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Conjugation of Payloads, Labels & Tags

End-to-end conjugation of drug payloads, fluorophore labels, affinity tags, chelators/radiometals, nanoparticles, and oligonucleotides to antibodies, proteins, peptides, and surfaces. ISO 9001/13485 systems with LC-MS/HPLC-verified QC.

ISO 9001/13485 LC-MS/HIC/SEC-MALS QC Bench → Preclinical
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Overview

Bio-Synthesis offers comprehensive conjugation of payloads, labels, and tags across biomolecules—antibodies, proteins/enzymes, peptides, oligonucleotides, nanoparticles, and device surfaces. We combine NHS-ester, maleimide–thiol, click chemistries (DBCO↔Azide, TCO↔Tetrazine), and glycan/enzymatic routes to deliver high-performance conjugates with controlled substitution and preserved activity.

Typical deliverables include ADC-like prototypes, fluorescent and biotinylated antibodies, chelator/radiometal constructs for imaging, DNA-barcoded antibodies, and nanoparticle conjugates for LFA and biosensors—each supported by a fit-for-purpose QC package.

Learn more about our antibody conjugation services and other custom conjugation capabilities.

Antibody-drug conjugate LC-MS analysis comparing IgG control and ADC DAR 3.2 under Bio-Synthesis conjugation
LC-MS analysis of an Antibody–Drug Conjugate (ADC) showing the molecular weight shift from IgG control (144,654 Da) to conjugated ADC (149,114 Da; DAR ≈ 3.2). Demonstrates precise payload loading and QC verification by Bio-Synthesis.

Capability Overview — Payloads, Labels & Tags

Class Linkers / Chemistry Representative Examples QC Focus
Cancer Drugs VC-PAB, disulfide, hydrazone; thioether; click MMAE/MMAF, DM1/DM4, Doxorubicin, SN-38 DAR (UV/Vis, LC-MS), HIC, release test
Antibiotics & Vitamins Amide, maleimide-thiol, click; enzymatic Rifamycin, Mitomycin, CIP/LEV; Biotin, Folate LC-MS integrity; binding/uptake if needed
Small Molecules NHS (amide), maleimide; orthogonal click Methotrexate, Indomethacin, steroid analogs SEC-MALS, LC-MS; functional assay
Technical Notes
  • For cleavable ADC prototypes choose VC-PAB/disulfide/hydrazone; for max stability choose thioether.
  • Dual payloads via orthogonal click (DBCO↔azide + TCO↔tetrazine) validated independently.
  • Submit ≥1–2 mg payload at ≥95% purity; note solvent and reactive handle (NHS, amine, thiol, azide, alkyne).

Oligo Type Linkers Applications QC Focus
ssDNA/dsDNA/RNA SMCC/LC-SMPT, DBCO↔Azide, TCO↔Tetrazine, NHS↔Amine PLA, Immuno-PCR, DNA barcoding, spatial/NGS LC-MS/MALDI, PAGE/SEC, hybridization
Technical Notes
  • Provide 5–10 nmol (single) or ≥20 nmol (duplex) with 5′/3′ handle (thiol, amine, azide, alkyne, biotin).
  • We can anneal duplex before conjugation; verify by melting curve or native PAGE.

Label Handle / Route Use Cases QC Focus
Fluorophores NHS (lysine), maleimide (cys), click Flow, IF/IHC, imaging F/P ratio; spectral; SEC free-dye
Enzymes Periodate (HRP), SMCC/EMCS (ALP/β-Gal/GOx), click ELISA/CLIA, blotting, biosensors Enzyme activity + binding
Technical Notes
  • Fluorophore F/P target 2–4; >5 risks quenching or affinity loss.
  • HRP is azide-sensitive; remove azide before coupling or use linkers.

Tag Chemistry Applications QC Focus
Biotin / DIG NHS / Sulfo-NHS-LC; maleimide; click-biotin Streptavidin capture, IP/ChIP, detection HABA/avidin binding; A280/A500
His / FLAG / Strep / HA Amide, click, or fusion workflows Purification, immobilization, epitope mapping Binding test to resin/antibody
Technical Notes
  • Use LC/PEG spacers to reduce steric hindrance in avidin systems.
  • Typical biotin load: 3–7 per IgG; verify by HABA or binding assay.

Chelator Route Metal / Use QC Focus
DOTA / NOTA / DTPA NHS or maleimide; click compatible Y, Lu, Cu, Zr — imaging/theranostic Metal loading %, isotope profile
Technical Notes
  • Coordinate metal after chelator install; confirm loading % before release.

Surface Activation Use case QC Focus
Au / Silica / Magnetic / Latex EDC/sulfo-NHS; silane; thiol; click LFA labels, SERS, biosensors DLS, zeta potential, stability
Technical Notes
  • Use low-salt buffers for coupling; add stabilizers (Tween-20/PEG) post-reaction.
  • Avoid Tris/citrate for direct Au–thiol reactions; avoid DTT/TCEP.

Technical Notes

Submission Checklist (What to send)
  • Amount: Antibody/protein ≥ 0.5–1.0 mg at ≥ 1 mg/mL (≥2 mg if DAR optimization or dual payloads).
  • Buffers: PBS/HEPES pH 7.0–7.5; avoid Tris/glycine (consume NHS) and DTT/TCEP (quench maleimide).
  • Payloads/Tags: ≥ 1–2 mg (≥95% purity by HPLC/LC-MS); specify solvent, concentration, and reactive handle.
  • Oligos: 5–10 nmol (single) or ≥20 nmol (duplex) with 5′/3′ handle (thiol, amine, azide, alkyne, biotin).
  • Docs: Name/clone/lot, concentration, buffer, desired chemistry & target F/P or DAR, return format.
  • Shipping: 2–8 °C (liquid) or dry ice (frozen); avoid weekend arrival; include SDS for hazardous payloads.
Which Route Should I Choose?
  • NHS-Ester (Amine coupling): Fast, broadly compatible lysine labeling. Best for general tags/labels. Avoid amine buffers (Tris/glycine).
  • Maleimide / Pyridazinedione (Thiol selective): Controlled cysteine labeling or reduced disulfides; ideal for stable thio-conjugates.
  • Re-bridging (Bis-maleimide / Dibromomaleimide): Restore disulfides while installing payload; produces homogeneous DAR≈2 ADC-like conjugates.
  • Click (DBCO↔Azide / TCO↔Tetrazine): Orthogonal, mild conditions; perfect for dual payloads or oligo + label systems.
  • Glycan / Enzymatic (Sortase/TGase/FGE): Uniform Fc or terminal labeling with minimal CDR impact; choose for maximum site control.
Buffer / Component NHS Maleimide Click Notes
PBS / HEPES (pH 7.0–7.5) ✓ ✓ ✓ Preferred; keep salt ≤150 mM during coupling.
Tris / Glycine / Ammonium ✗ ✓ ✓ Primary amines consume NHS-esters — avoid for amine labeling.
DTT / TCEP / β-ME ✓ ✗ ✓ Thiols quench maleimide — remove before thiol coupling.
Azide (0.02–0.05%) ✓ ✓ ✗ for CuAAC Compatible with SPAAC/IEDDA; avoid for copper-click.

*For re-bridging, use mild partial reduction (e.g., TCEP ≤1 mM, 5–10 min, RT) to expose hinge thiols, then add bis-maleimide and quench residual linker.

FAQ

How do I pick the right chemistry (NHS, maleimide, click, or enzymatic)?
Use NHS for fast, broad amine labeling; maleimide for thiol-selective control; click for orthogonal dual labels or fragile targets; glycan/enzymatic when you need site-specific uniformity.
What’s a typical QC package?
LC-MS (intact/subunit), HIC for F/P or DAR, SEC-MALS for aggregation, and binding/activity (ELISA/SPR/BLI). For biotin, HABA or streptavidin binding; for dyes, spectral and free-dye check.
Can you handle dual payloads (e.g., drug + fluorophore or biotin + dye)?
Yes—via orthogonal click pairs (DBCO↔Azide and TCO↔Tetrazine) or mixed thiol/amine routes. We validate each payload’s loading and function independently.
What information speeds up the quote?
Biomolecule identity, buffer & concentration, desired chemistry, target F/P or DAR, QC needs, and return format. For small molecules/oligos, include purity, solvent, and reactive handle.
More FAQ'sAll FAQ's

Speak to a Scientist

Full Name *
Email *
Company / Institution *
Phone *
Project Type *Pick the primary route; we’ll advise if a hybrid strategy is better.
Desired ScaleWe support bench through preclinical quantities.
Preferred Linker / Notes
Payload(s)Dual payloads supported via orthogonal click chemistry.
Project Summary
Attach Spec / Sequence (optional)Include purity/solubility and reactive handle info if available.

By submitting, you agree to be contacted regarding your request.

972-420-8505 (USA) 800-227-0627 (INTL.) info@biosyn.com Contact Us

References

  1. Bio-Synthesis Inc. Custom Antibody Conjugation Services. www.biosyn.com
  2. Hermanson GT. Bioconjugate Techniques, 3rd ed. Academic Press, 2013.
  3. Chari RVJ et al. Antibody–Drug Conjugates. Angew Chem Int Ed. 2014;53(15):3796–3827.
  4. Glen Research — Labels & Modifiers Catalog. glenresearch.com

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