A Green Synthesis of Au-Ag Alloy Nanoparticles using Polydopamine Chemistry: Evaluation of their Anticancer Potency Towards Both MCF-7 Cells and their Cancer Stem Cells Subgroup.

BACKGROUND: Limited chemotherapy efficacy and cancer stem cells (CSCs)-induced therapeutic resistance are major difficulties for tumour treatment. Adopting more efficient therapies to eliminate bulk-sensitive cancer cells and resistant CSCs is urgently needed. METHODS: Based on the potential and functional complementarity of gold and silver nanoparticles (AuNPs or AgNPs) on tumour treatment, bimetallic NPs (alloy) have been synthesized to obtain improved or even newly emerging bioactivity from a combination effect. This study reported a facile, green and economical preparation of Au-Ag alloy NPs using biocompatible polydopamine (PDA) as a reductant, capping, stabilizing and hydrophilic agent. RESULTS: These alloy NPs were quasi-spherical with rough surfaces and recorded in diameters of 80 nm. In addition, these alloy NPs showed good water dispersity, stability and photothermal effect. Compared with monometallic counterparts, these alloy NPs demonstrated a dramatically enhanced cytotoxic/pro-apoptotic/necrotic effect towards bulk-sensitive MCF-7 and MDA-MB-231 cells. The underlying mechanism regarding the apoptotic action was associated with a mitochondria-mediated pathway, as evidenced by Au3+/Ag+ mediated Mitochondria damage, ROS generation, DNA fragmentation and upregulation of certain apoptotic-related genes (Bax, P53 and Caspase 3). Attractively, these Au-Ag alloy NPs showed a remarkably improved inhibitory effect on the mammosphere formation capacity of MCF-7 CSCs. CONCLUSION: All the positive results were attributed to incorporated properties from Au, Ag and PDA, the combination effect of chemotherapy and photothermal therapy and the nano-scaled structure of Au-Ag alloy NPs. In addition, the high biocompatibility of Au-Ag alloy NPs supported them as a good candidate in cancer therapy.

Bimetallic Gold/Silver and Bioactive Camptothecin Hybrid Nanoparticles for Eradication of Cancer Stem Cells in a Combination Manner.

The defeat of cancer is still a challenge due to the existence of cancer stem cells (CSCs) because they resist conventional chemotherapy via multifactor regulated mechanisms. Consequently, one-dimensional action toward CSCs cannot work. Herein, we used rationally designed hybrid nanoparticles as a combined cancer therapy, hoping to form a multidimensional control network. In this paper, gold/silver alloy nanoparticle decorated camptothecin nanocrystals were formulated according to complementary anti-CSC mechanisms from gold, silver, and organic drug. This smart drug formulation could combine chemotherapy and thermotherapy, target different tumor sites, and demonstrate versatile toxicity profiles from each component. Major results indicated that this nanosystem demonstrated indiscriminately effective cytotoxic/proapoptotic/necrotic activity against bulk MCF-7 cells and their CSC subpopulation, in particular under laser ablation. Moreover, this nanosystem displayed enhanced antineoplastic activity against CSC spheroids, resulting in a significant reduction in their number and size, that is, their self-renewal capacity. All the results indicated that CSCs upon treatment of these new hybrid nanoparticles underwent reduced stemness and conversion from the original quiescent state and recovered their sensitivity toward chemotherapy. The relevant anticancer mechanism was ascribed to NIR-pH dual responsive drug release, synergistic/combined thermo-chemotherapy of organic drug and inorganic alloy nanoparticles, enhanced cellular uptake mediated by alloy nanoparticles, and Ag+-induced biomembrane damage. This thermo-chemotherapy platform provides a new combinatorial strategy for inorganic and organic agents in the complete elimination of CSCs.

Green Synthesis of Gold Nanoparticles and Study of Their Inhibitory Effect on Bulk Cancer Cells and Cancer Stem Cells in Breast Carcinoma.

Chemo-resistance from cancer stem cells (CSCs) subpopulation is a current issue in cancer treatment. It is important to select alternative therapies to efficiently eradicate both bulk cancer cells and CSCs. Here, gold nanoparticles (AuNPs) have been selected regarding their biocompatibility, facile and controllable synthesis, potent anti-cancer activity and photothermal conversion performance. We reported a green synthesis of functionalized AuNPs using hyaluronic acid (HA) as a reductant, capping, stabilizing and hydrophilic substance. The resultant AuNPs were spherical-shaped with an average diameter of around 30 nm. These AuNPs displayed improved physico-chemical (yield, stability, photothermal effect) and biological properties (cellular uptake, cytotoxicity and apoptotic effect) against bulk MDA-MB-231 cells, in comparison with other organic anti-cancer drugs. The intensified bioactivity was dependent on a mitochondria-mediated cascade, reflected by the damage in mitochondria, oxidative stress, intensified Caspase 3 activity and increased/decreased expression of certain pro-apoptotic (Bax, P53, Caspase 3)/anti-apoptotic (Bcl-2) genes. Moreover, these AuNPs posed a dramatically improved inhibitory effect in cell viability and self-renewable capacity on CSC subpopulation. All the results were attributed from the nano-scaled structure of AuNPs and combined effect from NIR-induced hyperthermia. In addition, the biocompatible nature of these AuNPs supported them to be a potential candidate in the development of novel chemotherapeutic drugs.

Converting evergreen broad-leaved forests into tea and Moso bamboo plantations affects labile carbon pools and the chemical composition of soil organic carbon.

This study aimed to explore the effects of conversion from evergreen broad-leaved forests (EBFs) to tea plantations (TPs) and Moso bamboo (Phyllostachys heterocycla var. pubescens) plantations (MBPs) and the subsequent long-term intensive management on the soil carbon pool and the chemical composition of soil organic carbon (SOC). Soil samples from three layers (0-10, 10-30 and 30-60 cm, respectively) were collected from adjacent EBFs, TPs and MBPs in An'ji County, Zhejiang Province, China. The physico-chemical properties of soils, including bulk density, SOC and its different fractions were determined. The chemical composition of SOC was also measured using 13C-nuclear magnetic resonance spectroscopy (NMR). The results showed that conversion from EBFs to TPs and MBPs decreased the concentrations of water soluble organic carbon (WSOC), light and heavy fraction organic carbon (LFOC, HFOC) and humus carbon (HC) (P < 0.05), reduced the O-alkyl C and carbonl C content, but increased the alkyl C, Aromatic C, aromaticity and the ratio of alkyl C/O-alkyl C (A/O-A) (P < 0.05). These results suggested that intensive management markedly altered the chemical structure of SOC and labile carbon pools. Our results demonstrated that converting EBFs to TPs and MBPs had a negative effect on SOC content and a positive effect on SOC stability. Therefore, management practices such as rational fertilization and sod cultivation are recommended after land-use conversion.

Pleiotropic effects of the wheat domestication gene Q on yield and grain morphology.

MAIN CONCLUSION: Transformation from q to Q during wheat domestication functioned outside the boundary of threshability to increase yield, grains m-2, grain weight and roundness, but to reduce grains per spike/spikelet. Mutation of the Q gene, well-known affecting wheat spike structure, represents a key domestication step in the formation of today's free-threshing, economically important wheats. In a previous study, multiple yield components and spike characteristics were associated with the Q gene interval in the bread wheat 'Forno' × European spelt 'Oberkulmer' recombinant inbred line population. Here, we reported that this interval was also associated with grain yield, grains m-2, grain morphology, and spike dry weight at anthesis. To clarify the roles of Q in agronomic trait performance, a functional marker for the Q gene was developed. Analysis of allelic effects showed that the bread wheat Q allele conferred free-threshing habit, soft glumes, and short and compact spikes compared with q. In addition, the Q allele contributed to higher grain yield, more grains m-2, and higher thousand grain weight, whereas q contributed to more grains per spike/spikelet likely resulting from increased preanthesis spike growth. For grain morphology, the Q allele was associated with reduced ratio of grain length to height, indicating a rounder grain. These results are supported by analysis of four Q mutant lines in the Chinese Spring background. Therefore, the transition from q to Q during wheat domestication had profound effects on grain yield and grain shape evolution as well, being a consequence of pleiotropy.

High performance of phosphonate-functionalized mesoporous silica for U(VI) sorption from aqueous solution.

The renaissance of nuclear energy promotes increasing basic research on the separation and enrichment of nuclear fuel associated radionuclides. Herein, we report the first study for developing mesoporous silica functionalized with phosphonate (NP10) as a sorbent for U(VI) sorption from aqueous solution. The mesoporous silica was synthesized by co-condensation of diethylphosphatoethyltriethoxysilane (DPTS) and tetraethoxysilane (TEOS), using cationic surfactant cetyltrimethylammonium bromide (CTAB) as the template. The synthesized silica nanoparticles were observed to possess a mesoporous structure with a uniform pore diameter of 2.7 nm, and to have good stability and high efficiency for U(VI) sorption from aqueous solution. A maximum sorption capacity of 303 mg g(-1) and fast equilibrium time of 30 min were achieved under near neutral conditions at room temperature. The adsorbed U(VI) can be easily desorbed by using 0.1 mol L(-1) HNO(3), and the reclaimed mesoporous silica can be reused with no decrease of sorption capacity. In addition, the preconcentration of U(VI) from a 100 mL aqueous solution using the functionalized mesoporous silica was also studied. The preconcentration factor was found to be as high as 100, suggesting the vast opportunities of this kind of mesoporous silica for the solid-phase extraction and enrichment of U(VI).