Cytosine-phosphodiester-guanine oligodeoxynucleotide (CpG ODN)-capped hollow mesoporous silica particles for enzyme-triggered drug delivery

We designed, for the first time, an enzyme-triggered drug delivery system that is based on cytosine-phosphodiester-guanine oligodeoxynucleotide (CpG ODN)-capped hollow mesoporous silica (HMS) particles as carriers. Fluorescein dye was used as a model drug, and the fluorescein loading, amino-grafting and CpG ODN capping were evaluated by UV/Vis analysis, zeta potential and N(2) adsorption-desorption measurements and gel electrophoresis. The fluorescein loading capacity and CpG ODN capping amount were 37.7 and 39.6 mu g mg(-1), respectively at the weight ratio of 10 Dye/HMS-NH(2)/CpG ODN. Importantly, fluorescein release can be triggered by the addition of deoxyribonuclease I (DNase I) for CpG ODN degradation, and the release rate can also be controlled by changing the DNase I concentration. Therefore, it might be a promising controlled drug delivery system for application in the field of biomedicine and cancer therapy.