Enhanced antitumor activity of polyoxometalates loaded solid lipid nanoparticles

Solid lipid nanoparticles (SLNs), prepared with physiologically compatible high melting point lipids as skeleton materials, are the carriers of a new drug delivery system with great development prospects. In this paper, we have successfully encapsulated two types of polyoxometalates (POMs) with SLNs to improve their biological efficacy. The in vitro antitumor activity of POMs in its free and nano-encapsulated forms was investigated using the MTT assay that was carried out on three types of human cancer cells, HeLa, HepG2 and SHY5Y. The results represent the enhancement of antitumor activity of POMs due to its encapsulation in SLNs. Moreover, the interactions of two types POMs towards ctDNA and bovine serum albumin have been illustrated by electron absorption spectroscopy. [Display omitted] •We have successfully encapsulated two types of POMs with solid lipid nanoparticles.•Nanoparticle size and good biocompatibility of SLNs may enhance the antitumor activity of POMs.•An interaction occurred between POMs with ctDNA and BSA. Polyoxometalates (POMs) have shown remarkable antitumor activity. However, the utilization of POMs is limited due to its poor water solubility, low bioavailability, thermodynamics and kinetic instability at physiological pH in water. In order to overcome these drawbacks, POMs with antitumor activity, [Na10(H2W12O42)]·26H2O and [Hbiz]5[HMo5P2O23]·5H2O, were encapsulated within solid lipid nanoparticles (abbreviated as NaW12-SLNs and P2Mo5-SLNs, respectively), which have been prepared and structurally characterized by Fourier transform infrared (FT–IR) spectroscopy, UV–Vis spectroscopy, X-ray diffraction (XRD), dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The results show that POMs retain its parent structure after entrapped by SLNs. The in vitro antitumor activity of NaW12 and P2Mo5 in its free and nano-encapsulated forms was investigated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetra-zolium bromide (MTT) assay that was carried out on three types of human cancer cells, HeLa, HepG2 and SHY5Y. The results represent the enhancement of antitumor activity of POMs due to its encapsulation in SLNs. Moreover, the interactions of two types POMs towards ctDNA and bovine serum albumin (BSA) have been illustrated by electron absorption spectroscopy.