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An ideal anti microbial should selectively kill or inhibit the growth of microbes but cause little or no adverse effect to the host. Each of the engineered nanomaterials reviewed here has its own advantages and disadvantages. Nanomaterials in general directly disrupt the microbial cell membrane, interact with DNA and proteins or they could indirectly initiate the production of reactive oxygen species (ROS) that damage microbial cell components and viruses. Some like silver nanoparticles have broad spectrum antibacterial activity while others like cadmium containing QDs shows both antibacterial as well as antiprotozoal activity. Nano material formulations can be used directly or as surface coatings or as effective carriers for delivering antibiotics. Polycationic nature of Chitosan NPs helps in conjugation and stabilization of metallic nanoparticles which will enhance their effective usage in antimicrobial therapy.

Titanate nanotubes (TiONts) are promising agents for biomedical applications. Microglial activation and associated oxidative burst are major challenges in drug delivery applications across the brain. Here, TiONts were designed for drug delivery systems by functionalizing them with (3-aminopropyl) triethoxysilane (APTES), their interactions and biocompatibility were studied in vitro using murine microglial BV-2 cells. TiONts-APTES exposure resulted in increased ROS production and transient mitochondrial hyperpolarization. However, there was no indication of microglial proliferation in BV-2 cells as suggested by cell cycle analysis and morphology evaluation. The endocytosis as well as passive diffusion mediated TiONts-APTES internalization were proved by transmission electron microscopy (TEM) with and without amiloride, an endocytosis inhibiting agent. In addition, the TiONts-APTES exhibited good biocompatibility on microglial BV-2 cells as revealed by the plasma membrane integrity, lysosmal membrane integrity, morphology and viability analysis.

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The presence and distribution of a few organochlorine pesticides (OCPs) in the paddy fields of the Kuttanad agroecosystem (KAE) was examined in the present study. Kuttanad forms a part of the Vembanad wetland system which is a Ramsar site of international importance in the state of Kerala. This study, to the best of our knowledge, is the first report on the occurrence of OCP residues in KAE. Pesticide residue analysis was done with gas chromatograph (GC-ECD). Twenty-one soil samples were collected for the multiresidual analysis of OCPs. Sixteen OCP residues with a notable concentration were observed from the study area. α-BHC; β-BHC; γ-BHC; δ-BHC; α-chlordane; γ-chlordane; heptachlor; 4,4-DDT; 4,4-DDE; 4,4-DDD; α-endosulfan; β-endosulfan; aldrin; dieldrin; endrin aldehyde; and endrin ketone were the residues observed. The percentage-wise occurrence of OCP residues in the soil samples analysed (total of 63 samples from 21 sites, three samples per site) exhibits the following order: Σ BHC˃ Σ chlordane ˃ Σ dieldrin ˃ Σ aldrin ˃ Σ endrin˃ Σ heptachlor = endosulfan˃ Σ DDT. All pesticides detected from KAE are in the list of priority pollutants of US Environmental Protection Agency (USEPA). The distribution pattern of OCPs in the KAE soils revealed their origin as both historical and recent application of pesticides. Health risk assessment of OCP residues on human population was also conducted. The findings indicated that the concentrations of OCPs were within the permissible limits of USEPA, thus, the human population in the study area was safe.

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Zinc oxide nanoparticles (ZnO NPs) are one of the widely used nanoparticles with spectrum of application, in the areas like daily care products, sensors, antibacterial agents, and biomedical sector. With extensive application the risk of exposure at occupational and consumer level also increases. Huge amount of data are available on the biointeraction of ZnO NPs. Though the toxicity of ZnO NPs is attributed to particle dissolution inside the cellular compartments and their ability to generate the reactive oxygen species, the ambiguity prevails over the exact mechanism of toxicity. The in vivo studies on different animal models and humans suggest different level of toxicity in these organisms. However the synthetic route, physiochemical properties of the nanoparticle, mode of exposure and nature of the test system often influences these studies. Hence the study results vary and sometimes contradict on one another. The current review focuses on the interaction of ZnO NPs with different organ systems. It also points to the factors to be considered while undertaking such studies in order to ensure reliability of the results.