---
title: "Carboxylated (COOH) Surface for EDC Covalent Coupling"
canonical: "https://www.biomat.it/surfaces/carboxylated-surfaces/"
description: "COOH-activated surface for covalent immobilization of amine-bearing peptides, drugs and haptens via EDC chemistry. When to choose covalent coupling over adsorption."
type: "surface"
manufacturer: "Biomat S.r.l."
updated: "2026-07"
---

# Carboxylated Coated Surface

Carboxylated Surface carries covalently bound carboxylic groups and is designed to promote the covalent immobilisation of compounds containing reactive free amino groups, through EDC-mediated amination.

## Why covalent immobilisation instead of passive adsorption

Covalent coupling on a carboxylated 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 the molecule's specific sites.
- It increases **storage stability** compared with physical adsorption, because the risk of spontaneous desorption is reduced.

## Coupling chemistry

The amino group present in a molecule (peptide, protein) binds to the carboxylated surface through the formation of an amide bond between that amino group and the surface carboxylic group, by the action of a carbodiimide (EDC).

This is the standard EDC chemistry for covalent coupling of amine-bearing compounds to a COOH surface. Without the addition of carbodiimide, covalent binding does not occur.

## Specifications

| Parameter | Value |
| --- | --- |
| Treatment | Surface modified with carboxylic groups |
| Volume of treatment | 200 µl/well (microplates, PCR 8-strip tubes, PCR plates) |
| Storage | Room temperature, sealed PE bags, until expiration date |
| Quality | All lots tested for uniformity and reproducibility; Certificate of Quality per lot |

## Carboxylated or aminated? How to choose

Carboxylated and aminated 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 amino group (NH2) | **Carboxylated** — amide bond via EDC |
| Free carboxyl group (COOH) | [Aminated](https://www.biomat.it/surfaces/aminated-surfaces/) — via EDC / Sulfo-NHS |
| Free thiol group (SH) | [Aminated](https://www.biomat.it/surfaces/aminated-surfaces/) via SMCC, or [Maleimide](https://www.biomat.it/surfaces/maleimide-coated-surfaces/) |

## 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

- [Carboxylated Plates, 96-well](https://www.biomat.it/product/microplates/96-well-plates/carboxylated-plates/)
- [Carboxylated PCR 8 Strip Tubes](https://www.biomat.it/product/pcr-products/coated-pcr-strip-tubes/carboxylated-pcr-8-strip-tubes/)
- [Carboxylated PCR Plates](https://www.biomat.it/product/pcr-products/coated-pcr-plates/carboxylated-pcr-plates/)

## Related

- [Aminated (primary amine) Surface](https://www.biomat.it/surfaces/aminated-surfaces/) — the complementary covalent chemistry
- [Choosing the Right Microplate](https://www.biomat.it/applications-techniques/choosing-microplate-for-assay/)
- [ELISA Assay technical guide](https://www.biomat.it/applications-techniques/elisa-assay/)
- Technical note: https://www.biomat.it/wp-content/uploads/2018/02/CARBOXYLATED-SURFACE-TN.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/)