BOC Sciences provides customized antibody-drug conjugate (ADC) services for discovery teams that need more than a simple antibody labeling reaction. We support ADC strategy design, linker-payload synthesis, antibody preparation, controlled conjugation, purification, DAR profiling, orthogonal characterization, and application-oriented testing for research-stage ADC programs.
Our scientists combine antibody handling, small-molecule chemistry, payload derivatization, bioconjugation, chromatographic separation, and mass spectrometry to help clients solve difficult ADC problems such as hydrophobic payload aggregation, broad DAR distribution, low recovery, unstable linkers, free payload carryover, and loss of target binding.
An antibody-drug conjugate is a targeted biologic construct in which a monoclonal antibody is covalently linked to a highly active cytotoxic drug payload through a designed chemical linker. By combining the target-recognition ability of the antibody with the potent cell-killing activity of the drug payload, ADCs are designed to deliver drug activity more selectively to antigen-expressing cells. More than a dozen ADC therapies have been launched worldwide, with major oncology targets including CD30 and CD22 in hematologic malignancies, as well as HER2, TROP2, and Nectin-4 in solid tumors.
Our microtubule inhibitor ADC services support the development of antibody conjugates carrying highly active tubulin-disrupting payloads. The workflow can include linker-payload synthesis, antibody preparation, controlled conjugation, DAR adjustment, purification, and analytical characterization, helping research teams evaluate payload potency, conjugate stability, aggregation tendency, and target-dependent cellular response.
For DNA-damaging agent ADCs, our team provides conjugation support for alkylating, crosslinking, and DNA-interacting payloads that require careful handling, precise linker design, and strong analytical control. We help clients balance payload activity with antibody integrity while monitoring DAR distribution, free payload removal, aggregate formation, and binding retention through orthogonal testing methods.
We provide ADC development support for topoisomerase inhibitor payloads, including linker-payload modification, hydrophilicity tuning, antibody conjugation, purification, and DAR profiling. Because this payload class often requires careful control of solubility, linker release, and conjugate heterogeneity, our specialists design project-specific workflows to improve ADC comparability, reduce free drug interference, and support structure-response evaluation.
Our capabilities support customized RNA polymerase inhibitor ADC projects involving highly potent payloads, controlled antibody attachment, and robust purification. The service covers payload reactivity assessment, linker compatibility review, antibody stability evaluation, conjugation process development, and analytical profiling of DAR, monomer content, residual payload, and target-associated functional activity.
Our experts develop antibody-immune stimulating conjugates by linking antibodies with immune-activating payloads such as TLR agonists, STING agonists, or other immune modulators. We support linker design, agonist derivatization, antibody conjugation, purification, and activity-oriented testing to help clients study targeted immune activation, tumor microenvironment modulation, and antigen-localized immune response.
We offer antibody-oligonucleotide conjugate services for targeted delivery of siRNA, ASO, PMO, aptamers, CpG oligonucleotides, and other modified nucleic acid payloads. Our workflow includes oligonucleotide functionalization, antibody modification, click or thiol-based conjugation, purification, OAR analysis, and binding evaluation to support receptor-mediated uptake and cell-selective nucleic acid delivery research.
Our antibody-radionuclide conjugate services include chelator installation, antibody functionalization, conjugation optimization, purification, and conjugate characterization. Working with chelator-linker systems designed for radionuclide-bearing constructs, we help clients evaluate antibody integrity, chelator loading, aggregation, target binding, and suitability for targeted imaging or radionuclide delivery research.
Our team supports antibody-degrader conjugate development by combining antibody-guided delivery with protein degrader payloads such as PROTAC-inspired molecules, molecular glue analogs, or E3 ligase-recruiting structures. Services can include degrader-linker design, payload derivatization, conjugation chemistry, purification, and analytical profiling to support targeted intracellular protein degradation research.
BOC Sciences helps research teams move from antibody format and payload structure to conjugation chemistry, DAR control, purification, LC-MS characterization, and application-ready ADC materials.
Cleavable linker ADCs are designed to release drug payloads in response to specific intracellular or microenvironmental conditions. This format is widely used for payload-release studies, target-dependent cytotoxicity evaluation, bystander-effect research, and linker-payload comparison in ADC discovery programs.
Non-cleavable linker ADCs provide a stable antibody-payload connection and are useful when conjugate stability, controlled DAR, and clean structure-performance interpretation are priorities. We support these ADCs for internalization studies, payload retention analysis, stability comparison, and target-specific activity screening.
BOC Sciences provides customized ADC conjugation, linker-payload chemistry, purification, and analytical support for pharmaceutical, biotechnology, and academic discovery teams. Our project scope can be adjusted from a single feasibility experiment to a comparative linker-payload panel.
| Development Stage | Service Scope & Key Outputs |
| Target & Antibody Feasibility Review | Review of target biology, antibody format, binding sensitivity, internalization goal, buffer composition, aggregate risk, and material availability to determine whether the antibody is suitable for ADC conjugation and comparative payload screening. |
| Linker-Payload Design | Design of cleavable peptide linkers, non-cleavable thioether linkers, disulfide linkers, hydrophilic spacers, self-immolative units, PEGn modifiers, and reactive handles matched to payload class and conjugation chemistry. |
| Payload Synthesis & Derivatization | Custom preparation, activation, purification, and structural confirmation of payload derivatives, including cytotoxic small molecules, kinase inhibitors, topoisomerase I inhibitor analogs, tubulin binders, immune modulators, and degrader payloads. |
| Antibody Preparation | Buffer exchange, concentration adjustment, reducing-agent control, stabilizer removal, reactive group installation, aggregation review, and antibody recovery measurement before conjugation. |
| Conjugation Process Development | Optimization of lysine, cysteine, glycan-directed, enzymatic, click-enabled, and site-specific conjugation by adjusting payload equivalents, pH, co-solvent level, temperature, reaction time, addition order, and quench condition. |
| Purification & Fraction Screening | Removal of unconjugated antibody, free payload, residual linker, aggregate, and fragments using SEC, HIC, RP-HPLC, IEX, affinity capture, desalting, ultrafiltration, and fraction comparison. |
| DAR & Structural Characterization | Analysis by UV-Vis, SEC-HPLC, HIC-HPLC, RP-HPLC, IEX, intact LC-MS, reduced LC-MS, peptide mapping, LC-MS/MS, fluorescence when applicable, and binding assessment to define ADC identity and distribution. |
| Stability & Handling Screening | Evaluation of aggregate formation, free payload change, DAR drift, linker stability, light sensitivity, freeze-thaw behavior, dilution compatibility, storage buffer performance, and assay-buffer compatibility. |
| In Vitro, Ex Vivo and In Vivo Research Evaluation | Research-stage assessment of target binding, cell uptake, internalization, payload response, target-positive and target-negative cell comparison, tissue-matrix compatibility, biodistribution models, and functional readouts where appropriate. |
| Data Interpretation & Next-Step Design | Integrated review of DAR, purity profile, aggregation, residual payload, binding retention, functional response, and stability data to recommend linker modification, conjugation condition adjustment, or payload-panel expansion. |
Share your antibody format, concentration, buffer, target antigen, linker-payload structure, reactive handle, target DAR range, assay goal, current conjugation issue, and required analytical readouts. Our specialists will design a project-specific plan covering linker-payload compatibility, conjugation route, purification logic, DAR analysis, analytical method optimization, and performance review.
We begin by discussing the client's antibody format, payload structure, linker preference, target DAR, application goal, sample condition, and key technical concerns. Based on these details, our team proposes a practical ADC project scheme covering antibody conjugation chemistry, material preparation, purification strategy, and analytical confirmation.
The project then moves into linker-payload preparation, antibody pretreatment, buffer adjustment, and antibody-payload conjugation. Our team can support custom synthesis of linker-payload intermediates and optimize the coupling reaction by adjusting payload equivalent, pH, co-solvent level, temperature, and reaction time.
After conjugation, the ADC is purified and analyzed to confirm key product attributes. Depending on the project, our analytical platform can evaluate DAR, molecular weight, monomer content, aggregation, residual free payload, linker-payload attachment, and binding retention using methods such as SEC-HPLC, HIC-HPLC, UV-Vis, and LC-MS.
The final ADC material is packaged according to project needs and delivered with related documentation. The report package may include preparation records, purification information, analytical results, chromatograms, mass data, DAR assessment, storage and handling suggestions, and project-specific findings for downstream research use.
Many ADC projects start with a promising antibody or payload but lack evidence that the full construct will work as a matched system. Target expression, internalization, antibody stability, payload potency, linker release, and DAR all interact. BOC Sciences helps clients map these variables at the beginning of the project and can connect ADC design with target identification, target validation, and assay planning when broader discovery support is needed.
Random lysine labeling can generate complex mixtures, while cysteine conjugation requires careful control of partial reduction and rebridging. Averages alone can hide important differences between DAR0, DAR2, DAR4, DAR6, and DAR8 species. We reduce uncertainty by optimizing reduction depth, payload equivalents, reaction time, and cleanup strategy, then using HIC, SEC, UV-Vis, LC-MS, and peptide mapping to understand the distribution behind the average DAR.
Many ADC payloads are aromatic, highly potent, and poorly water-soluble. When the payload or linker increases hydrophobic surface exposure, the ADC may precipitate, aggregate, lose binding, or show poor recovery during purification. BOC Sciences addresses this through hydrophilic spacer design, PEGn insertion, staged payload addition, lower co-solvent exposure, concentration adjustment, SEC-HPLC monitoring, and fraction selection based on both analytics and application performance.
An ADC with an apparently acceptable DAR can still perform poorly if binding is impaired, internalization is weak, payload release is inefficient, or free payload artifacts distort the result. BOC Sciences combines chemical analysis with binding and response assays, including cell proliferation and activity testing, to identify whether the issue is caused by antibody recognition, linker behavior, payload sensitivity, or assay format.
Collaborate with BOC Sciences to access custom ADC conjugation, linker-payload synthesis, DAR control, chromatographic purification, orthogonal characterization, and application-oriented research data packages.
ADC development requires coordination between biologics handling and small-molecule chemistry. BOC Sciences combines antibody preparation, payload derivatization, linker design, conjugation, purification, and testing in a connected workflow. This reduces handoff gaps and supports better decisions when antibody stability, payload hydrophobicity, linker cleavage, DAR target, and assay performance must be evaluated together.
We do not use one conjugation protocol for every ADC. Our scientists compare lysine, cysteine, site-specific, glycan-directed, enzymatic, and click-enabled approaches according to antibody format, payload reactivity, target DAR, homogeneity requirement, binding sensitivity, and purification feasibility. This application-first design helps clients obtain more interpretable ADC materials for decision-making.
ADC projects often fail because a promising payload is too hydrophobic, unstable, or chemically incompatible with the selected linker. BOC Sciences can prepare modified linker-payload analogs, compare spacer lengths, screen payload equivalents, and evaluate small ADC panels for early ranking. We also support high-throughput screening and high-content screening when projects require broader biological readouts.
ADCs are heterogeneous biomolecule-small-molecule systems, so single-method analysis is rarely enough. Our workflow combines chromatographic, spectroscopic, mass-based, and binding-related data to clarify DAR, distribution, aggregation, residual payload, and functional response. This gives clients stronger evidence for choosing the best conjugate or redesigning a linker, payload, or conjugation condition.
Client Needs: A discovery group required an IgG1 ADC carrying a topoisomerase I inhibitor analog for comparison in a target-positive tumor-cell model. The client supplied an antibody in stabilizer-containing buffer and a hydrophobic maleimide linker-payload.
Challenges: The first conjugation attempt showed visible turbidity, high SEC aggregate, and inconsistent DAR by UV-Vis. The payload required organic co-solvent, but the antibody showed concentration-dependent aggregation under the same condition.
Solution: We exchanged the antibody buffer, screened four reduction depths, three payload equivalents, and two co-solvent profiles across 24 microscale reactions. SEC-HPLC, HIC, UV-Vis, and intact LC-MS tracked aggregation and DAR. A staged payload addition with PEG4 spacer selection reduced precipitation and enabled recovery of the desired DAR4-enriched fraction for downstream comparison.
Outcome: The client received a cleaner ADC fraction with improved monomer profile, measurable DAR distribution, reduced free payload, and a repeatable condition for follow-up linker analog testing.
Client Needs: An antibody engineering team wanted a more homogeneous ADC using an engineered cysteine antibody and a valine-citrulline payload for internalization and payload-release comparison.
Challenges: Over-reduction produced antibody fragments, while insufficient reduction caused low payload incorporation. The team also needed to separate partially loaded species from the target conjugate without compromising binding.
Solution: We optimized cysteine exposure with controlled TCEP equivalents, short reduction windows, and immediate buffer cleanup before payload addition. Twelve conjugation conditions were compared by HIC, SEC, reduced LC-MS, and binding assay. The selected process used mild reduction, rapid quenching, and HIC-guided fraction selection to enrich the target DAR2 species while limiting fragments.
Outcome: The final material showed a narrower DAR profile and preserved binding response, giving the client a more interpretable ADC for target-engagement experiments.
Client Needs: A medicinal chemistry group needed to rank four linker-payload designs on the same antibody scaffold before selecting the most promising construct for deeper biological evaluation.
Challenges: The four payloads differed in hydrophobicity, reactive handle stability, and UV response. A single conjugation condition would not provide a fair comparison, and free payload interference could distort cell-response data.
Solution: We built a mini ADC panel by matching each linker-payload to a tailored conjugation condition, then normalized fractions by antibody concentration and DAR. HIC, SEC-HPLC, LC-MS, and UV-Vis were run for all 16 ADC fractions. The best three were advanced to binding, internalization, and cell-response assays with free payload controls.
Outcome: The client identified one linker-payload with stronger target-dependent response and lower aggregation, while two hydrophobic designs were deprioritized based on analytical and functional evidence.
ADC design should start from the biological target, antibody format, payload mechanism, linker behavior, and the intended research readout rather than from a fixed conjugation protocol. Key factors include antibody binding retention, internalization potential, payload hydrophobicity, linker stability, release mode, and the target DAR (drug-to-antibody ratio). BOC Sciences evaluates the antibody buffer, reactive groups, payload structure, solubility profile, and downstream application to recommend cleavable, non-cleavable, hydrophilic, PEG-modified, or site-directed linker strategies that reduce aggregation risk and support meaningful candidate comparison.
DAR control depends on the conjugation chemistry, available antibody reaction sites, reduction conditions, payload equivalents, pH, solvent tolerance, reaction time, and purification strategy. Lysine conjugation is often flexible but may produce broader distributions, while cysteine-based and site-specific approaches can provide tighter control when the antibody and payload are compatible. BOC Sciences uses small-scale reaction screening, optimized linker-payload activation, controlled reduction, staged payload addition, and orthogonal analytics such as HIC, SEC, UV-Vis, and LC-MS to compare DAR profiles and select workable ADC preparation conditions.
ADC aggregation is often driven by hydrophobic payloads, aromatic linker structures, excessive drug loading, antibody exposure to organic co-solvents, over-reduction, or unfavorable buffer conditions. Aggregation may also increase when conjugation changes the antibody surface charge or creates product species with poor solubility. BOC Sciences addresses these risks by adjusting payload equivalents, linker hydrophilicity, spacer length, reaction concentration, solvent percentage, buffer composition, and purification method. SEC-HPLC, DLS when needed, UV-Vis, HIC, and binding-related assays help distinguish aggregation from incomplete conjugation, product loss, or weak functional response.
ADC characterization usually requires multiple complementary methods because no single assay fully describes conjugation success, product distribution, aggregation, residual free payload, and antibody binding. Common workflows may include SEC-HPLC for size-related species, HIC for DAR distribution, intact LC-MS for molecular mass confirmation, peptide mapping or LC-MS/MS for conjugation site insight, UV-Vis for payload loading estimation, and IEX or RP-HPLC for charge or hydrophobicity changes. BOC Sciences designs analytical packages around the customer’s ADC format, linker-payload chemistry, and research decision points.
An ADC design is worth further optimization when the main limitations appear technically adjustable, such as broad DAR distribution, moderate aggregation, incomplete payload incorporation, removable free payload, or suboptimal linker hydrophilicity. Important decision points include whether antibody binding is retained, whether the payload remains functional, whether the conjugate can be separated into useful fractions, and whether repeated small-scale reactions show a consistent trend. If the antibody is intrinsically unstable or the payload strongly disrupts binding, redesigning the linker, attachment site, payload derivative, or antibody format may be more effective.
BOC Sciences did not provide a single fixed conjugation route. Their team compared different linker-payload designs, conjugation chemistries, and DAR control strategies, helping us choose a more suitable ADC design for our research model.
— Dr. Sinclair, Principal Scientist, ADC Discovery
The experimental platform was well organized, from antibody preparation and payload conjugation to purification and analytical confirmation. The team handled a challenging linker-payload with careful process control and gave us confidence in the final ADC material.
— Barrett, Bioconjugation Project Manager
Our ADC project moved forward efficiently, and communication was clear at each key stage. BOC Sciences coordinated synthesis, conjugation, purification, and testing smoothly, allowing our team to continue downstream evaluation without unnecessary delays.
— Dr. Weber, Senior Research Scientist
The final report was detailed and easy to review. It included preparation information, purification results, DAR assessment, chromatographic profiles, mass data, and practical interpretation, which helped our team understand the conjugate quality and plan the next experiment.
— Zimmerman, Director of Biologics Research
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