Towards the Development of an Optical Biosensor for the Detection of Human Blood for Forensic Analysis.

Blood is a common biological fluid in forensic investigations, offering significant evidential value. Currently employed presumptive blood tests often lack specificity and are sample destructive, which can compromise downstream analysis. Within this study, the development of an optical biosensor for detecting human red blood cells (RBCs) has been explored to address such limitations.

Enhancing Target Detection: A Fluorescence-Based Streptavidin-Bead Displacement Assay.

Fluorescence-based aptasensors have been regarded as innovative analytical tools for the detection and quantification of analytes in many fields, including medicine and therapeutics. Using DNA aptamers as the biosensor recognition component, conventional molecular beacon aptasensor designs utilise target-induced structural switches of the DNA aptamers to generate a measurable fluorescent signal. However, not all DNA aptamers undergo sufficient target-specific conformational changes for significant fluorescence measurements.

Assessment of a Single Quadrupole Mass Spectrometer Combined with an Atmospheric Solids Analysis Probe for the On-Site Identification of Amnesty Bin Drugs.

The surging number of people who abuse drugs has a great impact on healthcare and law enforcement systems. Amnesty bin drug analysis helps monitor the "street drug market" and tailor the harm reduction advice. Therefore, rapid and accurate drug analysis methods are crucial for on-site work.

The Development and Characterisation of ssDNA Aptamers via a Modified Cell-SELEX Methodology for the Detection of Human Red Blood Cells.

Blood is one of the most commonly found biological fluids at crime scenes, with the detection and identification of blood holding a high degree of evidential value. It can provide not only information about the nature of the crime but can also lead to identification via DNA profiling. Presumptive tests for blood are usually sensitive but not specific, so small amounts of the substrate can be detected, but false-positive results are often encountered, which can be misleading.

Analysis of drugs seized from amnesty bins at two major United Kingdom summer music festivals using two portable gas chromatography-mass spectrometry (GC-MS) instruments.

Globally, the number of drug users and the proportion of the drug using population has increased from 210 million in 2009 to 269 million in 2019. Several studies suggest that music festival attendees are more likely to abuse illicit substances and have a high-risk profile. Consequently, it is crucial to develop robust field drug analysis methods that facilitate harm reduction and drug monitoring.

Fingermarks in wildlife forensics: A review.

Wildlife forensics is defined as providing forensic evidence to support legal investigations involving wildlife crime, such as the trafficking and poaching of animals and/ or their goods. While wildlife forensics is an underexplored field of science, the ramifications of poaching can be catastrophic. The consequences of wildlife crime include disease spread, species and habitat loss, human injury, and cultural loss.

The classification of handwriting features of the Kazakh language written in Latin script.

In 2017, the Republic of Kazakhstan began the phased transition of its alphabet from Cyrillic to Latin script. This transition has presented significant challenges to Kazakhstani document examiners, who have yet to develop appropriate methodologies for the analysis of handwriting samples written in the Kazakh language using Latin letters. This study aims to identify distinguishing macro and micro features of letters within Kazakh writing samples produced using the Latin alphabet and determine their frequencies of occurrence and discriminating power indices.

Nanomaterials for optical biosensors in forensic analysis.

Biosensors are compact analytical devices capable of transducing a biological interaction event into a measurable signal outcome in real-time. They can provide sensitive and affordable analysis of samples without the need for additional laboratory equipment or complex preparation steps. Biosensors may be beneficial for forensic analysis as they can facilitate large-scale high-throughput, sensitive screening of forensic samples to detect target molecules that are of high evidential value.

Unlocking the potential of forensic traces: Analytical approaches to generate investigative leads.

Forensic investigation involves gathering the information necessary to understand the criminal events as well as linking objects or individuals to an item, location or other individual(s) for investigative purposes. For years techniques such as presumptive chemical tests, DNA profiling or fingermark analysis have been of great value to this process. However, these techniques have their limitations, whether it is a lack of confidence in the results obtained due to cross-reactivity, subjectivity and low sensitivity; or because they are dependent on holding reference samples in a pre-existing database.

3,4-Methylenedioxymethamphetamine quantification via benchtop H qNMR spectroscopy: Method validation and its application to ecstasy tablets collected at music festivals.

We describe a method validation for the quantification of 3,4-methylenedioxymethamphetamine (MDMA) in tablets based on the United Nations Office on Drugs and Crime (UNODC) guideline for quantitative Nuclear Magnetic Resonance analysis (qNMR). qNMR experiments were carried out on a 60 MHz benchtop NMR spectrometer employing ethylene carbonate as an internal calibrant. A series of 'ecstasy' tablets seized at music events were quantified and the results discussed regarding their within-batch variation and yearly median dose.

Technical Note: Lysis and purification methods for increased recovery of degraded DNA from touch deposit swabs.

Touch deposits are a routine yet challenging sample type in forensic casework and research. Recent work investigating their contents has indicated corneocytes to be the major cellular constituent while cell-free DNA is present at significant levels. Prolonged incubation including a reducing agent such as DTT has been shown to lyse corneocytes; a plasma cfDNA recovery kit which targets shorter DNA fragments has been demonstrated to improve cfDNA recovery from hand rinses.

Generating aptamers towards human sperm cells using massively parallel sequencing.

Determining the presence of sperm cells on an item or swab is often a crucial component of sexual offence investigation. However, traditional histological staining techniques used for the morphological identification of spermatozoa lack both specificity and sensitivity, making analysis a complex and time-consuming process. New methods for the detection of sperm cells based on aptamer recognition may be able to overcome these issues.

Accumulation of endogenous and exogenous nucleic acids in "Touch DNA" components on hands.

Successful forensic DNA profiling from handled items is increasingly routine in casework. This "touch DNA" is thought to contain both cellular and acellular nucleic acid sources. However, there is little clarity on the origins or characteristics of this material.

The forensic investigation of vehicle-pedestrian collisions: A review.

Rapid urbanisation, a steady increase in the number of vehicles, speeding, negligence in road safety, and other factors have led to the inevitable worldwide growth of road traffic accidents involving pedestrians. According to the 'Global Status Report on Road Safety' released by the World Health Organization, road traffic collisions are one of the leading causes of death for people of all ages, with approximately 1.35 million road fatality deaths occurring globally each year.

Corneocyte lysis and fragmented DNA considerations for the cellular component of forensic touch DNA.

DNA deposited by individuals' hands is a routine part of forensic analysis, yet little is understood about the precise cellular contents left by handling. "Dead" skin cells known as corneocytes make up the majority of the cellular material left in touch deposits by people's hands but are known to lack nuclei, making their DNA content ambiguous. Here we measure DNA released from anucleate corneocytes following various lysis methods to determine how much DNA may be present in these cells and how best to recover it from inside the cornified envelope.

Exploration of cell-free DNA (cfDNA) recovery for touch deposits.

Although touch deposit DNA is widely used in forensic casework, its cellular and acellular contents and their biological origins are poorly understood. There is evidence that the cell-free component of DNA deposited by handling may contribute substantial genetic information; however, most research into touch DNA recovery does not separate cellular and cell-free fractions or seek to characterize their contents. This work is an important early step in developing methods to isolate the cfDNA from biological material deposited by handling.

Illuminating touch deposits through cellular characterization of hand rinses and body fluids with nucleic acid fluorescence.

Forensic DNA typing from touched or handled items in routine casework is increasing as the sensitivity of detection techniques improves. Our understanding of the cellular/acellular content of touch deposits and the origins of the DNA therein is still limited. This work explores the cellular content of rinses from washed and unwashed hands, as well as saliva, nasal and eye washes which could be sources of transferred DNA onto hands.

A review of trace "Touch DNA" deposits: Variability factors and an exploration of cellular composition.

The use in courtrooms of forensic DNA typing results from presumably touched or handled items is increasing as the sensitivity of detection techniques improves. Research investigating how much DNA can be recovered from handled items, whether trace DNA can be detected under certain scenarios including varying degrees of indirect transfer, and factors which may influence these results is summarized here. Fundamentally, our current understanding of the cellular content of touch deposits and the origins of the potential trace DNA therein is extremely limited.

The use of the M-Vac® wet-vacuum system as a method for DNA recovery.

Collecting sufficient template DNA from a crime scene sample is often challenging, especially with low quantity samples such as touch DNA (tDNA). Traditional DNA collection methods such as double swabbing have limitations, in particular when used on certain substrates which can be found at crime scenes, thus a better collection method is advantageous. Here, the effectiveness of the M-Vac® Wet-Vacuum System is evaluated as a method for DNA recovery on tiles and bricks.

DNA Profiles from Fingerprint Lifts-Enhancing the Evidential Value of Fingermarks Through Successful DNA Typing.

This study evaluated the compatibility of the most common enhancement methods and lifting techniques with DNA profiling. Emphasis is placed on modern lifting techniques (i.e.

Feasibility of a handheld near infrared device for the qualitative analysis of bloodstains.

One of the most common tasks in criminal investigation is to determine from which tissue source a biological fluid stain originates. As a result, there are many tests that are frequently used to determine if a stain is blood, semen or saliva by exploiting the properties of certain molecules present within the fluids themselves. These include chemical reagents such as the Kastle-Meyer or Acid Phosphatase tests, as well as other techniques like the use of alternative light sources.

Analytical characterization of three cathinone derivatives, 4-MPD, 4F-PHP and bk-EPDP, purchased as bulk powder from online vendors.

Novel emerging drugs of abuse, also referred as new psychoactive substances, constitute an ever-changing mixture of chemical compounds designed to circumvent legislative controls by means of chemical modifications of previously banned recreational drugs. One such class, synthetic cathinones, namely β-keto derivatives of amphetamines, has been largely abused over the past decade. A number of new synthetic cathinones are detected each year, either in bulk powders/crystals or in biological matrices.

Touch DNA-The prospect of DNA profiles from cables.

Metal theft in the railroad industry poses significant challenges to transport investigators. Cable sheaths left behind at crime scenes, if appropriately analysed, could provide valuable evidence in a forensic investigation, but attempts at recovering DNA are not routinely made. Experiments were set up to ascertain the success in DNA recovery from the surface of cable sheaths after deposition of (a) sweat, (b) extracted DNA and (c) fingermarks.

Monitoring Criminal Activity through Invisible Fluorescent "Peptide Coding" Taggants.

Complementing the demand for effective crime reduction measures are the increasing availability of commercial forensic "taggants", which may be used to physically mark an object in order to make it uniquely identifiable. This study explores the use of a novel "peptide coding" reagents to establish evidence of contact transfer during criminal activity. The reagent, containing a fluorophore dispersed within an oil-based medium, also includes a unique synthetic peptide sequence that acts as a traceable "code" to identify the origin of the taggant.