Preparation of cationized gelatin nanospheres incorporating molecular beacon to visualize cell apoptosis.

The objective of this study is to prepare cationized gelatin nanospheres (cGNS) incorporating a molecular beacon (MB), and visualize cellular apoptosis. Two types of MB to detect the messenger RNA (mRNA) of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) (GAP MB), and caspase-3 (casp3 MB) were incorporated in cGNS, respectively. MB incorporated in cGNS showed the DNA sequence specificity in hybridization. The cGNS incorporation enabled MB to enhance the stability against nuclease to a significantly great extent compared with free MB. The cGNS incorporating GAP MB were internalized into the KUM6 of a mouse bone marrow-derived stem cell by an endocytotic pathway. The cGNS were not distributed at the lysosomes. After the incubation with cGNS, the cell apoptosis was induced at different concentrations of camptothecin. No change in the intracellular fluorescence was observed for cGNS. On the other hand, for the cGNS, the fluorescent intensity significantly enhanced by the apoptosis induction of cells. It is concluded that cGNS incorporating MB is a promising system for the visualization of cellular apoptosis.