Hi Miguel, -COOH surface functionalized nanoparticles are more useful that you think.

The  -COOH surface can be modified by  ethyl(dimethylaminopropyl) carbodiimide (EDC) and though that you can couple organic and inorganic compounds with primary amines. The possibilities are endless.

https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-biology-learning-center/protein-biology-resource-library/pierce-protein-methods/carbodiimide-crosslinker-chemistry.html

Hi Miguel, -COOH surface functionalized nanoparticles are more useful that you think.

The  -COOH surface can be modified by  ethyl(dimethylaminopropyl) carbodiimide (EDC) and though that you can couple organic and inorganic compounds with primary amines. The possibilities are endless.

https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-biology-learning-center/protein-biology-resource-library/pierce-protein-methods/carbodiimide-crosslinker-chemistry.html

Of course you can simply start with APTES and modify a unmodified SiO2 particle (or use a simple Stöber synthesis). The amine can also use to modify the surface under mild conditions. Be careful concerning the point of zero charge.

Article Functionalized polymer colloids bearing primary amino groups

Thanks Michael.

Silica containing COOH group is a versatile candidate for the further surface functionalization such as amide can be generated or esters can be generated to attach other molecules/bio molecules on surfaces. Moreover in many media for a stable suspension of silica nanoparticles the negative surface charge imparted by carboxylate is necessary. These groups impart a specific zeta potential to the particles in dispersing media determining their stability. Therefore silica with carboxylate is a useful nanomaterial.

Thanks for all the answers. He have developed an easy method for direct carboxylation of SiO2 nanoparticles. We are interested on find collaborators to try to use them in their research for testing. Please, contact me directly to: [email protected] in case you are interested.

Dr. Miguel A. Méndez-Rojas, UDLAP

how i can fictionalized silca for control drug delivery

I would like to know if Dr. Mendez-Rojas published his functionalization process.

Thank you, Márcia