A simple method for the synthesis of carboxymethylated wrinkled mesoporous silica nanoparticles and preparation of a WMS-curcumin conjugate

A simple and practical method for the direct surface carboxymethylation of wrinkled mesoporous silica nanoparticles (WMS-COOH) was developed. The surface carboxymethyl functional groups were easily obtained by reacting the silanol (Si–O–H) groups at the surface of mesoporous silica with chloroacetic acid (ClCH 2 –COOH) which can be further modified by chemical functionalization. The WMS-COOH nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The main objective of this paper is to report this chemical modification method that can be easily adapted to any silica material; the carboxyl groups at the surface of the nanoparticles can therefore be used to prepare a wide range of derivatives or to keep the silica nanoparticles stably dispersed in aqueous solution at different pH ranges, as well as tuning the surface charge of the silica nanoparticles. As a proof of method, the preparation of curcumin-labeled WMS nanoparticles is reported, as an example of the versatility of these carboxymethylated silica nanoparticles. Graphical abstract