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Mc Veigh M, Bellan LM. Microfluidic synthesis of radiotracers: recent developments and commercialization prospects. LAB ON A CHIP 2024; 24:1226-1243. [PMID: 38165824 DOI: 10.1039/d3lc00779k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2024]
Abstract
Positron emission tomography (PET) is a powerful diagnostic tool that holds incredible potential for clinicians to track a wide variety of biological processes using specialized radiotracers. Currently, however, a single radiotracer accounts for over 95% of procedures, largely due to the cost of radiotracer synthesis. Microfluidic platforms provide a solution to this problem by enabling a dose-on-demand pipeline in which a single benchtop platform would synthesize a wide array of radiotracers. In this review, we will explore the field of microfluidic production of radiotracers from early research to current development. Furthermore, the benefits and drawbacks of different microfluidic reactor designs will be analyzed. Lastly, we will discuss the various engineering considerations that must be addressed to create a fully developed, commercially effective platform that can usher the field from research and development to commercialization.
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Affiliation(s)
- Mark Mc Veigh
- Interdisciplinary Materials Science Program, Vanderbilt University, Nashville, TN, 37235, USA
| | - Leon M Bellan
- Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37235, USA
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2
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Lu Y, Collins J, Lin KS, van Dam RM. Scalable droplet-based radiosynthesis of [ 18F]fluorobenzyltriphenylphosphonium cation ([ 18F]FBnTP) via a "numbering up" approach. LAB ON A CHIP 2024; 24:728-737. [PMID: 38240629 PMCID: PMC10869106 DOI: 10.1039/d3lc01068f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
The [18F]fluorobenzyltriphenylphosphonium cation ([18F]FBnTP) has emerged as a highly promising positron emission tomography (PET) tracer for myocardial perfusion imaging (MPI) due to its uniform distribution in the myocardium and favorable organ biodistribution demonstrated in preclinical studies. However, a complex and low-efficiency radiosynthesis procedure has significantly hindered its broader preclinical and clinical explorations. Recently, Zhang et al. developed a pinacolyl arylboronate precursor, enabling a one-step synthesis process that greatly streamlines the production of [18F]FBnTP. Building upon this progress, our group successfully adapted the approach to a microdroplet reaction format and demonstrated improved radiosynthesis performance in a preliminary optimization study. However, scaling up to clinical dose amounts was not explored. In this work, we demonstrate that scale-up can be performed in a straightforward manner using a "numbering up" strategy (i.e. performing multiple droplet reactions in parallel and pooling the crude products). The resulting radiochemical yield after purification and formulation was high, up to 66 ± 1% (n = 4) for a set of experiments involving pooling of 4 droplet reactions, accompanied by excellent radiochemical purity (>99%) and molar activity (339-710 GBq μmol-1). Notably, we efficiently achieved sufficient activity yield (0.76-1.84 GBq) for multiple clinical doses from 1.6 to 3.7 GBq of [18F]fluoride in just 37-47 min.
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Affiliation(s)
- Yingqing Lu
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
| | - Jeffrey Collins
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
| | - Kuo-Shyan Lin
- Department of Molecular Oncology, BC Cancer Research Institute, Vancouver, British Columbia, Canada
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
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3
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Mallapura H, Ovdiichuk O, Jussing E, Thuy TA, Piatkowski C, Tanguy L, Collet-Defossez C, Långström B, Halldin C, Nag S. Microfluidic-based production of [ 68Ga]Ga-FAPI-46 and [ 68Ga]Ga-DOTA-TOC using the cassette-based iMiDEV™ microfluidic radiosynthesizer. EJNMMI Radiopharm Chem 2023; 8:42. [PMID: 38091157 PMCID: PMC10719436 DOI: 10.1186/s41181-023-00229-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 12/01/2023] [Indexed: 12/17/2023] Open
Abstract
BACKGROUND The demand for 68Ga-labeled radiotracers has significantly increased in the past decade, driven by the development of diversified imaging tracers, such as FAPI derivatives, PSMA-11, DOTA-TOC, and DOTA-TATE. These tracers have exhibited promising results in theranostic applications, fueling interest in exploring them for clinical use. Among these probes, 68Ga-labeled FAPI-46 and DOTA-TOC have emerged as key players due to their ability to diagnose a broad spectrum of cancers ([68Ga]Ga-FAPI-46) in late-phase studies, whereas [68Ga]Ga-DOTA-TOC is clinically approved for neuroendocrine tumors. To facilitate their production, we leveraged a microfluidic cassette-based iMiDEV radiosynthesizer, enabling the synthesis of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC based on a dose-on-demand (DOD) approach. RESULTS Different mixing techniques were explored to influence radiochemical yield. We achieved decay-corrected yield of 44 ± 5% for [68Ga]Ga-FAPI-46 and 46 ± 7% for [68Ga]Ga-DOTA-TOC in approximately 30 min. The radiochemical purities (HPLC) of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC were 98.2 ± 0.2% and 98.4 ± 0.9%, respectively. All the quality control results complied with European Pharmacopoeia quality standards. We optimized various parameters, including 68Ga trapping and elution, cassette batches, passive mixing in the reactor, and solid-phase extraction (SPE) purification and formulation. The developed synthesis method reduced the amount of precursor and other chemicals required for synthesis compared to conventional radiosynthesizers. CONCLUSIONS The microfluidic-based approach enabled the implementation of radiosynthesis of [68Ga]Ga-FAPI-46 and [68Ga]Ga-DOTA-TOC on the iMiDEV™ microfluidic module, paving the way for their use in preclinical and clinical applications. The microfluidic synthesis approach utilized 2-3 times less precursor than cassette-based conventional synthesis. The synthesis method was also successfully validated in a similar microfluidic iMiDEV module at a different research center for the synthesis of [68Ga]Ga-FAPI-46 with limited runs. Our study demonstrated the potential of microfluidic methods for efficient and reliable radiometal-based radiopharmaceutical synthesis, contributing valuable insights for future advancements in this field and paving the way for routine clinical applications in the near future.
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Affiliation(s)
- Hemantha Mallapura
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-17176, Stockholm, Sweden.
| | - Olga Ovdiichuk
- Nancyclotep, Molecular Imaging Platform, 5 Rue du Morvan, 54500, Vandoeuvre Les Nancy, France
| | - Emma Jussing
- Department of Oncology and Pathology, Karolinska Institutet, 17177, Stockholm, Sweden
- Department of Radiopharmacy, Karolinska University Hospital, 17176, Stockholm, Sweden
| | - Tran A Thuy
- Department of Oncology and Pathology, Karolinska Institutet, 17177, Stockholm, Sweden
- Department of Radiopharmacy, Karolinska University Hospital, 17176, Stockholm, Sweden
| | | | - Laurent Tanguy
- PMB-Alcen, Route des Michels CD56, 13790, Peynier, France
| | - Charlotte Collet-Defossez
- Nancyclotep, Molecular Imaging Platform, 5 Rue du Morvan, 54500, Vandoeuvre Les Nancy, France
- Inserm, IADI, Université de Lorraine, 54000, Nancy, France
| | - Bengt Långström
- Department of Chemistry, Uppsala University, 75123, Uppsala, Sweden
| | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-17176, Stockholm, Sweden
| | - Sangram Nag
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, SE-17176, Stockholm, Sweden
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Coll RP, Bright SJ, Martinus DKJ, Georgiou DK, Sawakuchi GO, Manning HC. Alpha Particle-Emitting Radiopharmaceuticals as Cancer Therapy: Biological Basis, Current Status, and Future Outlook for Therapeutics Discovery. Mol Imaging Biol 2023; 25:991-1019. [PMID: 37845582 DOI: 10.1007/s11307-023-01857-y] [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: 06/26/2023] [Revised: 09/03/2023] [Accepted: 09/05/2023] [Indexed: 10/18/2023]
Abstract
Critical advances in radionuclide therapy have led to encouraging new options for cancer treatment through the pairing of clinically useful radiation-emitting radionuclides and innovative pharmaceutical discovery. Of the various subatomic particles used in therapeutic radiopharmaceuticals, alpha (α) particles show great promise owing to their relatively large size, delivered energy, finite pathlength, and resulting ionization density. This review discusses the therapeutic benefits of α-emitting radiopharmaceuticals and their pairing with appropriate diagnostics, resulting in innovative "theranostic" platforms. Herein, the current landscape of α particle-emitting radionuclides is described with an emphasis on their use in theranostic development for cancer treatment. Commonly studied radionuclides are introduced and recent efforts towards their production for research and clinical use are described. The growing popularity of these radionuclides is explained through summarizing the biological effects of α radiation on cancer cells, which include DNA damage, activation of discrete cell death programs, and downstream immune responses. Examples of efficient α-theranostic design are described with an emphasis on strategies that lead to cellular internalization and the targeting of proteins involved in therapeutic resistance. Historical barriers to the clinical deployment of α-theranostic radiopharmaceuticals are also discussed. Recent progress towards addressing these challenges is presented along with examples of incorporating α-particle therapy in pharmaceutical platforms that can be easily converted into diagnostic counterparts.
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Affiliation(s)
- Ryan P Coll
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA
| | - Scott J Bright
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 6565 MD Anderson Blvd, Houston, TX, 77030, USA
| | - David K J Martinus
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 6565 MD Anderson Blvd, Houston, TX, 77030, USA
| | - Dimitra K Georgiou
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA
| | - Gabriel O Sawakuchi
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, 6565 MD Anderson Blvd, Houston, TX, 77030, USA
| | - H Charles Manning
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA.
- Cyclotron Radiochemistry Facility, The University of Texas MD Anderson Cancer Center, 1881 East Rd, Houston, TX, 77054, USA.
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5
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Lu Y, He Y, Schibli R, Mu L, van Dam RM. Proof-of-concept optimization of a copper-mediated 18F-radiosynthesis of a novel MAGL PET tracer on a high-throughput microdroplet platform and its macroscale translation. LAB ON A CHIP 2023; 23:4652-4663. [PMID: 37818614 PMCID: PMC10608794 DOI: 10.1039/d3lc00735a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
Copper-mediated radiofluorination has demonstrated remarkable potential in forming aromatic C-18F bonds of radioligands for positron emission tomography (PET). Achieving optimal results often requires optimization efforts, requiring a substantial amount of radiolabeling precursor and time, severely limiting the experimental throughput. Recently, we successfully showcased the feasibility of performing and optimizing Cu-mediated radiosynthesis on a high-throughput microdroplet platform using the well-known and clinically used radioligand [18F]FDOPA as an illustrative example. In our current work, we optimized the Cu-mediated synthesis of a novel monoacylglycerol lipase (MAGL) PET tracer ([18F]YH149), showing the versatility of droplet-based techniques for early stage tracer development. Across 5 days, we conducted a total of 117 experiments, studying 36 distinct conditions, while utilizing <15 mg of total organoboron precursor. Compared to the original report in which the radiochemical yield (RCY) was 4.4 ± 0.5% (n = 5), the optimized droplet condition provided a substantial improvement in RCY (52 ± 8%, n = 4) and showed excellent radiochemical purity (100%) and molar activity (77-854 GBq μmol-1), using a starting activity of 0.2-1.45 GBq. Furthermore, we showed for the first time a translation of the optimized microscale conditions to a vial-based method. With similar starting activity (0.2-1.44 GBq), the translated synthesis exhibited a comparable RCY of 50 ± 10% (n = 4) while maintaining excellent radiochemical purity (100%) and acceptable molar activity (20-46 GBq μmol-1). The successful translation to vial-based reactions ensures wider applicability of the optimized synthesis by leveraging widely available commercial vial-based synthesis modules.
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Affiliation(s)
- Yingqing Lu
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
| | - Yingfang He
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Roger Schibli
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - Linjing Mu
- Center for Radiopharmaceutical Sciences, Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zurich, Switzerland
| | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, UCLA, Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
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Jones J, Do V, Lu Y, van Dam RM. Accelerating radiochemistry development: Automated robotic platform for performing up to 64 droplet radiochemical reactions in a morning. CHEMICAL ENGINEERING JOURNAL (LAUSANNE, SWITZERLAND : 1996) 2023; 468:143524. [PMID: 37576334 PMCID: PMC10421640 DOI: 10.1016/j.cej.2023.143524] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
The growing discovery and development of novel radiopharmaceuticals and radiolabeling methods requires an increasing capacity for radiochemistry experiments. However, such studies typically rely on radiosynthesizers designed for clinical batch production rather than research, greatly limiting throughput. Two general solutions are being pursued to address this: developing new synthesis optimization algorithms to minimize how many experiments are needed, and developing apparatus with enhanced experiment throughput. We describe here a novel high-throughput system based on performing arrays of droplet-based reactions at 10 μL volume scale in parallel. The automatic robotic platform can perform a set of 64 experiments in ~3 h (from isotope loading to crude product, plus sampling onto TLC plates), plus ~1 h for off-line radio-TLC analysis and radioactivity measurements, rather than the weeks or months that would be needed using a conventional system. We show the high repeatability and low crosstalk of the platform and demonstrate optimization studies for two 18F-labeled tracers. This novel automated platform greatly increases the practicality of performing arrays of droplet reactions by eliminating human error, vastly reducing tedium and fatigue, minimizing radiation exposure, and freeing up radiochemist time for other intellectually valuable pursuits.
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Affiliation(s)
- Jason Jones
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA),Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA, US
| | - Viviann Do
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA),Los Angeles, CA, USA
- Department of Biochemistry, UCLA, USA
| | - Yingqing Lu
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA),Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA, US
| | - R Michael van Dam
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA),Los Angeles, CA, USA
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, USA
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA, US
- Department of Bioengineering, Henry Samueli School of Engineering and Applied Science, UCLA, USA
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7
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Laferriere-Holloway TS, Rios A, van Dam RM. Detrimental impact of aqueous mobile phases on 18F-labelled radiopharmaceutical analysis via radio-TLC. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:377-387. [PMID: 36542448 PMCID: PMC9891729 DOI: 10.1039/d2ay01206e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The list of new positron-emission tomography (PET) tracers has rapidly grown in the past decade, following discoveries of new biological targets and therapeutic strategies, with several compounds garnering recent regulatory approval for clinical use. During the development of synthesis methods and production of new tracers for imaging, analytical methods for radio-high performance liquid chromatography (radio-HPLC) and radio-thin layer chromatography (radio-TLC) separations need to be developed to assess radiochemical compositions. Radio-TLC is often faster, simpler, and sometimes more accurate than radio-HPLC (as there is no underestimation of [18F]fluoride when analyzing 18F-labeled radiopharmaceuticals). Many protocols have been developed for separating 18F-radiopharmaceuticals on silica TLC plates, typically with [18F]fluoride retained at the origin and the radiopharmaceutical (and impurities) migrating along the plate. Interestingly, many reports describe the use of aqueous conditions to mobilize polar species, but it is known that aqueous conditions can modify silica and alter its chromatographic behavior. In this technical note, we explore the effects that aqueous conditions have on the analysis of 18F-radiopharmaceutical mixtures, revealing that with sufficient water, the radionuclide ([18F]fluoride) can migrate away from the origin and can be split into multiple bands. Furthermore, water can hinder the migration of the radiopharmaceutical. These effects can lead to overlapped bands or reversal of the normally expected order of bands, potentially leading to the misinterpretation of results if care is not taken to validate the TLC method carefully.
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Affiliation(s)
- Travis S Laferriere-Holloway
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Alejandra Rios
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA.
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
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8
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Laferriere-Holloway TS, Rios A, Lu Y, Okoro CC, van Dam RM. A rapid and systematic approach for the optimization of radio thin-layer chromatography resolution. J Chromatogr A 2023; 1687:463656. [PMID: 36463649 PMCID: PMC9894532 DOI: 10.1016/j.chroma.2022.463656] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Radiopharmaceutical analysis is limited by conventional methods. Radio-HPLC may be inaccurate for some compounds (e.g., 18F-radiopharmaceuticals) due to radionuclide sequester. Radio-TLC is simpler, faster, and detects all species but has limited resolution. Imaging-based readout of TLC plates (e.g., using Cerenkov luminescence imaging) can improve readout resolution, but the underlying chromatographic separation efficiency may be insufficient to resolve chemically similar species such as product and precursor-derived impurities. This study applies a systematic mobile phase optimization method, PRISMA, to improve radio-TLC resolution. The PRISMA method optimizes the mobile phase by selecting the correct solvent, optimizing solvent polarity, and optimizing composition. Without prior knowledge of impurities and by simply observing the separation resolution between a radiopharmaceutical and its nearest radioactive or non-radioactive impurities (observed via UV imaging) for different mobile phases, the PRISMA method enabled the development of high-resolution separation conditions for a wide range of 18F-radiopharmaceuticals ( [18F]PBR-06, [18F]FEPPA, [18F]Fallypride, [18F]FPEB, and [18F]FDOPA). Each optimization required a single batch of crude radiopharmaceutical and a few hours. Interestingly, the optimized TLC method provided greater accuracy (compared to other published TLC methods) in determining the product abundance of one radiopharmaceutical studied in more depth ( [18F]Fallypride) and was capable of resolving a comparable number of species as isocratic radio-HPLC. We used the PRISMA-optimized mobile phase for [18F]FPEB in combination with multi-lane radio-TLC techniques to evaluate reaction performance during high-throughput synthesis optimization of [18F]FPEB. The PRISMA methodology, in combination with high-resolution radio-TLC readout, enables a rapid and systematic approach to achieving high-resolution and accurate analysis of radiopharmaceuticals without the need for radio-HPLC.
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Affiliation(s)
- Travis S Laferriere-Holloway
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA; Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA.
| | - Alejandra Rios
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA; Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Yingqing Lu
- Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA; Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Chelsea C Okoro
- Institute for Society and Genetics, UCLA, Los Angeles, CA, USA; Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, USA; Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA; Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA.
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9
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Ahmadi F, Simchi M, Perry JM, Frenette S, Benali H, Soucy JP, Massarweh G, Shih SCC. Integrating machine learning and digital microfluidics for screening experimental conditions. LAB ON A CHIP 2022; 23:81-91. [PMID: 36416045 DOI: 10.1039/d2lc00764a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Digital microfluidics (DMF) has the signatures of an ideal liquid handling platform - as shown through almost two decades of automated biological and chemical assays. However, in the current state of DMF, we are still limited by the number of parallel biological or chemical assays that can be performed on DMF. Here, we report a new approach that leverages design-of-experiment and numerical methodologies to accelerate experimental optimization on DMF. The integration of the one-factor-at-a-time (OFAT) experimental technique with machine learning algorithms provides a set of recommended optimal conditions without the need to perform a large set of experiments. We applied our approach towards optimizing the radiochemistry synthesis yield given the large number of variables that affect the yield. We believe that this work is the first to combine such techniques which can be readily applied to any other assays that contain many parameters and levels on DMF.
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Affiliation(s)
- Fatemeh Ahmadi
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada.
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Mohammad Simchi
- Department of Mechanical & Industrial Engineering, University of Toronto, 5 King's College Rd, Toronto, Ontario, M5S 3G8, Canada
| | - James M Perry
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Stephane Frenette
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Habib Benali
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada.
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
| | - Jean-Paul Soucy
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Québec, H3A 2B4, Canada
| | - Gassan Massarweh
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Québec, H3A 2B4, Canada
| | - Steve C C Shih
- Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec, H3G 1M8, Canada.
- PERFORM Centre, Concordia University, 7200 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
- Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec, H4B 1R6, Canada
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10
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Rapid Purification and Formulation of Radiopharmaceuticals via Thin-Layer Chromatography. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238178. [PMID: 36500272 PMCID: PMC9738419 DOI: 10.3390/molecules27238178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/17/2022] [Accepted: 11/18/2022] [Indexed: 11/25/2022]
Abstract
Before formulating radiopharmaceuticals for injection, it is necessary to remove various impurities via purification. Conventional synthesis methods involve relatively large quantities of reagents, requiring high-resolution and high-capacity chromatographic methods (e.g., semi-preparative radio-HPLC) to ensure adequate purity of the radiopharmaceutical. Due to the use of organic solvents during purification, additional processing is needed to reformulate the radiopharmaceutical into an injectable buffer. Recent developments in microscale radiosynthesis have made it possible to synthesize radiopharmaceuticals with vastly reduced reagent masses, minimizing impurities. This enables purification with lower-capacity methods, such as analytical HPLC, with a reduction of purification time and volume (that shortens downstream re-formulation). Still, the need for a bulky and expensive HPLC system undermines many of the advantages of microfluidics. This study demonstrates the feasibility of using radio-TLC for the purification of radiopharmaceuticals. This technique combines high-performance (high-resolution, high-speed separation) with the advantages of a compact and low-cost setup. A further advantage is that no downstream re-formulation step is needed. Production and purification of clinical scale batches of [18F]PBR-06 and [18F]Fallypride are demonstrated with high yield, purity, and specific activity. Automating this radio-TLC method could provide an attractive solution for the purification step in microscale radiochemistry systems.
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11
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Discovery, nuclear properties, synthesis and applications of technetium-101. Commun Chem 2022; 5:131. [PMID: 36697915 PMCID: PMC9814870 DOI: 10.1038/s42004-022-00746-9] [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: 07/11/2022] [Accepted: 09/29/2022] [Indexed: 01/28/2023] Open
Abstract
Technetium-101 (101Tc) has been poorly studied in comparison with other Tc isotopes, although it was first identified over ~80 years ago shortly after the discovery of the element Tc itself. Its workable half-life and array of production modes, i.e., light/heavy particle reactions, fission, fusion-evaporation, etc., allow it to be produced and isolated using an equally diverse selection of chemical separation pathways. The inherent nuclear properties of 101Tc make it important for research and applications related to radioanalytical tracer studies, as a fission signature, fusion materials, fission reactor fuels, and potentially as a radioisotope for nuclear medicine. In this review, an aggregation of the known literature concerning the chemical, nuclear, and physical properties of 101Tc and some its applications are presented. This work aims at providing an up-to-date and first-of-its-kind overview of 101Tc that could be of importance for further development of the fundamental and applied nuclear and radiochemistry of 101Tc.
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12
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Microliter-scale reaction arrays for economical high-throughput experimentation in radiochemistry. Sci Rep 2022; 12:10263. [PMID: 35715457 PMCID: PMC9205965 DOI: 10.1038/s41598-022-14022-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/31/2022] [Indexed: 01/14/2023] Open
Abstract
The increasing number of positron-emission tomography (PET) tracers being developed to aid drug development and create new diagnostics has led to an increased need for radiosynthesis development and optimization. Current radiosynthesis instruments are designed to produce large-scale clinical batches and are often limited to performing a single synthesis before they must be decontaminated by waiting for radionuclide decay, followed by thorough cleaning or disposal of synthesizer components. Though with some radiosynthesizers it is possible to perform a few sequential radiosyntheses in a day, none allow for parallel radiosyntheses. Throughput of one or a few experiments per day is not well suited for rapid optimization experiments. To combat these limitations, we leverage the advantages of droplet-radiochemistry to create a new platform for high-throughput experimentation in radiochemistry. This system contains an array of 4 heaters, each used to heat a set of 16 reactions on a small chip, enabling 64 parallel reactions for the rapid optimization of conditions in any stage of a multi-step radiosynthesis process. As examples, we study the syntheses of several 18F-labeled radiopharmaceuticals ([18F]Flumazenil, [18F]PBR06, [18F]Fallypride, and [18F]FEPPA), performing > 800 experiments to explore the influence of parameters including base type, base amount, precursor amount, solvent, reaction temperature, and reaction time. The experiments were carried out within only 15 experiment days, and the small volume (~ 10 μL compared to the ~ 1 mL scale of conventional instruments) consumed ~ 100 × less precursor per datapoint. This new method paves the way for more comprehensive optimization studies in radiochemistry and substantially shortening PET tracer development timelines.
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13
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Wang J, van Dam RM. Economical Production of Radiopharmaceuticals for Preclinical Imaging Using Microdroplet Radiochemistry. Methods Mol Biol 2022; 2393:813-828. [PMID: 34837213 DOI: 10.1007/978-1-0716-1803-5_43] [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] [Indexed: 06/13/2023]
Abstract
The short-lived radiolabeled "tracers" needed for performing whole body imaging in animals or patients with positron-emission tomography (PET) are generally produced via automated "radiosynthesizers". Most current radiosynthesizers are designed for routine production of relatively large clinical batches and are very wasteful when only a small batch of a tracer is needed, such as is the case for preclinical in vivo PET imaging studies. To overcome the prohibitively high cost of producing small batches of PET tracers, we developed a droplet microreactor system that performs radiochemistry at the 1-10μL scale instead of the milliliter scale of conventional technologies. The overall yield for the droplet-based production of many PET tracers is comparable to conventional approaches, but 10-100× less reagents are consumed, the synthesis can be completed in much less time (<30 min), and only a small laboratory footprint and minimal radiation shielding are needed. By combining these advantages, droplet microreactors enable the economical production of small batches PET tracers on demand. Here, we describe the fabrication method of the droplet microreactor and the droplet-based synthesis of an example radiotracer ([18F]fallypride).
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA.
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14
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Lisova K, Wang J, Hajagos TJ, Lu Y, Hsiao A, Elizarov A, van Dam RM. Economical droplet-based microfluidic production of [ 18F]FET and [ 18F]Florbetaben suitable for human use. Sci Rep 2021; 11:20636. [PMID: 34667246 PMCID: PMC8526601 DOI: 10.1038/s41598-021-99111-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/26/2021] [Indexed: 01/22/2023] Open
Abstract
Current equipment and methods for preparation of radiopharmaceuticals for positron emission tomography (PET) are expensive and best suited for large-scale multi-doses batches. Microfluidic radiosynthesizers have been shown to provide an economic approach to synthesize these compounds in smaller quantities, but can also be scaled to clinically-relevant levels. Batch microfluidic approaches, in particular, offer significant reduction in system size and reagent consumption. Here we show a simple and rapid technique to concentrate the radioisotope, prior to synthesis in a droplet-based radiosynthesizer, enabling production of clinically-relevant batches of [18F]FET and [18F]FBB. The synthesis was carried out with an automated synthesizer platform based on a disposable Teflon-silicon surface-tension trap chip. Up to 0.1 mL (4 GBq) of radioactivity was used per synthesis by drying cyclotron-produced aqueous [18F]fluoride in small increments directly inside the reaction site. Precursor solution (10 µL) was added to the dried [18F]fluoride, the reaction chip was heated for 5 min to perform radiofluorination, and then a deprotection step was performed with addition of acid solution and heating. The product was recovered in 80 µL volume and transferred to analytical HPLC for purification. Purified product was formulated via evaporation and resuspension or a micro-SPE formulation system. Quality control testing was performed on 3 sequential batches of each tracer. The method afforded production of up to 0.8 GBq of [18F]FET and [18F]FBB. Each production was completed within an hour. All batches passed quality control testing, confirming suitability for human use. In summary, we present a simple and efficient synthesis of clinically-relevant batches of [18F]FET and [18F]FBB using a microfluidic radiosynthesizer. This work demonstrates that the droplet-based micro-radiosynthesizer has a potential for batch-on-demand synthesis of 18F-labeled radiopharmaceuticals for human use.
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Affiliation(s)
- Ksenia Lisova
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Jia Wang
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA
| | | | - Yingqing Lu
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
| | | | | | - R Michael van Dam
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Physics in Biology and Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA.
- Bioengineering Department, University of California Los Angeles, Los Angeles, CA, USA.
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15
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Abstract
18F-fluorination is an important and growing field in organic synthesis that has attracted many chemists in the recent past. Here we present our own, biased perspective with a focus on our own chemistry that evaluates recent advances in the field and provides our opinion on the challenges for the development of new chemistry, so that it may have an impact on imaging. We hope that the manuscript will provide a useful guide to chemists to develop reliable and robust reaction chemistry suitable for radiofluorination to have a real impact on human health.
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Affiliation(s)
- Riya Halder
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Tobias Ritter
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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16
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Ovdiichuk O, Mallapura H, Pineda F, Hourtané V, Långström B, Halldin C, Nag S, Maskali F, Karcher G, Collet C. Implementation of iMiDEV™, a new fully automated microfluidic platform for radiopharmaceutical production. LAB ON A CHIP 2021; 21:2272-2282. [PMID: 33912890 DOI: 10.1039/d1lc00148e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
iMiDEV™ microfluidic system is a new automated tool for a small-scale production of radiopharmaceuticals. This new radiochemistry module utilizes microfluidic cassettes capable of producing diversified radiopharmaceuticals in liquid phase reactions in an automated synthesizer. The user interface is intuitive and designed to give the operator all the information required and to allow driving the synthesis either manually or fully automatically. In this work, we have demonstrated liquid phase reaction and presented the first results of an efficient fully automated [18F]NaF radiosynthesis on the iMiDEV™ platform. Different parameters such as a type of cyclotron targets, initial activity, concentration and volume of the fluoride-18 targetry have been investigated in order to elaborate the optimised radiolabelling of the ligand. Single and double sodium [18F]fluoride synthesis procedures have been successfully developed using two chambers of the cassette. A single-dose of radiotracer was produced in an average radiochemical yield of 87% (decay corrected) within 8 min and quality control tests were performed as per European Pharmacopoeia.
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Affiliation(s)
- Olga Ovdiichuk
- Nancyclotep, Molecular Imaging Platform, 5 rue du Morvan, F-54500 Vandoeuvre les Nancy, France.
| | - Hemantha Mallapura
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Florian Pineda
- PMB Alcen, Route des Michels CD56, F-13790 Peynier, France
| | | | | | - Christer Halldin
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Sangram Nag
- Department of Clinical Neuroscience, Center for Psychiatry Research, Karolinska Institutet and Stockholm County Council, Stockholm 17176, Sweden
| | - Fatiha Maskali
- Nancyclotep, Molecular Imaging Platform, 5 rue du Morvan, F-54500 Vandoeuvre les Nancy, France.
| | - Gilles Karcher
- Nancyclotep, Molecular Imaging Platform, 5 rue du Morvan, F-54500 Vandoeuvre les Nancy, France. and CHRU-Nancy, Department of Nuclear Medicine, F-54000, Vandoeuvre les Nancy, France
| | - Charlotte Collet
- Nancyclotep, Molecular Imaging Platform, 5 rue du Morvan, F-54500 Vandoeuvre les Nancy, France. and INSERM U1254 IADI, Université de Lorraine, F-54500 Vandoeuvre les Nancy, France
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17
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van Dam RM, Chatziioannou AF. Cerenkov Luminescence Imaging in the Development and Production of Radiopharmaceuticals. FRONTIERS IN PHYSICS 2021; 9:632056. [PMID: 36213527 PMCID: PMC9544387 DOI: 10.3389/fphy.2021.632056] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Over the past several years there has been an explosion of interest in exploiting Cerenkov radiation to enable in vivo and intraoperative optical imaging of subjects injected with trace amounts of radiopharmaceuticals. At the same time, Cerenkov luminescence imaging (CLI) also has been serving as a critical tool in radiochemistry, especially for the development of novel microfluidic devices for producing radiopharmaceuticals. By enabling microfluidic processes to be monitored non-destructively in situ, CLI has made it possible to literally watch the activity distribution as the synthesis occurs, and to quantitatively measure activity propagation and losses at each step of synthesis, paving the way for significant strides forward in performance and robustness of those devices. In some cases, CLI has enabled detection and resolution of unexpected problems not observable via standard optical methods. CLI is also being used in analytical radiochemistry to increase the reliability of radio-thin layer chromatography (radio-TLC) assays. Rapid and high-resolution Cerenkov imaging of radio-TLC plates enables detection of issues in the spotting or separation process, improves chromatographic resolution (and/or allows reduced separation distance and time), and enables increased throughput by allowing multiple samples to be spotted side-by-side on a single TLC plate for parallel separation and readout. In combination with new multi-reaction microfluidic chips, this is creating a new possibility for high-throughput optimization in radiochemistry. In this mini review, we provide an overview of the role that CLI has played to date in the radiochemistry side of radiopharmaceuticals.
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Affiliation(s)
- R. Michael van Dam
- UCLA Crump Institute for Molecular Imaging, Los Angeles, CA, United States
- UCLA Department of Molecular and Medical Pharmacology, Los Angeles, CA, United States
| | - Arion F. Chatziioannou
- UCLA Crump Institute for Molecular Imaging, Los Angeles, CA, United States
- UCLA Department of Molecular and Medical Pharmacology, Los Angeles, CA, United States
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18
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Rios A, Holloway TS, Wang J, van Dam RM. Optimization of Radiochemical Reactions using Droplet Arrays. J Vis Exp 2021:10.3791/62056. [PMID: 33645586 PMCID: PMC8253531 DOI: 10.3791/62056] [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] [Indexed: 10/31/2022] Open
Abstract
Current automated radiosynthesizers are designed to produce large clinical batches of radiopharmaceuticals. They are not well suited for reaction optimization or novel radiopharmaceutical development since each data point involves significant reagent consumption, and contamination of the apparatus requires time for radioactive decay before the next use. To address these limitations, a platform for performing arrays of miniature droplet-based reactions in parallel, each confined within a surface-tension trap on a patterned polytetrafluoroethylene-coated silicon "chip", was developed. These chips enable rapid and convenient studies of reaction parameters including reagent concentrations, reaction solvent, reaction temperature and time. This platform permits the completion of hundreds of reactions in a few days with minimal reagent consumption, instead of taking months using a conventional radiosynthesizer.
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Affiliation(s)
- Alejandra Rios
- Physics and Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles (UCLA); Crump Institute of Molecular Imaging, UCLA
| | - Travis S Holloway
- Crump Institute of Molecular Imaging, UCLA; Department of Molecular & Medical Pharmacology, David Geffen School of Medicine
| | - Jia Wang
- Crump Institute of Molecular Imaging, UCLA; Department of Bioengineering, UCLA
| | - R Michael van Dam
- Physics and Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles (UCLA); Crump Institute of Molecular Imaging, UCLA; Department of Molecular & Medical Pharmacology, David Geffen School of Medicine; Department of Bioengineering, UCLA;
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19
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Lisova K, Wang J, Chao PH, van Dam RM. A simple and efficient automated microvolume radiosynthesis of [ 18F]Florbetaben. EJNMMI Radiopharm Chem 2020; 5:30. [PMID: 33275179 PMCID: PMC7718361 DOI: 10.1186/s41181-020-00113-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Current automated radiosynthesizers are generally optimized for producing large batches of PET tracers. Preclinical imaging studies, however, often require only a small portion of a regular batch, which cannot be economically produced on a conventional synthesizer. Alternative approaches are desired to produce small to moderate batches to reduce cost and the amount of reagents and radioisotope needed to produce PET tracers with high molar activity. In this work we describe the first reported microvolume method for production of [18F]Florbetaben for use in imaging of Alzheimer's disease. PROCEDURES The microscale synthesis of [18F]Florbetaben was adapted from conventional-scale synthesis methods. Aqueous [18F]fluoride was azeotropically dried with K2CO3/K222 (275/383 nmol) complex prior to radiofluorination of the Boc-protected precursor (80 nmol) in 10 μL DMSO at 130 °C for 5 min. The resulting intermediate was deprotected with HCl at 90 °C for 3 min and recovered from the chip in aqueous acetonitrile solution. The crude product was purified via analytical scale HPLC and the collected fraction reformulated via solid-phase extraction using a miniature C18 cartridge. RESULTS Starting with 270 ± 100 MBq (n = 3) of [18F]Fluoride, the method affords formulated product with 49 ± 3% (decay-corrected) yield,> 98% radiochemical purity and a molar activity of 338 ± 55 GBq/μmol. The miniature C18 cartridge enables efficient elution with only 150 μL of ethanol which is diluted to a final volume of 1.0 mL, thus providing a sufficient concentration for in vivo imaging. The whole procedure can be completed in 55 min. CONCLUSIONS This work describes an efficient and reliable procedure to produce [18F]Florbetaben in quantities sufficient for large-scale preclinical applications. This method provides very high yields and molar activities compared to reported literature methods. This method can be applied to higher starting activities with special consideration given to automation and radiolysis prevention.
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Affiliation(s)
- Ksenia Lisova
- Physics & Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
| | - Jia Wang
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - Philip H Chao
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA
| | - R Michael van Dam
- Physics & Biology in Medicine Interdepartmental Graduate Program, University of California Los Angeles, Los Angeles, CA, USA.
- Crump Institute for Molecular Imaging, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Molecular & Medical Pharmacology, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Bioengineering, University of California Los Angeles, Los Angeles, CA, USA.
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20
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Iwata R, Terasaki K, Ishikawa Y, Harada R, Furumoto S, Yanai K, Pascali C. A concentration-based microscale method for 18F-nucleophilic substitutions and its testing on the one-pot radiosynthesis of [ 18F]FET and [ 18F]fallypride. Appl Radiat Isot 2020; 166:109361. [PMID: 32877862 DOI: 10.1016/j.apradiso.2020.109361] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/23/2020] [Accepted: 07/27/2020] [Indexed: 10/23/2022]
Abstract
When applied to a radiosynthesis, a microscale approach can help to save precursor and improve yields. Thus, a 5-10 μL microscale method based on a concentration procedure was developed and applied to the radiosynthesis of [18F]FET and [18F]fallypride. In spite of using an amount of precursor ca. 100 times smaller, radiochemical yields were comparable or even higher than those reported in literature. Because of the very low reaction volumes, the possible effects of concentrated dose of activity and carrier fluoride were also investigated.
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Affiliation(s)
- Ren Iwata
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | | | - Yoichi Ishikawa
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Ryuichi Harada
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Shozo Furumoto
- Cyclotron and Radioisotope Center, Tohoku University, Sendai, Japan
| | - Kazuhiko Yanai
- Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Claudio Pascali
- Fondazione IRCCS Istituto Nazionale dei Tumori, V. Venezian, 1, Milan, 20133, Italy.
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21
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Wang J, Holloway T, Lisova K, van Dam RM. Green and efficient synthesis of the radiopharmaceutical [ 18F]FDOPA using a microdroplet reactor. REACT CHEM ENG 2020; 5:320-329. [PMID: 34164154 PMCID: PMC8218909 DOI: 10.1039/c9re00354a] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From an efficiency standpoint, microdroplet reactors enable significant improvements in the preparation of radiopharmaceuticals due to the vastly reduced reaction volume. To demonstrate these advantages, we adapt the conventional (macroscale) synthesis of the clinically-important positron-emission tomography tracer [18F]FDOPA, following the nucleophilic diaryliodonium salt approach, to a newly-developed ultra-compact microdroplet reaction platform. In this first microfluidic implementation of [18F]FDOPA synthesis, optimized via a high-throughput multi-reaction platform, the radiochemical yield (non-decay-corrected) was found to be comparable to macroscale reports, but the synthesis consumed significantly less precursor and organic solvents, and the synthesis process was much faster. In this initial report, we demonstrate the production of [18F]FDOPA in 15 MBq [400 μCi] amounts, sufficient for imaging of multiple mice, at high molar activity.
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Affiliation(s)
- Jia Wang
- Department of Bioengineering, Henry Samueli School of Engineering
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Travis Holloway
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - Ksenia Lisova
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Physics in Biology and Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
| | - R Michael van Dam
- Department of Bioengineering, Henry Samueli School of Engineering
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine
- Physics in Biology and Medicine Interdepartmental Graduate Program, UCLA, Los Angeles, CA, USA
- Crump Institute for Molecular Imaging, UCLA, Los Angeles, CA, USA
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22
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Wang J, van Dam RM. High-Efficiency Production of Radiopharmaceuticals via Droplet Radiochemistry: A Review of Recent Progress. Mol Imaging 2020; 19:1536012120973099. [PMID: 33296272 PMCID: PMC7731702 DOI: 10.1177/1536012120973099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/02/2020] [Accepted: 10/12/2020] [Indexed: 12/13/2022] Open
Abstract
New platforms are enabling radiochemistry to be carried out in tiny, microliter-scale volumes, and this capability has enormous benefits for the production of radiopharmaceuticals. These droplet-based technologies can achieve comparable or better yields compared to conventional methods, but with vastly reduced reagent consumption, shorter synthesis time, higher molar activity (even for low activity batches), faster purification, and ultra-compact system size. We review here the state of the art of this emerging direction, summarize the radiotracers and prosthetic groups that have been synthesized in droplet format, describe recent achievements in scaling up activity levels, and discuss advantages and limitations and the future outlook of these innovative devices.
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Affiliation(s)
- Jia Wang
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
| | - R. Michael van Dam
- Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA, Los Angeles, CA, USA
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23
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Wang J, Chao PH, Slavik R, van Dam RM. Multi-GBq production of the radiotracer [18F]fallypride in a droplet microreactor. RSC Adv 2020; 10:7828-7838. [PMID: 35492189 PMCID: PMC9049805 DOI: 10.1039/d0ra01212b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 02/11/2020] [Indexed: 12/17/2022] Open
Abstract
Microfluidics offers numerous advantages for the synthesis of short-lived radiolabeled imaging tracers: performing 18F-radiosyntheses in microliter-scale droplets has exhibited high efficiency, speed, and molar activity as well as low reagent consumption. However, most reports have been at the preclinical scale. In this study we integrate a [18F]fluoride concentrator and a microdroplet synthesizer to explore the possibility of synthesizing patient doses and multi-patient batches of clinically-acceptable tracers. In the integrated system, [18F]fluoride (up to 41 GBq [1.1 Ci]) in [18O]H2O (1 mL) was first concentrated ∼80-fold and then efficiently transferred to the 8 μL reaction chip as a series of small (∼0.5 μL) droplets. Each droplet rapidly dried at the reaction site of the pre-heated chip, resulting in localized accumulation of large amounts of radioactivity in the form of dried [18F]TBAF complex. The PET tracer [18F]fallypride was synthesized from this concentrated activity in an overall synthesis time of ∼50 min (including radioisotope concentration and transfer, droplet radiosynthesis, purification, and formulation), in amounts up to 7.2 GBq [0.19 Ci], sufficient for multiple clinical PET scans. The resulting batches of [18F]fallypride passed all QC tests needed to ensure safety for clinical injection. This integrated technology enabled for the first time the impact of a wide range of activity levels on droplet radiosynthesis to be studied. Furthermore, this substantial increase in scale expands the applications of droplet radiosynthesis to the production of clinically-relevant amounts of radiopharmaceuticals, and potentially even centralized production of clinical tracers in radiopharmacies. The overall system could be applied to fundamental studies of droplet-based radiochemical reactions, or to the production of radiopharmaceuticals labeled with a variety of isotopes used for imaging and/or targeted radiotherapeutics. Using a micro-cartridge based radionuclide concentrator enables the production of multiple (10 s) of clinical doses of the PET tracer [18F]fallypride with a droplet micro-reactor platform (8 μL).![]()
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Affiliation(s)
- Jia Wang
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
| | - Philip H. Chao
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
| | - Roger Slavik
- Ahmanson Translational Imaging Division
- David Geffen School of Medicine
- University of California
- Los Angeles
- USA
| | - R. Michael van Dam
- Department of Bioengineering
- Henry Samueli School of Engineering
- UCLA
- Los Angeles
- USA
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Frank C, Winter G, Rensei F, Samper V, Brooks AF, Hockley BG, Henderson BD, Rensch C, Scott PJH. Development and implementation of ISAR, a new synthesis platform for radiopharmaceutical production. EJNMMI Radiopharm Chem 2019; 4:24. [PMID: 31659546 PMCID: PMC6751239 DOI: 10.1186/s41181-019-0077-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 08/30/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND PET radiopharmaceutical development and the implementation of a production method on a synthesis module is a complex and time-intensive task since new synthesis methods must be adapted to the confines of the synthesis platform in use. Commonly utilized single fluid bus architectures put multiple constraints on synthesis planning and execution, while conventional microfluidic solutions are limited by compatibility at the macro-to-micro interface. In this work we introduce the ISAR synthesis platform and custom-tailored fluid paths leveraging up to 70 individually addressable valves on a chip-based consumable. The ISAR synthesis platform replaces traditional stopcock valve manifolds with a fluidic chip that integrates all fluid paths (tubing) and valves into one consumable and enables channel routing without the single fluid bus constraint. ISAR can scale between the macro- (10 mL), meso- (0.5 mL) and micro- (≤0.05 mL) domain seamlessly, addressing the macro-to-micro interface challenge and enabling custom tailored fluid circuits for a given application. In this paper we demonstrate proof-of-concept by validating a single chip design to address the challenge of synthesizing multiple batches of [13N]NH3 for clinical use throughout the workday. RESULTS ISAR was installed at an academic PET Center and used to manufacture [13N]NH3 in > 96% radiochemical yield. Up to 9 batches were manufactured with a single consumable chip having parallel paths without the need to open the hot-cell. Quality control testing confirmed the ISAR-based [13N]NH3 met existing clinical release specifications, and utility was demonstrated by imaging a rodent with [13N]NH3 produced on ISAR. CONCLUSIONS ISAR represents a new paradigm in radiopharmaceutical production. Through a new system architecture, ISAR integrates the principles of microfluidics with the standard volumes and consumables established in PET Centers all over the world. Proof-of-concept has been demonstrated through validation of a chip design for the synthesis of [13N]NH3 suitable for clinical use.
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Affiliation(s)
| | - Georg Winter
- GE Healthcare, Oskar-Schlemmer-Str. 11, 80807 Munich, Germany
| | | | | | - Allen F. Brooks
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI 48109 USA
| | - Brian G. Hockley
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI 48109 USA
| | - Bradford D. Henderson
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI 48109 USA
| | | | - Peter J. H. Scott
- Department of Radiology, University of Michigan, 2276 Medical Science Bldg I, SPC 5610, Ann Arbor, MI 48109 USA
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Rios A, Wang J, Chao PH, van Dam RM. A novel multi-reaction microdroplet platform for rapid radiochemistry optimization. RSC Adv 2019; 9:20370-20374. [PMID: 35514735 PMCID: PMC9065505 DOI: 10.1039/c9ra03639c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 06/17/2019] [Indexed: 12/20/2022] Open
Abstract
During the development of novel tracers for positron emission tomography (PET), the optimization of the synthesis is hindered by practical limitations on the number of experiments that can be performed per day. Here we present a microliter droplet chip that contains multiple sites (4 or 16) to perform reactions simultaneously under the same or different conditions to accelerate radiosynthesis optimization. Multi-reaction microdroplet chip enables rapid radiotracer optimization for positron emission tomography.![]()
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Affiliation(s)
- Alejandra Rios
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA
| | - Jia Wang
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - Philip H Chao
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Department of Bioengineering, UCLA USA
| | - R Michael van Dam
- Crump Institute of Molecular Imaging, University of California Los Angeles (UCLA) Los Angeles CA USA .,Physics and Biology in Medicine Interdepartmental Graduate Program, UCLA USA.,Department of Bioengineering, UCLA USA.,Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, UCLA USA
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Kim HK, Javed MR, Chen S, Zettlitz KA, Collins J, Wu AM, Kim CJ“CJ, Michael van Dam R, Keng PY. On-demand radiosynthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) on an electrowetting-on-dielectric microfluidic chip for 18F-labeling of protein. RSC Adv 2019; 9:32175-32183. [PMID: 35530758 PMCID: PMC9072849 DOI: 10.1039/c9ra06158d] [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: 08/08/2019] [Accepted: 09/17/2019] [Indexed: 12/16/2022] Open
Abstract
An all-electronic, droplet-based batch microfluidic device, operated using the electrowetting on dielectric (EWOD) mechanism was developed for on-demand synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB), the most commonly used 18F-prosthetic group for biomolecule labeling. In order to facilitate the development of peptides, and proteins as new diagnostic and therapeutic agents, we have diversified the compact EWOD microfluidic platform to perform the three-step radiosynthesis of [18F]SFB starting from the no carrier added [18F]fluoride ion. In this report, we established an optimal microliter droplet reaction condition to obtain reliable yields and synthesized [18F]SFB with sufficient radioactivity for subsequent conjugation to the anti-PSCA cys-diabody (A2cDb) and for small animal imaging. The three-step, one-pot radiosynthesis of [18F]SFB radiochemistry was adapted to a batch microfluidic platform with a reaction droplet sandwiched between two parallel plates of an EWOD chip, and optimized. Specifically, the ratio of precursor to base, droplet volume, reagent concentration, reaction time, and evaporation time were found be to be critical parameters. [18F]SFB was successfully synthesized on the EWOD chip in 39 ± 7% (n = 4) radiochemical yield in a total synthesis time of ∼120 min ([18F]fluoride activation, [18F]fluorination, hydrolysis, and coupling reaction, HPLC purification, drying and reformulation). The reformulation and stabilization step for [18F]SFB was important to obtain a high protein labeling efficiency of 33.1 ± 12.5% (n = 3). A small-animal immunoPET pilot study demonstrated that the [18F]SFB-PSCA diabody conjugate showed specific uptake in the PSCA-positive human prostate cancer xenograft. The successful development of a compact footprint of the EWOD radiosynthesizer has the potential to empower biologists to produce PET probes of interest themselves in a standard laboratory. An all-electronic, droplet-based batch microfluidic device, operated using the electrowetting on dielectric (EWOD) mechanism was developed for on-demand synthesis of acommonly used 18F-prosthetic group for biomolecule labeling.![]()
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Affiliation(s)
- Hee-Kwon Kim
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Muhammad Rashed Javed
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Supin Chen
- Department of Materials Science and Engineering
- National Tsing Hua University
- Hsinchu
- Taiwan
| | - Kirstin A. Zettlitz
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Jeffrey Collins
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Anna M. Wu
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Chang-Jin “C. J.” Kim
- Bioengineering Department
- University of California, Los Angeles
- Los Angeles
- USA
- Mechanical and Aerospace Engineering Department
| | - R. Michael van Dam
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
| | - Pei Yuin Keng
- Department of Molecular and Medical Pharmacology
- University of California, Los Angeles
- Los Angeles
- USA
- Crump Institute for Molecular Imaging
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