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Dai Z. Recent Advances in the Development of Portable Electrochemical Sensors for Controlled Substances. SENSORS (BASEL, SWITZERLAND) 2023; 23:3140. [PMID: 36991851 PMCID: PMC10058808 DOI: 10.3390/s23063140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
This review article summarizes recent achievements in developing portable electrochemical sensing systems for the detection and/or quantification of controlled substances with potential on-site applications at the crime scene or other venues and in wastewater-based epidemiology. Electrochemical sensors employing carbon screen-printed electrodes (SPEs), including a wearable glove-based one, and aptamer-based devices, including a miniaturized aptamer-based graphene field effect transistor platform, are some exciting examples. Quite straightforward electrochemical sensing systems and methods for controlled substances have been developed using commercially available carbon SPEs and commercially available miniaturized potentiostats. They offer simplicity, ready availability, and affordability. With further development, they might become ready for deployment in forensic field investigation, especially when fast and informed decisions are to be made. Slightly modified carbon SPEs or SPE-like devices might be able to offer higher specificity and sensitivity while they can still be used on commercially available miniaturized potentiostats or lab-fabricated portable or even wearable devices. Affinity-based portable devices employing aptamers, antibodies, and molecularly imprinted polymers have been developed for more specific and sensitive detection and quantification. With further development of both hardware and software, the future of electrochemical sensors for controlled substances is bright.
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Affiliation(s)
- Zhaohua Dai
- Forensic Science Program, Department of Chemistry and Physical Sciences, Pace University, New York, NY 10038, USA
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2
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Azaldegui C, Aguilar G, Enriquez S, Madonna C, Parish Fisher C, Burks R. Benzoic acid derivatives as luminescent sublimation dyes in cyanoacrylate fuming of latent fingerprints. J Forensic Sci 2021; 66:1085-1093. [PMID: 33547641 DOI: 10.1111/1556-4029.14678] [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: 11/19/2020] [Revised: 12/21/2020] [Accepted: 01/11/2021] [Indexed: 12/01/2022]
Abstract
Development of latent prints employing cyanoacrylate ester (CA) can be a multistep process including CA fuming and subsequent fluorescent staining to produce fingerprints of sufficient contrast for comparison work. To enable a single-step CA fuming-staining process, a selection of fluorophores have been developed as sublimation dyes in CA fuming. A greater array of such luminescent sublimation dyes would allow users greater flexibility in selecting a particular dye-CA combination to best suit their processing needs. Toward this end, six benzoic acid derivatives were evaluated for use as luminescent sublimation dyes under elementary CA fuming conditions using a single non-porous surface type and an inexpensive handheld UV lamp for excitation. Two benzoic acid derivatives, 2-hydroxybenzoic acid (salicylic acid) and 2-aminobenzoic acid (anthranilic acid), were identified as new potential luminescent sublimation dyes with stained fingerprints excited at 254 nm. The fluorescence intensity and stability of prints produced via the sublimation of CA with 2-hydroxybenzoic acid and 2-aminobenzoic acid were evaluated over approximately six weeks using image and statistical analysis.
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Affiliation(s)
- Christopher Azaldegui
- Department of Chemistry, School of Natural Sciences, St. Edward's University, Austin, TX, USA.,Program in Chemical Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Guadalupe Aguilar
- Department of Forensic Science, School of Natural Sciences, St. Edward's University, Austin, TX, USA.,Travis County Medical Examiner's Office, Austin, TX, USA
| | - Sarahi Enriquez
- Department of Chemistry, School of Natural Sciences, St. Edward's University, Austin, TX, USA.,Endeavor DNA, El Paso, TX, USA
| | - Chris Madonna
- Department of Chemistry, School of Natural Sciences, St. Edward's University, Austin, TX, USA.,North Texas Fire Academy, Rockwall, TX, USA
| | - Casie Parish Fisher
- Department of Forensic Science, School of Natural Sciences, St. Edward's University, Austin, TX, USA
| | - Raychelle Burks
- Department of Chemistry, School of Natural Sciences, St. Edward's University, Austin, TX, USA.,Department of Chemistry, College of Arts and Science, American University, Washington, DC, USA
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3
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Abrahamsson CK, Nagarkar A, Fink MJ, Preston DJ, Ge S, Bozenko JS, Whitesides GM. Analysis of Powders Containing Illicit Drugs Using Magnetic Levitation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Amit Nagarkar
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Michael J. Fink
- Department of Chemistry and Chemical Biology Harvard University USA
| | | | - Shencheng Ge
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Joseph S. Bozenko
- Special Testing and Research Laboratory Drug Enforcement Administration (DEA) Dulles VA USA
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology Harvard University USA
- Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford St. Cambridge MA 02138 USA
- Kavli Institute for Bionano Inspired Science and Technology Harvard University 29 Oxford Street Cambridge MA 02138 USA
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4
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Abrahamsson CK, Nagarkar A, Fink MJ, Preston DJ, Ge S, Bozenko JS, Whitesides GM. Analysis of Powders Containing Illicit Drugs Using Magnetic Levitation. Angew Chem Int Ed Engl 2019; 59:874-881. [DOI: 10.1002/anie.201910177] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Indexed: 12/30/2022]
Affiliation(s)
| | - Amit Nagarkar
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Michael J. Fink
- Department of Chemistry and Chemical Biology Harvard University USA
| | | | - Shencheng Ge
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Joseph S. Bozenko
- Special Testing and Research Laboratory Drug Enforcement Administration (DEA) Dulles VA USA
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology Harvard University USA
- Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford St. Cambridge MA 02138 USA
- Kavli Institute for Bionano Inspired Science and Technology Harvard University 29 Oxford Street Cambridge MA 02138 USA
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5
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Cyclic Olefin Copolymer Microfluidic Devices for Forensic Applications. BIOSENSORS-BASEL 2019; 9:bios9030085. [PMID: 31277382 PMCID: PMC6784357 DOI: 10.3390/bios9030085] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/28/2019] [Accepted: 07/03/2019] [Indexed: 01/16/2023]
Abstract
Microfluidic devices offer important benefits for forensic applications, in particular for fast tests at a crime scene. A large portion of forensic applications require microfluidic chip material to show compatibility with biochemical reactions (such as amplification reactions), and to have high transparency in the visible region and high chemical resistance. Also, preferably, manufacturing should be simple. The characteristic properties of cyclic olefin copolymer (COC) fulfills these requirements and offers new opportunities for the development of new forensic tests. In this work, the versatility of COC as material for lab-on-a-chip (LOC) systems in forensic applications has been explored by realizing two proof-of-principle devices. Chemical resistance and optical transparency were investigated for the development of an on-chip presumptive color test to indicate the presence of an illicit substance through applying absorption spectroscopy. Furthermore, the compatibility of COC with a DNA amplification reaction was verified by performing an on-chip multiple displacement amplification (MDA) reaction.
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Kangas MJ, Wilson CL, Burks RM, Atwater J, Lukowicz RM, Garver B, Mayer M, Havenridge S, Holmes AE. An Improved Comparison of Chemometric Analyses for the Identification of Acids and Bases With Colorimetric Sensor Arrays. ACTA ACUST UNITED AC 2018; 10:36-55. [PMID: 31745401 DOI: 10.5539/ijc.v10n2p36] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Colorimetric sensor arrays incorporating red, green, and blue (RGB) image analysis use value changes from multiple sensors for the identification and quantification of various analytes. RGB data can be easily obtained using image analysis software such as ImageJ. Subsequent chemometric analysis is becoming a key component of colorimetric array RGB data analysis, though literature contains mainly principal component analysis (PCA) and hierarchical cluster analysis (HCA). Seeking to expand the chemometric methods toolkit for array analysis, we explored the performance of nine chemometric methods were compared for the task of classifying 631 solutions (0.1 to 3 M) of acetic acid, malonic acid, lysine, and ammonia using an eight sensor colorimetric array. PCA and LDA (linear discriminant analysis) were effective for visualizing the dataset. For classification, linear discriminant analysis (LDA), (k nearest neighbors) KNN, (soft independent modelling by class analogy) SIMCA, recursive partitioning and regression trees (RPART), and hit quality index (HQI) were very effective with each method classifying compounds with over 90% correct assignments. Support vector machines (SVM) and partial least squares - discriminant analysis (PLS-DA) struggled with ~85 and 39% correct assignments, respectively. Additional mathematical treatments of the data set, such as incrementally increasing the exponents, did not improve the performance of LDA and KNN. The literature precedence indicates that the most common methods for analyzing colorimetric arrays are PCA, LDA, HCA, and KNN. To our knowledge, this is the first report of comparing and contrasting several more diverse chemometric methods to analyze the same colorimetric array data.
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Kangas MJ, Burks RM, Atwater J, Lukowicz RM, Garver B, Holmes AE. Comparative Chemometric Analysis for Classification of Acids and Bases via a Colorimetric Sensor Array. JOURNAL OF CHEMOMETRICS 2018; 32:e2961. [PMID: 29795964 PMCID: PMC5962272 DOI: 10.1002/cem.2961] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
With the increasing availability of digital imaging devices, colorimetric sensor arrays are rapidly becoming a simple, yet effective tool for the identification and quantification of various analytes. Colorimetric arrays utilize colorimetric data from many colorimetric sensors, with the multidimensional nature of the resulting data necessitating the use of chemometric analysis. Herein, an 8 sensor colorimetric array was used to analyze select acid and basic samples (0.5 - 10 M) to determine which chemometric methods are best suited for classification quantification of analytes within clusters. PCA, HCA, and LDA were used to visualize the data set. All three methods showed well-separated clusters for each of the acid or base analytes and moderate separation between analyte concentrations, indicating that the sensor array can be used to identify and quantify samples. Furthermore, PCA could be used to determine which sensors showed the most effective analyte identification. LDA, KNN, and HQI were used for identification of analyte and concentration. HQI and KNN could be used to correctly identify the analytes in all cases, while LDA correctly identified 95 of 96 analytes correctly. Additional studies demonstrated that controlling for solvent and image effects was unnecessary for all chemometric methods utilized in this study.
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Affiliation(s)
| | | | - Jordyn Atwater
- Department of Chemistry, Doane University, Crete, NE, USA
| | | | - Billy Garver
- Department of Mathematics, Doane University, Crete, NE, USA
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8
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Philp M, Fu S. A review of chemical ‘spot’ tests: A presumptive illicit drug identification technique. Drug Test Anal 2017; 10:95-108. [DOI: 10.1002/dta.2300] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Morgan Philp
- Centre for Forensic Science, School of Mathematical and Physical Sciences; University of Technology Sydney (UTS); Australia
| | - Shanlin Fu
- Centre for Forensic Science, School of Mathematical and Physical Sciences; University of Technology Sydney (UTS); Australia
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9
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Kangas MJ, Burks RM, Atwater J, Lukowicz RM, Williams P, Holmes AE. Colorimetric Sensor Arrays for the Detection and Identification of Chemical Weapons and Explosives. Crit Rev Anal Chem 2016; 47:138-153. [PMID: 27636675 PMCID: PMC5351797 DOI: 10.1080/10408347.2016.1233805] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
There is a significant demand for devices that can rapidly detect chemical–biological–explosive (CBE) threats on-site and allow for immediate responders to mitigate spread, risk, and loss. The key to an effective reconnaissance mission is a unified detection technology that analyzes potential threats in real time. In addition to reviewing the current state of the art in the field, this review illustrates the practicality of colorimetric arrays composed of sensors that change colors in the presence of analytes. This review also describes an outlook toward future technologies, and describes how they could possibly be used in areas such as war zones to detect and identify hazardous substances.
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Affiliation(s)
- Michael J Kangas
- a Department of Chemistry , Doane University , Crete , Nebraska , USA
| | - Raychelle M Burks
- b Department of Chemistry , St. Edwards University , Austin , Texas , USA
| | - Jordyn Atwater
- a Department of Chemistry , Doane University , Crete , Nebraska , USA
| | - Rachel M Lukowicz
- a Department of Chemistry , Doane University , Crete , Nebraska , USA
| | | | - Andrea E Holmes
- a Department of Chemistry , Doane University , Crete , Nebraska , USA
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10
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Schumacher S, Muekusch S, Seitz H. Up-to-Date Applications of Microarrays and Their Way to Commercialization. MICROARRAYS (BASEL, SWITZERLAND) 2015; 4:196-213. [PMID: 27600220 PMCID: PMC4996390 DOI: 10.3390/microarrays4020196] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 12/12/2022]
Abstract
This review addresses up-to-date applications of Protein Microarrays. Protein Microarrays play a significant role in basic research as well as in clinical applications and are applicable in a lot of fields, e.g., DNA, proteins and small molecules. Additionally they are on the way to enter clinics in routine diagnostics. Protein Microarrays can be powerful tools to improve healthcare. An overview of basic characteristics to mediate essential knowledge of this technique is given. To reach this goal, some challenges still have to be addressed. A few applications of Protein Microarrays in a medical context are shown. Finally, an outlook, where the potential of Protein Microarrays is depicted and speculations how the future of Protein Microarrays will look like are made.
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Affiliation(s)
- Sarah Schumacher
- Branch Bioanalytics and Bioprocesses, Fraunhofer Institute for Cell Therapy and Immunology, Am Muehlenberg 13, 14476 Potsdam, Germany.
| | - Sandra Muekusch
- Branch Bioanalytics and Bioprocesses, Fraunhofer Institute for Cell Therapy and Immunology, Am Muehlenberg 13, 14476 Potsdam, Germany.
| | - Harald Seitz
- Branch Bioanalytics and Bioprocesses, Fraunhofer Institute for Cell Therapy and Immunology, Am Muehlenberg 13, 14476 Potsdam, Germany.
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11
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Batres G, Jones T, Johnke H, Wilson M, Holmes AE, Sikich S. Reactive Arrays of Colorimetric Sensors for Metabolite and Steroid Identification. ACTA ACUST UNITED AC 2014; 4. [PMID: 25019034 PMCID: PMC4091918 DOI: 10.4236/jst.2014.41001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The work described herein examines a rapid mix-and-measure method called DETECHIP suitable for screening of steroids and metabolites. The addition of steroids and metabolites to reactive arrays of colorimetric sensors generated characteristic color “fingerprints” that were used to identify the analyte. A color analysis tool was used to identify the analyte pool that now includes biologically relevant analytes. The mix-and-measure arrays allowed the detection of disease metabolites, orotic acid and argininosuccinic acid; and the steroids androsterone, 1,4-androstadiene, testosterone, stanozolol, and estrone. The steroid 1,4-androstadiene was also detected by this method while dissolved in synthetic urine. Some of the steroids, such as androstadiene, stanozolol, and androsterone were co-dissolved with (2-hydroxypropyl)-β-cyclodextrin in order to increase solubility in aqueous buffered solutions. The colorimetric arrays do not intend to eliminate ELISA or mass spectroscopy based screening, but to possibly provide an alternative analytical detection method for steroids and metabolites.
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Affiliation(s)
- Gary Batres
- Department Chemistry, Doane College, Crete, USA
| | - Talia Jones
- Department Chemistry, Doane College, Crete, USA
| | | | - Mark Wilson
- Department Chemistry, Doane College, Crete, USA
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12
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Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy. ACTA ACUST UNITED AC 2013; 2013. [PMID: 25018772 DOI: 10.1155/2013/245376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC) from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB), and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1) and the analyte (caffeine) that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed.
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13
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Hirtz M, Lyon M, Feng W, Holmes AE, Fuchs H, Levkin PA. Porous polymer coatings as substrates for the formation of high-fidelity micropatterns by quill-like pens. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2013; 4:377-84. [PMID: 23844343 PMCID: PMC3701425 DOI: 10.3762/bjnano.4.44] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2013] [Accepted: 05/29/2013] [Indexed: 05/08/2023]
Abstract
We explored the potentials of microarray printing using quill-like microcantilevers onto solid supports that are typically used in microspot printing, including paper, polymeric nitrocellulose and nylon membranes. We compared these membranes with a novel porous poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) support (HEMA) with narrow pore size distribution in the 150 nm range, which demonstrated advantages in pattern definition, spot homogeneity, and consistent spot delivery of different dyes (phloxine B and bromophenol blue) with diameters of several micrometres. The bromophenol blue arrays on HEMA support were used to detect the presence of bovine serum albumin (BSA). In the presence of BSA, the fluorescence spectrum observed from the bromophenol blue microarray exhibited a significant red shift of the maximum emission wavelength. Our results show that the porous HEMA substrates can improve the fidelity and quality of microarrays prepared by using the quill-like microcantilevers. The presented method sets the stage for further studies using chemical and biochemical recognition elements, along with colorimetric and fluorometric sensors that can be spotted by this method onto flat porous polymer substrates.
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Affiliation(s)
- Michael Hirtz
- Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Germany
| | - Marcus Lyon
- Department of Chemistry, Doane College, Crete, Nebraska, and the Center for Nanohybrid Functional Materials (CNFM), University of Nebraska-Lincoln, USA
| | - Wenqian Feng
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Germany
| | - Andrea E Holmes
- Department of Chemistry, Doane College, Crete, Nebraska, and the Center for Nanohybrid Functional Materials (CNFM), University of Nebraska-Lincoln, USA
| | - Harald Fuchs
- Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Germany
- Physical Institute and Center for Nanotechnology (CeNTech), University of Münster, Germany
| | - Pavel A Levkin
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology (KIT), Germany
- Applied Physical Chemistry, Heidelberg University, Germany
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Johnke H, Batres G, Wilson M, Holmes AE, Sikich S. Detecting Concentration of Analytes with DETECHIP: A Molecular Sensing Array. ACTA ACUST UNITED AC 2013; 3. [PMID: 24409399 PMCID: PMC3883435 DOI: 10.4236/jst.2013.33015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
DETECHIP® is a detection system made of various sensors that has been shown to detect and discriminate between small molecules of interest, including various illicit and over-the-counter drugs. Previously, detection was normalized to a single concentration of analyte. Now this detection assay can detect concentration differences in analytes via red, green, and blue color value changes and shifts in the UV-Vis spectra of the assay. To determine the concentrations differences, the exposed assays were scanned on a flatbed scanner and the images were analyzed for individual RGB values with a custom macro in ImageJ, an image analysis program. Increasing concentrations of the analyte resulted in greater differences in color values between control and analyte wells. These differences showed a linear relationship to concentration change, some with correlation coefficients greater than 98%. This work expands the capability of DETECHIP to give information about the concentration of analyte when the analyte identity is known.
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Affiliation(s)
| | - Gary Batres
- Department of Chemistry, Doane College, Crete, USA
| | - Mark Wilson
- Department of Chemistry, Doane College, Crete, USA
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Lyon M, Wilson MV, Rouhier KA, Symonsbergen DJ, Bastola K, Thapa I, Holmes AE, Sikich SM, Jackson A. Digital Image Analysis for DETCHIP ® Code Determination. ACTA ACUST UNITED AC 2012; 3:51-63. [PMID: 25267940 DOI: 10.5121/sipij.2012.3405] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
DETECHIP® is a molecular sensing array used for identification of a large variety of substances. Previous methodology for the analysis of DETECHIP® used human vision to distinguish color changes induced by the presence of the analyte of interest. This paper describes several analysis techniques using digital images of DETECHIP®. Both a digital camera and flatbed desktop photo scanner were used to obtain Jpeg images. Color information within these digital images was obtained through the measurement of red-green-blue (RGB) values using software such as GIMP, Photoshop and ImageJ. Several different techniques were used to evaluate these color changes. It was determined that the flatbed scanner produced in the clearest and more reproducible images. Furthermore, codes obtained using a macro written for use within ImageJ showed improved consistency versus pervious methods.
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Affiliation(s)
- Marcus Lyon
- Doane College, Department of Chemistry, 1014 Boswell Avenue, Crete, NE 68333
| | - Mark V Wilson
- Doane College, Department of Chemistry, 1014 Boswell Avenue, Crete, NE 68333
| | - Kerry A Rouhier
- Kenyon College, Department of Chemistry, 200 N. College, Gambier, OH 43022
| | | | - Kiran Bastola
- University of Nebraska at Omaha, School of Interdisciplinary Informatics, 6001 Dodge Street, Omaha, NE 68182
| | - Ishwor Thapa
- University of Nebraska at Omaha, School of Interdisciplinary Informatics, 6001 Dodge Street, Omaha, NE 68182
| | - Andrea E Holmes
- Doane College, Department of Chemistry, 1014 Boswell Avenue, Crete, NE 68333
| | - Sharmin M Sikich
- Doane College, Department of Chemistry, 1014 Boswell Avenue, Crete, NE 68333
| | - Abby Jackson
- Doane College, Department of Chemistry, 1014 Boswell Avenue, Crete, NE 68333
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Rodenhausen KB, Schmidt D, Kasputis T, Pannier AK, Schubert E, Schubert M. Generalized ellipsometry in-situ quantification of organic adsorbate attachment within slanted columnar thin films. OPTICS EXPRESS 2012; 20:5419-5428. [PMID: 22418349 DOI: 10.1364/oe.20.005419] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We apply generalized ellipsometry, well-known to be sensitive to the optical properties of anisotropic materials, to determine the amount of fibronectin protein that adsorbs onto a Ti slanted columnar thin film from solution. We find that the anisotropic optical properties of the thin film change upon organic adsorption. An optical model for ellipsometry data analysis incorporates an anisotropic Bruggeman effective medium approximation. We find that differences in experimental data from before and after fibronectin adsorption can be solely attributable to the uptake of fibronectin within the slanted columnar thin film. Simultaneous, in-situ generalized ellipsometry and quartz crystal microbalance measurements show excellent agreement on the amount and rate of fibronectin adsorption. Quantitative characterization of organic materials within three-dimensional, optically anisotropic slanted columnar thin films could permit their use in optical sensor applications.
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Affiliation(s)
- Keith B Rodenhausen
- Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, 207 Othmer Hall, Lincoln, NE 68588, USA.
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18
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Current Awareness in Drug Testing and Analysis. Drug Test Anal 2010. [DOI: 10.1002/dta.64] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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