Shouzhu Li

Polyoxometalate-Based Organic-Inorganic Hybrids as Antitumor Drugs

Polyoxometalates (POMs) have shown encouraging antitumor activity. However, their cytotoxicity in normal cells and unspecific interactions with biomolecules are two major obstacles that impede the practical applications of POMs in clinical cancer treatment. Derivatization of POMs with more biocompatible organic ligands is expected to cause a synergetic effect and achieve improved bioactivity and biospecificity. Herein, the synthesis of an amphiphilic organic-inorganic hybrid is reported by grafting a long-chain organoalkoxysilane lipid onto a POM. The amphiphilic POM hybrid could spontaneously assemble into the vesicles and exhibits enhanced antitumor activity for human colorectal cancer cell lines (HT29) compared to that of parent POMs. This detailed study reveals that the amphiphilic nature of POM hybrids enables the as-formed vesicles to easily bind to the cell membranes and then be uptaken by the cells, thus leading to a substantial increase in antitumor activity. Such prominent antitumor action is mostly accomplished via cell apoptosis, which ultimately results in cell death. Our finding demonstrates that novel POM hybrids-based drugs with increased bioactivity could be obtained by decorating POMs with selective organic ligands.

One-pot construction of doxorubicin conjugated magnetic silica nanoparticles

Doxorubicin (DOX) conjugated magnetic silica nanoparticles (DOX–Fe3O4–SiO2) are successfully fabricated using a new one-pot method without need for the process of inconvenient multistep synthesis in advance, based on the condensation of DOX and the silica precursor 3-isocyanatopropyltriethoxysilane (ICPTES), followed by the spontaneous formation of a silica coating onto the surface of Fe3O4nanoparticlesvia sol–gel polymerization of triethoxysilane. Mass spectroscopy provides evidence that doxorubicin is conjugated to ICPTES via a urea bond (–NHCONH–) via the reaction of the amino groups of DOX with the isocyanate group (–NCO) of ICPTES in water. The obtained magnetic nanoparticles are well dispersed. Their mean diameter is about 66.9 nm with a narrow size distribution. The conjugated DOX–SiO2–Fe3O4nanoparticles exhibited a higher loading efficiency of 60.5 ± 3.7% and a more sustained release profile than SiO2nanoparticles containing physically-entrapped DOX. It is anticipated that fine-tuning of other drugs or bioactive molecules containing –NH2groups to Fe3O4/SiO2nanoparticles would foster innovative avenues for the development of smart drug delivery and controlled release systems.

Highly efficient removal of trace level dieldrin from water resources utilizing a cerasomal strategy

In this work, a novel cerasomal removal strategy for persistent organic pollutants (POPs) from water resources is proposed for the first time using the synchronous cerasome-forming process of an organic–inorganic composite lipid to capture and remove POPs. It is proposed that hydrophobic POPs could be captured in the hydrophobic bilayer of the synchronously formed cerasomes in aqueous environments with dieldrin as the model POP. The method was found to be highly efficient in the removal of trace level dieldrin in a range of 5 μg L−1 to 60 μg L−1. Moreover, with the involvement of superparamagnetic Fe3O4 nanoparticles, a much more simple and efficient magnetic removal of POPs was achieved. In comparison with the non-magnetic cerasomal method, the removal rate of dieldrin of the magnetic cerasomal strategy was elevated by ∼10% at a high dieldrin concentration range of 80 μg L−1 to 160 μg L−1. The greater removal efficiency of the magnetic cerasomal strategy was assumed to be due to the accumulating effect of the hydrophobic sites on hydrophobic dieldrin due to hydrophobic dieldrin molecules being captured in the hydrophobic domain of the lipid bilayers, based on the principle of “like prefers like”. Herein, these results demonstrate the great promise of the cerasomal method, particularly the magnetic cerasomal strategy, as a promising novel cleaning method for POPs from water resources. In addition, all materials involved in non-magnetic cerasomes and magnetic cerasomes are biosafe, thus avoiding the problem of secondary environmental pollution. This paper also paves the way to bring magnetic cerasomes from fundamental research to practical wastewater treatment applications.