1
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Ghosh J, Cooks RG. Accelerated click reactions using boronic acids for heterocyclic synthesis in microdroplets. Chem Sci 2025; 16:8800-8806. [PMID: 40276635 PMCID: PMC12015631 DOI: 10.1039/d5sc00851d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2025] [Accepted: 04/10/2025] [Indexed: 04/26/2025] Open
Abstract
Click chemistry is important for its simplicity and versatility, however, condensation-based click reactions are limited by the general requirement of high temperatures and catalysts. Here, we report accelerated click reactions using boronic acids in microdroplets under ambient conditions without a catalyst. The reaction between 2-formyl phenylboronic acid (2-FPBA) and substituted amines leads to the formation of multi-step click products, including iminoboronates, boroxines, thiazolidines, and diazaborines, depending on the selected amine. The reactions occur during microdroplet flight and are three orders of magnitude faster than the corresponding bulk reactions. MS and NMR spectral analysis confirmed the nature of the products. We suggest that the air-liquid interface of microdroplets serves both as a superacid and as a drying surface, facilitating dehydration by its superacidicity to access these products. We also demonstrate the application of these accelerated reactions as a late-stage functionalization (LSF) tool to access a range of antihistamine drug derivatives.
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Affiliation(s)
- Jyotirmoy Ghosh
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University 560 Oval Drive West Lafayette IN 47907 USA
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2
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Shuluk J, Wight CD, Howard JR, King ME, Moor SR, DeHoog RJ, Dahlhauser SD, Eberlin LS, Anslyn EV. A Workflow Enabling the Automated Synthesis, Chain-End Degradation, and Rapid Mass Spectrometry Analysis for Molecular Information Storage in Sequence-Defined Oligourethanes. JACS AU 2025; 5:1232-1242. [PMID: 40151242 PMCID: PMC11937967 DOI: 10.1021/jacsau.4c01070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2024] [Revised: 01/08/2025] [Accepted: 01/10/2025] [Indexed: 03/29/2025]
Abstract
The field of molecular information storage has recently expanded to include abiotic sequence-defined polymers. While robust methods have been developed, there is a current bottleneck in the throughput of this work as information density is increased. Herein, we introduce an automated workflow in which a commercial peptide synthesizer composed of a single XYZ liquid-handling robot was adapted to both synthesize and sequence sequence-defined oligourethanes. Our sequencing method was improved to cut down the number of samples required for each oligomer from 13 to one. Additionally, we introduce the use of desorption electrospray ionization mass spectrometry as our analysis method for sequencing, which allowed for simplified and increased speed of data acquisition. Finally, we created a Python script that is able to reconstruct the sequence information from the MS data in an automated fashion. We demonstrate this new workflow by encoding and decoding a quote from the late Maya Angelou: "When you learn, teach, when you get, give".
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Affiliation(s)
- Julia
R. Shuluk
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
| | - Christopher D. Wight
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
- Department
of Chemistry, Texas State University, San Marcos, Texas 78666, United States
| | - James R. Howard
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
| | - Mary E. King
- Department
of Surgery, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Sarah R. Moor
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
| | - Rachel J. DeHoog
- Department
of Surgery, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Samuel D. Dahlhauser
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
| | - Livia S. Eberlin
- Department
of Surgery, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Eric V. Anslyn
- Department
of Chemistry, The University of Texas at
Austin, Austin, Texas 78712, United States
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3
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Ghosh J, Morato NM, Feng Y, Cooks RG. High-Throughput Drug Derivatization and Bioassay by Desorption Electrospray Ionization Mass Spectrometry. Chempluschem 2025:e2500164. [PMID: 40095503 DOI: 10.1002/cplu.202500164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2025] [Accepted: 03/17/2025] [Indexed: 03/19/2025]
Abstract
Adapting high-throughput (HT) synthetic methods to the modification of drugs and to testing of their bioactivity should expedite drug discovery. Herein, the applicability of HT desorption electrospray ionization mass spectrometry (DESI MS) to achieve late-stage functionalization (LSF) and rapidly generate a modified opioid library is demonstrated. Specifically, aza-Michael addition and sulfur (VI) fluoride exchange reactions are used for functionalization. The modified drugs are both synthesized and characterized using an automated HT-DESI MS platform, with the reaction occurring during the droplet flight. Analysis by MS characterizes reaction products at a throughput of >1 reaction per second. With this platform, multiple nor-opioid scaffolds and functionalization reagents are screened and a selection of the hits obtained is subjected to HT label-free bioassays using the same DESI-MS platform. This combination of accelerated LSF reactions to rapidly create a diverse library of functionalized drugs with direct bioassays of the crude reaction mixtures for structure-activity relationship evaluation, both using the same platform, is anticipated to help expedite the early drug discovery process.
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Affiliation(s)
- Jyotirmoy Ghosh
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Nicolás M Morato
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Yunfei Feng
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
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4
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Naveen K, Rawat VS, Verma R, Gnanamani E. Catalyst-free ring opening of azlactones in water microdroplets. Chem Commun (Camb) 2024; 60:13263-13266. [PMID: 39445768 DOI: 10.1039/d4cc04487h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2024]
Abstract
A catalyst-free method was developed for the ring opening of azlactones (also known as oxazolones) in water microdroplets. Azlactone was dissolved in a water : acetonitrile (1 : 1) mixture, and the solution is sprayed by using nitrogen gas at a pressure of 120 psi to generate microdroplets. This method promoted selective cleavage of the lactone bond to afford the corresponding N-benzoyl derivatives in up to 94% isolated yield with no epimerization. Our method produces the ring-opening products in milliseconds (up to 94 μmol for 33.3 minutes), and may have utility for high-throughput synthesis applications.
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Affiliation(s)
- Kumar Naveen
- Asymmetric Synthesis and Catalysis Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Vishesh Singh Rawat
- Asymmetric Synthesis and Catalysis Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Rahul Verma
- Asymmetric Synthesis and Catalysis Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
| | - Elumalai Gnanamani
- Asymmetric Synthesis and Catalysis Laboratory, Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India.
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5
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Henderson A, Heaney LM, Rankin-Turner S. Ambient ionisation mass spectrometry for drug and toxin analysis: A review of the recent literature. Drug Test Anal 2024; 16:1323-1344. [PMID: 38326879 DOI: 10.1002/dta.3644] [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: 08/31/2023] [Revised: 11/17/2023] [Accepted: 12/28/2023] [Indexed: 02/09/2024]
Abstract
Ambient ionisation mass spectrometry (AIMS) is a form of mass spectrometry whereby analyte ionisation occurs outside of a vacuum source under ambient conditions. This enables the direct analysis of samples in their native state, with little or no sample preparation and without chromatographic separation. The removal of these steps facilitates a much faster analytical process, enabling the direct analysis of samples within minutes if not seconds. Consequently, AIMS has gained rapid popularity across a diverse range of applications, in particular the analysis of drugs and toxins. Numerous fields rely upon mass spectrometry for the detection and identification of drugs, including clinical diagnostics, forensic chemistry, and food safety. However, all of these fields are hindered by the time-consuming and laboratory-confined nature of traditional techniques. As such, the potential for AIMS to resolve these challenges has resulted in a growing interest in ambient ionisation for drug and toxin analysis. Since the early 2000s, forensic science, diagnostic testing, anti-doping, pharmaceuticals, environmental analysis and food safety have all seen a marked increase in AIMS applications, foreshadowing a new future for drug testing. In this review, some of the most promising AIMS techniques for drug analysis will be discussed, alongside different applications of AIMS published over a 5-year period, to provide a summary of the recent research activity for ambient ionisation for drug and toxin analysis.
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Affiliation(s)
- Alisha Henderson
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Liam M Heaney
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Stephanie Rankin-Turner
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
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6
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Cooks RG, Feng Y, Huang KH, Morato NM, Qiu L. Re-Imagining Drug Discovery using Mass Spectrometry. Isr J Chem 2023; 63:e202300034. [PMID: 37829547 PMCID: PMC10569432 DOI: 10.1002/ijch.202300034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Indexed: 03/22/2023]
Abstract
It is argued that each of the three key steps in drug discovery, (i) reaction screening to find successful routes to desired drug candidates, (ii) scale up of the synthesis to produce amounts adequate for testing, and (iii) bioactivity assessment of the candidate compounds, can all be performed using mass spectrometry (MS) in a sequential fashion. The particular ionization method of choice, desorption electrospray ionization (DESI), is both an analytical technique and a procedure for small-scale synthesis. It is also highly compatible with automation, providing for high throughput in both synthesis and analysis. Moreover, because accelerated reactions take place in the secondary DESI microdroplets generated from individual reaction mixtures, this allows either online analysis by MS or collection of the synthetic products by droplet deposition. DESI also has the unique advantage, amongst spray-based MS ionization methods, that complex buffered biological solutions can be analyzed directly, without concern for capillary blockage. Here, all these capabilities are illustrated, the unique chemistry at droplet interfaces is presented, and the possible future implementation of DESI-MS based drug discovery is discussed.
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Affiliation(s)
- R Graham Cooks
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907 USA
| | - Yunfei Feng
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907 USA
| | - Kai-Hung Huang
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907 USA
| | - Nicolás M Morato
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907 USA
| | - Lingqi Qiu
- Department of Chemistry and Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907 USA
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7
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Rankin‐Turner S, Sears P, Heaney LM. Applications of ambient ionization mass spectrometry in 2022: An annual review. ANALYTICAL SCIENCE ADVANCES 2023; 4:133-153. [PMID: 38716065 PMCID: PMC10989672 DOI: 10.1002/ansa.202300004] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 04/16/2023] [Accepted: 04/17/2023] [Indexed: 06/28/2024]
Abstract
The development of ambient ionization mass spectrometry (AIMS) has transformed analytical science, providing the means of performing rapid analysis of samples in their native state, both in and out of the laboratory. The capacity to eliminate sample preparation and pre-MS separation techniques, leading to true real-time analysis, has led to AIMS naturally gaining a broad interest across the scientific community. Since the introduction of the first AIMS techniques in the mid-2000s, the field has exploded with dozens of novel ion sources, an array of intriguing applications, and an evident growing interest across diverse areas of study. As the field continues to surge forward each year, ambient ionization techniques are increasingly becoming commonplace in laboratories around the world. This annual review provides an overview of AIMS techniques and applications throughout 2022, with a specific focus on some of the major fields of research, including forensic science, disease diagnostics, pharmaceuticals and food sciences. New techniques and methods are introduced, demonstrating the unwavering drive of the analytical community to further advance this exciting field and push the boundaries of what analytical chemistry can achieve.
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Affiliation(s)
- Stephanie Rankin‐Turner
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public HealthJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Patrick Sears
- School of Chemistry and Chemical EngineeringUniversity of SurreyGuildfordUK
| | - Liam M Heaney
- School of Sport, Exercise and Health SciencesLoughborough UniversityLoughboroughUK
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8
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Talaty NN, Johnson RW, Sawicki J, Nacham O, Djuric SW. Recent Developments in Mass Spectrometry to Support Next-Generation Synthesis and Screening. ACS Med Chem Lett 2023; 14:711-718. [PMID: 37312853 PMCID: PMC10258828 DOI: 10.1021/acsmedchemlett.3c00040] [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: 02/02/2023] [Accepted: 05/10/2023] [Indexed: 06/15/2023] Open
Abstract
The complexity of new therapeutics continues to increase and the timeline for the discovery of these therapeutics continues to shrink. This creates demand for new analytical techniques to facilitate quicker discovery and development of novel drugs. Mass spectrometry is one of the most prolific analytical techniques that has been applied across the entire drug discovery pipeline. New mass spectrometers and the associated methods for sampling have been introduced at a rate that keeps pace with new chemistries, therapeutic types, and screening practices used by modern drug hunters. This microperspective covers application and implementation of new mass spectrometry workflows that enable current and future efforts in screening and synthesis for drug discovery.
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Affiliation(s)
- Nari N. Talaty
- Discovery
Platform Technologies, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - Robert W. Johnson
- Discovery
Platform Technologies, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - James Sawicki
- Discovery
Platform Technologies, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - Omprakash Nacham
- Discovery
Platform Technologies, AbbVie Inc., North Chicago, Illinois 60064, United States
| | - Stevan W. Djuric
- Discovery
Chemistry and Technology Consulting LLC, New Bern, North Carolina 28562, United States
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9
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Huang KH, Morato NM, Feng Y, Cooks RG. High-Throughput Diversification of Complex Bioactive Molecules by Accelerated Synthesis in Microdroplets. Angew Chem Int Ed Engl 2023; 62:e202300956. [PMID: 36941213 PMCID: PMC10182919 DOI: 10.1002/anie.202300956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/17/2023] [Accepted: 03/20/2023] [Indexed: 03/23/2023]
Abstract
Late-stage diversification of drug molecules is an important strategy in drug discovery that can be facilitated by reaction screening using high-throughput experimentation. Here we present a rapid method for functionalizing bioactive molecules based on accelerated reactions in microdroplets. Reaction mixtures are nebulized at throughputs better than 1 reaction/second and the accelerated reactions occurring in the microdroplets are followed by desorption electrospray ionization mass spectrometry (DESI-MS). Because the accelerated reactions occur on the millisecond timescale, they allow an overall screening throughput of 1 Hz working at the low nanogram scale. Using this approach, an opioid agonist (PZM21) and an antagonist (naloxone) were diversified using three reactions important in medicinal chemistry: sulfur fluoride exchange (SuFEx) click reactions, imine formation reactions, and ene-type click reactions. Some 269 functionalized analogs of naloxone and PZM21 were generated and characterized by tandem mass spectrometry (MS/MS) after screening over 500 reactions.
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Affiliation(s)
- Kai-Hung Huang
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Nicolás M Morato
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Yunfei Feng
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
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10
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Mass spectrometry in materials synthesis. Trends Analyt Chem 2023. [DOI: 10.1016/j.trac.2023.117010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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11
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Ghosh J, Mendoza J, Cooks RG. Accelerated and Concerted Aza-Michael Addition and SuFEx Reaction in Microdroplets in Unitary and High-Throughput Formats. Angew Chem Int Ed Engl 2022; 61:e202214090. [PMID: 36253886 PMCID: PMC10099520 DOI: 10.1002/anie.202214090] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Indexed: 11/12/2022]
Abstract
The sulfur fluoride exchange (SuFEx) reaction is significant in drug discovery, materials science, and chemical biology. Conventionally, it involves installation of SO2 F followed by fluoride exchange by a catalyst. We report catalyst-free Aza-Michael addition to install SO2 F and then SuFEx reaction with amines, both occurring in concert, in microdroplets under ambient conditions. The microdroplet reaction is accelerated by a factor of ∼104 relative to the corresponding bulk reaction. We suggest that the superacidic microdroplet surface assists SuFEx reaction by protonating fluorine to create a good leaving group. The reaction scope was established by performing individual reactions in microdroplets of 18 amines in four solvents and confirmed using high-throughput desorption electrospray ionization experiments. The study demonstrates the value of microdroplet-assisted accelerated reactions in combination with high-throughput experimentation for characterization of reaction scope.
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Affiliation(s)
- Jyotirmoy Ghosh
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Joshua Mendoza
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - R Graham Cooks
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
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12
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Morato NM, Brown HM, Garcia D, Middlebrooks EH, Jentoft M, Chaichana K, Quiñones-Hinojosa A, Cooks RG. High-throughput analysis of tissue microarrays using automated desorption electrospray ionization mass spectrometry. Sci Rep 2022; 12:18851. [PMID: 36344609 PMCID: PMC9640715 DOI: 10.1038/s41598-022-22924-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
Tissue microarrays (TMAs) are commonly used for the rapid analysis of large numbers of tissue samples, often in morphological assessments but increasingly in spectroscopic analysis, where specific molecular markers are targeted via immunostaining. Here we report the use of an automated high-throughput system based on desorption electrospray ionization (DESI) mass spectrometry (MS) for the rapid generation and online analysis of high-density (6144 samples/array) TMAs, at rates better than 1 sample/second. Direct open-air analysis of tissue samples (hundreds of nanograms) not subjected to prior preparation, plus the ability to provide molecular characterization by tandem mass spectrometry (MS/MS), make this experiment versatile and applicable to both targeted and untargeted analysis in a label-free manner. These capabilities are demonstrated in a proof-of-concept study of frozen brain tissue biopsies where we showcase (i) a targeted MS/MS application aimed at identification of isocitrate dehydrogenase mutation in glioma samples and (ii) an untargeted MS tissue type classification using lipid profiles and correlation with tumor cell percentage estimates from histopathology. The small sample sizes and large sample numbers accessible with this methodology make for a powerful analytical system that facilitates the identification of molecular markers for later use in intraoperative applications to guide precision surgeries and ultimately improve patient outcomes.
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Affiliation(s)
- Nicolás M. Morato
- grid.169077.e0000 0004 1937 2197Department of Chemistry, Purdue Center for Cancer Research, and Bindley Bioscience Center, Purdue University, 560 Oval Drive, West Lafayette, IN 47907 USA
| | - Hannah Marie Brown
- grid.169077.e0000 0004 1937 2197Department of Chemistry, Purdue Center for Cancer Research, and Bindley Bioscience Center, Purdue University, 560 Oval Drive, West Lafayette, IN 47907 USA ,grid.4367.60000 0001 2355 7002Present Address: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO USA
| | - Diogo Garcia
- grid.417467.70000 0004 0443 9942Department of Neurosurgery, Mayo Clinic, Jacksonville, FL USA
| | - Erik H. Middlebrooks
- grid.417467.70000 0004 0443 9942Department of Neurosurgery, Mayo Clinic, Jacksonville, FL USA ,grid.417467.70000 0004 0443 9942Department of Radiology, Mayo Clinic, Jacksonville, FL USA
| | - Mark Jentoft
- grid.417467.70000 0004 0443 9942Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, FL USA
| | - Kaisorn Chaichana
- grid.417467.70000 0004 0443 9942Department of Neurosurgery, Mayo Clinic, Jacksonville, FL USA
| | | | - R. Graham Cooks
- grid.169077.e0000 0004 1937 2197Department of Chemistry, Purdue Center for Cancer Research, and Bindley Bioscience Center, Purdue University, 560 Oval Drive, West Lafayette, IN 47907 USA
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13
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Qiu L, Cooks RG. Simultaneous and Spontaneous Oxidation and Reduction in Microdroplets by the Water Radical Cation/Anion Pair. Angew Chem Int Ed Engl 2022; 61:e202210765. [PMID: 35994573 PMCID: PMC9825976 DOI: 10.1002/anie.202210765] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Indexed: 01/11/2023]
Abstract
Microdroplets show unique chemistry, especially in their intrinsic redox properties, and to this we here add a case of simultaneous and spontaneous oxidation and reduction. We report the concurrent conversions of several phosphonates to phosphonic acids by reduction (R-P → H-P) and to pentavalent phosphoric acids by oxidation. The experimental results suggest that the active reagent is the water radical cation/anion pair. The water radical cation is observed directly as the ionized water dimer while the water radical anion is only seen indirectly though the spontaneous reduction of carbon dioxide to formate. The coexistence of oxidative and reductive species in turn supports the proposal of a double-layer structure at the microdroplet surface, where the water radical cation and radical anion are separated and accumulated.
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Affiliation(s)
- Lingqi Qiu
- Department of ChemistryPurdue University560 Oval. Dr.West LafayetteIN 47907USA
| | - R. Graham Cooks
- Department of ChemistryPurdue University560 Oval. Dr.West LafayetteIN 47907USA
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14
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Qiu L, Cooks RG. Simultaneous and Spontaneous Oxidation and Reduction in Microdroplets by the Water Radical Cation/Anion Pair. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202210765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lingqi Qiu
- Purdue University Chemistry UNITED STATES
| | - R Graham Cooks
- Purdue University Chemistry 560 Oval Drive 47907 West Lafayette UNITED STATES
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