Efficient capture of strontium from aqueous solutions using graphene oxide-hydroxyapatite nanocomposites.

Three-dimensional hierarchical flower-like graphene oxide-hydroxyapatite (GO-HAp) nanocomposites were synthesized by a simple biomimetic method in a modified simulated body fluid (mSBF). The obtained GO-HAp nanocomposites were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N2 adsorption-desorption analysis. The formation mechanism was proposed and the prepared GO-HAp was applied as an adsorbent to remove strontium from large volumes of aqueous solutions. A maximum adsorption capacity of 702.18 mg g(-1) was achieved on GO-HAp, almost two fold higher than that of bare HAp and nine fold higher than that of GO. The effects of pH, adsorbent content, contact time and Sr(2+) initial concentrations on Sr(2+) removal from solution by GO-HAp were systematically investigated, and the results indicated that the removal of Sr(2+) by GO-HAp was weakly dependent on solution pH. The results herein reveal that the GO-HAp nanocomposites had exceptional potential as a suitable material for preconcentration and solidification of radiostrontium from large volumes of aqueous solutions in nuclear waste management and radiostrontium pollution cleanup.

Bifunctional pH-sensitive Zn(ii)-curcumin nanoparticles/siRNA effectively inhibit growth of human bladder cancer cells in vitro and in vivo.

To overcome drug resistance, the combination of two or more therapeutic strategies with different mechanisms has received much attention in recent years. In this study, a common approach has been used to process curcumin and Zn2+ into colloidal dispersions known as "nanoparticles", which are cheap and easy to prepare with high reproducibility. This novel vehicle has good biocompatibility and high cellular uptake for simultaneously delivering the curcumin drug and siRNA into tumor cells. Complexation of Zn2+ with curcumin enhances the aqueous solubility of the hydrophobic drug curcumin and further improves the cellular uptake and bioavailability. The acid-labile coordination Zn(ii)-O bond in Zn(ii)-curcumin drug nanoparticles (Zn(ii)-Cur NPs) can respond to tumor intracellular acidic pH environments to release curcumin, and promoting acid-triggered intracellular drug release. The positively charged Zn(ii)-Cur NPs can efficiently deliver siRNA into human bladder cancer cells, protect siRNA against enzymatic degradation, and facilitate the escape of loaded siRNA from the endosome into the cytoplasm, which successfully downregulates the targeted EIF5A2 oncogene and consequently inhibits cancer cell growth in vitro and in vivo. Proliferation and migration of cancer cells are inhibited by silencing the expression of EIF5A2 and increasing the ratio of pro-apoptotic BAX to anti-apoptotic BCL-2. In vitro and in vivo experiments have demonstrated that bifunctional Zn(ii)-Cur NPs/siEIF5A2 can combine chemotherapy with gene therapy to afford higher therapeutic efficacy than the individual therapeutic protocols.

The inhibition of human bladder cancer growth by calcium carbonate/CaIP6 nanocomposite particles delivering AIB1 siRNA.

Previously, we reported that inorganic amorphous calcium carbonate (ACC) hybrid nanospheres functionalized with Ca(II)-IP6 compound (CaIP6) is a promising gene vector in vitro. Here, nonviral gene carrier, ACC/CaIP6 nanocomposite particles (NPACC/CaIP6), was evaluated for efficient in vitro and in vivo delivery of small interfering RNA (siRNA) targeting human Amplified in breast cancer 1 (AIB1). The nanoparticle is capable of forming ACC/CaIP6 nanoparticle-siRNA complexes and transferring siRNA into targeted cells with high transfection efficiency. Meanwhile the ACC/CaIP6 nanoparticle-siRNA complexes have no obvious cytotoxicity for human bladder cancer T24 cells. Furthermore, NPACC/CaIP6 effectively protected the encapsulated siRNA from degradation, AIB1 knockdown mediated by ACC/CaIP6/siRNA complexes transfection resulted in cells proliferation inhibition, apoptosis induction and cell cycle arrest in vitro. NPACC/CaIP6 exhibited well tissues penetrability in localized siRNA delivering, intratumoral injection of NPACC/CaIP6/siAIB1 could attenuate tumor growth and downregulation of PI3K/Akt signaling pathway in vivo. We conclude that ACC/CaIP6 nanoparticle is a promising system for effective delivery of siRNA for cancer gene therapy.

Promising plasmid DNA vector based on APTES-modified silica nanoparticles.

Nanoparticles have an enormous potential for development in biomedical applications, such as gene or drug delivery. We developed and characterized aminopropyltriethoxysilane-functionalized silicon dioxide nanoparticles (APTES-SiNPs) for gene therapy. Lipofectamine(®) 2000, a commonly used agent, served as a contrast. We showed that APTES-SiNPs had a gene transfection efficiency almost equal to that of Lipofectamine 2000, but with lower cytotoxicity. Thus, these novel APTES-SiNPs can achieve highly efficient transfection of plasmid DNA, and to some extent reduce cytotoxicity, which might overcome the critical drawbacks in vivo of conventional carriers, such as viral vectors, organic polymers, and liposomes, and seem to be a promising nonviral gene therapy vector.