Reactive · PEGylated Stealth Copolymer
Poly(NHSMA-co-PEGMA)
Also written P(NHSMA-co-PEGMA), NHSMA-PEGMA copolymer | Custom composition — no single CAS
A random copolymer of N-hydroxysuccinimide methacrylate (NHSMA) and PEGMA (poly/oligo(ethylene glycol) methacrylate). PEGMA makes up the majority of the chain, grafting a dense, non-ionic PEG brush that sterically shields the backbone from protein and cell adhesion; NHSMA is included as a minor, sparsely distributed comonomer, each unit carrying a reactive NHS ester. The result is a stealth, PEGylated scaffold that stays “conjugation-ready” — couple the NHS sites to an amine-bearing ligand, antibody, dye, or drug without disturbing the PEG brush around it.
- Moisture-sensitive — shipped and stored desiccated
Custom composition
(C₈H₉NO₄)ₘ-co-[C₅H₈O₂-(C₂H₄O)ₓ-OCH₃]ₙ
Poly(NHSMA-co-PEGMA)
Appearance: White to off-white powder
Character: PEG stealth + amine-reactive
Architecture: Random comb copolymer
Storage: -20 °C, dark, desiccated
ISO 9001:2015
Manufactured under certified quality management
Custom NHSMA:PEGMA Ratio
Reactive-site density tuned independently of PEG brush density
Batch-Level COA
Mn, Đ, composition, and NHS-ester activity per lot
Desiccated Cold-Chain Packaging
Preserves NHS-ester reactivity in transit and storage
CAS No.
Composition-dependent
Molecular Formula
(C₈H₉NO₄)ₘ-co-[C₅H₈O₂(C₂H₄O)ₓOCH₃]ₙ
Character
PEG stealth + amine-reactive
Mn Range
10K – 150K
Form
Powder
A stealth PEG brush with a few reactive handles
PEGMA and NHSMA aren't playing the same role here — one is the bulk material, the other is a sparse functional handle riding on top of it.
PEGMA: the stealth majority
Grafted PEG side chains hydrate and sterically shield the backbone from protein and cell approach — a non-ionic, charge-independent antifouling effect.
NHSMA: the sparse reactive minority
Each NHS ester reacts with a primary amine to install exactly one ligand, dye, or biomolecule per site — a small fraction of units is usually enough.
Ratio protects the PEG brush
Keeping NHSMA content low preserves a dense, contiguous PEG brush; too much reactive comonomer starts to thin out steric shielding.
Couple once, keep the brush intact
Reacting the NHS sites with your target amine doesn't touch the PEGMA units — the stealth behavior of the rest of the chain is unaffected.
Most reactive-PEGylated designs in the literature sit in the 2–15 mol% NHSMA range — enough reactive sites for practical conjugation density without materially thinning the PEG brush's steric shielding.
Values below are representative for this monomer pair. Batch-specific COAs with GPC, composition, and NHS-ester activity data are available on request.
| Chemical Name | Poly(N-hydroxysuccinimide methacrylate-co-poly(ethylene glycol) methacrylate) |
|---|---|
| Synonyms | P(NHSMA-co-PEGMA) · NHSMA-PEGMA copolymer · Reactive PEGylated copolymer |
| Monomer Units | N-hydroxysuccinimide methacrylate (NHSMA) · PEGMA (mono-methoxy PEG methacrylate / OEGMA) |
| Architecture | Random comb (graft-through) copolymer — not block |
| NHSMA : PEGMA Ratio | Custom / composition-dependent — commonly 2:98 to 20:80 mol% |
| PEG Side-Chain Mn | Typical macromonomer options: ~200, 300, 500, 950 g/mol (custom on request) |
| Reactive Group | N-hydroxysuccinimide (NHS) active ester on NHSMA units, reacts with primary amines |
| CAS Number | Not applicable — composition-specific random copolymers are not assigned a single CAS RN |
| Molecular Weight (Mn) | Custom synthesis, typically 10,000–150,000 g/mol |
| Dispersity (Đ) | 1.1–1.3 (RAFT/ATRP) · broader for free-radical routes |
| Appearance | White to off-white powder |
| Solubility | DMF, DMSO, THF, and dry organic solvents for coupling; limited aqueous stability due to NHS-ester hydrolysis |
| Reactivity Note | Hydrolytically unstable in water — dissolve and react promptly; avoid primary-amine buffers |
| Storage | Sealed, desiccated, −20 °C, protected from light and moisture |
Need a specific NHSMA:PEGMA ratio, PEG chain length, or the polymer pre-coupled to your ligand? Talk to technical sales →
Choose the reactive-site density that fits your conjugate
NHSMA:PEGMA feed ratio sets how many reactive sites are available per chain, and how much that trades off against PEG brush density.
NHSMA : PEGMA ≈ 2:98
PEGMA-dominant
Maximum stealth coverage with just enough reactive sites for sparse, well-controlled single-ligand conjugation.
NHSMA : PEGMA ≈ 10:90
Balanced
A common working range — meaningful conjugation density (e.g. multiple dyes or ligands per chain) while retaining a strong PEG brush.
NHSMA : PEGMA ≈ 20:80
Reactive-rich
Higher reactive-site density for dense multivalent conjugation, with some reduction in steric shielding.
Applications
PEGylated drug conjugates
Amine-bearing drugs couple to the NHS sites while the PEG brush extends circulation and reduces immune recognition.
Antibody-PEG conjugates
Couples directly to antibody lysine amines, giving a PEGylated antibody with reduced immunogenicity and extended half-life.
Diagnostic microarrays
A low-background PEG surface with defined reactive spots for spotting amine-modified capture probes.
Reactive antifouling membranes
Membrane surface modification that resists biofouling while remaining chemically addressable for later functionalization.
Biosensor capture surfaces
Low-fouling PEG background minimizes nonspecific signal, while NHS sites give oriented, covalent capture-antibody immobilization.
Targeted stealth nanoparticles
A PEGylated, low-fouling corona with a small number of reactive sites for attaching a targeting ligand or antibody fragment.
Stealth polymersomes with ligands
PEG-shielded vesicles that carry a defined number of surface-conjugated targeting or imaging ligands.
PEGylated PPM libraries
One reactive-PEGylated precursor batch can be split and coupled to different amines to build a library of functionalized stealth materials.
Data & safety documents
Batch-specific COAs with GPC, composition (¹H-NMR), and NHS-ester activity data available for order confirmations. Contact us for a specific lot number.
Safety Data Sheet
GHS-format · EN / ZH
Certificate of Analysis
Ratio + Mw confirmation
Amine Coupling Protocol
Recommended buffers & conditions
FAQ
Most frequent questions and answers
It’s used wherever you need a low-fouling, PEGylated surface or particle that still needs to carry something specific — a targeting ligand, antibody, dye, or drug. The PEGMA brush keeps nonspecific protein and cell adsorption low, while the sparse NHS sites let you attach exactly what you need without giving up that stealth character.
PEGMA units are the stealth workhorse — a non-ionic, hydrated PEG side chain that sterically shields the backbone from nonspecific adsorption. NHSMA units are a minor, reactive comonomer — each carries an NHS ester that reacts with a primary amine. Combining them gives a low-fouling material that isn’t a dead end: it still has a defined way to attach something useful.
NHSMA is typically kept to a small minority — commonly 2–20 mol% — so the PEGMA brush still dominates the chain’s overall behavior. Higher NHSMA content gives more reactive sites per chain but starts to thin the PEG coverage, so the ratio is chosen based on how much conjugation density you actually need.
No — PEGMA units don’t carry primary amines or otherwise compete for the NHS ester, so they’re chemically inert to the coupling reaction itself. The main practical consideration is the same as for any NHS-ester chemistry: work in an amine-free buffer and avoid excess water exposure before coupling.
Dissolve the polymer fresh in a dry organic solvent (or briefly in a cold, amine-free aqueous buffer, pH 7.5–8.5) and add your amine-bearing target promptly — protein, peptide, dye, or small molecule. The amine displaces the NHS leaving group to form a stable amide bond at each reacted site.
No. Commercial mPEG-NHS reagents are typically small, discrete PEG molecules with a single NHS ester at one end, meant for one-to-one labeling. This copolymer is a polymer backbone carrying many PEGMA side chains for stealth plus a sparse number of NHS sites along the same chain — a multivalent scaffold rather than a single-conjugation reagent.
No — composition-specific random copolymers like this one are not assigned a single CAS Registry Number, since the NHSMA:PEGMA ratio, PEG chain length, Mn, and dispersity are set per synthesis batch. Each lot’s COA documents the actual composition and NHS-ester activity.
Store sealed, desiccated, at −20 °C, protected from light and moisture — the NHS ester is sensitive to both heat and humidity, and PEG side chains are themselves hygroscopic. Allow the container to reach room temperature before opening, dissolve fresh, and react promptly for best coupling efficiency.