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Adegoke O, Oyinlola K, Adeniyi KO, Achadu OJ, Yang Z, Daeid NN. An organic-inorganic polyacrylamide-based surface imprinted quantum dots for the impedimetric and voltammetric detection of diazepam in saliva with smartphone readout. Talanta 2024; 285:127400. [PMID: 39706031 DOI: 10.1016/j.talanta.2024.127400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2024] [Revised: 11/25/2024] [Accepted: 12/15/2024] [Indexed: 12/23/2024]
Abstract
Diazepam (DZP) is a muscle-relaxing, anxiety-relieving sedative drug; nonetheless, it is also an addictive drug that may be abused. This work reports on the development of a novel electrochemical nanosensor for diazepam using SiO2-encapsulated-3-mercaptopropionic acid-capped AuZnCeSeS quantum dots (QDs) overcoated with a molecularly imprinted polymer (MIP) on screen-printed carbon electrodes (SPCEs). Electrochemical, spectroscopic and electron microscopic characterization of the nanomaterial and modified electrode surface was carried out and is reported herein. Specifically, electrochemical characterization of the QDs/SPCE using cyclic voltammetry (CV) revealed that the QDs exhibit a higher electrode surface area whilst electrochemical impedance spectroscopy (EIS) characterization demonstrated a lower charge transfer resistance (Rct). To fabricate the electrochemical nanosensor, firstly, alloyed AuZnCeSeS QDs were synthesized in the organic phase and thereafter capped with 3-mercaptopropionic acid (MPA) via a ligand exchange reaction. The MPA-AuZnCeSeS QDs were encapsulated in a SiO2 layer to form a SiO2-MPA AuZnCeSeS QDs system. The QDs were drop-casted onto SPCEs to form a SiO2-MPA AuZnCeSeS QDs/SPCE transducer interface. Organic based acrylamide, used as a functional monomer, was electropolymerized via CV on the QDs/SPCE in the presence of the diazepam template with ethylene glycol dimethacrylate as a crosslinker and 2,2'-azobis(2-methylpropionitrile) as an initiator. Under optimum experimental conditions, DZP was detected using EIS and square wave voltammetry (SWV). Using a portable potentiostat and a hand-held smartphone-based potentiostat, DZP was quantitatively detected in saliva using the MIP@QDs/SPCE with a limit of detection (LOD) of 2.3 μM and 2.7 μM, respectively. The LOD for DZP from SWV analysis was 1.0 μM.
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Arsenault H, Kuffel A, Dugard P, Nic Daeid N, Gray A. Trace DNA and its persistence on various surfaces: A long term study investigating the influence of surface type and environmental conditions - Part two, non-metals. Forensic Sci Int Genet 2024; 74:103151. [PMID: 39454483 DOI: 10.1016/j.fsigen.2024.103151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 09/23/2024] [Accepted: 09/24/2024] [Indexed: 10/28/2024]
Abstract
The work presented herein is the second part of a large-scale persistence project aimed at identifying trends in trace DNA persistence. This study aims to show how different environmental storage conditions and target surface characteristics influence the persistence of cellular and cell free DNA (cfDNA) over time. To eliminate variation within the experiment, we used a proxy DNA deposit consisting of a synthetic fingerprint solution, cellular DNA, and/or cfDNA. Samples were collected and analysed from eight non-metal surfaces over the course of 1 year (27 time points) under three different environmental storage conditions. The results of this experiment show that surface characteristics in conjunction with DNA type greatly influence DNA persistence. Variation in the amount of DNA recovered over time was greatly influenced by surface porosity. CfDNA persisted at significantly higher levels on non-porous surfaces, and cellular DNA persisted at higher levels on porous items. Furthermore, statistically significant differences in DNA persistence were found among the items classified as non-porous surfaces and among the items classified as porous surfaces. Additionally, this study showed that the sample storage environment had a larger impact on DNA persistence than previously observed for metal surfaces [1]. When considering DNA type, cellular DNA was shown to persist for longer than cfDNA and persistence as a whole appears to be better when DNA is deposited alone rather than in mixtures. Unsurprisingly, it was found that the amount of DNA recovered from trace deposits decreased over time. However, DNA decay is highly dependent on the surface type and exhibits higher variability at short time points and on porous surfaces. For each of the surfaces tested, DNA persisted 1 year past deposition (in some combination of DNA type and environmental condition), except for wood, on which DNA did not persist in any capacity past four months. This data is intended to add to our understanding of DNA persistence and the factors which affect it.
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Kuffel A, Cole C, Mallinder B, Nic Daeid N, Gray A. The potential of human leukocyte antigen alleles to assist with multiple-contributor DNA mixtures: Proof of concept study. Sci Justice 2024; 64:533-542. [PMID: 39277335 DOI: 10.1016/j.scijus.2024.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 07/19/2024] [Accepted: 08/04/2024] [Indexed: 09/17/2024]
Abstract
One of the most challenging issues still present in forensic DNA analysis is identifying individuals in samples containing DNA from multiple contributors. The introduction of novel identification markers may be a useful tool in the deconvolution of such DNA mixtures. In this study, we investigated the potential of alleles from the human leukocyte antigen system (HLA) to aid in identifying individuals in complex, multiple-donor DNA samples. The most advantageous characteristic of the HLA complex is its polymorphism in the human genome. A 22-loci multiplex with HLA markers was designed and applied to two-, three-, and four-person DNA mixtures. The results of the conducted experiments demonstrated that the identification of individuals in multiple contributor samples with the help of HLA markers is possible; however, it is clear that the reliability of the method is heavily dependent on the number of unique alleles for each individual in the analysed mixture. In order to compare this novel approach against the already established process, the same group of reference and multiple-contributor samples was analysed with a commonly used set of STR markers. This proof-of-concept research shows the importance of examining alternative solutions to the current deconvolution challenge in forensic DNA profiling.
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Kuffel A, Nic Daeid N, Gray A. Impact of swabbing solutions on the recovery of biological material from non-porous surfaces. Forensic Sci Int Synerg 2024; 9:100551. [PMID: 39281425 PMCID: PMC11399651 DOI: 10.1016/j.fsisyn.2024.100551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 07/25/2024] [Accepted: 08/20/2024] [Indexed: 09/18/2024]
Abstract
Cotton swabs are one of the most effective methods of retrieving biological evidence. The efficiency of swab-based DNA recovery is impacted by many factors, such as the swabbing technique, source of DNA and volume and type of wetting solution used to moisten the swab head. This study aimed to evaluate a series of different swab-moistening solutions. The types of swabbing solutions included buffers, detergent-based solutions, and chelating agents. The DNA deposits, including cell-free DNA, cellular DNA, blood, and saliva, were collected from three non-porous surfaces: plastic, glass, and metal. The difference in the performance of the swab-wetting solutions was heavily influenced by the type of biological fluid, with the chelating agents, EGTA and EDTA, being the most suitable for recovering DNA from saliva and blood samples. Conversely, water and detergent-based solutions were more appropriate for cell-free and cellular DNA material likely to be found in trace DNA deposits.
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Arsenault H, Kuffel A, Daeid NN, Gray A. Trace DNA and its persistence on various surfaces: A long term study investigating the influence of surface type and environmental conditions - Part one, metals. Forensic Sci Int Genet 2024; 70:103011. [PMID: 38324952 DOI: 10.1016/j.fsigen.2024.103011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/15/2024] [Accepted: 01/15/2024] [Indexed: 02/09/2024]
Abstract
It is imperative for proper evidence triage that forensic biologists understand what kind of results to expect from certain evidence types submitted for DNA analysis. The persistence of trace DNA has been insufficiently investigated and there is little data available pertaining to the persistence of DNA in different environmental conditions and on different materials. The goal of this study is to increase the available data on this topic which would, in turn, help forensic biologists manage expectations when submitting specific evidence types for DNA testing. The work presented herein is a large-scale persistence project aimed to identify trends in the persistence of trace DNA and indicate how different environmental storage conditions and target surface characteristics influence the persistence of cellular and cell free DNA (cfDNA) over time. To eliminate variation within the experiment we used a proxy DNA deposit consisting of a synthetic fingerprint solution, cellular DNA, and/or cfDNA. Samples were collected and analysed from 7 metals over the course of 1 year (27 time points) under 3 different environmental storage conditions. The results of this experiment show that metal type greatly influences DNA persistence. For instance, copper exhibited an expected poor DNA persistence (up to 4 h) which a purification step did not help increase the DNA yield. Alternatively, DNA can persist for up to a year on lead at levels potentially high enough to allow for forensic DNA testing. Additionally, this study showed that the sample storage environment had no impact on DNA persistence in most cases. When considering DNA type, cfDNA was shown to persist for longer than cellular DNA and persistence as a whole appears to be better when DNA is deposited as mixtures over when deposited alone. Unsurprisingly, it can be expected that DNA recovery rates from trace deposits will decrease over time. However, DNA decay is highly dependent on the metal surface and extremely variable at short time points but slightly less variable as time since deposition increases. This data is intended to add to our understanding of DNA persistence and the factors which affect it.
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Kuffel A, Nic Daeid N, Gray A. Comparison of swabbing and cutting-out DNA collection methods from cotton, paper, and cardboard surfaces. Forensic Sci Int Synerg 2024; 8:100453. [PMID: 38283046 PMCID: PMC10821607 DOI: 10.1016/j.fsisyn.2023.100453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/21/2023] [Accepted: 12/29/2023] [Indexed: 01/30/2024]
Abstract
Choosing an inappropriate method of sample collection can often have a detrimental impact on DNA recovery. Multiple studies highlight the importance of selecting the recovery method based on the type of surface the DNA sample is located on. This study aimed to investigate the efficacy of sample collection via the single cotton swabbing method in comparison to recovery directly from the material cut from the surface. The three types of surfaces included cotton, paper, and cardboard. DNA sources comprised cell-free and cellular DNA, as well as blood and saliva as examples of body fluids commonly encountered at crime scenes. The data analysis revealed that the cutting-out method resulted in higher DNA recovery from all but cardboard surfaces, making it the more efficient collection method. Despite its limitations, the cutting-out method should be considered as the DNA recovery method of choice when suitable.
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Mookiah MRK, Puch-Solis R, Nic Daeid N. Identification of bullets fired from air guns using machine and deep learning methods. Forensic Sci Int 2023; 349:111734. [PMID: 37267700 DOI: 10.1016/j.forsciint.2023.111734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/20/2023] [Accepted: 05/17/2023] [Indexed: 06/04/2023]
Abstract
Ballistics (the linkage of bullets and cartridge cases to weapons) is a common type of evidence encountered in criminal cases around the world. The interest lies in determining whether two bullets were fired using the same firearm. This paper proposes an automated method to classify bullets from surface topography and Land Engraved Area (LEA) images of the fired pellets using machine and deep learning methods. The curvature of the surface topography was removed using loess fit and features were extracted using Empirical Mode Decomposition (EMD) followed by various entropy measures. The informative features were identified using minimum Redundancy Maximum Relevance (mRMR), finally the classification was performed using Support Vector Machines (SVM), Decision Tree (DT) and Random Forest (RF) classifiers. The results revealed a good predictive performance. In addition, the deep learning model DenseNet121 was used to classify the LEA images. DenseNet121 provided a higher predictive performance than SVM, DT and RF classifiers. Moreover, the Grad-CAM technique was used to visualise the discriminative regions in the LEA images. These results suggest that the proposed deep learning method can be used to expedite the linkage of projectiles to firearms and assist in ballistic examinations. In this work, the bullets that were compared were air pellets fired from both air rifles and a high velocity air pistol. Air guns were used to collect the data because they were more accessible than other firearms and could be used as a proxy, delivering comparable LEAs. The methods developed here can be used as a proof-of-concept and are easily expandable to bullet and cartridge case identification from any weapon.
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Arsenault H, Nic Daeid N, Gray A. A synthetic fingerprint solution and its importance in DNA transfer, persistence and recovery studies. Forensic Sci Int Synerg 2023; 6:100330. [PMID: 37249970 PMCID: PMC10209804 DOI: 10.1016/j.fsisyn.2023.100330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/20/2023] [Accepted: 05/02/2023] [Indexed: 05/31/2023]
Abstract
A review of the literature on DNA transfer and persistence highlights many difficulties that are encountered when conducting research of this nature. One of the main problems highlighted repeatedly in the literature is the prevalence of inherent uncontrolled variation that accompany these studies, and in turn, the results obtained. This work aims to decrease the amount of intrinsic variability associated with DNA transfer and persistence experiments using a realistic proxy solution which is adaptable, of known composition, reproducible, and capable of being standardised. This proxy is composed of three parts: a synthetic fingerprint solution, cellular DNA, and cell free DNA. In this proof-of-concept study the proxy was tested with a small-scale DNA transfer and recovery experiment and the data obtained suggests that the use of a solution that mimics real fingerprint secretions, over an alternative (such as buffer or a body fluid), is important when working with non-donor provided trace DNA samples. This is because the DNA deposit solution likely impacts the transfer of DNA from fingers/hands to a surface as well as the ability to recover the biological material once deposited.
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Yu SH, Thomson G, Rinaldi V, Rowland C, Daeid NN. Development of a Dundee Ground Truth imaging protocol for recording indoor crime scenes to facilitate virtual reality reconstruction. Sci Justice 2023; 63:238-250. [PMID: 36870703 DOI: 10.1016/j.scijus.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 01/10/2023] [Accepted: 01/15/2023] [Indexed: 01/22/2023]
Abstract
Early and accurate visualisation of a crime scene is highly desirable such that a rapid, agile, and informed decision-making process can be undertaken by an investigative team. We present a new standard operating procedure for imaging an indoor scene using DSLR cameras conventionally used by crime scene investigators and examiners. The standard operating procedure (SOP) enables the systematic photography of indoor spaces in such a way that the Structure from Motion (SfM) photogrammetry technique can be implemented, allowing the scene to be recreated in Virtual Reality (VR). To demonstrate the method's validity, we compare two VR-rendered representations of an example scene using (a) photographs taken by an experienced crime scene examiner using a conventional photographic method and (b) photographs taken by a novice photographer following the developed SOP.
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Gray A, Kuffel A, Daeid NN. An improved rapid method for DNA recovery from cotton swabs. Forensic Sci Int Genet 2023; 64:102848. [PMID: 36821959 DOI: 10.1016/j.fsigen.2023.102848] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 12/13/2022] [Accepted: 02/14/2023] [Indexed: 02/17/2023]
Abstract
We present a novel rapid method for the recovery of cellular and free DNA from cotton swabs based on a simple elution buffer containing a high molecular weight polymer and detergent combined with a short proteinase K digestion to release cellular DNA. This method shows increased yields approaching 80% recovery of the input DNA compared to the QIAamp DNA Mini kit standard extraction protocol for swabs which has a recovery of 20-30%. The buffer components in the described method are compatible with direct PCR analysis of the isolated DNA without further purification. Recovery efficiencies were estimated by qPCR.
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Miller J, Puch-Solis R, Buchanan HAS, Nic Daeid N. A ground truth data set of gas chromatography mass spectrometry (GCMS) analysed synthesised methylenedioxymethylamphetamine (MDMA). Data Brief 2023; 47:108931. [PMID: 36819899 PMCID: PMC9929198 DOI: 10.1016/j.dib.2023.108931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/10/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Controlled drug samples are normally chemically analysed to determine their identity and in some cases, their purity. There are also circumstances where a more broad chemical characterisation of drug samples may also be required. This involves investigating the chemical impurities that may be present in a drug sample as a consequence of their synthesis. This impurity or drug profiling can be derived from drugs which are synthesised chemically or extracted from plant materials and then modified chemically. Impurity profiling can provide some insight into the synthetic methods used and sometimes the starting chemicals used. We report on the data generated from repetitive ( n = 18 ) synthesis of ecstasy (methylenedioxymethylamphetamine or MDMA) made by three different synthetic methods. Each data sample is expressed in multiple formats. This article uses the template for publishing GCMS data provided in Miller et al.(2022)[1]. The template provides a robust and systematic approach to organise GCMS data that is both useful for practitioners and amenable for automated data manipulation by data scientists.
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Burton K, Nic Daeid N, Adegoke O. Surface plasmon-enhanced aptamer-based fluorescence detection of cocaine using hybrid nanostructure of cadmium-free ZnSe/In2S3 core/shell quantum dots and gold nanoparticles. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Nsuamani ML, Zolotovskaya S, Abdolvand A, Daeid NN, Adegoke O. Thiolated gamma-cyclodextrin-polymer-functionalized CeFe 3O 4 magnetic nanocomposite as an intrinsic nanocatalyst for the selective and ultrasensitive colorimetric detection of triacetone triperoxide. CHEMOSPHERE 2022; 307:136108. [PMID: 35995197 DOI: 10.1016/j.chemosphere.2022.136108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/11/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Explosives are powerful destructive weapons used by criminals and terrorists across the globe and their use within military installation sites poses serious environmental health problems. Existing colorimetric sensors for triacetone triperoxide (TATP) relies on detecting its hydrolysed H2O2 form. However, such detection strategy limits the practicability for on-site TATP sensing. In this work, we have developed a novel peroxidase mimic catalytic colorimetric sensor for direct recognition of TATP. Ceria (Ce)-doped Fe3O4 nanoparticles (CeFe3O4) were synthesized via the hot-injection organic synthetic route in the presence of metal precursors and organic ligands. Thereafter, the organic-capped CeFe3O4 nanoparticles were surface-functionalized with amphiphilic polymers (Amp-poly) to render the nanoparticle stable, compact and biocompatible. Thiolated γ-cyclodextrin (γ-CD) was adsorbed on the Amp-poly-CeFe3O4 nanocomposite (NC) surface to form a γ-CD-Amp-poly-CeFe3O4 NC. γ-CD served both as a receptor and as a catalytic enhancer for TATP. Hemin (H), used as a catalytic signal amplifier was adsorbed on the γ-CD-Amp-poly-CeFe3O4 NC surface to form a γ-CD-Amp-poly-CeFe3O4-H NC that served as a functional nanozyme for the enhanced catalytic colorimetric detection of TATP. Under optimum experimental reaction conditions, TATP prepared in BIS-TRIS-Trisma Ac-KAc-NAc buffer, pH 3, was selectively and ultrasensitively detected without the need for acid hydrolysis based on the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine by H2O2 in the presence of the γ-CD-Amp-poly-CeFe3O4-H hybrid nanozyme. The obtained limit of detection of ∼0.05 μg/mL when compared with other published probes demonstrated superior sensitivity. The developed peroxidase mimic γ-CD-Amp-poly-CeFe3O4-H catalytic colorimetric sensor was successfully applied to detect TATP in soil, river water and tap water samples.
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Norman C, Reid R, Hill K, Cruickshanks F, Daeid NN. Newly emerging synthetic cannabinoids and novel modes of use of benzodiazepines in prisons: An update from the Scottish Prisons Non-Judicial Seizures Drug Monitoring Project. TOXICOLOGIE ANALYTIQUE ET CLINIQUE 2022. [DOI: 10.1016/j.toxac.2022.06.253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Adegoke O, Zolotovskaya S, Abdolvand A, Daeid NN. Fabrication of a near-infrared fluorescence-emitting SiO2-AuZnFeSeS quantum dots-molecularly imprinted polymer nanocomposite for the ultrasensitive fluorescence detection of levamisole. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Adegoke O, Daeid NN. Alloyed AuFeZnSe quantum dots@gold nanorod nanocomposite as an ultrasensitive and selective plasmon-amplified fluorescence OFF-ON aptasensor for arsenic (III). J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Adegoke O, Daeid NN. Polymeric-coated Fe-doped ceria/gold hybrid nanocomposite as an aptasensor for the catalytic enhanced colorimetric detection of 2,4-dinitrophenol. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kuffel A, Gray A, Daeid NN. Impact of metal ions on PCR inhibition and RT-PCR efficiency. Int J Legal Med 2021; 135:63-72. [PMID: 32621147 PMCID: PMC7782418 DOI: 10.1007/s00414-020-02363-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/24/2020] [Indexed: 12/24/2022]
Abstract
Inhibition of PCR by metal ions can pose a serious challenge in the process of forensic DNA analysis. Samples contaminated with various types of metal ions encountered at crime scenes include swabs from metal surfaces such as bullets, cartridge casings, weapons (including guns and knives), metal wires and surfaces as well as bone samples which contain calcium. The mechanism behind the impact of metal ions on DNA recovery, extraction and subsequent amplification is not fully understood. In this study, we assessed the inhibitory effects of commonly encountered metals on DNA amplification. Of the nine tested metals, zinc, tin, iron(II) and copper were shown to have the strongest inhibitory properties having IC50 values significantly below 1 mM. In the second part of the study, three commercially available DNA polymerases were tested for their susceptibility to metal inhibition. We found that KOD polymerase was the most resistant to metal inhibition when compared with Q5 and Taq polymerase. We also demonstrate how the calcium chelator ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) can be used as an easy and non-destructive method of reversing calcium-induced inhibition of PCR reactions.
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Adegoke O, Zolotovskaya S, Abdolvand A, Daeid NN. Rapid and highly selective colorimetric detection of nitrite based on the catalytic-enhanced reaction of mimetic Au nanoparticle-CeO 2 nanoparticle-graphene oxide hybrid nanozyme. Talanta 2020; 224:121875. [PMID: 33379084 DOI: 10.1016/j.talanta.2020.121875] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/02/2020] [Accepted: 11/04/2020] [Indexed: 10/23/2022]
Abstract
The International Agency for Research cancer (IARC) has classified nitrite in Group 2A of probable carcinogens to human. Herein, we report on the rapid and selective colorimetric detection of nitrite using a chemically modified gold nanoparticle (AuNP)-cerium oxide (CeO2) NP-anchored graphene oxide (GO) hybrid nanozyme in a catalytic colorimetric assay where nitrite acts as the main oxidant/target analyte and 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate. CeO2 NPs and GO were synthesized separately and incorporated in-situ, in a synthetic solution involving the chemical reduction of Au salt to AuNPs. The chemical modification process aided the adsorption of CeO2 NPs and AuNPs on GO nanosheets, yielding a highly catalytic AuNP-CeO2 NP@GO nanohybrid material. Under optimum experimental conditions, a novel colorimetric assay for nitrite recognition was constructed in which AuNP-CeO2 NP@GO hybrid nanozyme catalysed the oxidation of TMB in the presence of nitrite prepared in a 2-(n-morpholino)ethanesulfonic acid-2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)propane-1,3-diol-tris(hydroxymethyl)aminomethane acetate (MES-BIS-TRIS-Trisma Ac)-citric acid buffer solution, pH 2. Nitrite was quantitatively detected in a concentration dependent manner from 100 μM to 5000 μM with a correlation coefficient of 0.9961 and a limit of detection of 4.6 μM. Selective detection of nitrite was confirmed by the generation of a unique green colour reaction upon nitrite interaction in the AuNP-CeO2 NP@GO hybrid nanozyme redox cycle with TMB. None of the several tested metal ions and including H2O2 yielded a positive colour response, thus demonstrating the superior selectivity of the catalytic colorimetric assay for nitrite recognition. The AuNP-CeO2 NP@GO hybrid nanozyme catalytic colorimetric assay was successfully applied in the detection of nitrite in tap water.
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Adegoke O, Zolotovskaya S, Abdolvand A, Daeid NN. Biomimetic graphene oxide-cationic multi-shaped gold nanoparticle-hemin hybrid nanozyme: Tuning enhanced catalytic activity for the rapid colorimetric apta-biosensing of amphetamine-type stimulants. Talanta 2020; 216:120990. [DOI: 10.1016/j.talanta.2020.120990] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022]
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21
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Baptista-Hon DT, Smith M, Singleton S, Antonides LH, Nic Daeid N, McKenzie C, Hales TG. Activation of μ-opioid receptors by MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) and its fluorinated derivatives. Br J Pharmacol 2020; 177:3436-3448. [PMID: 32246840 PMCID: PMC7348096 DOI: 10.1111/bph.15064] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 03/03/2020] [Accepted: 03/21/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE A fluorinated derivative (2F-MT-45) of the synthetic μ-opioid receptor agonist MT-45 (1-cyclohexyl-4-(1,2-diphenylethyl)piperazine) was recently identified in a seized illicit tablet. While MT-45 is a Class A drug, banned in a number of countries, nothing is known about the pharmacology of 2F-MT-45. This study compares the pharmacology of MT-45, its fluorinated derivatives and two of its metabolites. EXPERIMENTAL APPROACH We used a β-arrestin2 recruitment assay in CHO cells stably expressing μ receptors to quantify the apparent potencies and efficacies of known (MT-45, morphine, fentanyl and DAMGO) and potential agonists. In addition, the GloSensor protein was transiently expressed to quantify changes in cAMP levels. We measured Ca2+ to investigate whether MT-45 and its metabolites have effects on GluN1/N2A NMDA receptors stably expressed in Ltk- cells. KEY RESULTS The fluorinated MT-45 derivatives have higher apparent potencies (2F-MT-45: 42 nM) than MT-45 (1.3 μM) for inhibition of cAMP accumulation and β-arrestin2 recruitment (2F-MT-45: 196 nM; MT-45: 23.1 μM). While MT-45 and 2F-MT-45 are poor recruiters of β-arrestin2, they have similar efficacies for reducing cAMP levels as DAMGO. Two MT-45 metabolites displayed negligible potencies as μ receptor agonists, but one, 1,2-diphenylethylpiperazine, inhibited the NMDA receptor with an IC50 of 29 μM. CONCLUSION AND IMPLICATIONS Fluorinated derivatives of MT-45 are potent μ receptor agonists and this may pose a danger to illicit opioid users. Inhibition of NMDA receptors by a metabolite of MT-45 may contribute to the reported dissociative effects.
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Adegoke O, Pereira-Barros MA, Zolotovskaya S, Abdolvand A, Daeid NN. Aptamer-based cocaine assay using a nanohybrid composed of ZnS/Ag 2Se quantum dots, graphene oxide and gold nanoparticles as a fluorescent probe. Mikrochim Acta 2020; 187:104. [PMID: 31912290 PMCID: PMC6946730 DOI: 10.1007/s00604-019-4101-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/27/2019] [Indexed: 12/12/2022]
Abstract
Authors report on a new fluoro-graphene-plasmonic nanohybrid aptamer-based fluorescent nanoprobe for cocaine. To construct the nanoprobe, newly synthesized glutathione-capped ZnS/Ag2Se quantum dots (QDs) were first conjugated to graphene oxide (GO) to form a QD-GO nanocomposite. The binding interaction resulted in a fluorescence turn-ON. Thereafter, cetyltrimethylammonium bromide (CTAB)-gold nanoparticles (AuNPs) were directly adsorbed on the QD-GO nanocomposite to form a novel QD-GO-CTAB-AuNP nanohybrid assembly that resulted in a fluorescence turn-OFF. Streptavidin (strep) was then adsorbed on the QDs-GO-CTAB-AuNP nanohybrid assembly which allowed binding to a biotinylated MNS 4.1 anticocaine DNA aptamer (B) receptor. The addition of cocaine into the strep-B-QDs-GO-CTAB-AuNP aptamer nanoprobe system aided affinity to the aptamer receptor and in turn turned on the fluorescence of the nanoprobe in a concentration-dependent manner. Under optimum experimental conditions, we found the strep-B-QD-GO-CTAB-AuNP to be far superior in its sensitivity to cocaine than the tested strep-B-QDs (no GO and CTAB-AuNPs), strep-B-QD-CTAB-AuNP (no GO) and strep-B-QD-GO (no CTAB-AuNP). In addition, the investigation of localized surface plasmon resonance (LSPR) amplified signal from tested plasmonic NPs shows that CTAB-AuNPs was far superior in amplifying the fluorescence signal of the nanoprobe. A detection limit of 4.6 nM (1.56 ng.mL−1), rapid response time (~2 min) and excellent selectivity against other drugs, substances and cocaine metabolites was achieved. The strep-B-QD-GO-CTAB-AuNP aptamer-based fluorescent nanoprobe was successfully applied for the determination of cocaine in seized adulterated cocaine samples.
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