Novel and efficient method for loading aptamer-conjugated liposomes with arsenic trioxide for targeting cancer cells.

Although the therapeutic effect of liposomal arsenic trioxide arsenic trioxide (ATO) in the treatment of solid tumours has been confirmed, its dose-limiting loading is a challenging issue. To solve the problems in the preparation of liposomal ATO, different loading strategies were evaluated and compared. In addition, liposomes decorated with anti-nucleolin aptamers were developed as a novel formulation for targeted delivery with high loading efficiency and sustained releasing property in order to treat solid tumours. The liposomes were prepared by a thin-film method exploiting the passive loading strategy of Co(II) hydrogen arsenite (CHA). The structural characteristics of the liposomes were also investigated by Fourier transform infra-red spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potentiometry, field emission scanning electron microscopy (FESEM), and Energy Dispersive X-ray Diffraction (EDX) techniques. To evaluate the potential cytotoxicity of this liposomal drug vehicle in vitro, MTT assay was performed on HT-29 cancer cell line. The results showed that the synthesised liposomes loaded with CHA exhibited high entrapment efficiency (77%). MTT assays showed a significant difference between the percentage of viable cells when HT -29 cells were treated with free ATO and liposomal formulation which can be corresponded to the sustained release of the drug from the liposomes. The results of this study may lead to a promising strategy for the effective treatment of solid tumours.