Tumor microenvironment-initiated lipid redox cycling for efficient triple-negative breast cancer therapy.

The use of overwhelming reactive oxygen species (ROS) attack has shown great potential for treating aggressive malignancies; however, targeting this process for further applications is greatly hindered by inefficiency and low selectivity. Here, a novel strategy for ROS explosion induced by tumor microenvironment-initiated lipid redox cycling was proposed, which was developed by using soybean phosphatidylcholine (SPC) to encapsulate lactate oxidase (LOX) and sorafenib (SRF) self-assembled nanoparticles (NPs), named LOX/SRF@Lip. SPC is not only the delivery carrier but an unsaturated lipid supplement for ROS explosion. And LOX catalyzes excessive intratumoral lactate to promote the accumulation of large amounts of H2O2. Then, H2O2 reacts with excessive endogenous iron ions to generate amounts of hydroxyl radical for the initiation of SPC peroxidation. Once started, the reaction will proceed via propagation to form new lipid peroxides (LPO), resulting to devastating LPO explosion and widespread oxidative damage in tumor cells. Furthermore, SRF makes contribution to mass LPO accumulation by inhibiting LPO elimination. Compared to normal tissue, tumor tissue has higher levels of lactate and iron ions. Therefore, LOX/SRF@Lip shows low toxicity in normal tissues, but generates efficient inhibition on tumor proliferation and metastasis, enabling excellent and safe tumor-specific therapy. This work offers new ideas on how to magnify anticancer effect of ROS through rational nanosystem design and tumor-specific microenvironment utilization.

The distribution and risk of microplastics discharged from sewage treatment plants in terrestrial and aquatic compartment.

Many microplastics (MPs) were produced in daily life, which would enter sewage treatment plants (STPs) with the wastewater. Although the STPs has a good interception effect on these MPs, there will still be a part of MPs entering the environment with the effluent and sludge treatment, causing a certain ecological risk. This study investigated the abundance, characteristics and retention of MPs in different STPs, as well as the ecological risks caused by MPs entering the environment. The abundance of MPs in influent and effluent was ranged from 2.02 to 2.50 items L-1 and 0.27-0.48 items L-1, respectively. The abundance of MPs in dewatered sludge and sediment of Lake Dianchi was ranged from 3.719-6.949 × 103 items (kg Ds)-1 and 1.84-5.23 × 103 items (kg Ds)-1, respectively. So roughly 80% of the MPs were trapped and transferred into the dewatered sludge. The observed colors of MPs were transparent, black, blue, red, pale brown, green and gray, and their main species were polypropylene (PP) and polyethylene (PE). To further evaluate the ecological risks of MPs, the oyster mushroom was cultivated in a medium supplemented with MPs. It was found that MPs could be absorbed by oyster mushrooms with a 7-11% of absorption rate, the fibers were widely distributed in the stipes and the pileus. This study had theoretical significance for exploring the distribution of MPs in STPs and clarifying the ecological risk posed by MPs in the environment.

Functional imaging of glucose-evoked rat islet activities using transient intrinsic optical signals.

We demonstrate intrinsic optical signal (IOS) imaging of intact rat islet, which consists of many endocrine cells working together. A near-infrared digital microscope was employed for optical monitoring of islet activities evoked by glucose stimulation. Dynamic NIR images revealed transient IOS responses in the islet activated by low-dose (2.75mM) and high-dose (5.5mM) glucose stimuli. Comparative experiments and quantitative analysis indicated that both glucose metabolism and calcium/insulin dynamics might contribute to the observed IOS responses. Further investigation of the IOS imaging technology may provide a high resolution method for ex vivo functional examination of the islet, which is important for advanced study of diabetes associated islet dysfunctions and for improved quality control of donor islets for transplantation.