Carbon-11 Methylation
Carbon-11 Methylation - Related Videos
09:25
Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers
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Cited by 1 •
2019
We report an efficient carbon-11 radiolabeling technique to produce clinically relevant tracers for Positron Emission Tomography (PET) using solid phase extraction cartridges. 11C-methylating agent is passed through a cartridge preloaded with precursor and successive elution with aqueous ethanol provides chemically and radiochemically pure PET tracers in high radiochemical yields.
09:08
Enhancing Efficiency and Radiolabeling Yields of Carbon-11 Radioligands for Clinical Research Using the Loop Method
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2024
This protocol presents a detailed procedure to prepare four carbon-11 radiotracers by way of the “loop method” [11C]methylation. We describe the procedure to synthesize [11C]ER-176, with data for three additional radiotracers: [11C]MRB, [11C]mHED, and [11C]PiB. The loop method provides an efficient synthesis with increased radiochemical yields against traditional reaction vessel [11C]methylation.
08:47
DNA Methylation Analysis
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2023
Methylation at CpG dinucleotides is a chemical modification of DNA hypothesized to play important roles in regulating gene expression. In particular, the methylation of clusters of methylation sites, called “CpG islands”, near promoters and other gene regulatory elements may contribute to the stable silencing of genes, for example, during epigenetic processes such as genomic imprinting and X-chromosome inactivation. At the same time, aberrant CpG methylation has been shown to be associated with...
21:24
Methylated DNA Immunoprecipitation
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Cited by 43 •
2009
This video demonstrates the protocol for methylated DNA immunoprecipitation (MeDIP). MeDIP is a two day procedure that selectively extracts methylated DNA fragments from a genomic DNA sample using antibodies with specificity for 5 -methylcytosine (anti-5 mC).
08:40
Methyl-binding DNA capture Sequencing for Patient Tissues
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Cited by 1 •
2016
Here we present a protocol to investigate genome wide DNA methylation in large scale clinical patient screening studies using the Methyl-Binding DNA Capture sequencing (MBDCap-seq or MBD-seq) technology and the subsequent bioinformatics analysis pipeline.
FAQs
The key bond-forming step is nucleophilic substitution: a nucleophilic precursor attacks the methyl group carried by [11C]methyl iodide or [11C]methyl triflate. This transfers the radioactive methyl group onto the target molecule, allowing the precursor’s existing chemical framework to become a labeled tracer. The reaction therefore focuses labeling at a defined methylation site.
Because carbon-11’s 20.4-minute half-life continuously reduces the available activity after production. The synthesis must therefore move quickly from cyclotron-produced material through precursor methylation and tracer preparation. Efficient processing is not merely convenient: it helps retain enough radioactive product for PET measurement. Automation can coordinate this sequence with consistent timing and reduced handling delays.
[11C]methyl iodide and [11C]methyl triflate are the two carbon-11 methylating forms identified for this synthesis. Each supplies the radioactive methyl group that reacts with a nucleophilic precursor. The source material does not assign them different biological functions; their shared role is to provide a chemical intermediate between cyclotron production and incorporation of carbon-11 into the final molecule.
Preserving the labeled compound’s chemical behavior matters because the tracer should remain a biologically active compound capable of reflecting interactions with its intended molecular target. Carbon-11 methylation supports this goal by adding the isotope to an organic molecule while retaining the broader structure responsible for its biological activity. This makes the resulting signal relevant to molecular function rather than merely isotope presence.
A typical workflow begins with cyclotron production of carbon-11, followed by conversion into [11C]methyl iodide or [11C]methyl triflate. The selected intermediate then reacts with a nucleophilic precursor through a rapid substitution reaction. Subsequent tracer preparation must be completed efficiently because the isotope’s short half-life limits the available time for synthesis and use.
Automation is important because carbon-11’s activity decreases during every handling and transfer step. An automated system can connect production, conversion of the isotope into a methylating intermediate, and reaction with the nucleophilic precursor in a tightly timed sequence. This reduces delays associated with manual operations and supports reproducible preparation for PET studies.
The resulting tracers can support PET investigations of receptors, enzymes, transporters, and drug distribution. Because labeling occurs on biologically active organic compounds, the method connects molecular synthesis with noninvasive measurement of where compounds go and how molecular systems function in living subjects. These applications make the approach useful for studying molecular recognition and pharmacological behavior.
In chemistry, the method illustrates how isotope production, organic reactivity, and tracer design operate as one workflow. The methylation reaction supplies a specific route for attaching carbon-11, while PET uses the labeled molecule to investigate biological targets or distribution. Its value lies in linking a controlled chemical transformation to an observable molecular outcome in living systems.