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Custom Synthesis & Conjugation Services for NHS Ester Chemistry
Custom NHS Ester Synthesis and Fluorescent Conjugation Services
Custom NHS ester synthesis covers the design and preparation of N-hydroxysuccinimide activated esters that are not available as standard catalog reagents. Researchers working with novel fluorescent dye scaffolds, specialized linker systems, PEG spacers, sulfo-modified dye versions, or multi-functional reagents often need a chemistry partner that can activate a carboxylic acid dye, purify the reactive ester, characterize it fully, and supply it in the quantity and format required for downstream conjugation.
This guide explains when custom NHS ester reagents are needed, how custom synthesis is performed and characterized, what conjugation services typically include, how projects progress from consultation to delivery, how quality is controlled, and how providers support scale-up from milligrams to kilograms.
What Can BOC Sciences Help You Solve?
Need a dye that is not sold as an NHS ester?
Custom activation of a novel dye scaffold or intermediate into a purified, amine-reactive NHS ester reagent.
Catalog reagents do not fit your linker or spacer needs?
Design and build specialized linkers, PEG spacers, and heterobifunctional architectures around your dye and target.
Struggling with poor solubility or labeling efficiency?
Develop sulfo-NHS versions and water-soluble formats, and optimize conjugation conditions for your biomolecule.
Need labeled conjugates with controlled quality?
Custom fluorescent conjugation for proteins, antibodies, peptides, oligonucleotides, small molecules, and nanoparticles.
Moving from discovery amounts to larger batches?
Scale custom NHS ester synthesis from milligram research batches to kilogram supply with consistent quality.
Overview: Custom NHS Ester Synthesis and Conjugation Services
NHS esters are amine-reactive activated carboxylic acids that form stable amide bonds with primary amines. In practice, the majority of fluorescent labeling projects start with a catalog NHS ester dye. However, many research programs require reagents that do not exist in standard catalogs: a newly reported fluorophore, a dye with a special spacer, a water-soluble sulfo version, a bifunctional probe, or a conjugate of a difficult biomolecule. Custom NHS ester synthesis and fluorescent conjugation services close this gap by turning a chemical need into a characterized reagent or conjugate that can be used directly in the assay.
A custom NHS ester project typically starts with a carboxylate-containing dye or intermediate, activates it with EDC/NHS or an uronium reagent, and purifies the product by HPLC before characterizing it by LC-MS and NMR. The finished reagent can then be used for conjugation, either by the researcher or by the service provider, to prepare labeled proteins, antibodies, peptides, oligonucleotides, small molecules, and nanoparticles.
This article covers why researchers need custom NHS ester reagents, the synthesis and purification routes available, the classes of fluorescent conjugates that can be prepared, the standard project workflow, quality assurance measures, and scale-up from milligrams to kilograms.
Core principle:
The value of a custom NHS ester reagent lies in its active ester content and stability, not just its chemical purity. A reagent that has partially
hydrolyzed back to the free carboxylic acid will label inefficiently regardless of how clean it appears by chromatography. Custom synthesis programs
therefore combine synthetic chemistry, purification, quantitative characterization, and controlled handling so that the reagent arrives at the
conjugation step in a usable form.
Why Custom NHS Ester Reagents Are Needed
Catalog NHS ester reagents cover the most common fluorescent dyes and linker formats, but many research and development projects need structures that fall outside standard catalogs. The reasons range from chemistry requirements, such as a new dye scaffold or a longer PEG spacer, to practical constraints, such as the need for a water-soluble sulfo version or a reagent with two reactive groups in one molecule.
Novel dye scaffolds:
When a research group develops or selects a new fluorophore, it is rarely available as an NHS ester. Custom activation converts the dye carboxylate into an amine-reactive reagent so the new scaffold can be tested in labeling experiments.
When a research group develops or selects a new fluorophore, it is rarely available as an NHS ester. Custom activation converts the dye carboxylate into an amine-reactive reagent so the new scaffold can be tested in labeling experiments.
Specialized linkers:
Some assays require a defined distance or a cleavable connection between the dye and the biomolecule. Custom synthesis can place an NHS ester at the end of a tailored linker rather than relying on a fixed catalog structure.
Some assays require a defined distance or a cleavable connection between the dye and the biomolecule. Custom synthesis can place an NHS ester at the end of a tailored linker rather than relying on a fixed catalog structure.
PEG spacers:
PEG spacers improve aqueous solubility, reduce aggregation, and increase conjugate flexibility. A custom PEG-NHS ester with a chosen chain length is often needed when the standard reagent is too short or too hydrophobic.
PEG spacers improve aqueous solubility, reduce aggregation, and increase conjugate flexibility. A custom PEG-NHS ester with a chosen chain length is often needed when the standard reagent is too short or too hydrophobic.
Sulfo versions for water solubility:
Hydrophobic dyes can be converted into sulfonated, water-soluble versions. The sulfonate group is introduced on the dye or linker before NHS activation.
Hydrophobic dyes can be converted into sulfonated, water-soluble versions. The sulfonate group is introduced on the dye or linker before NHS activation.
Multi-functional reagents:
Probes that carry both an NHS ester and a second handle, such as an azide, alkyne, maleimide, or biotin, enable two-step conjugation and dual detection strategies.
Probes that carry both an NHS ester and a second handle, such as an azide, alkyne, maleimide, or biotin, enable two-step conjugation and dual detection strategies.
Format and quantity flexibility:
Catalog products come in fixed formats and pack sizes. Custom programs can supply the reagent as a solid, a stock solution, or a pre-aliquoted set, in quantities from single-use milligrams to bulk kilograms.
Catalog products come in fixed formats and pack sizes. Custom programs can supply the reagent as a solid, a stock solution, or a pre-aliquoted set, in quantities from single-use milligrams to bulk kilograms.
Note:
Custom NHS ester work does not replace the standard
NHS ester products
that cover routine fluorescent labeling needs. It extends the same chemistry to structures and formats that are not otherwise available, and it
connects directly to broader
bioconjugation
workflows when linkers, spacers, and multi-functional reagents are required.
Custom NHS Ester Synthesis Capabilities
The preparation of a custom NHS ester follows a well-established sequence: activate the carboxylic acid, isolate the activated ester, purify it, and characterize it. The difficulty varies with the dye scaffold, the linker, and the solubility of the intermediates.
Carboxylate activation with EDC/NHS:
The carboxylic acid is treated with EDC in the presence of N-hydroxysuccinimide in anhydrous solvent. This is the most common route for dye carboxylates and tolerates the functional groups found in most fluorescent scaffolds.
The carboxylic acid is treated with EDC in the presence of N-hydroxysuccinimide in anhydrous solvent. This is the most common route for dye carboxylates and tolerates the functional groups found in most fluorescent scaffolds.
Uronium reagent activation:
Coupling reagents such as HATU or TSTU provide fast, high-yield activation, particularly for hindered or electron-poor carboxylic acids where carbodiimide activation is slow.
Coupling reagents such as HATU or TSTU provide fast, high-yield activation, particularly for hindered or electron-poor carboxylic acids where carbodiimide activation is slow.
Sulfonation and sulfo-NHS design:
For water-soluble reagents, a sulfonate group is introduced on the dye or linker, and the corresponding sulfo-NHS ester is prepared so that the conjugate can be made without organic co-solvents.
For water-soluble reagents, a sulfonate group is introduced on the dye or linker, and the corresponding sulfo-NHS ester is prepared so that the conjugate can be made without organic co-solvents.
Purification by HPLC:
Preparative HPLC is the standard purification tool because it separates the desired NHS ester from the free acid, urea byproducts, and hydrolyzed material. Fractions are pooled and dried under controlled conditions.
Preparative HPLC is the standard purification tool because it separates the desired NHS ester from the free acid, urea byproducts, and hydrolyzed material. Fractions are pooled and dried under controlled conditions.
Characterization by LC-MS and NMR:
LC-MS confirms the molecular weight of the activated ester, and NMR confirms the succinimide protons and the overall structure.
LC-MS confirms the molecular weight of the activated ester, and NMR confirms the succinimide protons and the overall structure.
Moisture-controlled handling and storage:
NHS esters hydrolyze in the presence of water. Custom reagents are dried, packaged under inert gas, and stored at low temperature with desiccant.
NHS esters hydrolyze in the presence of water. Custom reagents are dried, packaged under inert gas, and stored at low temperature with desiccant.
| Activation Route | Reagents | Best Used For | Key Considerations |
|---|---|---|---|
| Carbodiimide activation | EDC with N-hydroxysuccinimide | Standard dye carboxylates and linker acids | Moisture control; urea byproduct removed by extraction or HPLC. |
| Uronium salt activation | HATU or TSTU with an amine base | Hindered, electron-poor, or complex acids | Fast activation; base and time optimized; HPLC purification required. |
| Sulfo-NHS preparation | Sulfonation step followed by activation | Water-soluble reagent versions | Adds charged group; salt form and counterion controlled. |
| One-pot conjugation | EDC/NHS in aqueous buffer with the biomolecule | Simple conjugates where isolation is unnecessary | Lower efficiency and more side products; rarely used for quality-critical conjugates. |
Once the custom NHS ester is in hand, the conjugation step follows the same amine-reactive chemistry described for catalog reagents. Review NHS ester reagents for fluorescent labeling to align custom reagent design with conjugation conditions.
Custom Fluorescent Conjugation Services
Custom fluorescent conjugation services use the prepared NHS ester dye, or a selected catalog dye, to label a target molecule under controlled conditions. The service is most valuable when the target is scarce, the degree of labeling must be tightly controlled, or the buffer system is difficult.
Protein Conjugation
NHS ester dyes label lysine side chains and the N-terminus of proteins. Custom services can prepare fluorescent enzymes, receptors, and other proteins for binding studies and tracking while monitoring activity retention.
Antibody Conjugation
Antibody conjugates are prepared with a controlled dye-to-antibody ratio to preserve antigen binding and minimize background. Custom services can use FITC, rhodamine, cyanine, TAMRA, BODIPY, and coumarin derivatives as needed.
Peptide Conjugation
Peptides are labeled at the N-terminus or at lysine residues. Custom conjugation can be directed toward a chosen position to avoid disrupting a receptor-binding motif, and the labeled product is purified to homogeneity.
Oligonucleotide Conjugation
Amino-modified oligonucleotides react with NHS ester dyes to form probes for qPCR, FISH, microarrays, and other nucleic acid detection workflows. Label position and hybridization performance are verified.
Small Molecule Conjugation
Amine-containing small molecules, including drug-like scaffolds and probe intermediates, can be conjugated to fluorescent dyes to produce tracers and assay reagents for research.
Nanoparticle and Bead Conjugation
Amine-presenting nanoparticles and beads are functionalized with NHS ester dyes for imaging, capture, and multiplexed detection. Surface dye density and colloidal stability are controlled.
| Target Molecule | Reactive Site | Typical Use of the Conjugate | Key Quality Parameter |
|---|---|---|---|
| Protein | Lysine and N-terminus | Fluorescent enzymes and receptors for binding and tracking studies | Degree of labeling and activity retention |
| Antibody | Lysine and N-terminus | Detection reagents for immunofluorescence and flow cytometry | Controlled DOL and antigen binding retention |
| Peptide | N-terminus, lysine | Receptor binding and cellular uptake probes | Label position and peptide purity |
| Oligonucleotide | Amino-modified base or terminal amine | qPCR probes, FISH probes, microarray detection | Hybridization efficiency and label position |
| Small molecule | Primary amine | Tracers and assay probes | Purity and photophysical properties |
| Nanoparticle | Surface amine | Imaging agents and capture reagents | Surface dye density and colloidal stability |
Custom conjugation can be combined with specialized surfaces and particles. fluorescent labeling services cover proteins and antibodies, while fluorescent bead services, fluorescent nanoparticle services, and fluorescent protein labeling services address particle-based and protein conjugate formats.
Project Workflow: From Consultation to Delivery
A custom NHS ester synthesis or conjugation project follows a structured path from a conversation about the chemistry to a delivered reagent or conjugate plus supporting data.
Step 1: Consultation
The researcher describes the dye, the linker, the target molecule, the quantity, and the intended application. This discussion defines what the reagent must do in the final assay.
The researcher describes the dye, the linker, the target molecule, the quantity, and the intended application. This discussion defines what the reagent must do in the final assay.
Step 2: Feasibility assessment
The provider evaluates the starting materials, the proposed route, the expected difficulty of activation and purification, and the timeline. A feasibility note summarizes the proposed route and its risks.
The provider evaluates the starting materials, the proposed route, the expected difficulty of activation and purification, and the timeline. A feasibility note summarizes the proposed route and its risks.
Step 3: Synthesis and purification
The custom NHS ester is prepared, purified by preparative HPLC, and dried under conditions that preserve the active ester.
The custom NHS ester is prepared, purified by preparative HPLC, and dried under conditions that preserve the active ester.
Step 4: Characterization and QC
The final reagent is characterized by LC-MS and NMR, and the active ester content is checked. A certificate of analysis is issued.
The final reagent is characterized by LC-MS and NMR, and the active ester content is checked. A certificate of analysis is issued.
Step 5: Conjugation and purification
If a conjugate is requested, the NHS ester is reacted with the target molecule under optimized pH, ratio, and buffer conditions, and the conjugate is purified to remove free dye.
If a conjugate is requested, the NHS ester is reacted with the target molecule under optimized pH, ratio, and buffer conditions, and the conjugate is purified to remove free dye.
Step 6: Delivery and documentation
The reagent or conjugate is shipped with batch records, analytical data, storage recommendations, and handling instructions.
The reagent or conjugate is shipped with batch records, analytical data, storage recommendations, and handling instructions.
Quality Assurance for Custom Reagents and Conjugates
Quality assurance in custom NHS ester projects covers both the reagent and the conjugate. For the reagent, the critical metrics are chemical purity and active ester content. For the conjugate, the critical metrics are the degree of labeling and the retention of biological activity.
Purity by HPLC:
The reagent is analyzed by reverse-phase HPLC with UV detection. Typical acceptance is 95 percent or higher, with any residual free acid quantified.
The reagent is analyzed by reverse-phase HPLC with UV detection. Typical acceptance is 95 percent or higher, with any residual free acid quantified.
Active ester content:
Because hydrolyzed material is unreactive, the active ester fraction is estimated from LC-MS and, for dyes with known extinction coefficients, from absorbance at the dye maximum.
Because hydrolyzed material is unreactive, the active ester fraction is estimated from LC-MS and, for dyes with known extinction coefficients, from absorbance at the dye maximum.
Degree of labeling control:
For conjugates, DOL is calculated from the absorbance ratio of dye to protein or nucleic acid. The service targets a defined DOL window rather than simply maximizing dye loading.
For conjugates, DOL is calculated from the absorbance ratio of dye to protein or nucleic acid. The service targets a defined DOL window rather than simply maximizing dye loading.
Activity validation:
Conjugates are tested in a binding or functional assay appropriate to the target, such as an antibody binding check, to confirm that labeling did not destroy function.
Conjugates are tested in a binding or functional assay appropriate to the target, such as an antibody binding check, to confirm that labeling did not destroy function.
Batch records:
Each batch receives documentation covering the synthetic route, purification data, analytical results, and storage instructions, which is essential for reproducibility and later scale-up.
Each batch receives documentation covering the synthetic route, purification data, analytical results, and storage instructions, which is essential for reproducibility and later scale-up.
| QC Test | Method | Typical Acceptance |
|---|---|---|
| Chemical purity | HPLC-UV | 95 percent or higher for the main peak |
| Identity | LC-MS and NMR | Molecular weight and structure confirmed |
| Active ester content | LC-MS plus absorbance at the dye maximum | Matches label claim within an agreed tolerance |
| Degree of labeling | UV-Vis absorbance ratio | Within the target DOL window for the application |
| Conjugate activity | Binding or functional assay | Retains expected activity compared with the unlabeled control |
DOL control is the most frequently discussed quality topic in custom conjugation, and it applies to every target molecule class. Fluorescent dyes for protein labeling explains how dye choice, ratio, and buffer conditions combine to determine the final labeling density.
Scale-Up: From Milligrams to Kilograms
Custom NHS ester projects often start as a small research batch and later need to be produced in larger quantities for extended studies, panel production, or preclinical programs. Scale-up is not a simple multiplication of the recipe. It requires process control, impurity tracking, and batch consistency checks because reaction time, mixing, and drying behavior change with batch size.
Batch consistency:
Each scaled batch is compared with the reference batch on purity, active ester content, and performance in a standard labeling test so that larger quantities behave like the material validated earlier.
Each scaled batch is compared with the reference batch on purity, active ester content, and performance in a standard labeling test so that larger quantities behave like the material validated earlier.
Process control:
Activation time, temperature, reagent equivalents, and drying conditions are locked down at pilot scale and monitored during production to keep the active ester intact.
Activation time, temperature, reagent equivalents, and drying conditions are locked down at pilot scale and monitored during production to keep the active ester intact.
Impurity control:
Residual coupling reagents, urea byproducts, and hydrolyzed acid are tracked at each scale. HPLC methods developed at milligram scale are revalidated for larger batches.
Residual coupling reagents, urea byproducts, and hydrolyzed acid are tracked at each scale. HPLC methods developed at milligram scale are revalidated for larger batches.
Packaging and stability:
Larger batches are packaged in moisture-protected containers under inert gas, with stability data to support the recommended storage window.
Larger batches are packaged in moisture-protected containers under inert gas, with stability data to support the recommended storage window.
| Scale Stage | Typical Quantity | Primary Focus |
|---|---|---|
| Research grade | Milligram scale (5 to 100 mg) | Route validation, feasibility, and analytical development |
| Pilot scale | Gram scale (0.1 to 100 g) | Process refinement, impurity control, and batch consistency |
| Production scale | Kilogram scale | Reproducible manufacturing, documentation, and bulk packaging |
Need a Custom NHS Ester Reagent or Conjugate for Your Research?
BOC Sciences can support custom NHS ester synthesis, dye activation, sulfo-NHS development, linker design, and fluorescent conjugation, with analytical data delivered alongside every batch.
Request Custom Synthesis and Conjugation SupportHow to Engage a Custom Synthesis and Conjugation Service Provider
Working with a service provider is straightforward when the researcher comes prepared with key information about the target molecule, the dye, and the intended application.
Step 1: Define the scope
Write down the dye scaffold or intermediate, the desired NHS ester or sulfo-NHS format, the linker or spacer, the target molecule for conjugation, and the required quantity and purity.
Write down the dye scaffold or intermediate, the desired NHS ester or sulfo-NHS format, the linker or spacer, the target molecule for conjugation, and the required quantity and purity.
Step 2: Share the specifications
Send the structure or the closest available reference structure, any relevant spectra, the buffer system, and the assay in which the reagent will be used. This drives the feasibility review.
Send the structure or the closest available reference structure, any relevant spectra, the buffer system, and the assay in which the reagent will be used. This drives the feasibility review.
Step 3: Receive a feasibility note and quote
The provider responds with a proposed route, an estimated timeline, the expected deliverables, and a quote covering synthesis, purification, and characterization.
The provider responds with a proposed route, an estimated timeline, the expected deliverables, and a quote covering synthesis, purification, and characterization.
Step 4: Review and approve the plan
The researcher confirms the route, the QC panel, the target DOL if a conjugate is requested, and the delivery format.
The researcher confirms the route, the QC panel, the target DOL if a conjugate is requested, and the delivery format.
Step 5: Project execution and updates
The synthesis and conjugation are run according to the approved plan, with progress updates at key milestones and early notification if any route adjustment is needed.
The synthesis and conjugation are run according to the approved plan, with progress updates at key milestones and early notification if any route adjustment is needed.
Step 6: Delivery and follow-up
The reagent or conjugate is shipped with the certificate of analysis and batch records. After delivery, the researcher can return for support or scale-up.
The reagent or conjugate is shipped with the certificate of analysis and batch records. After delivery, the researcher can return for support or scale-up.
Common Challenges in Custom NHS Ester Projects
Custom NHS ester synthesis and conjugation projects are rarely risk-free. The challenges below appear most often, and each has a practical mitigation strategy.
Instability of the activated ester
NHS esters hydrolyze in water and can degrade during drying or storage. Mitigations include anhydrous activation, controlled drying, inert gas packaging, and stability monitoring at low temperature.
Poor solubility of hydrophobic dyes
Non-sulfonated dyes often dissolve poorly in aqueous buffers. Custom sulfo-NHS versions, PEG spacers, and controlled co-solvent additions address solubility without sacrificing labeling quality.
Low active ester content
A product that looks clean by HPLC can still contain hydrolyzed acid. Quantitative LC-MS and absorbance checks distinguish the active ester from the free acid before the reagent is released.
Loss of activity after conjugation
Random lysine labeling can disrupt binding sites or catalytic residues. Reducing the target DOL, choosing an alternate label site, or switching to a site-selective strategy preserves function.
Batch-to-batch variability
Small changes in activation time, drying, or reagent quality cause drift between batches. Locked processes, reference standards, and comparison of each batch against the reference batch control variability.
Incomplete documentation
Reproducibility depends on records. A complete batch record covering route, purification, analytical results, and handling instructions is essential for repeat orders and scale-up, so it should be agreed as a deliverable from the start.
Custom NHS Ester Synthesis and Conjugation Services from BOC Sciences
BOC Sciences provides a complete custom service scope for NHS ester chemistry, from the activation of novel dye carboxylates to the delivery of characterized fluorescent conjugates at research, pilot, and production scale. The services below can be combined into one end-to-end project.
Custom Dye NHS Ester Synthesis
Activation of novel dye scaffolds and custom carboxylic acids into purified, amine-reactive NHS ester reagents.
- EDC/NHS and uronium-based activation routes
- Preparative HPLC purification
- LC-MS and NMR characterization
- Active ester content verification
Linker and Spacer Design
Design and synthesis of specialized linkers, PEG spacers, and cleavable connectors between the dye and the NHS ester group.
- PEG chain length control for solubility
- Cleavable and rigid spacer options
- Heterobifunctional NHS ester combinations
- Linker-optimized conjugation geometry
Sulfo-NHS Reagent Development
Conversion of hydrophobic dyes into water-soluble sulfonated versions and preparation of the corresponding sulfo-NHS ester reagents.
- Scaffold sulfonation strategy
- Sulfo-NHS ester activation
- Salt form and counterion control
- Co-solvent-free conjugation protocols
Fluorescent Conjugation Services
Custom labeling of proteins, antibodies, peptides, oligonucleotides, small molecules, and nanoparticles using the prepared reagents.
- Targeted DOL control for each molecule class
- Conjugate purification to remove free dye
- Activity validation after labeling
- Batch-specific certificate of analysis
Multi-Functional Probe Construction
Assembly of probes that combine an NHS ester with click handles, maleimides, biotin, or other groups for two-step strategies.
- NHS ester plus azide or alkyne handles
- Biotin-NHS ester combinations
- FRET donor and acceptor pairing
- Probe design for imaging and assay workflows
Scale-Up and Batch Supply
Scale-up of custom NHS ester reagents and conjugates from milligram research batches to gram and kilogram production.
- Pilot and production scale synthesis
- Batch-to-batch consistency testing
- Moisture-protected bulk packaging
- Full batch records and analytical documentation
Start Your Custom NHS Ester Project with BOC Sciences
Whether you need a novel dye converted into an NHS ester, a sulfo-NHS version of a difficult scaffold, a labeled antibody with a controlled DOL, a functionalized nanoparticle, or a scaled supply of a validated reagent, BOC Sciences can define a project plan and deliver the data you need.
Send Your Project RequirementsRecommended NHS Ester Products
The following products are recommended for researchers working with NHS ester chemistry, amine-reactive labeling, bioconjugation, and conjugate preparation. The selection includes fluorescent NHS esters, cyanine and BODIPY derivatives, biotinylation reagents, click chemistry building blocks, and other activated esters for protein, antibody, peptide, and nucleic acid modification.
| Catalog | Product Name | CAS | Inquiry |
|---|---|---|---|
| R01-0029 | Sulfo-Cyanine3 NHS ester | Bulk Inquiry | |
| R01-0035 | Sulfo-Cyanine7 NHS ester | Bulk Inquiry | |
| R01-0032 | Sulfo-Cyanine5 NHS ester | Bulk Inquiry | |
| R01-0037 | TAMRA NHS ester, 5-isomer | 321862-17-3 | Bulk Inquiry |
| R01-0036 | Sulfo-Cyanine7.5 NHS ester | Bulk Inquiry | |
| R01-0034 | Sulfo-Cyanine7 bis-NHS ester | Bulk Inquiry | |
| R01-0033 | Sulfo-Cyanine5.5 NHS ester | Bulk Inquiry | |
| R01-0031 | Sulfo-Cyanine5 bis-NHS ester | Bulk Inquiry | |
| R01-0028 | ROX NHS ester, 6-isomer | 117491-83-5 | Bulk Inquiry |
| F02-0030 | Cy3-NHS ester | 146368-16-3 | Bulk Inquiry |
| R01-0019 | Cyanine5 NHS ester | 350686-88-3 | Bulk Inquiry |
| R01-0476 | Digoxigenin NHS-ester | 129273-26-3 | Bulk Inquiry |
| R01-0024 | DBCO-C6-NHS ester | 1384870-47-6 | Bulk Inquiry |
| R01-0023 | Cyanine7.5 NHS ester | Bulk Inquiry | |
| R01-0020 | Cyanine5 NHS ester minimal dye | Bulk Inquiry | |
| R01-0018 | Cyanine3.5 NHS ester | 2231670-85-0 | Bulk Inquiry |
| R01-0030 | sulfo-Cyanine3.5 NHS ester | Bulk Inquiry | |
| R01-0016 | Cyanine3 NHS ester | Bulk Inquiry | |
| R01-0017 | Cyanine3 NHS ester minimal dye | Bulk Inquiry | |
| R01-0015 | Cyanine2 NHS ester minimal dye | Bulk Inquiry | |
| R01-0438 | Cy5-NHS ester tetrafluoroborate | 1263093-76-0 | Bulk Inquiry |
| R01-0441 | Cy5.5 NHS ester (potassium salt) | 910482-46-1 | Bulk Inquiry |
| R01-0014 | Coumarin 343 X NHS ester | 946123-12-2 | Bulk Inquiry |
| R01-0012 | BDP TR NHS ester | 150152-65-1 | Bulk Inquiry |
| R01-0011 | BDP TMR NHS ester | 485397-12-4 | Bulk Inquiry |
| R01-0010 | BDP R6G NHS ester | 335193-70-9 | Bulk Inquiry |
| R01-0007 | BDP 630/650 X NHS ester | 2213445-35-1 | Bulk Inquiry |
| R01-0006 | BDP 581/591 NHS ester | 654651-21-5 | Bulk Inquiry |
| R01-0022 | Cyanine7 NHS ester | 1432019-64-1 | Bulk Inquiry |
| R01-0003 | Alkyne-PEG3-NHS ester | Bulk Inquiry | |
| R01-0001 | AF488 NHS ester | Bulk Inquiry | |
| R01-0005 | BDP 558/568 NHS ester | 150173-73-2 | Bulk Inquiry |
| R01-0474 | Biotin-PEG4-NHS ester | 459426-22-3 | Bulk Inquiry |
| R01-0439 | 6-Azidohexanoic acid sulfo-NHS ester | Bulk Inquiry | |
| R01-0002 | 5-hexynoic NHS ester | 906564-59-8 | Bulk Inquiry |
| R01-0440 | 3-Azidopropionic Acid Sulfo-NHS ester | 2055198-09-7 | Bulk Inquiry |
Explore More NHS Ester Resources
Explore our technical resources to better understand NHS ester chemistry, fluorophore selection, conjugation mechanisms, reagent stability, and biomolecule labeling. These guides provide practical background for defining reagent requirements and planning NHS ester-based labeling projects.
- NHS vs Sulfo-NHS Esters: Water Solubility and Conjugation Performance
- How to Choose the Right NHS Ester Dye for Your Labeling Experiment
- NHS Ester Labeling of Proteins and Antibodies: Protocols and Optimization
- What Are NHS Ester Reagents? Chemistry, Reactivity, and Role in Fluorescent Labeling
- NHS Ester Labeling of Peptides, Oligonucleotides, and Small Molecules
- NHS Ester Storage, Stability, and Quality Control: Preventing Hydrolysis and Failed Labeling
Frequently Asked Questions
These questions address common decision points in custom NHS ester synthesis, conjugation services, and project planning with a service provider.
When should I request a custom NHS ester reagent instead of using a catalog product?
Choose a custom reagent when the dye scaffold, linker, spacer, or reactive format you need is not available as a catalog product. Common cases include novel dye scaffolds, custom PEG spacers, sulfo versions, and multi-functional reagents. Catalog products remain the fastest option for routine labeling.
How is a custom NHS ester synthesized and purified?
The carboxylic acid of the dye or intermediate is activated with EDC/NHS or an uronium reagent such as HATU or TSTU. The activated ester is then purified by preparative HPLC and characterized by LC-MS and NMR before release.
What does degree of labeling mean in a custom conjugation project?
Degree of labeling is the average number of dye molecules attached per protein, antibody, or other target molecule, calculated from the absorbance ratio of dye to biomolecule. Custom conjugation services control DOL to a target window because too little dye gives weak signal and too much dye can reduce activity.
Can custom NHS ester reagents be scaled from milligrams to kilograms?
Yes. Custom NHS ester synthesis can be scaled from milligram research batches through gram pilot batches to kilogram production. Scale-up requires process control, impurity tracking, and batch-to-batch consistency testing so that larger batches match the reference material.
What information should I provide when requesting a custom NHS ester or conjugation service?
Provide the dye structure or the closest reference structure, the desired NHS ester or sulfo-NHS format, any linker requirements, the target molecule for conjugation, the buffer system, and the required quantity and purity.
Request Custom NHS Ester Synthesis or Conjugation Support
Share your dye scaffold, linker requirements, target molecule, and quantity needs with BOC Sciences. Our team can evaluate the feasibility of the synthesis, define the QC panel, and propose a project plan with clear deliverables and timelines.
Feasibility assessment
Review of the proposed dye, linker, and activation route with an honest assessment of difficulty and timeline.
Review of the proposed dye, linker, and activation route with an honest assessment of difficulty and timeline.
Custom synthesis and purification
Activation of your dye into a purified NHS ester with HPLC purification and LC-MS/NMR characterization.
Activation of your dye into a purified NHS ester with HPLC purification and LC-MS/NMR characterization.
Conjugation with DOL control
Labeling of proteins, antibodies, peptides, oligonucleotides, small molecules, or nanoparticles with a defined degree of labeling.
Labeling of proteins, antibodies, peptides, oligonucleotides, small molecules, or nanoparticles with a defined degree of labeling.
Scale-up and batch records
Supply from milligram to kilogram quantities with consistency data and complete documentation.
Supply from milligram to kilogram quantities with consistency data and complete documentation.
