Development and evaluation of rosmarinic acid loaded novel fluorescent porous organosilica nanoparticles as potential drug delivery system for cancer treatment

Rosmarinic acid is a bioactive compound that possesses high anticancer activity, but its poor water-solubility and ineffective membrane permeability are the main causes of low bioavailability. This study aimed to improve these limitations by encapsulating rosmarinic acid in tetrasulfide-based porous organosilica nanoparticles to deliver it to cancer cells. To date, no reports on the use of these organosilica nanoparticles as a nanocarrier for rosmarinic acid. The synthesized nanoparticles were small, approximately 50 nm in size, with a high surface area of around 498.1 m2/g and an average pore diameter of 2.3 nm. Especially, fluorescent-labeled nanospheres were synthesized and further indicated the effective accumulation in the cytosol after 24 h incubation. In addition, the nanoparticles were non-toxic to human AGS gastric adenocarcinoma cells and mouse CT26 colon cancer cells within concentrations ranging from 0 to 240 μg/mL. Treatment with nanoparticles containing 140 μg/mL of rosmarinic acid resulted in the death of approximately 39.2% of AGS cells and 36.9% of CT26 cells after 72 hours. Importantly, neither the silica nanospheres nor the rosmarinic acid-containing nanoparticles showed any significant toxic effects on HEK-293T and NIH-3T3 fibroblasts at the tested concentrations. These results suggested that the pharmacological effects of rosmarinic acid can be enhanced by encapsulating it into our novel synthesized biodegradable tetrasulfide-based porous organosilica nanoparticles.