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Peptide Bioconjugation & Peptide–Drug Conjugation Services

High-loading, low-background peptide conjugates — including peptide–drug conjugates (PDCs), peptide–oligonucleotide conjugates, peptide–protein conjugates, and peptide–nanoparticle or surface conjugates — engineered with full analytics and documentation by Bio-Synthesis.

Speak to a Scientist Overview Peptide–Drug Conjugates
45+ Years of Peptide & Bioconjugation Experience
ISO 9001:2015 / ISO 13485:2016
Custom & OEM / Kit Support
Texas, USA
Overview Peptide–Drug Peptide–Oligo Peptide–Protein Peptide–Polymer Peptide–Lipid Peptide–Carbohydrate Peptide–Imaging Peptide–Surface Click-Ready Therapeutic Diagnostic

Overview

Bio-Synthesis provides end-to-end peptide bioconjugation services, spanning peptide–drug conjugates (PDCs), peptide–oligonucleotide conjugates, peptide–protein conjugates, and peptide-decorated polymers, nanoparticles, lipids, carbohydrates, and surfaces. We focus on high functional loading, low non-specific binding, and tight lot-to-lot reproducibility.

Peptide bioconjugation links cell-penetrating peptides (CPPs), targeting peptides, cleavable peptides, and functional peptide scaffolds to small-molecule drugs, oligonucleotides, proteins, polymers, and nanoparticles to create targeted therapeutics, delivery systems, diagnostics, imaging agents, and biosensor components.

Our platform covers design, synthesis, and peptide conjugation through purification, analytics, and documentation — supporting feasibility studies, optimization campaigns, preclinical development, and OEM/kit programs.

Peptide Carrier
CPP · Targeting · Cleavable
Linker & Chemistry
NHS · Maleimide · Click · Enzymatic
Payload
Drug · Oligo · Protein · Polymer · NP/Surface
Therapeutic & Delivery Conjugates

Peptide–drug conjugates, peptide–siRNA and peptide–ASO conjugates, and peptide–protein fusions designed for targeted delivery, intracellular uptake, and controlled release.

Diagnostic & Imaging

Peptide–fluorophore, peptide–chelator, and peptide–enzyme conjugates for imaging, biosensors, proximity assays, and activity-based probes.

Documentation & Scale

Method summaries, Certificates of Analysis, and optional tech transfer packages aligned with your discovery, preclinical, or OEM requirements.

Peptide Bioconjugation Product & Service Categories
  • Peptide–Oligonucleotide Conjugates (peptide–siRNA, peptide–ASO, peptide–PNA, peptide–DNA/RNA).
  • Peptide–Protein / Peptide–Antibody Conjugates for targeting, capture, and reporter formats.
  • Peptide–Drug Conjugates (PDCs) for oncology, anti-infective, immunomodulatory, and theranostic use.
  • Peptide–Polymer & Biomaterial Conjugates including PEG, hydrogels, and scaffolded peptide displays.
  • Peptide–Lipid Conjugates for membrane anchoring, self-assembly, and lipid-based delivery systems.
  • Peptide–Carbohydrate / Ligand Conjugates for glycan targeting, receptor binding, and multivalent display.
  • Peptide–Fluorophore & Imaging Conjugates using visible, NIR, and specialty imaging dyes or chelators.
  • Peptide–Surface & Solid-Support Conjugates on beads, plates, chips, and biosensor surfaces.
  • Peptide–Chemical Handle / Click-Ready Conjugates (azide, alkyne, tetrazine, DBCO, thiol, and more).
  • Peptide Therapeutic Conjugates integrating peptides with drugs, biologics, or carriers for therapy.
  • Peptide Diagnostic & Biosensor Conjugates tailored for in vitro diagnostics, point-of-care, and biosensing.

Peptide bioconjugation can also be integrated with carrier delivery systems (ADC, LNP, and polymer platforms) and broader bioconjugation services from Bio-Synthesis.

Peptide–Drug Conjugates (PDCs)

Peptide–drug conjugates use targeting, cell-penetrating, or cleavable peptides to deliver highly potent small-molecule drugs more selectively to diseased cells or tissues. Bio-Synthesis designs and produces peptide–drug conjugates with tailored linkers, drug-to-peptide ratios, and analytics appropriate for oncology, anti-infective, immunomodulatory, and imaging applications.

Peptide Carrier
Targeting · CPP · Cleavable
Linker & Chemistry
Stable · Cleavable · Click · Amide
Drug Payload
Cytotoxic · Kinase Inhibitor · Probe
Product Highlights
  • Custom PDCs using cytotoxic agents, kinase inhibitors, antibiotics, and immunomodulatory drugs.
  • Stable or enzyme-/pH-/redox-cleavable linkers designed around your mechanism of action.
  • Optimized peptide sequence placement to preserve receptor binding or cell penetration.
  • Controlled drug-to-peptide ratio and aggregation management.
  • Analytics including LC-MS, HPLC/UPLC, and functional assays as required.
Preferred Applications
  • Targeted delivery of cytotoxic drugs to tumors with reduced off-target toxicity.
  • Peptide-guided delivery of anti-infectives and antimicrobial agents.
  • Immunomodulatory PDCs that reshape the tumor microenvironment.
  • Theranostic PDCs combining therapy and imaging in a single construct.
  • Structure–activity relationship (SAR) studies on linker and peptide design.

Peptide & Drug Design
  • Define peptide role (targeting, CPP, cleavable, spacer) and attachment position(s).
  • Map reactive sites (Lys, Cys, non-natural amino acids) to control drug loading.
  • Match drug functionality with appropriate conjugation chemistry and stability.
  • Consider overall hydrophobicity and charge to avoid aggregation.
Linker, Release & QC
  • Select stable vs cleavable linkers (enzyme-, pH-, redox-triggered) based on biology.
  • Establish target drug-to-peptide ratio and release profile.
  • Use LC-MS and HPLC/UPLC to confirm identity, purity, and loading.
  • Include potency, binding, or cell-based assays where appropriate.
Example Drug Classes for Peptide–Drug Conjugates
Cytotoxic Payloads
  • Auristatins (MMAE, MMAF)
  • Maytansinoids (DM1, DM4)
  • Taxanes (Paclitaxel, Docetaxel)
  • Anthracyclines (Doxorubicin, Daunorubicin, Epirubicin, Idarubicin)
  • Topoisomerase inhibitors (SN-38, Camptothecin analogs)
Targeted Small Molecules
  • Kinase inhibitors (EGFR, BTK, BRAF, etc.)
  • PARP inhibitors, HDAC inhibitors
  • BCL-2 inhibitors, proteasome inhibitors
  • Hormonal agents (ER/AR modulators)
  • Enzyme- or receptor-directed inhibitors
Anti-Infective & Immuno Agents
  • Antibiotics (Vancomycin, Gentamicin, Rifamycins)
  • Antifungals and antimicrobials
  • TLR, STING, & immune agonists
  • Checkpoint pathway inhibitors
  • Specialty & customer-supplied payloads
Imaging & Theranostic Payloads
  • Fluorophores (FITC, Cy dyes, Alexa Fluor®)
  • Near-IR dyes (IRDye®, etc.)
  • Metal chelators (DOTA, NOTA, DTPA)
  • MRI contrast agents (Gd-chelates)
  • Photoactive/photothermal agents
Specialty & Custom Payloads
  • Enzyme substrates & activity-based probes
  • Hypoxia/redox-activated prodrugs
  • PROTAC components
  • Metabolic tracers & clickable analogs
  • Customer-supplied proprietary compounds
Representative Oncology Drug Payloads

Examples of small-molecule & biologic cancer drugs compatible with peptide conjugation we offer:

  • Anthracyclines: Doxorubicin, Epirubicin, Daunorubicin, Idarubicin, Mitoxantrone
  • Antitumor antibiotics: Actinomycin D, Bleomycin, Mithramycin, Mitomycin, Elsamicin A
  • Microtubule agents: Paclitaxel (Taxol), Docetaxel, Tesetaxel, Vincristine, Vinblastine, Vinorelbine
  • Other cancer drug catagory include: Topoisomerase inhibitors, Platinums & alkylators, Antimetabolites, Targeted biologics & mAbs and other targeted agents

*Highly potent oncology payloads are handled under NDA and feasibility review.

A tumor-homing peptide was conjugated to a small-molecule cytotoxic drug via an enzyme-cleavable linker to create a peptide–drug conjugate with improved selectivity and tolerability.

  • Multiple linkers and peptide positions were screened for potency and safety.
  • Drug-to-peptide ratio was tuned to balance payload delivery and solubility.
  • Cell-based assays showed enhanced kill in receptor-positive versus receptor-negative cells.
Example Peptide–Drug Construct
  • Peptide: tumor-homing peptide, MW ~1,200 Da.
  • Drug payload: small-molecule cytotoxic, MW ~800 Da.
  • Conjugate: single drug per peptide via enzyme-cleavable linker; purity >95% by HPLC.

Peptide–Oligonucleotide Conjugates

Peptide–oligonucleotide conjugates combine targeting or cell-penetrating peptides with siRNA, ASO, or DNA/RNA to improve cellular uptake, tissue targeting, and subcellular localization. Bio-Synthesis manufactures peptide–siRNA, peptide–ASO, peptide–PNA, and related constructs with controlled architecture and QC support.

Peptide Carrier
CPP · Targeting · NLS
Conjugation Chemistry
Amide · Click · Thiol/Maleimide
Oligonucleotide Payload
siRNA · ASO · DNA/RNA · PNA
Product Highlights
  • Peptide–siRNA and peptide–ASO conjugates for receptor- or CPP-mediated delivery.
  • Nuclear localization signal (NLS) and endosomal escape peptides linked to oligonucleotides.
  • Peptide–PNA and peptide–DNA/RNA conjugates for hybridization-based applications.
  • Single- and multi-valent architectures with defined peptide:oligo stoichiometry.
Preferred Applications
  • Targeted gene knockdown and splice modulation with peptide–siRNA/ASO conjugates.
  • Intracellular delivery of oligos via CPPs and endosomal escape sequences.
  • Peptide–oligo constructs used as probes, beacons, or biosensor components.
  • Exploration of sequence, backbone, and peptide design in early discovery campaigns.

Design & Conjugation
  • Choose 5′ vs 3′ attachment on the oligo based on mechanism and potency data.
  • Place conjugation sites on peptide to preserve binding or penetration motifs.
  • Align oligo chemistry (phosphorothioate, 2′-OMe, 2′-F, etc.) with desired stability and activity.
  • Use spacers or PEG to reduce steric hindrance between peptide and oligo.
Assay & Analytics
  • Confirm identity and purity by LC-MS and HPLC/UPLC.
  • Assess cell uptake, localization, and knockdown in relevant models.
  • Evaluate serum stability and off-target effects as needed.
  • Use unconjugated oligo and peptide controls for benchmarking.

A cationic CPP was conjugated to an siRNA targeting a cytosolic enzyme to improve cellular uptake and functional knockdown efficiency in primary cells.

  • Single CPP per siRNA with defined 5′-end attachment on the sense strand.
  • Improved uptake and knockdown relative to unconjugated siRNA at matched doses.
  • Maintained viability and acceptable off-target profile at optimized concentration.
Peptide-siRNA Conjugates
  • Peptide: MW 1100.33
  • Sense strand of siRNA MW: 6696.49
  • Targeting with Sense Strand Conjugates MW: 8112.17
Final Construct
siRNA Conjugation
Figure 1. Sense strand of siRNA conjugation to peptide
HPLC and Mass Spec
Figure 1. Sense strand of siRNA conjugation to peptide

Peptide–Protein & Peptide–Antibody Conjugates

Peptide–protein and peptide–antibody conjugates enable targeting, signal amplification, immobilization, and controlled orientation for assays and therapeutics. Bio-Synthesis offers custom conjugation of peptides to antibodies, enzymes, and other proteins using optimized chemistries and spacers.

Protein / Antibody
mAb · Fab · Enzyme
Conjugation Chemistry
NHS · Maleimide · Click
Peptide Module
Tag · Targeting · Scaffold
Product Highlights
  • Peptide-tagged antibodies and proteins (His-tag, FLAG-like, custom tags) for capture or detection.
  • Peptide–enzyme conjugates for signal amplification in ELISA, IHC, and activity assays.
  • Peptide–protein fusions to enable targeting, docking, or multimerization.
  • Site-aware approaches to maintain activity and binding.
Preferred Applications
  • Assay reagents and kit components with peptide-tagged proteins.
  • Peptide–enzyme reporters for sensitive colorimetric or chemiluminescent detection.
  • Peptide–antibody conjugates for targeted delivery or pretargeting strategies.
  • Protein engineering campaigns requiring tailored peptide handles.

Conjugation Strategy
  • Match peptide handle (amine, thiol, azide/alkyne) with accessible sites on the protein.
  • Avoid critical binding or catalytic regions when placing conjugation sites.
  • Use PEG or flexible linkers to maintain activity and reduce steric clash.
  • Monitor aggregation and oligomerization by SEC or DLS.
QC & Functional Readouts
  • Confirm conjugation by MS, SDS-PAGE, and HPLC as appropriate.
  • Verify binding (for antibodies) or catalytic activity (for enzymes) post-conjugation.
  • Define acceptance criteria around activity, binding, and purity for lot release.

An affinity peptide was conjugated to an enzyme reporter to create a sensitive detection reagent for a plate-based immunoassay.

  • Conjugation preserved both peptide binding and enzyme catalytic function.
  • Signal-to-background improved versus a non-targeted enzyme control.
  • Reagent showed robust performance across multiple sample matrices.

Peptide–Polymer & Biomaterial Conjugates

Peptide–polymer and peptide–biomaterial conjugates decorate PEGs, hydrogels, scaffolds, and other matrices with functional peptides to tune biodistribution, release, cell adhesion, and bioactivity. Bio-Synthesis supports custom peptide–polymer architectures for delivery, tissue engineering, and device interfaces.

Polymer / Biomaterial
PEG · Hydrogel · Scaffold
Conjugation Strategy
Covalent · Grafting · Click
Peptide Payload
Adhesion · Targeting · Bioactive
Product Highlights
  • Peptide–PEG and peptide–polymer conjugates for half-life extension and delivery.
  • Peptide-decorated hydrogels and scaffolds for tissue and cell interaction control.
  • Multi-peptide displays for synergy between adhesion, growth, and signaling motifs.
  • Control of peptide density and distribution along the polymer backbone.
Preferred Applications
  • Drug depot and controlled-release formulations.
  • Tissue engineering scaffolds and cell culture matrices.
  • Polymer conjugates for pharmacokinetic tuning and solubility.
  • Biomaterial surfaces with tailored cell adhesion and signaling.

Design & Density
  • Define target peptide density to balance activity with steric hindrance and viscosity.
  • Use spacers and PEG linkers to enhance accessibility of peptide motifs.
  • Coordinate polymer architecture (linear, branched, star) with biological function.
Materials & QC
  • Work with customer-supplied polymers or sourced materials under specification.
  • Characterize conjugates by MS (where applicable), HPLC/UPLC, SEC, and functional assays.
  • Establish stability and storage conditions for long-term performance.

Peptide–Lipid Conjugates

Peptide–lipid conjugates and lipopeptides combine membrane-active peptides with fatty acids, cholesterol, or other lipids to drive membrane association, self-assembly, and delivery. Bio-Synthesis supports design and production of peptide–lipid conjugates for vaccine, delivery, and adjuvant applications.

Peptide
Antigenic · CPP · Fusion
Lipid Link
Amide · Thioether · Click
Lipid Moiety
Fatty Acid · Cholesterol
Product Highlights
  • Lipopeptides for vaccine and adjuvant formulations.
  • Peptide–cholesterol and other lipid conjugates for membrane anchoring.
  • Peptide–lipid constructs compatible with liposome or LNP systems.
  • Design for solubility, aggregation, and formulation compatibility.
Preferred Applications
  • Vaccine antigens and immune-modulating lipopeptides.
  • Membrane-anchored ligands or receptors.
  • Delivery systems combining peptides with lipid carriers.
  • Biophysical studies of peptide–membrane interactions.

Peptide–Carbohydrate & Ligand Conjugates

Peptide–carbohydrate and peptide–ligand conjugates couple peptides with glycans or small-molecule ligands to engage lectins, receptors, and other binding partners with defined valency and spacing.

Peptide Core
Scaffold · Targeting
Spacer & Chemistry
Amide · Oxime · Click
Carbohydrate / Ligand
Glycan · Small Molecule
Product Highlights
  • Glycopeptide conjugates for lectin targeting and immune receptor engagement.
  • Peptide–small ligand conjugates for receptor or enzyme targeting.
  • Multivalent displays with controlled spacing and geometry.
Preferred Applications
  • Glycobiology and receptor–glycan interaction studies.
  • Targeted delivery or blocking ligands presented on peptide scaffolds.
  • Diagnostic and biosensor applications involving lectin or receptor capture.

Peptide–Fluorophore & Imaging Conjugates

Peptide–fluorophore and peptide–imaging conjugates allow sensitive visualization of peptide distribution, interaction, and activity in cells, tissues, and in vivo models.

Peptide
Targeting · Reporter
Spacer & Handle
Amide · Click · Thiol
Imaging Payload
Fluorophore · Chelator · NIR
Product Highlights
  • Peptide–fluorophore conjugates using FITC, Cy dyes, Alexa Fluor®, and other visible labels.
  • Near-IR peptide imaging agents for in vivo work.
  • Peptide–chelator conjugates (e.g., DOTA, NOTA) for radiometal labeling.
Preferred Applications
  • Cell uptake and localization studies.
  • In vivo peptide targeting and biodistribution imaging.
  • Biosensor and assay readouts requiring labeled peptides.

Peptide–Surface & Solid-Support Conjugates

Peptide–surface and solid-support conjugates immobilize peptides on magnetic beads, microplates, biosensor chips, and chromatography resins for capture, screening, and interaction studies.

Surface / Solid Support
Beads · Plates · Chips · Resins
Surface Chemistry
EDC/NHS · Maleimide · Biotin–SA
Peptide Payload
Capture · Motif · Library
Product Highlights
  • Peptide-coated magnetic beads for capture, depletion, or enrichment.
  • Peptide-functionalized plates and chips for interaction and binding assays.
  • Peptide–resin conjugates for affinity chromatography and purification.
  • High loading with controlled blocking to reduce non-specific binding.
Preferred Applications
  • Target capture and pull-down workflows.
  • Affinity chromatography and peptide-based purification.
  • Biosensor chips and SPR/BLI surfaces with immobilized peptides.

Peptide–Chemical Handle & Click-Ready Conjugates

Peptide–chemical handle and click-ready conjugates introduce azide, alkyne, tetrazine, DBCO, thiol, and other reactive groups at specific positions, enabling modular downstream conjugation and library assembly.

Peptide
Backbone · Side Chain
Chemical Handle
Azide · Alkyne · Tetrazine · DBCO · Thiol
Future Payload
Drug · Oligo · Dye · NP
Product Highlights
  • Peptides bearing single or multiple orthogonal click handles.
  • Strategic placement to preserve peptide function while enabling conjugation.
  • Compatibility with aqueous or mixed organic click conditions.
Preferred Applications
  • Modular library synthesis and late-stage functionalization.
  • Tool compound and probe generation.
  • Platform peptides for internal conjugation workflows.

Peptide Therapeutic Conjugates

Peptide therapeutic conjugates integrate peptides with drugs, oligonucleotides, proteins, lipids, or carriers to create targeted, long-acting, or multifunctional therapeutic candidates for discovery and preclinical work.

Product Highlights
  • Integration of targeting, CPP, or cleavable peptides with small-molecule or biologic payloads.
  • Support for non-GMP discovery and preclinical conjugates across multiple modalities.
  • Flexible lot sizes for feasibility, SAR, and lead optimization campaigns.
Preferred Applications
  • Preclinical peptide–drug, peptide–oligonucleotide, or peptide–protein candidate evaluation.
  • Mechanism-of-action and PK/PD exploration using conjugate formats.
  • Early-stage therapeutic concept testing with custom peptide conjugates.

Peptide Diagnostic & Biosensor Conjugates

Peptide diagnostic and biosensor conjugates are engineered as capture reagents, reporters, and surface ligands for in vitro diagnostics, point-of-care tests, and analytical biosensors.

Product Highlights
  • Peptide–enzyme, peptide–fluorophore, and peptide–nanoparticle reagents for assay signal generation.
  • Peptide-decorated beads, plates, and chips for capture and detection.
  • OEM- and kit-ready formats with documentation and lot control.
Preferred Applications
  • ELISA, lateral flow, and multiplexed diagnostic assays.
  • SPR/BLI and other biosensor platforms using peptide capture or reporter constructs.
  • Activity-based and proximity-based assays built around peptide conjugates.

Technical Summary — Peptide Bioconjugation Platform

Workflow
  • Project intake and design review (peptide, payload, application, and risk mapping).
  • Conjugation route scouting and linker/spacer optimization.
  • Scale-up with in-process monitoring and process control.
  • Purification and polishing tailored to conjugate type.
  • QC and documentation aligned with downstream needs.
Controls & Comparators
  • Unconjugated peptide and payload controls.
  • Spacer length, linker type, and conjugation site variants.
  • Cleavable vs non-cleavable conjugate comparisons.
  • Functional benchmarks (potency, binding, assay performance).
Analytics & Documentation
  • Identity and purity by LC-MS and HPLC/UPLC; SDS-PAGE or CE as needed.
  • Loading, aggregation, and functional assay panels where applicable.
  • Certificates of Analysis and optional tech transfer documents.

FAQ

Which peptide and payload types do you support?

We work with linear and modified peptides, small-molecule drugs, oligonucleotides (siRNA, ASO, DNA/RNA, PNA), proteins/antibodies, polymers, nanoparticles, lipids, carbohydrates, and surfaces. We can advise on conjugation handles and design options during project scoping.

Can you synthesize the peptide and perform the conjugation?

Yes. Bio-Synthesis can synthesize and purify the peptide, then perform bioconjugation to your payload and deliver the final peptide conjugate as a unified workflow.

Do you offer peptide–drug conjugates (PDCs) for oncology projects?

We support non-GMP PDC work for discovery and preclinical research, including peptide design guidance, linker selection, and analytical characterization. We align scope with your internal safety and regulatory requirements.

What information do you need to scope a peptide bioconjugation project?

At minimum, we need peptide sequence and role, payload identity, desired conjugation format (e.g., peptide–drug, peptide–siRNA, peptide–protein, peptide–polymer, peptide–nanoparticle), application context, and any required performance metrics (potency, binding, assay readout, or stability).

Can you support diagnostic kit or OEM reagent programs?

Yes. We work with customers who require enhanced documentation, lot control, and stability programs suitable for kit/OEM and regulated environments, and can align release criteria to your specifications.

Do you work under NDA and handle proprietary sequences or payloads?

Bio-Synthesis routinely works under NDA/MSA and treats all sequences, structures, and project results as confidential. We can coordinate secure material transfer and data exchange as part of project setup.

Contact

Speak to a Peptide Bioconjugation Scientist

Share your peptide sequence, payload, application, and target performance. We will recommend a conjugation route, linker strategy, and QC package, then provide a project quote.

Request a Quote Feasibility Review OEM / Kit Partner Sample Submission
Email: sales@biosyn.com
Phone: +1-972-420-8505
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Recommended Reading & Bio-Synthesis Resources

  • Hermanson, G. T. (2013). Bioconjugate Techniques, 3rd Ed. Academic Press — Core reference for peptide, protein, and small-molecule bioconjugation chemistries.
  • Krall, N., Da Cruz, F. P., Boutureira, O., & Bernardes, G. J. L. (2016). Bioconjugation of Peptides and Proteins — Overview of strategies for peptide and protein conjugates.
  • Polakis, P. and others — Reviews on peptide–drug conjugates and targeted therapeutics discussing linker design, payload selection, and clinical translation.
  • Bio-Synthesis, Inc. — Application notes, technical bulletins, and white papers on custom peptide bioconjugation and peptide–drug conjugation, available upon request or via the company website.

Why Choose Bio-Synthesis

Trusted by biotech leaders worldwide for over 40+ years of delivering high quality, fast and scalable synthetic biology solutions.

Greetings Researchers,

Please be advised that any information, guidelines, writeups, and oral/video/graphic content on our website are intended solely as general guidelines.
It is the researcher's sole responsibility to conduct thorough research on the designs of the products intended for their experiments before submitting
their designs to Biosynthesis for review of production feasibility.
Thank you for your understanding.

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