Fabrication of Nano-Onion-Structured Graphene Films from Citrus sinensis Extract and Their Wetting and Sensing Characteristics.

Graphene and its derivatives have acquired substantial research attention in recent years because of their wide range of potential applications. Implementing sustainable technologies for fabricating these functional nanomaterials is becoming increasingly apparent, and therefore, a wide spectrum of naturally derived precursors has been identified and reformed through various established techniques for the purpose. Nevertheless, most of these methods could only be considered partially sustainable because of their complexity as well as high energy, time, and resource requirements. Here, we report the fabrication of carbon nano-onion-interspersed vertically oriented multilayer graphene nanosheets through a single-step, environmentally benign radio frequency plasma-enhanced chemical vapor deposition process from a low-cost carbon feedstock, the oil from the peel of Citrus sinensis orange fruits. C. sinensis essential oil is a volatile aroma liquid principally composed of nonsynthetic hydrocarbon limonene. Transmission electron microscopy studies on the structure unveiled the presence of hollow quasi-spherical carbon nano-onion-like structures incorporated within graphene layers. The as-fabricated nano-onion-incorporated graphene films exhibited a highly hydrophobic nature showing a water contact angle of up to 1290. The surface energies of these films were in the range of 41 to 35 mJ·m-2. Moreover, a chemiresistive sensor directly fabricated using C. sinensis-derived onion-structured graphene showed a p-type semiconductor nature and a promising response to acetone at room temperature. With its unique morphology, surface properties, and electrical characteristics, this material is expected to be useful for a wide range of applications.

Review on the Antimicrobial Properties of Carbon Nanostructures.

Swift developments in nanotechnology have prominently encouraged innovative discoveries across many fields. Carbon-based nanomaterials have emerged as promising platforms for a broad range of applications due to their unique mechanical, electronic, and biological properties. Carbon nanostructures (CNSs) such as fullerene, carbon nanotubes (CNTs), graphene and diamond-like carbon (DLC) have been demonstrated to have potent broad-spectrum antibacterial activities toward pathogens. In order to ensure the safe and effective integration of these structures as antibacterial agents into biomaterials, the specific mechanisms that govern the antibacterial activity of CNSs need to be understood, yet it is challenging to decouple individual and synergistic contributions of physical, chemical and electrical effects of CNSs on cells. In this article, recent progress in this area is reviewed, with a focus on the interaction between different families of carbon nanostructures and microorganisms to evaluate their bactericidal performance.