Silica Nanoparticles Loaded with Curcumin—Encapsulation Efficiency ^†

Curcumin is a natural compound, being a well-known ingredient in different foods. There are also multiple therapeutic benefits favorable to the dietary intake of curcumin, most of these benefits being due to its antioxidant and anti-inflammatory effects [1,2]. Despite its benefits, one of the major problems associated with ingesting curcumin is its poor bioavailability, which is mainly due to poor absorption, rapid metabolism and rapid elimination. Several methods have been tested to overcome these drawbacks, one of them being encapsulation. In this study, DMSO-solubilized curcumin was in situ encapsulated in silica nanoparticles as transport vectors.

Silica nanoparticles were produced by the sol–gel process, starting from tetraethyl orthosilicate (TEOS) and vinyltriethoxysilane (VTES). The in situ growing of silica nanoparticles was carried out in the presence of three different surfactants: polyethylene glycol tert-octylphenyl ether (Triton X), polysorbate 80 (Tween 80) and dioctyl sodium sulfosuccinate (AOT). Purification by dialysis was also performed on the obtained nanoparticles, to eliminate the DMSO and the excess of surfactant.

UV–Vis, Dynamic Light Scattering (DLS) and TEM analyses were performed on the obtained transport vectors in order to study their structure, size and morphological aspect. Figure 1 shows the overlap of the UV–Vis spectra of samples B1–B3, the observed maxima being at the value of 425 nm [3]. According to the TEM analysis (Figure 2), the particle size ranges between 20 and 40 nanometers. The particle shape is spherical, but traces of surfactant can still be observed, indicating that this component has not been completely removed by dialysis.

In situ encapsulation of curcumin in silica nanoparticles was successfully achieved using three different types of surfactants. The obtained transport vectors are expected to increase the bioavailability of curcumin in the human body.