Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.

Understanding biophysicochemical interactions at the nano–bio interface

Chemical doping with foreign atoms is an effective method to intrinsically modify the properties of host materials. Among them, nitrogen doping plays a critical role in regulating the electronic properties of carbon materials. Recently, graphene, as a true two-dimensional carbon material, has shown fascinating applications in bioelectronics and biosensors. In this paper, we report a facile strategy to prepare N-doped graphene by using nitrogen plasma treatment of graphene synthesized via a chemical method. Meanwhile, a possible schematic diagram has been proposed to detail the structure of N-doped graphene. By controlling the exposure time, the N percentage in host graphene can be regulated, ranging from 0.11 to 1.35%. Moreover, the as-prepared N-doped graphene has displayed high electrocatalytic activity for reduction of hydrogen peroxide and fast direct electron transfer kinetics for glucose oxidase. The N-doped graphene has further been used for glucose biosensing with concentrations as low as 0.01 mM ...

Nitrogen-Doped Graphene and Its Application in Electrochemical Biosensing

Bio-nanocomposites for food packaging applications

Boron atoms, with strong electron-withdrawing capability, are doped into graphene frameworks forming boron doped graphene (BG) via a catalyst-free thermal annealing approach in the presence of boron oxide. Atomic force microscopic (AFM) and transmission electron microscopic (TEM) characterizations reveal that the as-prepared BG has a flake-like structure with an average thickness of ca. 2 nm. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that boron atoms can be successfully doped into graphene structures with the atomic percentage of 3.2%. Due to its particular structure and unique electronic properties, the resultant BG exhibits excellent electrocatalytic activity towards oxygen reduction reaction (ORR) in alkaline electrolytes, similar to the performance of Pt catalysts. In addition, the non-metallic BG catalyst shows long-term stability and good CO tolerance superior to that of Pt-based catalysts. These results demonstrate that the BG, as a promising candidate in advanced electrode materials, may substitute Pt-based nanomaterials as a cathode catalyst for ORR in fuel cells as well as other electrochemical applications similar to the reported nitrogen doped graphene.

Synthesis of boron doped graphene for oxygen reduction reaction in fuel cells

Food packaging based on polymer nanomaterials

In this report, we compare the toxicological effects between pure carbon multiwalled nanotubes (MWNTs) and N-doped multiwalled carbon (CNx) nanotubes. Different doses of tubes were administered in various ways to mice:  nasal, oral, intratracheal, and intraperitoneal. We have found that when MWNTs were injected into the mice's trachea, the mice could die by dyspnea depending on the MWNTs doses. However, CNx nanotubes never caused the death of any mouse. We always found that CNx nanotubes were far more tolerated by the mice when compared to MWNTs. Extremely high concentrations of CNx nanotubes administrated directly into the mice's trachea only induced granulomatous inflammatory responses. Importantly, all other routes of administration did not induce signs of distress or tissue changes on any treated mouse. We therefore believe that CNx nanotubes are less harmful than MWNTs or SWNTs and might be more advantageous for bioapplications.

Mancilla R

Papers

Biocompatibility and toxicological studies of carbon nanotubes doped with nitrogen.