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  1. Article ; Online: Quantification of Analyte Concentration in the Single Molecule Regime Using Convolutional Neural Networks.

    Thrift, William John / Ragan, Regina

    Analytical chemistry

    2019  Volume 91, Issue 21, Page(s) 13337–13342

    Abstract: Single molecule (SM) detection represents the ultimate limit of chemical detection. Over the years, many experimental techniques have emerged with this capacity. Yet, SM detection and imaging methods produce large spectral data sets that benefit from ... ...

    Abstract Single molecule (SM) detection represents the ultimate limit of chemical detection. Over the years, many experimental techniques have emerged with this capacity. Yet, SM detection and imaging methods produce large spectral data sets that benefit from chemometric methods. In particular, surface enhanced Raman scattering spectroscopy (SERS), with extensive applications in biosensing, is demonstrated to be particularly promising because Raman active molecules can be identified without recognition elements and is capable of SM detection. Yet quantification at ultralow analyte concentrations requiring detection of SM events remains an ongoing challenge, with the few existing methods requiring carefully developed calibration curves that must be redeveloped for each analyte molecule. In this work, we demonstrate that a convolutional neural network (CNN) model when applied to bundles of SERS spectra yields a robust, facile method for concentration quantification down to 10 fM using SM detection events. We further demonstrate that transfer learning, the process of reusing the weights of a trained CNN model, greatly reduces the amount of data required to train CNN models on new analyte molecules. These results point the way for unambiguous analysis of large spectral data sets and the use of SERS in important ultra low concentration chemical detection applications such as metabolomic profiling, water quality evaluation, and fundamental research.
    Language English
    Publishing date 2019-10-09
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1508-8
    ISSN 1520-6882 ; 0003-2700
    ISSN (online) 1520-6882
    ISSN 0003-2700
    DOI 10.1021/acs.analchem.9b03599
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Graph-pMHC: graph neural network approach to MHC class II peptide presentation and antibody immunogenicity.

    Thrift, William John / Perera, Jason / Cohen, Sivan / Lounsbury, Nicolas W / Gurung, Hem R / Rose, Christopher M / Chen, Jieming / Jhunjhunwala, Suchit / Liu, Kai

    Briefings in bioinformatics

    2024  Volume 25, Issue 3

    Abstract: Antigen presentation on MHC class II (pMHCII presentation) plays an essential role in the adaptive immune response to extracellular pathogens and cancerous cells. But it can also reduce the efficacy of large-molecule drugs by triggering an anti-drug ... ...

    Abstract Antigen presentation on MHC class II (pMHCII presentation) plays an essential role in the adaptive immune response to extracellular pathogens and cancerous cells. But it can also reduce the efficacy of large-molecule drugs by triggering an anti-drug response. Significant progress has been made in pMHCII presentation modeling due to the collection of large-scale pMHC mass spectrometry datasets (ligandomes) and advances in machine learning. Here, we develop graph-pMHC, a graph neural network approach to predict pMHCII presentation. We derive adjacency matrices for pMHCII using Alphafold2-multimer and address the peptide-MHC binding groove alignment problem with a simple graph enumeration strategy. We demonstrate that graph-pMHC dramatically outperforms methods with suboptimal inductive biases, such as the multilayer-perceptron-based NetMHCIIpan-4.0 (+20.17% absolute average precision). Finally, we create an antibody drug immunogenicity dataset from clinical trial data and develop a method for measuring anti-antibody immunogenicity risk using pMHCII presentation models. Our model increases receiver operating characteristic curve (ROC)-area under the ROC curve (AUC) by 2.57% compared to just filtering peptides by hits in OASis alone for predicting antibody drug immunogenicity.
    MeSH term(s) Histocompatibility Antigens Class II/chemistry ; Peptides/chemistry ; Antigen Presentation ; Neural Networks, Computer
    Chemical Substances Histocompatibility Antigens Class II ; Peptides
    Language English
    Publishing date 2024-03-30
    Publishing country England
    Document type Journal Article
    ZDB-ID 2068142-2
    ISSN 1477-4054 ; 1467-5463
    ISSN (online) 1477-4054
    ISSN 1467-5463
    DOI 10.1093/bib/bbae123
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Sensing Antibiotics in Wastewater Using Surface-Enhanced Raman Scattering.

    Huang, Yen-Hsiang / Wei, Hong / Santiago, Peter J / Thrift, William John / Ragan, Regina / Jiang, Sunny

    Environmental science & technology

    2023  Volume 57, Issue 12, Page(s) 4880–4891

    Abstract: Rapid and cost-effective detection of antibiotics in wastewater and through wastewater treatment processes is an important first step in developing effective strategies for their removal. Surface-enhanced Raman scattering (SERS) has the potential for ... ...

    Abstract Rapid and cost-effective detection of antibiotics in wastewater and through wastewater treatment processes is an important first step in developing effective strategies for their removal. Surface-enhanced Raman scattering (SERS) has the potential for label-free, real-time sensing of antibiotic contamination in the environment. This study reports the testing of two gold nanostructures as SERS substrates for the label-free detection of quinoline, a small-molecular-weight antibiotic that is commonly found in wastewater. The results showed that the self-assembled SERS substrate was able to quantify quinoline spiked in wastewater with a lower limit of detection (LoD) of 5.01 ppb. The SERStrate (commercially available SERS substrate with gold nanopillars) had a similar sensitivity for quinoline quantification in pure water (LoD of 1.15 ppb) but did not perform well for quinoline quantification in wastewater (LoD of 97.5 ppm) due to interferences from non-target molecules in the wastewater. Models constructed based on machine learning algorithms could improve the separation and identification of quinoline Raman spectra from those of interference molecules to some degree, but the selectivity of SERS intensification was more critical to achieve the identification and quantification of the target analyte. The results of this study are a proof-of-concept for SERS applications in label-free sensing of environmental contaminants. Further research is warranted to transform the concept into a practical technology for environmental monitoring.
    MeSH term(s) Wastewater ; Spectrum Analysis, Raman/methods ; Metal Nanoparticles/chemistry ; Limit of Detection ; Gold/chemistry
    Chemical Substances Wastewater ; Gold (7440-57-5)
    Language English
    Publishing date 2023-03-19
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, N.I.H., Extramural
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.3c00027
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Quantification of Analyte Concentration in the Single Molecule Regime Using Convolutional Neural Networks

    Thrift, William John / Ragan, Regina

    Analytical chemistry. 2019 Oct. 07, v. 91, no. 21

    2019  

    Abstract: Single molecule (SM) detection represents the ultimate limit of chemical detection. Over the years, many experimental techniques have emerged with this capacity. Yet, SM detection and imaging methods produce large spectral data sets that benefit from ... ...

    Abstract Single molecule (SM) detection represents the ultimate limit of chemical detection. Over the years, many experimental techniques have emerged with this capacity. Yet, SM detection and imaging methods produce large spectral data sets that benefit from chemometric methods. In particular, surface enhanced Raman scattering spectroscopy (SERS), with extensive applications in biosensing, is demonstrated to be particularly promising because Raman active molecules can be identified without recognition elements and is capable of SM detection. Yet quantification at ultralow analyte concentrations requiring detection of SM events remains an ongoing challenge, with the few existing methods requiring carefully developed calibration curves that must be redeveloped for each analyte molecule. In this work, we demonstrate that a convolutional neural network (CNN) model when applied to bundles of SERS spectra yields a robust, facile method for concentration quantification down to 10 fM using SM detection events. We further demonstrate that transfer learning, the process of reusing the weights of a trained CNN model, greatly reduces the amount of data required to train CNN models on new analyte molecules. These results point the way for unambiguous analysis of large spectral data sets and the use of SERS in important ultra low concentration chemical detection applications such as metabolomic profiling, water quality evaluation, and fundamental research.
    Keywords Raman spectroscopy ; calibration ; chemometrics ; data collection ; image analysis ; learning ; metabolomics ; neural networks ; spectral analysis ; water quality
    Language English
    Dates of publication 2019-1007
    Size p. 13337-13342.
    Publishing place American Chemical Society
    Document type Article
    ZDB-ID 1508-8
    ISSN 1520-6882 ; 0003-2700
    ISSN (online) 1520-6882
    ISSN 0003-2700
    DOI 10.1021/acs.analchem.9b03599
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Surface-Enhanced Raman Scattering-Based Odor Compass: Locating Multiple Chemical Sources and Pathogens.

    Thrift, William John / Cabuslay, Antony / Laird, Andrew Benjamin / Ranjbar, Saba / Hochbaum, Allon I / Ragan, Regina

    ACS sensors

    2019  Volume 4, Issue 9, Page(s) 2311–2319

    Abstract: Olfaction is important for identifying and avoiding toxic substances in living systems. Many efforts have been made to realize artificial olfaction systems that reflect the capacity of biological systems. A sophisticated example of an artificial ... ...

    Abstract Olfaction is important for identifying and avoiding toxic substances in living systems. Many efforts have been made to realize artificial olfaction systems that reflect the capacity of biological systems. A sophisticated example of an artificial olfaction device is the odor compass which uses chemical sensor data to identify odor source direction. Successful odor compass designs often rely on plume-based detection and mobile robots, where active, mechanical motion of the sensor platform is employed. Passive, diffusion-based odor compasses remain elusive as detection of low analyte concentrations and quantification of small concentration gradients from within the sensor platform are necessary. Further, simultaneously identifying multiple odor sources using an odor compass remains an ongoing challenge, especially for similar analytes. Here, we show that surface-enhanced Raman scattering (SERS) sensors overcome these challenges, and we present the first SERS odor compass. Using a grid array of SERS sensors, machine learning analysis enables reliable identification of multiple odor sources arising from diffusion of analytes from one or two localized sources. Specifically, convolutional neural network and support vector machine classifier models achieve over 90% accuracy for a multiple odor source problem. This system is then used to identify the location of an
    MeSH term(s) Escherichia coli/chemistry ; Escherichia coli/physiology ; Odorants/analysis ; Spectrum Analysis, Raman/methods ; Surface Properties ; Volatile Organic Compounds/analysis
    Chemical Substances Volatile Organic Compounds
    Language English
    Publishing date 2019-08-28
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 2379-3694
    ISSN (online) 2379-3694
    DOI 10.1021/acssensors.9b00809
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Deep Learning Analysis of Vibrational Spectra of Bacterial Lysate for Rapid Antimicrobial Susceptibility Testing.

    Thrift, William John / Ronaghi, Sasha / Samad, Muntaha / Wei, Hong / Nguyen, Dean Gia / Cabuslay, Antony Superio / Groome, Chloe E / Santiago, Peter Joseph / Baldi, Pierre / Hochbaum, Allon I / Ragan, Regina

    ACS nano

    2020  Volume 14, Issue 11, Page(s) 15336–15348

    Abstract: Rapid antimicrobial susceptibility testing (AST) is an integral tool to mitigate the unnecessary use of powerful and broad-spectrum antibiotics that leads to the proliferation of multi-drug-resistant bacteria. Using a sensor platform composed of surface- ... ...

    Abstract Rapid antimicrobial susceptibility testing (AST) is an integral tool to mitigate the unnecessary use of powerful and broad-spectrum antibiotics that leads to the proliferation of multi-drug-resistant bacteria. Using a sensor platform composed of surface-enhanced Raman scattering (SERS) sensors with control of nanogap chemistry and machine learning algorithms for analysis of complex spectral data, bacteria metabolic profiles post antibiotic exposure are correlated with susceptibility. Deep neural network models are able to discriminate the responses of
    MeSH term(s) Anti-Bacterial Agents/pharmacology ; Bayes Theorem ; Cell Extracts ; Deep Learning ; Microbial Sensitivity Tests
    Chemical Substances Anti-Bacterial Agents ; Broncho-Vaxom ; Cell Extracts
    Language English
    Publishing date 2020-10-23
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ISSN 1936-086X
    ISSN (online) 1936-086X
    DOI 10.1021/acsnano.0c05693
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Longitudinal Monitoring of Biofilm Formation via Robust Surface-Enhanced Raman Scattering Quantification of Pseudomonas aeruginosa-Produced Metabolites.

    Nguyen, Cuong Quoc / Thrift, William John / Bhattacharjee, Arunima / Ranjbar, Saba / Gallagher, Tara / Darvishzadeh-Varcheie, Mahsa / Sanderson, Robert Noboru / Capolino, Filippo / Whiteson, Katrine / Baldi, Pierre / Hochbaum, Allon I / Ragan, Regina

    ACS applied materials & interfaces

    2018  Volume 10, Issue 15, Page(s) 12364–12373

    Abstract: Detection of bacterial metabolites at low concentrations in fluids with complex background allows for applications ranging from detecting biomarkers of respiratory infections to identifying contaminated medical instruments. Surface-enhanced Raman ... ...

    Abstract Detection of bacterial metabolites at low concentrations in fluids with complex background allows for applications ranging from detecting biomarkers of respiratory infections to identifying contaminated medical instruments. Surface-enhanced Raman scattering (SERS) spectroscopy, when utilizing plasmonic nanogaps, has the relatively unique capacity to reach trace molecular detection limits in a label-free format, yet large-area device fabrication incorporating nanogaps with this level of performance has proven difficult. Here, we demonstrate the advantages of using chemical assembly to fabricate SERS surfaces with controlled nanometer gap spacings between plasmonic nanospheres. Control of nanogap spacings via the length of the chemical crosslinker provides uniform SERS signals, exhibiting detection of pyocyanin, a secondary metabolite of Pseudomonas aeruginosa, in aqueous media at concentration of 100 pg·mL
    MeSH term(s) Anti-Bacterial Agents ; Biofilms ; Limit of Detection ; Pseudomonas aeruginosa ; Spectrum Analysis, Raman
    Chemical Substances Anti-Bacterial Agents
    Language English
    Publishing date 2018-04-09
    Publishing country United States
    Document type Journal Article
    ISSN 1944-8252
    ISSN (online) 1944-8252
    DOI 10.1021/acsami.7b18592
    Database MEDical Literature Analysis and Retrieval System OnLINE

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