Peptide–DNA Conjugation Services

• Defined 1:1 stoichiometry supporting reproducible characterization and comparability
• Reduced variability versus electrostatic complexation strategies
• Modular architecture for targeting ligands, CPP concepts, and assay constructs
• Clear structure–property relationships to support rational optimization
• Compatibility with program-aligned purification and analytical documentation

ssDNA (peptide–ssDNA conjugates)

Single-stranded DNA constructs with defined terminal handles (5′/3′) and optional internal handles (program-dependent).

• 5′ or 3′ functional handles
• Short to moderate-length ssDNA
• Optional labels/handles (design-dependent)

dsDNA (peptide–dsDNA conjugates)

Typically assembled from annealed strands; peptide attachment can be planned on one strand or at defined termini.

• Annealed duplex constructs
• Defined attachment placement
• Program-dependent size range

Modified DNA

Selected modified DNA designs can be evaluated when compatible handles and purification strategy are defined.

• Phosphorothioate DNA (PS)
• Chimera designs (design-dependent)
• Other specialty modifications (program-dependent)

CPP prototypes

Often used starting points to increase cellular association (performance is context-dependent).

• TAT-derived peptides
• Penetratin-derived peptides
• Oligo-arginine (R8 / R9)
• Transportan-related designs

Targeting ligands

Selected to bias uptake via receptor-mediated pathways (selection depends on model and goals).

• RGD / iRGD motifs
• Other receptor-binding peptides (program-dependent)
• Affinity tags for assay constructs

Architectures

Optional designs when the program requires multivalency or additional functional features.

• Branched peptides (site-defined)
• PEG/spacer tuning for sterics
• Dual-handle constructs (program-dependent)

Copper-free click (DBCO/BCN)

A common default for oligonucleotide compatibility and site specificity.

• Azide–DBCO / azide–BCN
• High selectivity and reproducible conversions
• Straightforward workup and cleanup

Thiol–maleimide

Fast coupling using terminal thiols and maleimide handles.

• Useful for feasibility builds and research constructs
• Handle planning reduces multi-site mixtures
• Stabilized designs can be considered

Amide coupling

Activated ester routes when suitable handles are available.

• Useful when click handles are constrained
• Requires strict control to limit heterogeneity
• Often paired with protected handles

Cleavable linkers

Selected when intracellular release is required (program-dependent).

• Disulfide (reducible)
• Other cleavable designs (program-dependent)

Non-cleavable linkers

Preferred when stable linkage is the priority.

• Stable thioether or triazole linkages
• Construct stability for tracking/controls

Design inputs we review

Practical peptide–DNA design starts with constraints. We review DNA format, length, modification map, and attachment site options to propose a handle + linker plan that preserves DNA integrity and limits conjugate heterogeneity.

• DNA format: ssDNA vs dsDNA; strand/terminus selection
• Attachment location: 5′ / 3′ or internal handle placement (program-dependent)
• Peptide selection: targeting ligands vs CPP concepts; charge/hydrophobicity constraints; optional branching
• Linker choice: stable vs cleavable; spacer length (PEG/alkyl) to manage sterics and solubility
• Purification strategy: RP-HPLC / IEX / SEC selection based on construct polarity and size

Mechanism note (CPPs and targeting peptides)

Peptides used in DNA conjugates may support cellular association and uptake through multiple pathways (including receptor-mediated endocytosis for targeted ligands and other uptake routes for cationic CPPs). Design decisions (net charge, hydrophobicity, and linker architecture) are made to match the intended uptake concept while balancing stability, solubility, and analytical clarity.

Note: uptake and activity are sequence- and context-dependent; we focus on providing well-defined materials and documentation suitable for your program stage.

Standard QC

• Purity assessment (chromatography-based)
• Identity and conjugation confirmation using mass-based and orthogonal methods where applicable
• COA + method summary

Optional controls

• DNA-only control
• Peptide-only control
• Matched design variants (linker/handle comparisons)

Aligned to intended use

Analytical depth and documentation can be aligned to feasibility, preclinical, or translational workflows.

Bio-Synthesis is committed to Total Quality Management (TQM) to ensure consistent quality, traceability, and customer satisfaction across DNA synthesis, peptide synthesis, and peptide–DNA conjugation services.

Each DNA–peptide conjugate is produced under controlled procedures with in-process monitoring and final analytical verification. Identity confirmation is performed by mass spectrometry, and purity is assessed using HPLC and/or capillary gel electrophoresis, as appropriate for the construct.

Purification and quality assurance (QA) procedures are applied to deliver high-quality oligo–peptide conjugates suitable for reproducible research and development workflows. Our quality system follows ISO 9001–aligned practices, with documentation and release criteria scaled to the intended use and program stage.