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Single-Walled Carbon Nanotubes (SWCNTs) are widely used as potential carriers in drug delivery systems. The objective of this work was to observe the effects of pristine, and single-stranded DNA oligonucleotide functionalized SWCNT over the locomotion pattern in the nematode model, Caenorhabditis elegans. The implication of ssDNA in the as-modified SWCNT has been understood in terms of lowering the toxic effects of the pristine SWCNT and thereby normalizing the altered navigation pattern of the worms. Chemotaxis assay displayed an increased migration of the worms towards pristine and ssDNA functionalized SWCNT in comparison to ultrapure water as control. Additionally, paralytic movement was observed with SWCNT exposure in contrast to ssDNA-functionalized SWCNT-exposed animals. High doses of pristine SWCNT further displayed an increased expression of specific proteins obtained from the total protein extracts of the animals. Thus, the alteration in the navigation pattern of the worms, treated with pristine SWCNT, might be ascribed as a result of differentially expressed muscle proteins. Moreover, it is interesting to note that the modified SWCNT was effective in alleviating the atypical form of the inherent movements of the worm. Future investigation will further reveal the protein targets responsible for the altered navigation pattern of the worms. [ABSTRACT FROM AUTHOR]

In this study, electronic properties of Manganese atom doped Graphene are studied using Atomistix Tool Kit-Virtual NanoLab (ATK-VNL), QuantumWise simulation package. All the calculations are done using density functional theory. The doping of Manganese atom creates a small band gap and this gap increases with increasing doping concentrations. Chemical potential measurements exhibit a rise in the values for pristine Graphene is − 10.48 to − 9.91 eV for single doped atom to − 9.87 eV for double doped Manganese atom to − 9.57 eV for triple atom doped Manganese. Total energy calculated for pristine, one, two and three Manganese atom doped Graphenes are as − 4506.6, − 4599.5, − 4691.97 and − 4789.31 eV, respectively. Optical spectrum plots also support the aforementioned characteristics deviation in the pristine Graphene. Transmission spectrum is also varied for pristine Graphene in comparison to one, two and three Manganese atom doped nanosheets. Density of states calculations also illustrates the rise in the values for the number of states occupied by electrons for pristine Graphene, one to three Manganese atom doped nanosheet, respectively. The flow of current reduces with increasing number of impure atoms. Understanding the effect of Manganese as dopant at different lattice sites of 2D-Graphene helps in designing conductivity tunable Graphene based electro-mechanical devices and sensors for myriad nanoelectronic applications. [ABSTRACT FROM AUTHOR]

DEHP (Di-ethyl hexyl phthalate), an ubiquitous chemical constituent of plasticizer, cosmetics etc. poses different abnormal neurological and behavioral responses in eukaryotic model organism C. elegans (Caenorhabditis elegans). Based upon such reports, we hypothesized that due to exposure of DEHP, the larval growth of C. elegans was altered and animals went into dauer at high concentrations of exposure at 8.26 ppm. Using chemosensory assay, the orientation of repulsion (− 0.1) of the nematodes were determined with exposure of DEHP at 4.78 ppm and 8.26 ppm. We show that N2 wild type worms display a preferential food choice and search for favorable food, and alter two modes of locomotion (forward and backward) that measures the maximum bending rate of an adult worm. Thermo sensation also plays a crucial role in determining the toxicity level in C. elegans at 15 °C, 20 °C, and 25 °C. Understanding the chemosensory pattern towards a specific chemical for C. elegans, the recent work could shed light in exploring the molecular mechanism involved in the tactile movement of the worms against a specific chemical, thereby making worms a potential biological sensing platform for external stimuli perception. [ABSTRACT FROM AUTHOR]

Graphene has been conjugated with Silicene which is a 2D nanosheet of silicon crystal to analyze myriad physico-chemical properties. Upon intercalation of silicene between two graphene nanosheets, there has been a significant shift in the energy of electronic configuration at different isovalues from − 0.12 to + 0.12. Similarly, by analyzing the electronic energy states of silicene–graphene–silicene, a range of isovalues from − 0.08 to + 0.08 were observed. I–V curve exhibited a linear response for graphene–silicene–graphene sandwiched structure and a semiconducting like behavior for silicene–graphene–silicene structure. Band gap measurement in case of graphene–silicene–graphene system is reported to be ~ 0.18 eV, which is a narrow region. While in case of silicene–graphene–silicene, a band gap value of ~ 1.01 eV is calculated that appears to be a pretty broad region. Transmission spectrum also shows intensity in peaks for Gr–Si–Gr case as compared to Si–Gr–Si combinations. Silicon is widely perceived to exhibit outstanding semiconducting behavior and has already been used in devising various electronic devices. In this present work, we try to analyze the outcome of the silicene and graphene at the nanometer scale in various combinations in a bid to understand the potential interaction mechanism between the two nanosheets which would help in the fabrication of the silicene–graphene based optoelectronic devices. [ABSTRACT FROM AUTHOR]

Conversion of the metallic SWCNT to semiconducting SWCNT was achieved by band structure engineering of the nanotube by functionalization of the DNA nucleobase, guanine. The band structure analysis revealed that metallic SWCNT (6, 0), when surface engineered with guanine nucleobase with H-atom attachment as the functional group, is converted to a semiconductor one by opening a narrow bandgap with a value of 0.08 eV. This phenomenon was brought about by strong chemisorption due to hydrogenation by inducing partial sp3 hybridization in the nanotube structure. No bandgap openings were observed when guanine was adsorbed on the pristine nanotube surface by its nitrogen site and oxygen site respectively. Related zero-bias transmission spectra and IV-curve supported the result also. The entire study was done at room temperature using ATK-VNL simulation software. [ABSTRACT FROM AUTHOR]

Pristine metallic single-walled carbon nanotubes (6, 0), surface engineered with pyrimidine type DNA nucleobases, thymine and cytosine respectively, are transformed into semimetal forms by band structure engineering of the nanotubes. The hybrid systems are designed using ATK–VNL simulation software. Band structure and zero bias transmission spectra analysis witness a very small overlap between the conduction and valence bands around the Fermi level. IV-characteristic curves also support the semimetallic nature of SWCNT–DNA nucleobase coupling. The altered electronic structure of SWCNT is achieved due to strong chemisorption imparted by hydrogenation of DNA nucleobases which induce partial sp3 hybridization in the nanotube structure. Metal to semimetal conversion results in conductivity modulation in SWCNT and it has several applications in various fields like nano-electronics including NEMS design. [ABSTRACT FROM AUTHOR]