Peptide-Based Nucleic Acid Delivery Services

Peptide-Based Nucleic Acid Delivery Services

siRNA DeliverymRNA Carrier DesignPNA / PMO ConjugatesCPP-Oligo Formulation

At Creative Peptides, we provide peptide-based nucleic acid delivery services for research and non-clinical development programs that need practical, customizable solutions for intracellular cargo transport. Our team supports the design, synthesis, conjugation, formulation, and analytical characterization of peptide-enabled delivery systems for siRNA, mRNA, antisense oligonucleotides, splice-switching oligos, peptide nucleic acids (PNA), and phosphorodiamidate morpholino oligomers (PMO). By combining peptide synthesis, cargo-specific delivery design, and custom conjugation service capabilities, we help academic, biotech, and pharmaceutical teams build delivery constructs that are better matched to their sequence chemistry, uptake pathway, and downstream assay goals.

Why Peptide-Based Nucleic Acid Delivery Matters in Development

Nucleic acid cargo can show excellent sequence specificity, but delivery usually becomes the decisive technical bottleneck long before a project reaches reliable biological readout. siRNA and many oligos require efficient cell entry while preserving duplex or strand integrity. mRNA adds further complexity because cargo length, charge density, RNase sensitivity, and cytosolic release all influence whether expression is measurable. PNA and PMO often need a different design logic altogether, because charge-neutral cargo may not benefit from the same electrostatic assembly strategy used for RNA.

Peptide-based delivery services help address these issues by:

Matching delivery mode to cargo chemistry: We help determine when covalent peptide conjugation is more appropriate than non-covalent complex formation, and when hybrid systems are worth exploring.

Improving intracellular performance: Carrier peptides can be designed to support cellular uptake, endosomal escape, cargo release, and trafficking behavior relevant to the intended assay.

Reducing formulation uncertainty: N/P ratio, particle size, surface charge, linker architecture, and buffer conditions can be screened in a more structured way instead of by trial and error.

Generating decision-ready materials: Well-characterized conjugates or peptide-cargo complexes support cleaner interpretation in uptake studies, reporter assays, splice-switching work, and comparative screening.

Our Peptide-Based Nucleic Acid Delivery Services

We offer flexible service workflows for teams developing peptide-mediated nucleic acid delivery systems from early concept through research-ready material supply. Projects can be configured around client-supplied cargos, new carrier peptide design, or integrated workflows that combine formulation and conjugation modules with peptide modification services for labeling, shielding, linker installation, and follow-on optimization.

Delivery Route Design

The first design question is usually not which peptide to choose, but which delivery architecture makes sense for the cargo. We review cargo class, strand length, backbone chemistry, sequence constraints, target cell context, and required readout before proposing a practical route.

Cargo-specific planning for siRNA, mRNA, antisense oligos, SSO, PNA, and PMO delivery.

Selection between peptide-cargo conjugates, electrostatic complexes, peptide nanoparticles, or hybrid peptide-lipid systems.

Early assessment of uptake barriers, endosomal trapping risk, nuclease exposure, and release requirements.

Definition of recommended screening parameters, analytical package, and material specifications.

This front-end design work helps reduce avoidable reformulation cycles and aligns chemistry with the biological question from the start.

Carrier Peptide Design

We design and prepare carrier peptides using solid-phase peptide synthesis (SPPS) routes selected for the required sequence architecture, scale, and downstream coupling plan.

Cationic, amphipathic, histidine-rich, targeting, branched, cyclic, or hybrid carrier peptide formats.

Introduction of reactive handles, shielding elements, fatty-acid motifs through peptide lipidation, or hydrophilic balance through PEGylation where needed.

Orthogonal protection and site-defined functionalization for controlled downstream cargo attachment.

Preparation of single candidates or parallel peptide panels for screening campaigns.

Our focus is to produce carrier sequences that are synthetically practical and directly usable in conjugation or formulation studies.

PNA/PMO Conjugates

PNA and PMO projects often call for chemically defined peptide conjugates rather than loose formulations. We support peptide-PNA and peptide-PMO construct design for uptake enhancement, trafficking studies, and structure-activity comparison.

Site-specific conjugation planning for N- or C-terminal attachment, spacer insertion, and cleavable or non-cleavable linker selection.

Support for charge-balanced, amphipathic, targeting, or endosomal escape-oriented peptide motifs.

Preparation of single conjugates or matched analog sets with varied peptide sequence, linker length, or attachment position.

Analytical confirmation of conjugate identity, purity, and composition by LC-MS, HPLC, and gel-based methods when appropriate.

These services are well suited to teams that need defined delivery constructs for neutral nucleic acid analogs where conjugation strategy strongly influences performance.

siRNA/Oligo Complexes

For siRNA and many negatively charged oligonucleotides, non-covalent assembly with cationic or amphipathic peptides is often the more useful development route. We build and optimize peptide-based complexes for screening and assay support.

Peptide/siRNA and peptide/oligo complex preparation across defined peptide:cargo or N/P ratios.

Duplex integrity and formulation compatibility review for phosphorothioate, mixed-backbone, or otherwise modified oligos.

Screening of condensation strength, dispersion behavior, aggregation tendency, and buffer dependence.

Optional incorporation of targeting motifs, lipophilic components, or imaging labels for mechanistic comparison.

The goal is to generate complexes that are stable enough to handle, yet still capable of cargo release once internalized.

mRNA Carrier Systems

mRNA delivery requires a distinct formulation strategy because cargo size, secondary structure, and degradation sensitivity can rapidly expose weaknesses in otherwise acceptable peptide carriers. We support peptide-enabled mRNA delivery system development for transfection and expression-focused studies.

Formulation of peptide/mRNA complexes or peptide-assisted hybrid assemblies for capped and polyadenylated mRNA cargo.

Evaluation of carrier architecture for condensation, protection, intracellular release, and compatibility with reporter expression studies.

RNase-aware handling workflows and formulation conditions selected to reduce avoidable cargo loss during processing.

Comparative screening of cationic, amphipathic, histidine-rich, or branched peptide formats for large RNA payloads.

We help teams move beyond simple binding toward delivery systems that balance packaging with productive cytosolic release.

Targeting & Escape

Many nucleic acid delivery projects fail not because the cargo cannot enter the cell, but because too little reaches the correct intracellular compartment. We support targeted uptake and endosomal escape optimization as separate design variables rather than afterthoughts.

Histidine-rich, amphipathic, membrane-active, or pH-responsive peptide motifs for improved endosomal release behavior.

Receptor-binding or cell-associated peptide motifs for exploratory targeted delivery studies.

Linker and spacer selection for conjugates that need controlled cleavage, reduced steric hindrance, or improved presentation.

Comparative testing of unmodified versus targeted or escape-enabled carrier designs.

This module is especially useful when uptake signal is present but functional readout remains weak or inconsistent.

QC & Screening

Delivery projects need more than a sequence confirmation. We provide analytical characterization and screening-oriented support to help technical teams understand what was made, how it behaves, and which versions deserve follow-up.

LC-MS, analytical HPLC, PAGE or agarose gel assessment, UV-based quantitation, and conjugate composition review where applicable.

DLS particle size, PDI, zeta potential, encapsulation or complexation assessment for formulated systems.

Preparation of labeled constructs using fluorescence and dye labeling to support uptake and trafficking studies.

Research-scale material supply with reporting packages aligned to screening, transfection, and mechanism-focused work.

Cargo-Specific Peptide Delivery Strategies

Not all nucleic acid cargos should be developed through the same peptide delivery route. The table below summarizes how cargo properties typically influence delivery architecture, design focus, and project output.

siRNA

Cationic or amphipathic peptide complexes, peptide nanoparticles, peptide-lipid hybrids

Improve cellular uptake while preserving duplex integrity and enabling cytosolic release

Balancing condensation strength with endosomal escape and productive unpacking

Screened peptide/siRNA formulations with particle and analytical characterization

mRNA

Peptide polyplexes, branched peptide systems, amphipathic peptide assemblies, hybrid carriers

Protect large RNA cargo and support intracellular release for measurable expression

Cargo fragility, high charge density, RNase sensitivity, and incomplete endosomal escape

Formulated peptide/mRNA systems with ratio screening and transfection-oriented support

ASO / SSO / Other Oligos

Peptide complexes, targeted peptide conjugates, or hybrid systems depending backbone chemistry

Increase uptake, intracellular exposure, or splice-switching readout

Sequence-dependent uptake behavior and variable tolerance to complexation or attachment chemistry

Cargo-specific delivery prototypes with comparative chemistry options

PNA

Defined peptide-PNA conjugates, lipophilic peptide conjugates, targeted CPP constructs

Overcome poor intrinsic cellular uptake of charge-neutral analogs

Choosing peptide architecture and linker design without undermining hybridization function

Site-defined PNA-peptide conjugates with identity and purity data

PMO

Peptide-PMO conjugates, amphipathic or cationic CPP-linked constructs

Improve intracellular delivery and endosomal release of steric-blocking cargo

Attachment-site effects, endosomal trapping, and conjugate solution behavior

PPMO-style research constructs and matched analog panels for screening

Key Design Variables for Delivery Development

Peptide-mediated nucleic acid delivery depends on several adjustable variables that can be screened systematically. The table below links those variables to practical project decisions and the readouts typically used to compare candidates.

Peptide Architecture

Controls condensation, membrane interaction, and compatibility with the chosen cargo

Cationic, amphipathic, histidine-rich, branched, cyclic, targeting, or hybrid peptides

Complexation behavior, uptake signal, reporter response, conjugate purity

Identifies which carrier class fits the cargo and assay objective

Attachment Chemistry

Determines whether the cargo remains chemically defined, releasable, and analytically tractable

Amide, click, thiol-based, disulfide, spacer-assisted, cleavable, or non-cleavable linkers

LC-MS confirmation, intact mass shift, release comparison, stability assessment

Reduces rework in conjugate-heavy PNA and PMO programs

Peptide:Cargo Ratio

Strongly affects packing strength, surface charge, and cargo release

Defined molar ratios, N/P screening matrices, staged titration studies

Gel shift, DLS, zeta potential, uptake trend, expression or knockdown signal

Helps locate the usable formulation window rather than a single arbitrary condition

Particle Properties

Size distribution and surface behavior influence reproducibility and cellular interaction

Compact polyplexes, loose complexes, hybrid nanoparticles, sterically shielded systems

Particle size, PDI, dispersion stability, turbidity, storage sensitivity

Supports candidate selection for downstream biological testing

Endosomal Escape Logic

Internalization alone may not produce functional delivery if cargo remains trapped intracellularly

Histidine-rich motifs, amphipathic sequences, membrane-active designs, cleavable elements

Uptake versus function comparison, trafficking studies, reporter expression, splice response

Clarifies why some high-uptake candidates still underperform biologically

Analytical Labeling

Tracking tools are often needed to separate uptake, localization, and activity questions

Fluorophore-tagged peptides, labeled oligos, dual-labeled systems, affinity handles

Fluorescence intensity, localization imaging, co-localization, comparative uptake

Produces more interpretable mechanism data during carrier optimization

Why Choose Our Peptide–Nucleic Acid Delivery Platform

Cargo-Specific Planning

We distinguish between RNA formulations, oligo delivery systems, and defined PNA/PMO conjugates instead of forcing one platform across every cargo type.

Peptide Chemistry Depth

Our workflows integrate carrier peptide synthesis, linker installation, lipidation, PEGylation, and follow-on modification in one coordinated project path.

Conjugate & Complex Coverage

We support both chemically defined peptide-oligo conjugates and non-covalent peptide-cargo assemblies, which is important when moving across siRNA, mRNA, PNA, and PMO programs.

Practical Optimization Focus

Services are built around real project variables such as conjugation site, N/P ratio, endosomal escape, aggregation tendency, and cargo release behavior.

Delivery-Relevant Analytics

We combine peptide and nucleic acid characterization with particle analysis and labeling options so teams can connect chemistry with biological readout more clearly.

Flexible Screening Support

From single prototype constructs to comparative candidate panels, we support workflows suited to feasibility studies, optimization rounds, and non-clinical research supply.

Peptide-Based Nucleic Acid Delivery Service Workflow

Our workflow is designed to move from cargo review to delivery-ready constructs or formulations with clear analytical documentation and practical decision support.

1

Cargo Review & Project Scoping

We review cargo type, backbone chemistry, strand length, labeling needs, target cell system, quantity requirement, and intended biological readout.

A development plan is proposed that defines the preferred delivery route, screening variables, analytical scope, and expected technical risks.

2

Peptide & Linker Design

Carrier peptide sequence, branching pattern, targeting motif, escape feature, and optional linker or shielding element are selected for the project.

For conjugate projects, attachment position and chemistry are locked before synthesis to avoid avoidable redesign later.

3

Synthesis & Assembly

Peptides are synthesized and modified as required, then used for cargo conjugation or peptide-cargo assembly under controlled conditions.

Parallel variants can be generated to compare sequence, linker, or formulation parameters within the same workflow.

4

Characterization & Optimization

Conjugates or formulations are characterized by methods selected for the construct, such as LC-MS, HPLC, PAGE, gel shift, DLS, zeta potential, or fluorescence-based tracking.

Key formulation variables such as ratio, particle quality, and release-related behavior can be optimized in focused rounds.

5

Delivery Package & Follow-On Support

Final materials are supplied with the agreed data package for research, screening, and non-clinical evaluation.

Follow-on work may include expanded peptide panels, targeted variants, labeled constructs, or second-round optimization based on early biological results.

Research Uses of Peptide–Nucleic Acid Delivery Systems

Peptide-mediated nucleic acid delivery is useful across discovery and assay-development settings where intracellular exposure, trafficking, or readout sensitivity must be improved. Below are representative research directions supported by this service model.

siRNA Knockdown Screening

Prepare peptide/siRNA delivery systems for comparative gene-silencing studies across different carrier architectures.

Compare formulation windows that influence uptake, release, and assay reproducibility.

Generate labeled or targeted versions for mechanism-focused uptake studies.

mRNA Expression Studies

Build peptide-enabled mRNA carrier systems for reporter expression, transfection optimization, and intracellular release studies.

Compare cationic, amphipathic, branched, or hybrid peptide designs for large RNA cargo.

Support early ranking of candidate carriers before broader biology work.

Splice-Switching Workflows

Develop delivery constructs for steric-blocking oligos and PMO cargo used in exon-skipping or splice-modulation research.

Compare conjugate versus complex strategies where uptake and endosomal release behave differently.

Provide defined materials for structure-activity assessment.

PNA Delivery Research

Prepare peptide-PNA conjugates for antisense, hybridization, or intracellular target engagement studies.

Evaluate linker placement, peptide class, and lipophilic balance in PNA transport systems.

Support mechanistic studies on uptake barriers and intracellular localization.

Targeted Uptake Exploration

Add receptor-associated or cell-interactive peptide motifs to evaluate whether uptake can be redirected in exploratory models.

Compare targeted and non-targeted systems under the same analytical framework.

Generate tracking-ready constructs for localization and trafficking studies.

Delivery Mechanism Studies

Use labeled carriers and cargo to separate uptake, endosomal retention, and functional release questions.

Build matched analog sets to study how charge, linker, peptide sequence, or shielding changes delivery behavior.

Produce decision-supportive datasets for next-round carrier design.

Start Your Peptide-Based Nucleic Acid Delivery Project

If your team needs a practical peptide delivery strategy for siRNA, mRNA, oligonucleotides, PNA, or PMO cargo, Creative Peptides can support your program with cargo-aware design, peptide synthesis, conjugation, formulation development, and delivery-relevant analytics. We work with academic groups, biotech companies, pharmaceutical teams, and outsourcing partners on custom research and non-clinical projects tailored to sequence chemistry and assay goals. Contact us today to discuss your cargo type, delivery challenge, and preferred project scope.

FAQs

We can support peptide-enabled delivery projects for siRNA, mRNA, antisense oligonucleotides, splice-switching oligos, PNA, PMO, and related modified nucleic acid cargos used in research workflows.

The choice depends on cargo charge, backbone chemistry, strand length, release requirements, and assay purpose. PNA and PMO often fit defined peptide conjugates, while siRNA and many oligos are more often developed as peptide-cargo complexes or nanoparticles.

Yes. We can build projects around client-supplied siRNA, mRNA, oligos, PNA, or PMO, or around carrier peptides that need to be newly designed and synthesized.

Common options include cationic, amphipathic, histidine-rich, branched, cyclic, targeting, lipidated, or otherwise modified peptide carriers, depending on the delivery objective.

Yes. Depending on the project, we can provide LC-MS, HPLC, PAGE or gel-based analysis, particle size, PDI, zeta potential, and other delivery-relevant characterization data.