Reactive · Thermoresponsive Copolymer
Poly(NHSMA-co-NIPAM)
Also written P(NHSMA-co-NIPAM), NHSMA-NIPAM copolymer | Custom composition — no single CAS
A random copolymer of N-hydroxysuccinimide methacrylate (NHSMA) and N-isopropylacrylamide (NIPAM). NIPAM makes up the majority of the chain, giving the polymer PNIPAM’s classic thermoresponsive lower critical solution temperature (LCST, ~32 °C for the homopolymer); NHSMA is included as a minor, sparsely distributed comonomer, each unit carrying a reactive NHS ester. The result is a thermoresponsive scaffold that stays “conjugation-ready” — couple the NHS sites to a protein, peptide, dye, or drug, then use temperature alone to trigger precipitation, surface release, or a phase change in the conjugate.
- Moisture-sensitive — shipped and stored desiccated
Custom composition
(C₈H₉NO₄)ₘ-co-(C₆H₁₁NO)ₙ
Poly(NHSMA-co-NIPAM)
Appearance: White to off-white powder
Character: Thermoresponsive + amine-reactive
Architecture: Random copolymer
Storage: −20 °C, desiccated, dark
ISO 9001:2015
Manufactured under certified quality management
Custom NHSMA:NIPAM Ratio
Reactive-site density tuned independently of cloud point
Batch-Level COA
Mn, Đ, cloud point, 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-(C₆H₁₁NO)ₙ
Character
Thermoresponsive + amine-reactive
Mn Range
10K – 120K
Form
Powder
A thermal switch with a few reactive handles
NIPAM 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.
NIPAM: the thermoresponsive majority
Pure PNIPAM undergoes a sharp coil-to-globule collapse above ~32 °C — its lower critical solution temperature — and this is what most of the chain is doing.
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 cloud point
Keeping NHSMA content low preserves a sharp transition near PNIPAM's ~32 °C baseline; too much reactive comonomer — or a large conjugated cargo — shifts it.
Couple once, keep the switch
Reacting the NHS sites with your target amine doesn't touch the NIPAM units — the thermoresponsive behavior of the rest of the chain still works.
Most reactive-thermoresponsive designs in the literature sit in the 2–15 mol% NHSMA range — enough reactive sites for practical conjugation density without materially shifting the cloud point away from useful working temperatures. Note that the conjugated cargo itself also affects the final cloud point: attaching a large, hydrophilic protein typically raises it, while a small hydrophobic dye may lower it.
Values below are representative for this monomer pair. Batch-specific COAs with GPC, cloud-point, and NHS-ester activity data are available on request.
| Chemical Name | Poly(N-hydroxysuccinimide methacrylate-co-N-isopropylacrylamide) |
|---|---|
| Synonyms | P(NHSMA-co-NIPAM) · NHSMA-NIPAM copolymer · Reactive thermoresponsive copolymer |
| Monomer Units | N-hydroxysuccinimide methacrylate (NHSMA) · N-isopropylacrylamide (NIPAM) |
| Architecture | Random (statistical) copolymer — not block or graft |
| NHSMA : NIPAM Ratio | Custom / composition-dependent — commonly 2:98 to 20:80 mol% |
| Cloud Point / LCST | Batch- and conjugate-dependent, typically 30–40 °C (pure PNIPAM reference: ~32 °C) |
| 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 10,000–120,000 g/mol |
| Dispersity (Đ) | 1.1–1.3 (RAFT/ATRP) · broader for free-radical routes |
| Appearance | White to off-white powder |
| Solubility | DMF, DMSO, and dry organic solvents for coupling; cold water below the cloud point |
| Reactivity Note | Hydrolytically unstable in water — dissolve and react promptly; avoid primary-amine buffers |
| Storage | Sealed, desiccated, −20 °C, protected from light and moisture |
Choose the reactive-site density that fits your conjugate
NHSMA:NIPAM feed ratio sets how many reactive sites are available per chain, and how much that trades off against a sharp, predictable cloud point.
NHSMA : NIPAM ≈ 2:98
NIPAM-dominant
Cloud point stays close to the ~32 °C PNIPAM baseline, with just enough reactive sites for sparse, well-controlled conjugation.
NHSMA : NIPAM ≈ 10:90
Balanced
A common working range for smart bioconjugates — meaningful conjugation density while retaining a usable thermal transition.
NHSMA : NIPAM ≈ 20:80
Applications
Smart affinity precipitation
Couple an antibody or ligand to the NHS sites, then use temperature alone to precipitate and recover the conjugate — no chromatography needed.
Thermally triggered drug delivery
An amine-bearing drug coupled to the NHS sites is released or exposed as the carrier collapses past its cloud point (e.g. under local hyperthermia).
Thermoresponsive cell/protein release surfaces
Capture molecules immobilized via NHS coupling on a NIPAM-grafted surface, with temperature controlling attachment and release.
Reversible bioseparation
Reusable, temperature-switchable capture reagents for isolating a target analyte from complex biological samples.
Temperature-responsive chromatography
A reactive-thermoresponsive stationary phase with a covalently attached ligand for temperature-tunable retention.
Dual-signal biosensors
Thermal collapse near the cloud point provides an amplification or gating mechanism alongside covalently captured analyte binding.
Thermoresponsive microgel functionalization
NHS sites on crosslinked PNIPAM microgels allow covalent attachment of targeting or reporter molecules after gel formation.
Thermoresponsive PPM libraries
One reactive-thermoresponsive precursor batch can be split and coupled to different amines to build a library of smart conjugates.
Data & safety documents
Batch-specific COAs with GPC, cloud-point (turbidimetry), 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 want a bioconjugate or surface that switches behavior with temperature — smart affinity precipitation for antibody/protein purification, thermally triggered drug delivery, reversible bioseparation, and thermoresponsive cell or protein release surfaces — because the PNIPAM background gives a sharp thermal transition and the sparse NHS sites let you attach exactly what you need.
NIPAM units are the thermoresponsive workhorse — they drive the sharp coil-to-globule collapse above the cloud point. NHSMA units are a minor, reactive comonomer — each carries an NHS ester that reacts with a primary amine. Combining them gives a thermoresponsive 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 NIPAM background still dominates the chain’s overall thermal behavior. Higher NHSMA content gives more reactive sites per chain but broadens and shifts the cloud point away from a sharp, predictable transition.
No — NIPAM 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, keep the solution cold (well below the cloud point) to avoid premature collapse, and avoid excess water exposure before coupling.
The unconjugated polymer’s cloud point sits close to PNIPAM’s ~32 °C baseline, shifted slightly by the NHSMA content. Once you couple a cargo molecule, the cloud point shifts again — attaching a large, hydrophilic protein typically raises it, while a small hydrophobic dye may lower it — so the final conjugate’s cloud point should be measured rather than assumed.
Couple a capture ligand (e.g. an antibody or aptamer) to the NHS sites, mix the conjugate with your sample so the ligand binds its target, then raise the temperature above the cloud point to precipitate the whole conjugate-target complex out of solution. Cooling back down redissolves the polymer for a subsequent cycle.
No — composition-specific random copolymers like this one are not assigned a single CAS Registry Number, since the NHSMA:NIPAM ratio, Mn, and dispersity are set per synthesis batch. Each lot’s COA documents the actual composition, measured cloud point, 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. Dissolve fresh, keep solutions cold during the coupling step to stay below the cloud point, and react promptly for best coupling efficiency.