Aptamer-Protein/Peptide Conjugate Development Service

Aptamer-Protein/Peptide Conjugate Development Service

Creative Biolabs develops aptamer-protein and aptamer-peptide conjugates for researchers who need to combine the molecular recognition of an aptamer with the biological activity, delivery properties, catalytic function, immune activity, or structural features of a protein or peptide. We support conjugate design, site-selective chemistry, linker optimization, purification, analytical characterization, and fit-for-purpose functional validation.

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Service Overview

Connect Aptamer Recognition with Protein or Peptide Function

Custom conjugates designed around the biological mechanism

Our service is built for programs in which a nucleic acid aptamer must be physically linked to a functional protein or peptide without compromising either component. Typical needs include targeted delivery of enzymes or toxins, bispecific aptamer-antibody constructs, peptide-assisted cellular uptake, affinity enhancement, immune-cell engagement, biosensor labeling, and development of multifunctional research reagents.

Projects may begin with a customer-supplied aptamer and payload or be integrated with our aptamer development service. When a suitable sequence has not yet been established, our one-stop aptamer in vitro selection service can be incorporated before conjugation development.

Aptamersequence, fold, target recognition
Payloadprotein, antibody, enzyme, peptide
Linkagesite, spacer, stoichiometry
Functionbinding, activity, delivery
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Conjugate Formats

Protein and Peptide Architectures for Different Research Objectives

The payload class determines the most important development risks. We therefore select chemistry, purification, and validation methods according to the size, stability, reactive groups, and mechanism of the protein or peptide.

Targeted biologics

Aptamer-Protein Conjugates

Conjugation of aptamers with recombinant proteins, toxins, cytokines, growth factors, binding proteins, or other functional proteins for targeted delivery or dual-function molecular systems.

Bispecific design

Aptamer-Antibody Conjugates

Hybrid constructs that combine an aptamer-defined target with antibody recognition or Fc-mediated biology. Programs can examine conjugation orientation, aptamer-to-antibody ratio, retained binding, and cell-based activity.

Catalytic readout

Aptamer-Enzyme Conjugates

Enzyme labeling or enzyme-payload formats for biosensing, signal generation, catalytic delivery, and mechanistic studies, with evaluation of enzyme activity after conjugation.

Compact payloads

Aptamer-Therapeutic Peptide Conjugates

Direct coupling of bioactive peptides to an aptamer to introduce a second binding interface, modulate target function, improve localization, or enable targeted peptide delivery.

Delivery support

Cell-Penetrating Peptide Conjugates

CPP-linked aptamers designed to improve cellular entry, intracellular trafficking, or endosomal escape while retaining target recognition and controlling nonspecific uptake.

Custom architecture

Multicomponent Conjugates

Project-specific combinations involving proteins, peptides, aptamers, imaging labels, cleavable motifs, or secondary payloads can be developed when each component has a defined mechanistic role.

Need help choosing between a protein, peptide, or small-molecule payload?

We can compare architecture options against the required mechanism and downstream assays.

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Molecular Engineering

Design the Interface Before Optimizing the Reaction

A conjugation reaction can be chemically successful and still produce a poor biological reagent. Our development strategy therefore considers aptamer folding, payload orientation, reactive-site accessibility, linker behavior, stoichiometry, purification, and the intended biological environment together.

Design Variable Options Key Development Question Representative Evidence
Aptamer modification 5′/3′ amine, thiol, azide, alkyne, biotin, spacer-equipped or other project-defined handle Can the aptamer be functionalized without disturbing its binding fold? Binding before/after modification and conjugation
Protein reactive site Native lysines/cysteines, introduced cysteine, glycan-directed or affinity-assisted approaches Can conjugation be controlled sufficiently to preserve protein function? Conjugation ratio, intact-mass or electrophoretic analysis
Peptide attachment N- or C-terminal coupling, side-chain attachment, solid-phase compatible conjugation Which orientation keeps both aptamer and peptide pharmacophores accessible? Identity, purity, binding and activity comparison
Linker architecture PEG, disulfide, protease-cleavable, acid-labile, noncleavable or custom spacers Should the payload remain tethered or be released in a defined environment? Stability, cleavage profile, functional response
Stoichiometry Defined 1:1 format or controlled multivalent ratios Does added valency improve function or create steric and aggregation risk? Ratio determination, binding, size and activity
Explore Aptamer Modification Services
Conjugation Chemistry

Select Chemistry That Matches the Biomolecules, Not Just the Available Handle

Selective thiol chemistry

Maleimide-Thiol Coupling

Useful when a defined thiol is available on the aptamer, peptide, or engineered protein. Reaction pH, competing thiols, hydrolysis, and conjugate stability are optimized as part of feasibility work.

Amine chemistry

NHS Ester Coupling

Suitable for amino-functionalized aptamers or accessible protein amines, with careful control of reagent ratio and reaction conditions to reduce over-modification and heterogeneity.

Orthogonal ligation

Click Chemistry

Azide-alkyne approaches support selective coupling and can be useful for peptides, proteins, and multicomponent systems when compatible handles can be installed.

Reversible linkage

Disulfide-Based Conjugation

Redox-sensitive linkages can be considered for intracellular release or for protein payloads where a reducible connection is mechanistically useful.

Affinity assembly

Biotin / Affinity-Mediated Formats

Noncovalent or semi-modular assembly can be useful for rapid feasibility studies, biosensor development, or systems requiring interchangeable components.

Site-selective development

Custom Conjugation Routes

Alternative site-selective methods can be evaluated when random amine or cysteine modification is unacceptable because of payload activity, heterogeneity, or downstream analytical requirements.

Already have both components?

Start with a focused conjugation feasibility study comparing one or more chemistry and linker options.

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Analytical Characterization

Confirm Identity, Purity, Stoichiometry, and Retained Function

Conjugate Identity

Electrophoresis, chromatography, mass-based analysis, or orthogonal confirmation selected according to construct size and chemistry.

Purity and Free Components

Assessment of residual free aptamer, protein, peptide, linker, or reaction by-products after purification.

Conjugation Ratio

Estimation or determination of aptamer-to-protein ratio, degree of labeling, or defined product stoichiometry.

Stability

Storage, dilution, serum or matrix challenge, nuclease exposure, freeze-thaw, and linker-specific stability as relevant.

Functional evidence can include

Aptamer target binding
Protein binding retention
Enzyme activity
Peptide bioactivity
Target-positive/negative selectivity
Competition/blocking
Internalization
Cellular localization
Cytotoxic or pathway response
Immune-cell functional response

Assays are selected to show that conjugation has not simply created the expected molecular mass, but has retained the biological roles needed for the proposed mechanism. Broader aptamer testing can be connected with our aptamer characterization services and aptamer in vitro analysis services.

Stage-Gated Development

Resolve Conjugation Risk Before Scaling the Construct

Programs can be configured as a compact feasibility package or an integrated development sequence. Decision gates are used to avoid carrying poorly characterized conjugates into expensive biological studies.

Define the Mechanism

Align target, aptamer, protein/peptide role, required linkage behavior, controls, and success criteria.

Prepare Components

Review or generate functional handles and establish quality criteria for the aptamer and payload.

Conjugation Screen

Compare chemistry, linker, ratios, buffer, time, temperature, and purification conditions.

Characterize Lead

Confirm identity, purity, ratio, stability, and retained activity of both functional components.

Validate Function

Test target-dependent binding, uptake, catalytic, signaling, cytotoxic, or immune response as appropriate.

Need a complete aptamer-to-conjugate workflow?

Sequence discovery, modification, conjugation, and biological validation can be coordinated in one program.

View Aptamer Development Capabilities
Research Applications

Build Conjugates for Delivery, Therapeutics, Diagnostics, and Mechanistic Research

Targeted Protein Delivery

Use aptamer recognition to enrich a toxin, enzyme, cytokine, or other protein payload at a target cell or molecular compartment.

Targeted Peptide Delivery

Direct bioactive, inhibitory, signaling, or cell-penetrating peptides toward a defined target while reducing nonspecific exposure.

Bispecific Molecular Systems

Combine aptamer recognition with antibody or protein binding to bridge two molecular targets or cellular populations.

Post-SELEX Aptamer Optimization

Extend the aptamer recognition interface with a rationally selected peptide to alter affinity or functional activity.

Biosensors and Enzyme Labels

Attach enzymes or reporter proteins while preserving aptamer recognition for analytical and diagnostic assay development.

Related Research

Research Informing Aptamer-Protein and Aptamer-Peptide Conjugate Design

These open-access original studies illustrate three different development questions: how peptide sequence can extend aptamer function, how a bispecific aptamer-antibody conjugate can retain both binding activities, and how enzyme labeling can be integrated into an aptamer detection system.

Thrombin-binding aptamer peptide conjugate design
Peptide-assisted affinity engineering

Regioselective thrombin aptamer-peptide conjugation

Varizhuk and colleagues optimized a tripeptide extension on a 15-nt thrombin aptamer and reported substantially improved anticoagulant activity, illustrating how peptide identity and attachment position can alter functional performance.

View research via DOI
EGFR aptamer ipilimumab immunoconjugate characterization
Aptamer-antibody bispecific format

EGFR aptamer-ipilimumab immunoconjugate

Passariello and colleagues chemically linked an EGFR-targeting RNA aptamer with ipilimumab and showed that the conjugate retained parental target binding while supporting enhanced immune-cell activity against cancer cells.

View research via DOI
Enzyme-based labeling strategy for DNA aptamer electrochemical detection
Aptamer-protein assay engineering

Enzyme-assisted aptamer detection of VEGF

Lee and colleagues used a glucose dehydrogenase fusion protein as a functional labeling element in a DNA aptamer electrochemical system, demonstrating how aptamer recognition can be integrated with protein-based catalytic signal generation.

View research via DOI
Questions and Answers

Frequently Asked Questions

Which proteins and peptides can be conjugated to an aptamer?

Projects may involve recombinant proteins, antibodies or antibody-derived formats, enzymes, toxins, cytokines, binding proteins, therapeutic peptides, cell-penetrating peptides, signaling peptides, or customer-defined research payloads. Feasibility depends on available conjugation handles, payload stability, required orientation, and the assays needed to confirm retained function.

Can Creative Biolabs work with my existing aptamer and protein or peptide?

Yes. We can begin with customer-supplied components and review sequence, modifications, purity, available reactive groups, target-binding data, payload activity, and material quantities before recommending a conjugation strategy.

How do you choose the conjugation chemistry?

The chemistry is selected from the molecular constraints of both components. Common considerations include the aptamer terminal handle, accessible protein cysteines or amines, peptide termini or side chains, desired site selectivity, linker stability, purification route, and whether the payload should remain attached or be released.

Can the aptamer-to-protein ratio be controlled?

Depending on the payload and chemistry, development can aim for a defined 1:1 product or a controlled degree of labeling. Analytical methods are selected to assess conjugation ratio and product heterogeneity before functional testing.

How do you verify that both components remain functional?

We combine analytical confirmation with fit-for-purpose functional tests. These can compare aptamer binding before and after conjugation and separately evaluate protein binding, enzyme activity, peptide bioactivity, target-selective uptake, immune-cell response, or another mechanism-specific endpoint.

Can you develop cleavable aptamer-peptide or aptamer-protein linkers?

Yes. Redox-sensitive, protease-cleavable, acid-labile, or other project-defined linkers can be considered when payload release is part of the intended mechanism. Stability and cleavage testing can be incorporated where suitable methods are available.

What information is useful for project scoping?

Please provide the target and research objective, aptamer sequence and modifications, protein or peptide identity, available reactive groups, known binding or activity data, preferred conjugate format, required material quantity, biological model, controls, and the decision the final data should support.

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Scientific Literature

References

  1. Varizhuk, Irina V., et al. “The Regioselective Conjugation of the 15-nt Thrombin Aptamer with an Optimized Tripeptide Sequence Greatly Increases the Anticoagulant Activity of the Aptamer.” Pharmaceutics, vol. 15, no. 2, 2023, article 604. https://doi.org/10.3390/pharmaceutics15020604.
  2. Passariello, Margherita, et al. “Ipilimumab and Its Derived EGFR Aptamer-Based Conjugate Induce Efficient NK Cell Activation against Cancer Cells.” Cancers, vol. 12, no. 2, 2020, article 331. https://doi.org/10.3390/cancers12020331.
  3. Lee, Jinhee, et al. “Application of a Glucose Dehydrogenase-Fused with Zinc Finger Protein to Label DNA Aptamers for the Electrochemical Detection of VEGF.” Sensors, vol. 20, no. 14, 2020, article 3878. https://doi.org/10.3390/s20143878.

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