Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. Through the development of a drug delivery system that tethers doxorubicin onto the surface of gold nanoparticles with a poly(ethylene glycol) spacer via an acid-labile linkage (DOX-Hyd@AuNPs), we have demonstrated that multidrug resistance in cancer cells can be significantly overcome by a combination of highly efficient cellular entry and a responsive intracellular release of doxorubicin from the gold nanoparticles in acidic organelles. DOX-Hyd@AuNPs achieved enhanced drug accumulation and retention in multidrug resistant MCF-7/ADR cancer cells when it was compared with free doxorubicin. It released doxorubicin in response to the pH of acidic organelles following endocytosis, opposite to the noneffective drug release from doxorubicin-tethered gold nanoparticles via the carbamate linkage (DOX-Cbm@AuNPs), which was shown by the recovered fluorescence of doxorubicin from quenching due to the nanosurface energy transfer between the doxorubicinyl groups and the gold nanoparticles. DOX-Hyd@AuNPs therefore significantly enhanced the cytotoxicity of doxorubicin and induced elevated apoptosis of MCF-7/ADR cancer cells. With a combined therapeutic potential and ability to probe drug release, DOX-Hyd@AuNPs represent a model with dual roles in overcoming MDR in cancer cells and probing the intracellular release of drug from its delivery system.

While the immunogenicity and cytotoxicity of gold nanoparticles (AuNPs) are noted by many researchers, the mechanisms by which AuNPs exert these effects are poorly understood. In this study, we investigated the effects of polyethylene glycolylated AuNPs (PEG@AuNPs) on lipopolysaccharide (LPS)-induced nitric oxide (NO) and interleukin-6 (IL-6) production and the associated molecular mechanism in RAW264.7 cells. The results showed that PEG@AuNPs were internalized more quickly by LPS-activated RAW264.7 cells than unstimulated cells, and they reached saturation within 24 hours. PEG@AuNPs enhanced LPS-induced production of NO and IL-6 and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells, partially by activating p38 mitogen-activated protein kinases (p38 MAPK) and nuclear factor-kappaB pathways. In addition, the p38 MAPK inhibitor SB203580 attenuated PEG@AuNP-enhanced LPS-induced NO production and iNOS expression. Overproduction of NO and IL-6 is known to be closely correlated with the pathology of many diseases and inflammations. Thus, it is speculated that the highly biocompatible gold nanoparticles can induce immunotoxicity due to their potency to stimulate macrophages to release aberrant or excessive pro-inflammatory mediators.

During the process of human civilization, owning household pets has become increasingly popular. However, dogs and cats may be reservoirs or vectors of transmissible diseases to humans. Confronted with the overpopulation of pets, traditional contraception methods, surgical methods of sterilization, for animals are used, namely, ovariohysterectomy and orchidectomy. Therefore, a simple, nonsurgical, controllable, more effective and less expensive contraception method is highly desirable. In this study, we show that in situ testicular injection of methoxy poly(ethylene glycol)-modified gold nanorods with near-infrared irradiation in male mice can achieve short-lived or permanent male infertility. In a lower hyperthermia treatment, the morphology of testes and seminiferous tubules is only partly injured, and fertility indices are decreased to 10% at day 7, then recovered to 50% at day 60. In a higher hyperthermia treatment, the morphology of testes and seminiferous tubules are totally destroyed, and fertility indices are decreased to 0 at day 7. Overall, our results indicate a potential application of plasmonic nanomaterials for male contraception.

P2-type layered Na x MnO 2 cathode shows great potential in practical sodium ion batteries, especially for grid-level applications due to its ecofriendly and cost-effective sodium and manganese resources, and high theoretical specific capacity. However, several obstacles including severe phase transitions of P2-O2 and P2-P2′, low redox potential of Mn 3+ /Mn 4+ , disproportionation reaction and Jahn-Teller distortion of Mn 3+ , and deficient behavior have already hindered its practical applications. Herein, a Li, Cu co-doping strategy to tackle the mentioned obstacles by activating the oxygen redox is presented. The Li, Cu co-doped material exhibits solid solution reaction without any phase transitions as proved by in situ X-ray diffraction measurement and reduces the dissolution of active manganese element. With this modification treatment, it can dramatically raise the cycling stability from 30.4% to 80.1% after 150 cycles and simultaneously improves the deficient behavior due to the capacity contribution of oxygen redox at high voltage. More importantly, the coin-cell type sodium ion full cell assembled with this cathode and commercial hard carbon anode delivers a promising energy density of 225.1 Wh kg -1 .