Conjugation Services
Project-Based Synthetic Conjugates
Raysun evaluates conjugation programs on a project basis, with scope defined around molecular design, payload or oligonucleotide format, linker chemistry, purification strategy and analytical requirements. Each program is reviewed for technical fit before a development plan is proposed.
Potential projects may include peptide–drug conjugates (PDCs), peptide–oligonucleotide conjugates (POCs and PPMOs), and selected peptide–small-molecule conjugates. Conjugation sites, linkage options and characterization methods are selected according to the intended research use and stage of development.
Conjugate Design Framework
Linkage and analytical plans are confirmed through project-specific feasibility review.
POC & PPMO Development
Peptide–Oligonucleotide Conjugates
Peptide–oligonucleotide conjugates combine a peptide component with an ASO, siRNA, PMO or other selected oligonucleotide format. The development challenge is not only to form the linkage, but also to preserve the intended properties of both components while establishing a practical purification and characterization strategy.
01 / MOLECULAR DESIGN
Component & Site Selection
Review peptide sequence, oligonucleotide format, conjugation position and steric accessibility before selecting a terminal or internal attachment site.
02 / PROCESS STRATEGY
Reaction & Purification Planning
Evaluate functional-group compatibility, reaction conditions, expected side products and the separation approach required for the proposed construct.
03 / CHARACTERIZATION
Identity & Quality Assessment
Define fit-for-purpose identity, purity and molecular-mass confirmation based on the construct, intended research use and stage of the program.
Linkage Strategy
Conjugation Method Planning
The linkage route is selected after reviewing the available functional groups, desired stability, component sensitivity and downstream analytical needs. The options below illustrate common starting points; final feasibility and availability are confirmed through technical review.
Amide Coupling
Amino- and carboxyl-functional partners may provide a direct, stable route when protecting-group strategy and reaction selectivity are compatible.
Disulfide Strategy
Thiol-bearing components can support reversible disulfide linkages where the required handling, redox sensitivity and product stability are acceptable.
Thioether Formation
Thiol-selective routes may be considered for stable carbon–sulfur linkages, subject to sequence context, competing groups and purification behavior.
Click Chemistry
Azide–alkyne handles can enable copper-catalyzed or strain-promoted coupling, with the route selected according to component compatibility and project needs.
Design Considerations
Conjugation Site Options
Attachment position can influence accessibility, reaction efficiency and the behavior of the final conjugate. Site selection is assessed together with sequence design, linker length and the planned analytical workflow.
3′-Amino Modifiers
A terminal amino handle may support amide-forming routes while keeping the reactive group separate from many sequence-dependent internal positions.
5′-Amino Modifiers
A 5′ attachment point may offer an alternative orientation for peptide or linker installation when compatible with synthesis and purification plans.
Thiol-Enabled Sites
Thiol functionality may be introduced through suitable peptide residues or oligonucleotide modifiers for disulfide or thioether-based strategies.
Click-Compatible Handles
Azide or alkyne groups may be placed at selected terminal or internal sites when an orthogonal click-conjugation route is technically appropriate.