Drug Detection at Your Fingertips: Illicit Drugs in Fingerprint Sweat

Drug Detection at Your Fingertips: Illicit Drugs in Fingerprint Sweat

Researchers have developed a new tool for the rapid detection of a number of illicit drugs using only the sweat of an individual’s fingerprint.

Typically, the procedure to test for drugs in human beings necessitates the collection of blood or urine and laboratory-based analysis by gas or liquid chromatography with mass spectrometry. Unfortunately these standard methods are somewhat invasive, require potentially time-consuming laboratory-based analysis, and use complex pieces of analytical instrumentation requiring a trained operator to use. They are inevitably unsuitable for rapid, in-situ screening of potential drug users.

Researchers at the University of East Anglia and Intelligent Fingerprinting Ltd (a spin-out company from the university) have been working on a method of conducting simple, rapid drug analysis using sweat from a person’s finger. The technique has been developed to detect four classes of drugs – cannabis, cocaine, amphetamines and opiates, with cannabis being detected based on the presence of Δ9-tetrahydrocannabinol (THC), cocaine on the presence of benzoylecgonine, and opiates via the detection of morphine.

The finger of an individual is firmly pressed onto the Drug Screening Cartridge. This is then filled with a buffer solution before insertion into the reader for analysis. Capable of detecting drugs down to the picogram level, the system is a fluorescence-based lateral flow competition assay containing four drug-bovine serum albumin conjugate lines on a nitrocellulose test strip.  In short, when a sample is introduced to the test strip, fluorescently-tagged antibodies pass over the conjugate lines. As these antibodies are specific to each drug class of interest, if that drug is present they will bind to the drug. At the end of the test, a fluorescence signal is measured. If none of the four drug classes were present, a maximum fluorescence signal will be obtained. However if any drugs were present to bind with the antibodies, there will be a decrease in the fluorescence signal proportional to the drug concentration. Within about 10 minutes, the device then gives a simple pass/fail response, requiring no specialist knowledge or excessive training to operate and interpret the results.

Furthermore, the technique has also been demonstrated to be effective when applied to the deceased. Researchers worked with a number of UK-based coroners to obtain fingerprint sweat samples from 75 deceased individuals. The most common drug detected was opiates, which is a logical finding considering the number of terminally ill patients who are prescribed morphine during palliative care.

In order to compare the new technique with those typically employed in the detection of drugs in human beings, analysis of blood samples was conducted by LC-MS-MS. The results between the two methods correlated well, with the accuracy between DSC of fingerprints and LC-MS-MS of blood being 88-97%, depending on the drug. This demonstrates the effectiveness of the method and its ability to stand up to existing techniques, though there are inevitably some shortcomings. Authors of the study have stated that there are known accuracy issues with lateral flow measurement devices, thus this new technology should be used as a presumptive screening method prior to confirmation by mass spectrometry. Furthermore, the range of target drugs is clearly currently limited, though future development could no doubt enable other classes of drug to be included.

Full details of the findings can be found in the Journal of Analytical Toxicology.

 

References

Hudson, T. Stuchinskaya, S. Ramma, J. Patel, C. Sievers, S. Goetz, S. Hines, E. Menzies and D. A. Russell, J. Anal. Toxicol., 2018, 6–10.

Forensic Magazine. Fingerprint Drug Screen Test Works on the Living and Deceased. [Available online] https://www.forensicmag.com/news/2018/10/fingerprint-drug-screen-test-works-living-and-deceased

 

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Forensic Failures: Philip Scott Cannon & Bullet Analysis Blunders

Forensic Failures: Philip Scott Cannon & Bullet Analysis Blunders

In December 2009, Philip Scott Cannon of Polk County, Oregon was released from prison after his conviction was found to be based on ‘junk science’. By this time, he had served over 10 years.

The story of his wrongful imprisonment began on 23rd November 1998, when Bimla Boyd noticed that the mobile home of a neighbour appeared to be on fire. Upon investigating, she discovered the bodies of three people; Jason Kinser, his girlfriend Suzan Osborn, and Celesta Graves. All three victims had been shot. Boyd promptly called the police, and a murder investigation ensued.

Boyd stated that earlier in the day she had noticed a maroon van parked nearby, a van which happened to belong to Philip Scott Cannon. Around the same time, local men Jeremy Olsen and Larry Weaver were on their way to deliver water to the victims’ trailer. Upon arrival at the trailer, Olsen and Weaver claimed that they were met by Cannon, who was said to be “acting strangely”. Cannon informed the men that they should not go into the trailer because Jason Kinser was upset and in the midst of a heated argument with an unknown Hispanic man. Olsen and Weaver subsequently left without entering the trailer. Based on this eyewitness testimony and the fact that Cannon owned the maroon van spotted nearby, he soon became the prime suspect.

Credit: Polk County Itemizer-Observer

When questioned by police, Cannon maintained his innocence and claimed Kinser had called him over to give an estimate for fixing a plumbing problem in the trailer, after which he promptly left when Kinser began arguing with another man. However the police had a very different impression of the situation, believing that Cannon was a meth user and Kinser his dealer. Further suspicion fell on Cannon when a prisoner, Steven Brobston, informed police that he had entrusted Cannon with a box containing $16,000 to be used to support Celesta Graves, Brobston’s girlfriend and one of the victims. With the circumstantial evidence mounting, investigators searched Cannon’s home, finding the lockbox but no sign of the money. They did however stumble upon a number of weapons and ammunition. This was sufficient to arrest Cannon, who was taken into custody on 3rd December and charged with three counts of aggravated murder and the illegal possession of a firearm.

During the trail, Olsen, Weaver and Boyd were all called upon to recount their experiences of seeing Cannon near the trailer on the day of the murder. Of course this evidence was purely circumstantial, so an expert witness was called upon to study the bullets collected from the crime scene and those recovered from the suspect’s home. Michael Conrady of Oregon State University’s radiation center conducted a metallurgic analysis of the bullets known as comparative bullet lead analysis. This technique involves the application of various analytical techniques, but primarily atomic emission spectroscopy, to bullet composition determination. The method aims to establish the composition of metals in the bullet, such as copper, tin, antimony and silver, and compare profiles to ascertain whether two bullets are chemically identical. Based on this analysis, Conrady testified that the bullets from the crime scene and those from Cannon’s home were chemically identical, therefore Cannon’s ammunition was used to kill the three victims. However the weapons found in Cannon’s home were not connected to the murders, nor did police establish a reasonable motive for the triple homicide. Despite these shortcomings, on 28th February 2000, Cannon was found guilty and sentenced to three life sentences with no parole.

At the time of Cannon’s trial, the use of comparative bullet lead analysis was already under scrutiny, with some believing the reliability of the technique was unfounded. In 2005, the national Academy of Science discredited the technique and deemed it ‘junk science’, and soon after the FBI abandoned the use of this method altogether. As Cannon’s conviction was so heavily reliant on the bullet analysis, in 2009 a Polk County Circuit judge vacated Cannon’s original conviction. Incidentally it was now apparent that police involved in the original trial had hired Conrady to conduct the bullet analysis because the Oregan State crime lab had refused on the basis of the technique being scientifically unreliable. In order for a re-trial to take place, the original bullets were demanded in order to conduct further analysis. Polk County prosecutors insisted that the original trial evidence had been sent to the Department of Justice when Cannon had appealed his conviction, however Assistant Attorney General Susan Gerber, who had been assigned the case, claimed she had never received this evidence. It later came to light, when Gerber was suspended from her position on assault charges, that she had had the evidence all along, locked away in a filing cabinet.

In light of all of this, Cannon’s conviction was dismissed and he was released from prison. By this point he had spent over a decade behind bars. No other arrests have been made in relation to the murder of Kinser, Osborn and Graves.

 

References

Michigan State University National Registry of Exonerations. Philip Scott Cannon. [Available online] https://www.law.umich.edu/special/exoneration/Pages/casedetail.aspx?caseid=3083

Photo Credit: Polk County Itemizer Observer. Cannon retrial up to Polk DA. [Available online] http://www.polkio.com/news/2011/oct/25/cannon-retrial-up-to-polk-da

 

Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting

Scientist Special: Galton, Herschel & Faulds – The Competing Pioneers of Fingerprinting

The use of fingerprints as a means of identification has been successfully implemented worldwide. But how did the idea of using these unique impressions in a forensic setting first come about? Many scientists are known to have been involved in the early research relating to fingerprinting, dating right back to the 1600s, but Sir Francis Galton and William Herschel are widely recognised as the real pioneers of forensic fingerprinting.

However the story actually begins with the work of another man: Henry Faulds. In the late 1880s, the Scottish physician was working in Japan in a number of roles, one of which caused him to be involved in various archaeological digs. During this time he first stumbled upon the uniqueness of fingerprints after discovering prints left behind by craftsmen in old pieces of ceramic pottery. This allegedly inspired his notion of using fingerprints to identify criminals, at which point he promptly published an article in Nature detailing his thoughts on the matter. In his manuscript, “On the Skin-Furrows of the Hand”, Faulds suggested the possibility of using fingerprints to identify individuals, however did not provide anything to support his theory other than the anecdotal evidence of his own use of fingerprints to identify the perpetrator of a break-in at his hospital. Back in the UK, Faulds shared his ideas with Scotland Yard, but they unsurprisingly had no interest in this somewhat unsupported theory. Incidentally, Faulds also shared his work with Charles Darwin. Although Darwin did not pursue the research himself, he did forward the information to his cousin, Francis Galton. At the time, nothing came of this interaction.

Shortly after Fauld’s publication in Nature, William Herschel, a British civil servant who was based in India at the time, soon published a responding letter in Nature claiming he had been using fingerprints as a means of identification for years. A very public argument over who should claim credit for this idea ensued between the two scientists which lasted for years, though the world paid little attention. There was quite simply no data to support the claims of the two men.

A couple of years later, Sir Francis Galton once again enters the picture. Now heavily involved in the field of anthropometry (the study of measurements of the human body), he began working with Herschel to gather the much-needed data necessary to support the theory of fingerprints as a means of identification. Galton’s research allowed him to collect thousands of fingerprints and ultimately conclude that fingerprints were in fact unique to the individual, could persist on a surface for years if not decades, and could be easily used to develop a system of storing and comparing prints. Galton presented his findings at the Royal Institution, sharing his and Herschel’s research in fingerprinting as a means of identification. Based on Galton’s work, the use of fingerprinting was finally considered by Parliament in 1894, and was soon implemented in criminal investigations. Galton and Herschel were now viewed as the original pioneers of forensic fingerprinting, whereas Faulds later spent years fighting to be recognised as the true founder, petitioning to academic journals, newspapers and even the Prime Minister.

In 1892, anthropologist Juan Vucetich made history by using fingerprint evidence to positively identify the culprit in a criminal case. When the children of Francisca Rojas were found murdered, Vucetich implicated Rojas when a bloody print allegedly proved she was the murderer. Since then, the study and use of fingerprints has been a fundamental aspect of forensic investigations worldwide.

References

Faulds, H. On the Skin-Furrows of the Hand. Nature, 1880, 22.

Stigler, S. M. Galton and Identification by Fingerprints. Genetics. 1995, 140(3), 857-860.

University of Glasgow. Henry Faulds. [online] Available: http://www.universitystory.gla.ac.uk/biography/?id=WH25214&type=P

Interview with Program Director Max Houck

What is your current job role and what does this position involve?

My current role is Visiting Assistant Professor and Director of the Forensic Studies & Justice Program at University of South Florida St. Petersburg. The Program teaches forensic investigative techniques and scientific applications in criminal cases, using structured analytic techniques borrowed from the intelligence community to mitigate and reduce bias, and how to improve the criminal justice system and avoid wrongful convictions. I created the Program, teach in it, and conduct research in these areas.

How did you come to work in the field of forensic science?

I became interested in forensic science through taking anthropology courses for my undergraduate minor; I was originally in International Relations and was going to be a translator (Russian and Japanese). Ultimately, bones made more sense than conjugating irregular Russian verbs and I changed majors. In my Masters work, I was a student of Jay Siegel, who set me on my path to a forensic science career.

What would you say has been the highlight of your career to date?

Being Director of the Washington, D.C. Department of Forensic Sciences. I structured the new agency, created many of its new policies for independent science, and worked with people who remain my heroes for what they do.

During your years working in forensic science, how do you feel the field has changed?

I worry that the field has become a bit of a cargo-cult science–we’ve “drunk our own Kool-aid”, as the saying goes. We believe if we SAY something is “scientific”, then it IS scientific. We’ve also come up with some fairly suspect ways of justifying bad or marginal science and these have been accepted by an all-too-willing court system. That is beginning to change, a little, with some good basic research into the fundamentals of our science but we’re still hampered by trying to be the servant of justice instead of a partner in the process.

In recent years, concerns over the reliability of some forensic techniques have been raised in the media. What steps do you think we need to be taking to ensure that only scientifically reliable techniques are utilised in legal investigations?

First and foremost, forensic agencies need to be independent of law enforcement; that won’t solve everything but it’s a good start to ensure we’re not marginalized. Second, we need to stop worrying about new methods and shore up the ones we’re already using–do they work and, if so, how well? Finally, we have to be better communicators about what we can and cannot say and why. Being pressured by money, time, or politics only gets you shoddy results–just look at any of the latest “forensic failures”.

Finally, do you have any words of wisdom for those pursuing a career in forensic science?

Be a scientist first; the application to criminal cases can come later. Don’t job hop; keep your first job at least two years and then move up or out. And last, don’t worry about ethics, worry about integrity. Ethics is knowing right from wrong and prisons are full of people who know the difference, they just lacked the integrity to make the right choice.

 

Sweat Security: Using Skin Secretions for Authentication

Sweat Security: Using Skin Secretions for Authentication

The use of passwords and pin numbers is part of our daily lives, being a necessity in ensuring our data and money doesn’t fall into the wrong hands. However passwords and pattern-based pins have their obvious limitations, and they are only as secure as the user is cautious.  One method of improving security utilises biometric technology, which is based on the biological or behavioural characteristics of an individual. Biometric-based security systems are certainly nothing new. The concept of using fingerprints, retinal scans and voice recognition as security measures materialised decades ago, and such techniques are frequently used for authentication purposes. Despite these technological developments, ongoing research is attempting to develop more robust and secure methods of identification.

Researchers at the University of Albany are developing a unique new technique of biometric identification using only a person’s sweat. Human sweat, and all body fluids for that matter, contains a plethora of chemical compounds, ranging from small weight molecules to large proteins. These compounds originate from a variety of sources, with some resulting from endogenous metabolic processes within the body, and others being introduced through diet and environmental exposure. Metabolite levels can be affected by an endless array of factors, including sex, ethnicity, age and lifestyle. Interestingly, it is now known that the presence and amount of some of these compounds can vary greatly between different people, thus in theory unique metabolome profiles could be harnessed for identification purposes.

phone

The compounds the technique will focus on is vital, as certain chemical levels can fluctuate wildly throughout the day depending on what we have eaten, for instance. However levels of certain chemicals have been found to be relatively stable or at least only vary gradually. In this research, Assistant Professor Jan Halámek and his team focused on using amino acid profiles of sweat to offer a unique means of authentication.

By first establishing which amino acids are present in a person’s skin secretions, a wearable device can then be constructed which will monitor the levels of these compounds. The device would initially require a kind of enrolment period, during which time the user’s skin secretions would be constantly measured in order to develop a unique profile of metabolites. It is already known that the metabolites released by the body vary throughout the day, so such a monitoring period would be necessary to take into account these changes.

Over time a profile of the user’s skin secretions would be built up and stored within the device, acting as a kind of standard for comparison. When future skin secretions are analysed by the device, the profiles will be compared with the known user profile and used to confirm the identity of the user. In the event of anyone else picking up the device, the instrument would detect a different skin secretion profile and lock the device or turn it off, thus ensuring security of the smartphone or computer.

If successful, the technology could offer an improved active authentication system, either as a standalone system or supplementing existing technology. However the technique is very much in its infancy and a great deal more research will be required before this kind of technology is rolled out commercially, if it ever is possible. It is likely that such a technique will be affected by contamination, for instance as the user’s hands become dirty throughout the day or if cleaning or cosmetic products are applied to the skin. Furthermore, if authentication is based on comparison with an electronically stored profile, the device may still be susceptible to hacking in order to bypass the security system. But if this technique could reach a sufficient level of robustness, the days of struggling to remember your password could be eliminated.

 

Agudelo, J. Privman, V. Halamek, J. Promises and Challenges in Continuous Tracking Utilizing Amino Acids in Skin Secretions for Active Multi-Factor Biometric Authentication for Cybersecurity. ChemPhysChem. 18, 1714-1720 (2017).

Instant Insect Identification to Aid Forensic Entomology Investigations

Instant Insect Identification to Aid Forensic Entomology Investigations

During the investigation of a suspicious death, entomological (that is, insect-related) evidence may be able to provide vital clues as to when the victim died. Determining time since death, or post-mortem interval, can be one of the most important aspects of such an investigation, so it comes as no surprise that a great deal of research has been directed towards improving these estimations.

Insects can play a huge role in estimating time since death. Various types of species of insect will often visit the scene of a death in a relatively predictive manner, either to feed on the decomposing remains (known as necrophagous insects), to prey on other insects present, or to find a suitable place to lay their eggs. Blow flies, a group which includes common flies such as the bluebottle and the greenbottle, are often of particular interest. Forensic entomologists will typically study the insects, eggs and larvae present at a death scene, utilising the type of bugs found and their stage of development to track back to the likely time at which they arrived, thus when the victim may have died. However in order to accurately do this, entomologists must often collect insect specimens for closer inspection and even to rear to adulthood in order to determine the exact species, which is evidently a time-consuming process requiring a high level of expert knowledge.

For the first time, researchers at the University of Albany have applied a technique called direct analysis in real time with high resolution mass spectrometry, or DART-HRMS for short, to the analysis of blow fly eggs. Published in the latest issue of the journal Analytical Chemistry, the technique has demonstrated the possibility of almost instantly differentiating between different fly species based on the amino acid profiles of the eggs.

DART-MS, developed in 2005 by Dr Chip Cody of JEOL, is an ambient ionisation mass spectrometry technique that allows for samples to be directly analysed without any time-consuming sample preparation steps, and perhaps most importantly without destroying the sample. The sample is simply presented in its native state between the ion source and the inlet of the mass spectrometer, enabling compounds present in the sample to be ionised and drawn into the instrument for analysis and identification.

dartms

Sampling interface of DART-MS. Source: Wikimedia Commons

During this investigation, researchers used pieces of pork liver to attract a number of different blow fly species before transporting them to the laboratory. The flies were reared until they lay new eggs, which would be the focus of the analysis. The study utilised specimens of a number of species, including Calliphora vicinia, Lucilia coeruleiviridis, Lucilia sericata, Phormia regina, along with specimens from the Phoridae and Sarcophagidae families. Even to the eye of an expert, the eggs of these specimens are often indistinguishable. The eggs were simply placed in an ethanol solution and the mixtures directly subjected to DART-HRMS analysis.

The technique focused on the analysis and identification of amino acids in the eggs, essentially enabling researchers to produce a chemical fingerprint unique to eggs of a particular species. Examination of the mass spectra showed that the different species exhibited a unique chemical fingerprint, and by using multivariate analysis it was possible to better visualise the similarities and differences between amino acids detected in the eggs of different species.

Unsurprisingly, many amino acids were common to multiple species. For instance, alanine, isoleucine and proline were detected in four of the species, whereas valine was detected in all but one of the egg samples. However some compounds were unique to particular species, and it is these unique amino acids that will prove to be most beneficial in differentiating between the eggs of different species. For instance, glutamine and tryptophan were only present in the eggs belonging to P. regina. Interestingly, the research also demonstrated the ability to distinguish between families as well as species, with some compounds only detected in the eggs of specific families.

By using this particular technique, almost instantaneous identification could be achieved. Of course this research has included only a very limited number of species, thus a much bigger investigation would be necessary before the technique would really be beneficial to a legal investigation. Not only would further species need to be included, but another potential development would be the production of a chemical profile database against which unknown insect samples could be compared. Developed further, the use of DART-MS could save investigators a lot of time in the identification of insects of forensic interest.

 

References

Cody, R. B., Laramée, J. A. & Durst, H. D. Versatile New Ion Source for the Analysis of Materials in Open Air under Ambient Conditions. Anal. Chem. 77, 2297–2302 (2005).

Giffen, J. E., Rosati, J. Y., Longo, C. M. & Musah, R. A. Species Identification of Necrophagous Insect Eggs Based on Amino Acid Profile Differences Revealed by Direct Analysis in Real Time-High Resolution Mass Spectrometry. Anal. Chem. (2017) In Press

 

Interview with Forensic Physician Samar Abdel azim Ahmed

samar

What is your professional background in forensic science?

I am an associate professor of Forensic Medicine in Ainshams University Faculty of Medicine in Egypt. I received my doctorate degree 10 years ago with honours from ASU and then proceeded to work on my educational capacity. I studied for a second Masters degree from Maastricht University and Suez Canal University in Health professions education. I then received a scholarship from ECFMG in USA for a fellowship program in Health professions education in FAIMER, Philadelphia.

What is your current job role and what does this work involve?

Currently I teach forensic Medicine to fourth year medical students together with my administrative job as the director of the Centre of Excellence in Forensic Psychiatric research. This centre is a product of a Newton Mosharafa Fund that I received from the British council and the Science Technology Development fund in Egypt to establish forensic psychiatry research trends in Egypt. At the moment I am working on establishing partnerships within the scope of forensic psychiatric service improvement.

What initially attracted you to this field of work?

I am a physician by training but I was attracted to the field of forensics mainly challenged by the importance of the service that one can offer to justice by giving a voice to the voiceless. My work as a forensic physician is mainly to advocate for those who are victimized and to prevent further injustice by uncovering the truth that can only be seen by forensics.

Can you tell us about the research you are currently involved in?

At the moment my point of focus is forensic psychiatric patients. I am indulged in studying the service offered in my country with the hope that I can import state of the art practices from the UK utilizing the cooperation agreement that I have set with them. The first part of the study is mapping the patient’s body in Egypt with special reference to the determinants of the length of their stay in the high secure wards. This requires a lot of work to establish a culture and understanding of predictors of violent behaviour. This work comes within my funded project that we have now come to call LIFE project.

Why is this work important to the field of forensic science and what do you hope to achieve by carrying out this research?

Our hope is to be able to establish guidelines to predict violent patient behaviours and thus be able to predict patients who are in need of extended stay in forensic wards. This will help in turn to reduce unnecessary length of stay of patients. By the end of this work I hope to be able to publish a white paper of effective forensic psychiatric practice as a guiding document to help in the decision making process when patients are discharged.

Do you have any words of advice for students wishing to pursue a career in your field of work?

My advice for students who want to pursue a career in forensic medicine is to specialize as early as possible. The earlier you specialize and maybe even subspecialize the quicker you grow in the field. Master your passion area and own it then try to build on it from early on. You build your name from day one in the field so build a name that goes with a specialization. It is also important to understand why you are in the field. Understand that you give bones a voice and that without you the truth will be buried indefinitely so it is important to take this calling very seriously.