---
title: "Aminated (NH2) Surface for Covalent Coupling"
canonical: "https://www.biomat.it/surfaces/aminated-surfaces/"
description: "Primary amine surface for covalent immobilization of carboxyl- and thiol-bearing molecules via NHS, SMCC, EDC or glutaraldehyde crosslinkers. Protocols and guidance."
type: "surface"
manufacturer: "Biomat S.r.l."
updated: "2026-07"
---

# Aminated (Primary Amine) Coated Surface

Aminated Surface carries covalently bound primary amino groups and promotes the covalent immobilisation of compounds containing reactive moieties (amino, carboxyl or thiol groups) via well-known homo- and heterobifunctional linkers, such as N-hydroxysuccinimide (NHS) or succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC).

## Why covalent immobilisation instead of passive adsorption

Covalent coupling on an aminated surface overcomes three limitations of physical adsorption:

- It immobilises molecules that bind **weakly or not at all** by passive adsorption, namely small peptides (MW 1,000-5,000 Da), drugs, toxins and hormones.
- It allows **oriented immobilisation**, preserving the integrity and accessibility of specific sites and avoiding their inhibition by casual physical adsorption. This matters for molecules such as Fab-SH antibody fragments, streptavidin, polysaccharides and nucleic acids (single or double strand).
- It increases **storage stability** compared with physical adsorption, because the risk of spontaneous desorption is reduced.

## Coupling chemistry by reactive group

The interaction between the surface amino group and the functional group of the molecule to be bound is a covalent bond mediated by homo- and heterofunctional crosslinkers. The choice of crosslinker depends on the reactive group carried by the biomolecule:

| Reactive group on the molecule | Crosslinker / method |
| --- | --- |
| Carboxyl group | EDC (ethyldiethylaminopropylcarbodiimide), with or without Sulfo-NHS |
| ε-amino groups of lysine | Glutaraldehyde, with stable amine linkage formed on reduction with sodium cyanoborohydride |
| Amino groups (alternatives) | Dimethylpimelimidate, disuccinimidyl suberate |
| Thiol groups (Fab-SH, peptides with terminal cysteine) | Maleimide-bearing crosslinkers such as SMCC |

## Application guidelines

Biomat publishes worked examples that users can adapt to develop their own bio-specific assays:

- [Coupling of NHS-activated compounds](https://www.biomat.it/wp-content/uploads/2018/02/AMINATED-SURFACE-TN-12.pdf)
- [Coupling a hapten or peptide bearing a carboxylic group](https://www.biomat.it/wp-content/uploads/2018/02/AMINATED-SURFACE-TN-12.pdf)
- [DNA binding](https://www.biomat.it/wp-content/uploads/2018/02/AMINATED-SURFACE-TN-8.pdf)
- [Peptide binding](https://www.biomat.it/wp-content/uploads/2018/02/AMINATED-SURFACE-TN-8.pdf)

## Specifications

| Parameter | Value |
| --- | --- |
| Treatment | Surface modified with primary amino groups |
| Volume of treatment | 200 µl/well |
| Storage | Room temperature, sealed PE bags, until expiration date |
| Quality | All lots tested for uniformity and reproducibility; Certificate of Quality per lot |

## Aminated or carboxylated? How to choose

Aminated and carboxylated surfaces are complementary strategies within the same covalent coupling family. The choice depends on which reactive group is available and accessible on the molecule to be immobilised:

| Reactive group on your molecule | Surface to choose |
| --- | --- |
| Free carboxyl group (COOH) | **Aminated** — via EDC / Sulfo-NHS |
| Free thiol group (SH) | **Aminated** via SMCC, or [Maleimide](https://www.biomat.it/surfaces/maleimide-coated-surfaces/) |
| Free amino group (NH2) | [Carboxylated](https://www.biomat.it/surfaces/carboxylated-surfaces/) — amide bond via EDC |

## Main features

- Ready to use
- Manufactured under ISO 9001 guidelines
- All lots tested for uniformity and reproducibility
- Certificate of Quality released for every lot
- For Research Use Only

## Products with this surface

- [Amine Treated Plates, 96-well](https://www.biomat.it/product/microplates/96-well-plates/amine-activated-96-well-plates/)

## Related

- [Carboxylated Surface](https://www.biomat.it/surfaces/carboxylated-surfaces/) — the complementary covalent chemistry
- [Maleimide Surface](https://www.biomat.it/surfaces/maleimide-coated-surfaces/) — for thiol-bearing molecules
- [Choosing the Right Microplate](https://www.biomat.it/applications-techniques/choosing-microplate-for-assay/)
- Technical note: https://www.biomat.it/wp-content/uploads/2018/02/AMINATED-SURFACE-TN-6.pdf

## Manufacturer

Biomat S.r.l., Via Trento 124, 38061 Ala (TN), Italy. ISO 9001:2015 certified. Founded 1992. Contact: info@biomat.it | +39 0464 357951 | [Request a quote](https://www.biomat.it/request-quote/)