deposition resulted in a significant increase in the amount of fatty acids and squalene deposited in the resulting 'groomed' fingerprints. Serine was the most abundant amino acid identified followed by glycine, alanine and aspartic acid. The significant quantitative differences between the 'natural' and 'groomed' fingerprint samples seen for fatty acids were not observed in the case of the amino acids. This study demonstrates the variation in latent fingerprint composition between individuals and the impact of the sampling protocol on the quantitative analysis of fingerprints. <s> BIB009 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The identification of aged latent fingerprints is often difficult, especially for those of children. To understand this phenomenon, the chemical composition of children's versus adults latent fingerprints was examined over time using Fourier transform infrared microscopy. Hierarchical cluster analysis revealed that children's and adults prints were distinguishable for up to 4 weeks after deposition, based on differences in sebum composition. Specifically, adults had a higher lipid content than children, but both decreased over time, attributable to the volatility of free fatty acids. The aliphatic CH{sub 3}, aliphatic CH{sub 2}, and carbonyl ester compositions changed differently in adults versus children over time, consistent with higher cholesterol and cholesteryl esters in children's prints and wax esters and glycerides in adults prints. Thus, fingerprint composition changes with time differently in children versus adults, making it a sensitive metric to estimate the age of an individual, especially when the age of the print is known. <s> BIB010 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Two types of amorphous, silica nanoparticles have been produced and used as surface assisting agents during laser desorption/ionisation time-of flight-mass spectrometry (SALDI-TOF-MS). The first is hydrophilic possessing surface aminopropyl groups and the second hydrophobic containing surface phenyl groups. Each particle type acts as a solid phase adsorbent, adsorbing analytes according to their charge and hydrophobicity. The adsorbed analytes can be directly analysed on the particles using SALDI-TOF-MS. Intrinsically magnetisable versions of the hydrophobic particles act as magnetic solid phase extraction (MSPE) materials which are used to selectively adsorb analytes within a mixture deposited onto a surface, transfer the adsorbed components using a magnetic wand and to deposit the particles at a site adjacent to that of the original mixture. Non-adsorbed components remain at the original site. The extracted and residual analytes are then directly analysed on the surface by SALDI-TOF-MS. Using fingerprints as an example of a complex biological matrix, this new approach has been used to separate polar (amino acids) and non-polar constituents (squalene and fatty acids) within latent fingerprints deposited on a surface and for their subsequent direct analysis on the surface by SALDI-TOF-MS. Alanine, ornithine, lysine and aspartic acid which were undetected or poorly detected prior to separation showed improved signal detection after separation. <s> BIB011 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Abstract: Determining the time since deposition of fingermarks may prove necessary to assess their relevance to criminal investigations. The crucial factor is the initial composition of fingermarks, because it represents the starting point of any aging model. This study mainly aimed to characterize the initial composition of fingerprints, which show a high variability between donors (inter-variability), but also to investigate the variations among fingerprints from the same donor (intra-variability). Solutions to reduce this initial variability using squalene and cholesterol as target compounds are proposed and should be further investigated. The influence of substrates was also evaluated, and the initial composition was observed to be larger on porous surface than nonporous surfaces. Preliminary aging of fingerprints over 30 days was finally studied on a porous and a nonporous substrate to evaluate the potential for dating of fingermarks. Squalene was observed to decrease in a faster rate on a nonporous substrate. <s> BIB012 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> The chemistry of children's latent fingerprint residues was investigated as a function of time and temperature by non-destructive spectrochemical analysis. Latent fingerprints from children, ranging in age from 2 to 11 years, were deposited onto aluminum-coated glass slides and were analyzed by Fourier-Transform Infrared Microspectroscopy. The results revealed that there are three major classes of compounds present in children's latent fingerprints: carboxylic acid salts, proteins, and esters. By studying the changes in the fingerprint residues as a function of time and at elevated temperatures, we discovered that the salts in the fingerprint residues are stable relative to the esters. These findings have relevant forensic implications; by targeting the acid salts instead of the esters or proteins, children's latent fingerprints may be recovered after extended periods of time have elapsed. <s> BIB013 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Abstract This article describes the composition of fingermark residue as being a complex system with numerous compounds coming from different sources and evolving over time from the initial composition (corresponding to the composition right after deposition) to the aged composition (corresponding to the evolution of the initial composition over time). This complex system will additionally vary due to effects of numerous influence factors grouped in five different classes: the donor characteristics, the deposition conditions, the substrate nature, the environmental conditions and the applied enhancement techniques. The initial and aged compositions as well as the influence factors are thus considered in this article to provide a qualitative and quantitative review of all compounds identified in fingermark residue up to now. The analytical techniques used to obtain these data are also enumerated. This review highlights the fact that despite the numerous analytical processes that have already been proposed and tested to elucidate fingermark composition, advanced knowledge is still missing. Thus, there is a real need to conduct future research on the composition of fingermark residue, focusing particularly on quantitative measurements, aging kinetics and effects of influence factors. The results of future research are particularly important for advances in fingermark enhancement and dating technique developments. <s> BIB014 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Matrix Assisted Laser Desorption Ionisation Mass Spectrometry (MALDI MS) can detect and image a variety of endogenous and exogenous compounds from latent fingermarks. This opportunity potentially provides investigators with both an image for suspect identification and chemical information to be used as additional intelligence. The latter becomes particularly important when the fingermark is distorted or smudged or when the suspect is not a previously convicted offender and therefore their fingerprints are not present in the National Fingerprint Database. One of the desirable pieces of intelligence would be the sex of the suspect from the chemical composition of a fingermark. In this study we show that the direct detection of peptides and proteins from fingermarks by MALDI MS Profiling (MALDI MSP), along with the multivariate modeling of the spectra, enables the determination of sex with 85% accuracy. The chemical analysis of the fingermark composition is expected to additionally provide information on traits such as nutritional habits, drug use or hormonal status. <s> BIB015 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Friction ridge examination is one of the bedrock disciplines in forensic science and has been employed for over 100 years. It is considered the pre-eminent method of individualization in forensic science. That status, however, has recently been upset by court challenges and high-profile misidentifications. Friction ridge examination will no doubt continue as a mainstay of forensic science, but changes in methodology and interpretation may be on the horizon. How the discipline weathers these changes depends on the willingness of the profession to critically examine their foundations, procedures, and methods. <s> BIB016 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Abstract A more comprehensive understanding of the variability of latent fingermark composition is essential to improving current fingermark detection capabilities in an informed manner. Gas chromatography–mass spectrometry was used to examine the composition of the lipid fraction of latent fingermarks collected from a population of over 100 donors. Variations in the appearances of chromatograms from different donors were apparent in the relative peak sizes of compounds including free fatty acids, squalene, cholesterol and wax esters. Principal component analysis was used as an exploratory tool to explore patterns in this variation, but no correlation to donor traits could be discerned. This study also highlights the practical and inherent difficulties in collecting reproducible samples. <s> BIB017 </s> Relevant visualization technologies for latent fingerprints on wet objects and its challenges: a review <s> Rationale of this review <s> Fingerprints have been used for human identification in criminal investigation for over 100 years. The detection of invisible or latent marks at crime scenes has been one of the great scientific challenges in forensic science and there have been considerable advances in this capability. The technological age and increasing power of computing has had a major influence on fingerprint identification providing the capacity to search large databases and provide rapid identification of persons of interest. This chapter discusses the important contribution of fingerprints to criminal investigation. <s> BIB018
The different chemical reactions between the respective visualization methods with that of the available water-soluble (e.g., amino acids) and water -insoluble (e.g,. fatty acids) constituents of fingerprints serve as one of the bases for successful visualization of latent fingerprints BIB016 BIB018 . Therefore, understanding the chemical interactions/mechanisms as well as advantages and disadvantages of the available  BIB004 BIB005 BIB008 BIB011 BIB017 mainly focusing on the development and/or improvement of the visualizing reagents, dating of fingerprints, and donor profiling BIB014 . It has been reported that fingerprints are principally formed by natural secretions of eccrine and sebaceous glands. While eccrine glands secrete mainly water (about 98%)  , organic (e.g., amino acids) (Ramotowski 2001; BIB004 BIB005 BIB008 BIB011 , and inorganic compounds (e.g., sodium and potassium)  , sebaceous glands secrete mostly fatty acids, squalene, cholesterols   BIB009  BIB011 , and wax esters  BIB009  . The presence of exogenous contaminants in fingerprint constituents such as food residues, dust, bacterial spores  , and drugs BIB006 BIB007 were also reported in the literature. The initial constituents of fingerprints tend to vary over time, attributable to factors such as donor characteristics (e.g., age and gender), deposition conditions (e.g., pressure and duration of contact) BIB014 BIB017 , and nature of the substrate (e.g., porous and non-porous) BIB014 . Additionally, it has been described that the amount of fingerprint constituents varies significantly between samples of the same (intra-variability) and different donors (inter-variability) BIB003 BIB012 , presumably due to reasons such as uneven deposition pressure and contact. However, BIB003 also argued that because of the wide variability of fingerprint constituents, predictions of the age of fingerprints within reasonable margins remain limited. Besides, researchers have documented about the notable differences in sebum constituents in children and adult's fingerprints within 4 weeks of observation BIB010 . Similarly, BIB013 stated that the number of total residues obtained and the ratio of droplets to particles are noticeably higher in female adult when compared to children of the same gender. However, the authors also pointed out the similarity between the fingerprint deposits of female children with that of adults in certain cases, probably due to the physiological changes associated with the onset of puberty. In a study by BIB002 , the author investigated the longevity of a child's fingerprints with that of adults. He reported that the fingerprints of children disappeared much sooner than that of adults (in as early as the fifth day of the observation), probably because children are known to have considerable amounts of volatile esters in their fingerprint constituents BIB013 which subsequently evaporated at a faster rate than that of adults BIB001 . In another study by BIB009 , the researchers reported higher individual mean of amino acids (particularly asparagine) in females as compared to males. On the contrary, the authors reported lower mean amounts of most fatty acids per fingerprints in females than that of males, although this was reported as statistically insignificant. BIB015 while studying the direct detection of peptides and small proteins in fingerprint constituents using matrix-assisted laser desorption ionization mass spectrometry profiling with multivariate statistical analysis reported 85% accuracy at distinguishing gender. Considering the varying factors that can affect the quality of fingerprints discussed above, visualizing latent fingerprints for forensic purposes are often challenging. The relevant methods for visualizing wetted latent fingerprints are discussed below.