No abstract

To effectively inhibit the growth of breast cancer cells (MDA-MB-231 cells) by the combination method of chemotherapy and magnetic hyperthermia, we fabricated a biomimetic drug delivery (CSiFePNs) system composed of mesoporous silica nanoparticles (MSNs) containing superparamagnetic ferroferric oxide and Paclitaxel (PTX) coated with MDA-MB-231 cell membranes (CMs). In the in vitro cytotoxicity tests, the MDA-MB-231 cells incubated with CSiFePNs obtained IC50 value of 0.8 μgL−1, 3.5-fold higher than that of SiFePNs. The combination method of chemotherapy and magnetic hyperthermia can effectively inhibit the growth of MDA-MB-231 cells.

Ionizing radiation (IR) plays an important role in the treatment of epithelial tumors, such as lung and prostate cancer, by wounding and killing cancer cells. However, IR also activates sophisticated anti-apoptotic transcriptional factors such that cancer cells fail to repair DNA damage and obtain resistance to apoptosis under conditions of radiotherapy. Among these transcription factors, the transcription factor nuclear factor kappa B (NF-κB) is recognized as a key feature for protecting cells from apoptosis in most cell types. Moreover, the induction of radioresistance is mediated by several genes that are regulated by NF- κB. The primary purpose of this review is to introduce the studies of the signaling mechanisms of IR in NF-κB activation, such as ROS/NF-κB, ATM or DNA-PK/MAPKK/ p90rsk, PI3K/AKT/IKK and k-ras/c-raf/ MEKK/ NF-κB pathways. Moreover, we describe how the expression of the target genes (e.g., XIAP, A20, FLIP, Bcl-xL) are induced by NF-κB to regulate the activation of survival signaling pathways and to inhibit apoptotic signaling pathways. In addition, IR activates NF-κB to express cell cycle-specific genes, for example cyclin D1, which is associated with reinforcing radioresistance. We exhibit the signaling pathways that are induced by IR stimulation of NF-κB and illustrate the molecular mechanisms of radioresistance.

A graphene-based magnetic nanocomposite (graphene-ferriferrous oxide; G-Fe(3)O(4)) was synthesized and used as an effective adsorbent for the preconcentration of some triazole fungicides (myclobutanil, tebuconazole, and hexaconazole) in environmental water samples prior to high-performance liquid chromatography-ultraviolet detection. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid the time-consuming experimental procedures commonly involved in the traditional solid phase extraction such as centrifugation and filtrations. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, the pH values of the sample solution, salt concentration, and desorption conditions were investigated. Under the optimum conditions, the enrichment factors of the method for the three analytes were 5824, 3600, and 4761, respectively. A good linearity was observed in the range of 0.1-50 ng/mL for tebuconazole and 0.05-50 ng/mL for myclobutanil and hexaconazole, respectively, with the correlation coefficients ranging from 0.9992 to 0.9996. The limits of detection (S/N = 3) of the method were between 0.005 and 0.01 ng/mL. The results indicated that as a magnetic solid-phase extraction adsorbent, the graphene-ferriferrous oxide (G-Fe(3)O(4)) has a great potential for the preconcentration of some compounds from liquid samples.

We have developed a highly sensitive microextraction method for the preconcentration of some phthalate esters such as diethyl phthalate, di-n-propylphthalate, di-nbutyl-phthalate, dicyclohexyl-phthalate, and diethyl-hexyl phthalate prior to their determination by HPLC. It is based on a magnetic graphene nanocomposite as an effective adsorbent. The effects of the amount of the extractant composite employed, extraction time, pH values, salt concentration and desorption conditions were investigated. Under the optimum conditions, the enrichment factors range from 1574 to 2880. Response is linear in the concentration range from 0.1 to 50 ng mL −1 . The limits of detection (at S/N03) were between 0.01 and 0.04 ng mL −1 . The method was successfully applied to the determination of five phthalate esters in water and beverage samples.