Antibodies or proteins can be covalently linked to the surface of carboxylated microparticles through activation of the carboxyl groups with water-soluble 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide (EDC). The reaction forms an active intermediate (O-acylisourea) that reacts quickly with primary amines to form a stable amide bond. To increase the efficiency of EDC-mediated coupling reactions, N-hydroxysulfosuccinimide (sulfo-NHS) can be added to the reaction, which stabilizes the amine-reactive intermediate by converting it to a more stable amine-reactive sulfo-NHS ester. The RayBio^® Carboxyl Bead Conjugation Kit provides a simple and efficient method for conjugation of proteins or antibodies to carboxylmodified microparticles.

Pair this kit with our Multiplex Magnetic Beads to build your own multiplex assay for use with a standard flow cytometer or Luminex system.

• Wash Buffer I
• Wash Buffer II
• Activation Buffer
• Quenching Buffer
• Storage Buffer
• Lyophilized EDC
• Lyophilized Sulfo-NHS

• Carboxylmodified microparticles
• Antibody or protein
• Deionized (DI) water
• 1.5 mL polypropylene microcentrifuge tubes or similar
• Orbital shaker for tubes (with ability to reach 1000 rpm)
• Microcentrifuge (with ability to reach 4000 g)
• Vortex mixer
• (Optional) Magnetic stand
• (Optional) Glycerol

1. Wash microparticles with activation buffer.
2. Add reconstituted EDC and Sulfo-NHS.
3. Wash with Wash Buffer I.
4. Add antibodies or proteins to activated microparticles.
5. Wash with Wash Buffer I.
6. Add Quenching Buffer.
7. Wash with Wash Buffer II.
8. Store in Storage Buffer at 4°C, protected from light.

The whole kit should be stored at 4°C for up to 6 months from the date of shipment. Avoid reusing the reconstituted lyophilized chemicals.