Photoinduced DNA cleavage by alpha-, beta-, and gamma-cyclodextrin-bicapped C60 supramolecular complexes

DNA Cleavage by Chemically Exfoliated Molybdenum Disulfide Nanosheets

Chemically exfoliated MoS₂ (ce-MoS₂) nanosheets have been widely used in biomedical and environmental fields. Some in vitro studies demonstrated that ce-MoS₂ might induce toxicity. However, the understanding of the mechanism of potential toxicity is lacking. In this study, we found that ce-MoS₂ could directly induce breakage of double-stranded DNA with or without an external energy input, making it different from other two-dimensional nanomaterials. In a dark environment, the DNA cleavage exhibited a pH-dependent trend due to reactive oxygen species generation under different pH values. Under photoirradiation, DNA cleavage could be enhanced. This study provides insights into the potential environmental risk and toxicity of ce-MoS₂ in the aquatic environment.

Environmental transformation of graphene oxide in the aquatic environment

In recent years, research on graphene oxide (GO) has developed rapidly in both academic and industrial applications such as electronic, biosensor, drug delivery, water treatment and so forth. Based on the large amount of applications, it is anticipated that GO will inevitably find its own way to the environment, if used are not restricted to prevent their release. Environmental transformation is an important transformation process in the natural environment. In this review, we will summarize the recent developments on environmental transformation of GO in the aquatic environment. Although papers on environmental transformation of graphene-based nanomaterials can be found, a systematic picture describing photo-transformation of GO (dividing into different irradiation sources), environmental transformation of GO in the dark environmental, the environmental toxicity of GO are still lacking. Thus, it is essential to summarize how different light sources will affect the GO structure and reactive oxygen species generation in the photo-transformation process, how GO will react with various natural constituents in the aquatic environment, whether GO will toxic to different aquatic organisms and what will be the interactions between GO and the intracellular receptors in the intracellular level once GO released into the aquatic environment. This review will arouse the realization of potential risk that GO can bring to the aquatic environment and enlighten us to pay attention to behaviors of other two-dimensional GO-like nanomaterials, which have been intensively applied and studied in recent years.

Interaction of DNA and a series of aromatic donor-viologen acceptor molecules with and without the presence of CB[8]

A series of 1-ethyl-1'-arylmethyl-4,4'-bipyridinium compounds is synthesized, where the aryl is phenyl (BEV), 2-naphthyl (NEV), 2-anthracenyl (AEV) or 1-pyrenyl (PEV). Among them, PEV and AEV can bind with calf thymus DNA mainly through intercalation and groove-binding modes, and both of them can be observed to photocleave plasmid pBR 322 DNA significantly under irradiation with a xenon arc lamp. After inclusion of cucurbit[8]uril (CB[8]), all of the aromatic donor-viologen acceptor compounds exhibit efficient DNA photocleavage ability. The reason is that CB[8] can inhibit the intramolecular backwards electron transfer in the aromatic donor-viologen acceptor molecule, prolonging the lifetime of the charge separated excited state to some extent. These studies bring a new subject in DNA photocleavage research and a potential application of the host-guest supramolecular system.

Current studies into the genotoxic effects of nanomaterials

Nanotechnology has created opportunities for engineers to manufacture superior and more efficient devices and products. Nanomaterials (NMs) are now widely used in consumer products as well as for research applications. However, while the lists of known toxic effects of nanomaterials and nanoparticles (NPs) continue to grow, there is still a vast gap in our knowledge about the genotoxicity of NMs. In this paper, we highlight some NMs of interest and discuss the current in vivo and in vitro studies into genotoxic effects of NMs.