Cetylpyridinium bromide/montmorillonite-graphene oxide composite with good antibacterial activity.

In this study, a cetylpyridinium bromide (CPB)/montmorillonite-graphene oxide (GM) composite (GM-CPB) was prepared by loading CPB in a carrier of GM. The chemical structure, elemental composition, morphology, thermogravimetric analysis, antibacterial activity, sustained release property and cytotoxicity were analyzed. The loading rate of CPB in a GM carrier was higher than that of the graphene oxide (GO) carrier under the same loading condition. The antibacterial activity and sustained release performance of GM-CPB were also better than that of GO-CPB; furthermore, GM-CPB showed lower cytotoxicity than CPB.

Adsorption of Cd2+ and Ni2+ from Aqueous Single-Metal Solutions on Graphene Oxide-Chitosan-Poly(vinyl alcohol) Hydrogels.

The applications of graphene-based adsorbents were limited because of their complicated manufacturing technology and hi cost, thus it is very important to prepare new inexpensive and easily manufactured graphene-based adsorbents. Herein, novel GCP hydrogels with different graphene oxide (GO), chitosan (CS), and poly(vinyl alcohol) (PVA) ratios were facilely prepared through a method of freeze-thaw physical cross-linking, which was green and low-cost, and the structural characterization and adsorptive property of the optimum GCP1:2:4 hydrogel toward Cd2+ and Ni2+ in wastewater was evaluated. It was found that the GCP1:2:4 hydrogel had good mechanical strength and a special 3D interconnection porous structure. The isotherms of adsorption used the Langmuir model, and the kinetics of adsorption following the pseudo-second-order model were confirmed. Moreover, the adsorption property with respect to Cd2+ and Ni2+ in wastewater has been largely effected by the pH and was less influenced by the ionic strength and humic acid, and the GCP1:2:4 hydrogel possessed excellent adsorptive and recyclable properties. These results demonstrated that the GCP1:2:4 hydrogel could serve as a desirable adsorbent to get rid of heavy metal ions in sewage.

Antibacterial Nanorods Made of Carbon Quantum Dots-ZnO Under Visible Light Irradiation.

Due to secondary pollution from bactericidal substances, the importance of eliminating microbial contamination has become a controversial topic. Three antibacterial nanorod materials of carbon quantum dots-zinc oxide (1/3CQDs-ZnO, CQDs-ZnO, and 2CQDs-ZnO), in which ZnO nanorods are surrounded by carbon quantum dots (CQDs), were successful prepared via in-situ sol-gel chemistry. Antibacterial nanorods of CQDs-ZnO had strong antibacterial activity under visible light irradiation, and a concentration of 0.1 mg/L was able to kill more than 96% of bacteria. The photocatalytic antibacterial mechanism was also studied. CQDs-ZnO produced more than three times the free radicals than pure ZnO under visible light irradiation. These free radicals destroyed the bacterial matrix of the cell wall and released cell proteins and nucleic acids. Moreover, CQDs-ZnO showed low cytotoxicity and can be used in medical applications.

Montmorillonite-Modified Reduced Graphene Oxide Stabilizes Copper Nanoparticles and Enhances Bacterial Adsorption and Antibacterial Activity.

To increase antibacterial activity and reduce the cytotoxicity of copper nanoparticles (CuNPs), we used reduced graphene oxide with montmorillonite to support CuNPs and fixed CuNPs on reduced graphene oxide to synthesize the hybrid montmorillonite-reduced graphene oxide copper nanoparticles (MMT-rGO-CuNPs). The synthesized MMT-rGO-CuNPs complex showed a stronger antibacterial activity against Gram-positive bacteria S. aureus than Gram-negative E. coli. This may be due to the protective effect of the outer membrane of E. coli, as well as the fact that the MMT-rGO-CuNPs complex adsorbs S. aureus more strongly than E. coli. The hybrid molecule's antibacterial efficacy is the combined result of the synergistic effects of electrostatic adsorption and copper ion sterilization ability. At the same time, the MMT-rGO-CuNPs complex exhibits a lower cytotoxicity than PVP-CuNPs and provides a biocompatible composite material with a reduced cytotoxicity.

A colon targeted drug delivery system based on alginate modificated graphene oxide for colorectal liver metastasis.

A major problem associated with colon cancer is liver metastasis. A colon-targeted drug delivery system is one way to address this problem after the resection of colorectal cancer. However, traditional drug delivery systems face many challenges, such as an inability to control the release rate, inaccurate targeting, susceptibility to the microenvironment and poor stability. Here, we report the development of a graphene oxide (GO)-based, sodium alginate (ALG) functionalized colon-targeting drug delivery system, that is loaded with 5-fluorouracil (5-FU) as the anti-cancer drug (denoted as GO-ALG/5-FU). Our results demonstrate that the as-prepared drug delivery system possesses a much lower toxicity and better colon-targeting controlled-release behaviours. We show that GO-ALG/5-FU significantly inhibited tumour growth and liver metastasis and prolonged the survival time of mice. We anticipate that our assay will help improve basic research of colon-targeted drug delivery systems and provide a new way to treat colon cancer liver metastasis.