Electronic transport properties of electrically doped cytosine‐based optical molecular switch with single‐wall carbon nanotube electrodes

This study represents an empirical model of cytosine‐based optical molecular switch. This possible biomolecular switch has been designed using the first principle approach which is based on density functional theory and non‐equilibrium Green''s function. The quantum‐ballistic transport property and current–voltage (I–V) characteristics of cytosine‐based optomolecular switch have been investigated at 25 THz operating frequency. The influence of highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gaps on the electronic transmission and I–V characteristics has been discussed in detail. The aim of this study is to highlight the minimum conformational change during a single ON–OFF switching cycle. The biomolecule comprises switching behaviour when converts from straightened to twisted form during photo‐excitement. The straightened and twisted forms of the molecule are represented as logic ‘0’ and logic ‘1’, respectively. This p and n regions of this switch has been made using electrical doping process. The current through the twisted form of the cytosine biomolecule is ∼1000 times higher than the straightened form. The maximum switching ratio 62.1 is obtained at 1 V bias. The origin of the switching behaviour of the biomolecule can be interpreted by quantum–ballistic transport model along with HOMO–LUMO gaps.Inspec keywords: ballistic transport, organic compounds, Green''s function methods, ab initio calculations, density functional theory, molecular biophysics, optical switches, single‐wall carbon nanotubes, electrochemical electrodesOther keywords: electrical doping process, cytosine biomolecule, electronic transport properties, single‐wall carbon nanotube electrodes, cytosine‐based optical molecular switch, density functional theory, electronic transmission, HOMO‐LUMO gaps, current–voltage characteristics, biomolecular switching behaviour, quantum–ballistic transport property model, electrically doped cytosine‐based optical molecular switch, first principle approach, nonequilibrium Green''s function, I‐V characteristics, highest occupied molecular orbital–lowest unoccupied molecular orbital gaps, single ON–OFF switching cycle, photoexcitement, frequency 25.0 THz, voltage 1.0 V, C     

In‐vitro toxicity of carbon nanotube/polylysine colloids to colon cancer cells

Single‐walled carbon nanotubes (SWCNTs) are thoroughly purified and dispersed in an aqueous solution of high molecular weight poly‐L‐lysine (pLlys). Human intestinal epithelial Caco‐2/TC7 cells are incubated with the SWCNT dispersions in pLlys, and their effects on cell viability are studied by image flow cytometry. No significant changes are observed in the cell culture wells up to pLlys concentrations of 10 μg ml⁻¹. However, high mortality is detected at pLlys concentrations of 100 μg ml⁻¹. The presence of oxygen‐free SWCNTs does not modify the effects of pLlys on cell cultures at any of the tested concentrations (≤1 μg ml⁻¹). In addition, SWCNTs having an 8 wt.% of surface oxygen are tested with identical results. Thus, purified SWCNTs, even bearing oxygen functional groups, act as inert particles in the cell culture medium. This result supports the applicability of SWCNTs as carriers in pharmacological formulations against digestive tract diseases.Inspec keywords: single‐wall carbon nanotubes, cellular biophysics, molecular weight, filled polymers, biochemistry, cancer, colloidsOther keywords: surface oxygen, mortality, cell culture wells, image flow cytometry, human intestinal epithelial Caco‐2/TC7 cells, molecular weight, aqueous solution, single walled carbon nanotubes, colon cancer cells, carbon nanotube‐polylysine colloids, toxicity     

Modelling epigenetic regulation of gene expression in 12 human cell types reveals combinatorial patterns of cell‐type‐specific genes

The maintenance of the diverse cell types in a multicellular organism is one of the fundamental mysteries of biology. Modelling the dynamic regulatory relationships between the histone modifications and the gene expression across the diverse cell types is essential for the authors to understand the mechanisms of the epigenetic regulation. Here, the authors thoroughly assessed the histone modification enrichment profiles at the promoters and constructed quantitative models between the histone modification abundances and the gene expression in 12 human cell types. The author''s results showed that the histone modifications at the promoters exhibited remarkably cell‐type‐dependent variability in the cell‐type‐specific (CTS) genes. They demonstrated that the variable profiles of the modifications are highly predictive for the dynamic changes of the gene expression across all the cell types. Their findings revealed the close relationship between the combinatorial patterns of the histone modifications and the CTS gene expression. They anticipate that the findings and the methods they used in this study could provide useful information for the future studies of the regulatory roles of the histone modifications in the CTS genes.Inspec keywords: cellular biophysics, genetics, genomics, physiological models, proteinsOther keywords: CTS gene expression, variable profiles, cell‐type‐dependent variability, histone modification abundances, constructed quantitative models, promoters, histone modification enrichment profiles, dynamic regulatory relationship modelling, biology, multicellular organism, cell‐type‐specific genes, combinatorial patterns, human cell types, epigenetic regulation modelling     

Experimental and theoretical investigation of sensing parameters in carbon nanotube‐based DNA sensor

Nowadays, sensitive biosensors with high selectivity, lower costs and short response time are required for detection of DNA. The most preferred materials in DNA sensor designing are nanomaterials such as carbon and Au nanoparticles, because of their very high surface area and biocompatibility which lead to performance and sensitivity improvements in DNA sensors. Carbon nanomaterials such as carbon nanotubes (CNTs) can be considered as a suitable DNA sensor platform due to their high surface‐to‐volume ratio, favourable electronic properties and fast electron transfer rate. Therefore, in this study, the CNTs which are synthesised by pulsed AC arc discharge method on a high‐density polyethylene substrate are used as conducting channels in a chemiresistor for the electrochemical detection of double stranded DNA. Moreover, the response of the proposed sensor is investigated experimentally and analytically in different temperatures, which confirm good agreement between the presented model and experimental data.Inspec keywords: electrochemical sensors, polymers, arcs (electric), biological techniques, nanosensors, carbon nanotubes, DNAOther keywords: C, chemiresistor, double stranded DNA detection, CNT, electronic properties, surface‐to‐volume ratio, nanoparticles, biosensors, electrochemical detection, high‐density polyethylene substrate, pulsed AC arc discharge method, electron transfer rate, carbon nanomaterials, carbon nanotube‐based DNA sensor     

Facile synthesis of multi‐walled carbon nanotube via folic acid grafted nanoparticle for precise delivery of doxorubicin

The motive of work was to develop a multi‐walled carbon nanoplatform through facile method for transportation of potential anticancer drug doxorubicin (DOX). Folic acid (FA)‐ethylene diamine (EDA) anchored and acid functionalised MWCNTs were covalently grafted with DOX via π–π stacking interaction. The resultant composite was corroborated by ¹ H NMR, FTIR, XRD, EDX, SEM, and DSC study. The drug entrapment efficiency of FA‐conjugated MWCNT was found high and stability study revealed its suitability in biological system. FA‐EDA‐MWCNTs‐DOX conjugate demonstrated a significant in vitro anticancer activity on human breast cancer MCF‐7 cells. MTT study revealed the lesser cytotoxicity of folate‐conjugated MWCNTs. The obtained results demonstrated the targeting specificity of FA‐conjugate via overexpressed folate receptor deemed greater scientific value to overcome multidrug protection during cancer therapy. The proposed strategy is a gentle contribution towards development of biocompatible targeted drug delivery and offers potential to address the current challenges in cancer therapy.Inspec keywords: toxicology, nanoparticles, biomedical materials, scanning electron microscopy, drug delivery systems, nanofabrication, nanomedicine, nanocomposites, cellular biophysics, cancer, drugs, multi‐wall carbon nanotubes, Fourier transform infrared spectra, X‐ray chemical analysis, differential scanning calorimetry, proton magnetic resonance, organic compoundsOther keywords: facile synthesis, multiwalled carbon nanotube, precise delivery, multiwalled carbon nanoplatform, drug entrapment efficiency, FA‐conjugated MWCNT, stability study, biological system, human breast cancer MCF‐7 cells, MTT study, folate‐conjugated MWCNTs, overexpressed folate receptor, cancer therapy, biocompatible targeted drug delivery, anticancer drug doxorubicin, π‐π stacking interaction, composite material, ¹ H NMR, in vitro anticancer activity, folic acid grafted nanoparticle, folic acid‐ethylene diamine, acid functionalised MWCNT, FTIR spectra, XRD, EDX, SEM, FA‐EDA‐MWCNT‐DOX conjugate, cytotoxicity, DSC, C     

Cytotoxicity properties of functionalised carbon nanotubes on pathogenic bacteria

Nanobiotechnology is a promising field concerned with the using of engineered nanomaterials, which leads to the improvement of new human remedial against pathogenic bacteria modalities. In this work, silver nanoparticles (AgNPs) were prepared by an easy, cheap and low‐cost electro‐chemical method. The AgNPs were then loaded successfully on to multi‐walled carbon nanotubes (MWCNTs) using a modified chemical reaction process. The AgNPs on the MWCNTs were well spread and evenly distributed on the surfaces of the long nanotubes with well‐graphitised walls as examined by high‐resolution transmission electron microscopy. X‐ray diffraction and transmission electron microscopy were used for sample characterisation. Good dispersion of AgNPs was obtained on the surface of MWCNTs, resulting in an efficient reactivity of the carbon nanotubes surfaces. Finally, the antibacterial activity of AgNPs/MWCNTs hybrid was evaluated against two pathogenic bacteria Pseudomonas aeruginosa and Staphylococcus aureus exhibited excellent activity.Inspec keywords: nanocomposites, X‐ray diffraction, nanofabrication, nanoparticles, transmission electron microscopy, toxicology, silver, antibacterial activity, microorganisms, nanomedicine, multi‐wall carbon nanotubes, electrochemistryOther keywords: engineered nanomaterials, human remedial, pathogenic bacteria modalities, silver nanoparticles, multiwalled carbon nanotubes, modified chemical reaction process, well‐graphitised walls, high‐resolution transmission electron microscopy, cytotoxicity properties, functionalised carbon nanotubes, carbon nanotube surfaces, nanobiotechnology, low‐cost electrochemical method, AgNP‐MWCNT hybrid, X‐ray diffraction, antibacterial activity, Pseudomonas aeruginosa, Staphylococcus aureus, Ag‐C     

MPGraph: multi‐view penalised graph clustering for predicting drug–target interactions

Identifying drug–target interactions has been a key step for drug repositioning, drug discovery and drug design. Since it is expensive to determine the interactions experimentally, computational methods are needed for predicting interactions. In this work, the authors first propose a single‐view penalised graph (SPGraph) clustering approach to integrate drug structure and protein sequence data in a structural view. The SPGraph model does clustering on drugs and targets simultaneously such that the known drug–target interactions are best preserved in the clustering results. They then apply the SPGraph to a chemical view with drug response data and gene expression data in NCI‐60 cell lines. They further generalise the SPGraph to a multi‐view penalised graph (MPGraph) version, which can integrate the structural view and chemical view of the data. In the authors'' experiments, they compare their approach with some comparison partners, and the results show that the SPGraph could improve the prediction accuracy in a small scale, and the MPGraph can achieve around 10% improvements for the prediction accuracy. They finally give some new targets for 22 Food and Drug Administration approved drugs for drug repositioning, and some can be supported by other references.Inspec keywords: graphs, drug delivery systems, drugs, proteins, molecular biophysics, molecular configurations, optimisation, eigenvalues and eigenfunctions, Laplace equations, cancer, cellular biophysics, gene therapy, medical computingOther keywords: MPGraph, multiview penalised graph clustering, drug‐target interactions, drug repositioning, drug discovery, drug design, computational methods, single‐view penalized graph clustering approach, drug structure, protein sequence data, SPGraph model, optimisation problem, spectral clustering, eigenvalue decomposition, Laplacian model, gene expression data, NCI‐60 cell lines     

High‐performance immunosensor for urine albumin using hybrid architectures of ZnO nanowire/carbon nanotube

In this work, the authors reported the hybrid architecture of carbon nanotube (CNT)–zinc oxide (ZnO) nanowire as a multi‐functional probe in amperometric immunosensor for the detection of urine albumin. Low‐cost substrate such as glass is possible because of novel low‐temperature growth process of CNT/ZnO nanowires as a multi‐function electrode in this sensor. Based on Schottky like behaviour this structure exhibit excellent high current density to achieve higher performance. Measurement of urine albumin is a new way for early detection of diabetic and also low concentration of it in culture media is also considered in order to verify the conversion of stem cells to liver cells. Human albumin serum antibody is used as a selective and sensitive part. The amperometric performance of immunosensor is studied and showed excellent performance for detection of albumin in urine samples. Very high linear range (from 3.3 ng/µl to 3.3 mg/µl) with a correlation coefficient of 0.825 and low detection limit (3.3 ng/µl or 4.96 × 10⁻⁸ mol l⁻¹) are the main characteristics of this sensor. Due to the high dynamic range and sensitivity, this sensor was also used in medical diagnosis and biomedical applications.Inspec keywords: biosensors, zinc compounds, wide band gap semiconductors, nanosensors, nanowires, carbon nanotubes, amperometric sensors, II‐VI semiconductors, electrochemical electrodes, Schottky effect, current density, chemical variables measurementOther keywords: amperometric immunosensor, low‐temperature growth process, current density, multifunction electrode probe, nanowire‐carbon nanotube architectures, CNT, human albumin serum antibody detection, Schottky like behaviou, urine albumin measurement, diabetic detection, stem cell conversion, liver cell conversion, medical diagnosis, biomedical applications, ZnO‐C     

Electrochemical assessment of the interaction of microbial living cells and carbon nanomaterials

This work considers the effects of various carbon nanomaterials and fibres on bioelectrocatalytic and respiratory activity of bacterial cells during the oxidation of ethanol in the presence of an electron transport mediator. Gluconobacter oxydans sbsp. industrius VKM B‐1280 cells were immobilised on the surfaces of graphite electrodes and had an adsorption contact with a nanomaterial (multi‐walled carbon nanotubes, thermally expanded graphite, highly oriented pyrolytic graphite, graphene oxide, reduced graphene oxide). The electrochemical parameters of the electrodes (the polarisation curves, the value of generated current at the introduction of substrate, the impedance characteristics) were measured in two‐electrode configuration. Modification by multi‐walled carbon nanotubes led to the increase of microbial fuel cell (MFC) electric power by 26%. The charge transfer resistance of modified electrodes was 47% lower than unmodified ones. Thermally expanded and pyrolytic graphites had a slight negative effect on the electrochemical properties of modified electrodes. The respiratory activity of bacterial cells did not change in the presence of nanomaterials. The data can be used in the development of microbial biosensors and MFC electrodes based on Gluconobacter cells.Inspec keywords: nanofabrication, catalysis, microorganisms, adsorption, charge exchange, microbial fuel cells, electrochemical electrodes, graphite, graphene, oxidation, multi‐wall carbon nanotubes, cellular biophysicsOther keywords: reduced graphene oxide, electrochemical parameters, two‐electrode configuration, multiwalled carbon nanotubes, microbial fuel cell, respiratory activity, bacterial cells, microbial biosensors, MFC electrodes, microbial living cells, electron transport mediator, graphite electrodes, adsorption contact, highly oriented pyrolytic graphite, Gluconobacter oxydans sbsp. industrius VKM B‐1280 cells, polarisation curves, bioelectrocatalytic activity, ethanol, thermally expanded graphite, charge transfer resistance, C     

Nano‐biosensor based on reduced graphene oxide and gold nanoparticles,for detection of phenylketonuria‐associated DNA mutation

Phenylketonuria (PKU)‐associated DNA mutation in newborn children can be harmful to his health and early detection is the best way to inhibit consequences. A novel electrochemical nano‐biosensor was developed for PKU detection, based on signal amplification using nanomaterials, e.g. gold nanoparticles (AuNPs) decorated on the reduced graphene oxide sheet on the screen‐printed carbon electrode. The fabrication steps were checked by field emission scanning electron microscope imaging as well as cyclic voltammetry analysis. The specific alkanethiol single‐stranded DNA probes were attached by self‐assembly methodology on the AuNPs surface and Oracet blue was used as an intercalating electrochemical label. The results showed the detection limit of 21.3 fM and the dynamic range of 80–1200 fM. Moreover, the selectivity results represented a great specificity of the nano‐biosensor for its specific target DNA oligo versus other non‐specific sequences. The real sample simulation was performed successfully with almost no difference than a synthetic buffer solution environment.Inspec keywords: biosensors, nanosensors, nanoparticles, graphene compounds, gold, nanomedicine, DNA, molecular biophysics, biomedical equipment, electrochemical sensors, electrochemical electrodes, field emission scanning electron microscopy, voltammetry (chemical analysis), self‐assembly, biochemistryOther keywords: reduced graphene oxide, gold nanoparticles, phenylketonuria‐associated DNA mutation, newborn children, electrochemical nanobiosensor, signal amplification, nanomaterials, reduced graphene oxide sheet, screen‐printed carbon electrode, field emission scanning electron microscopy imaging, cyclic voltammetry, alkanethiol single‐stranded DNA probes, self‐assembly methodology, Oracet blue, intercalating electrochemical label, Au‐CO     

Preparation and characterisation of CNF/MWCNT carbon aerogel as efficient adsorbents

In recent years, carbon aerogels have attracted much attention in basic research and as potential applications in many fields. Herein, the authors report a novel approach using bamboo powder as raw material to fabricate cellulose nanofibers (CNFs)/multi‐walled carbon nanotubes (MWCNTs) carbon aerogels by a simple dipping and carbonisation process. The developed material exhibits many exciting properties including low density (0.056 g cm⁻³), high porosity (95%), efficient capability for separation of oily droplets from water, and high adsorption capacity for a variety of oils and organic solvents by up to 110 times its own weight. Furthermore, the CNF/MWCNT carbon aerogels (CMCA) can be recycled many times by distillation and combustion, satisfying the requirements of practical oil‐water separation. Taken together with its economical, environmentally benign manufacturing process, sustainability of the precursor and versatility of material, the CMCA developed in this study will be a promising candidate for addressing the problems arising from the spills of oily compounds.Inspec keywords: aerogels, adsorption, nanofibres, filled polymers, nanocomposites, multi‐wall carbon nanotubes, porosity, drops, distillation, combustion, nanofabrication, polymer fibresOther keywords: CNF‐MWCNT carbon aerogel, adsorbents, bamboo powder, cellulose nanofibers, multiwalled carbon nanotubes, dipping, carbonisation, density, porosity, oily droplets, adsorption capacity, organic solvents, distillation, combustion, practical oil‐water separation, manufacturing process, sustainability, C     

First principle study of the self‐switching characteristics of the guanine based single optical molecular switch using carbon nanotube electrodes

The switching property of an optical single molecular switch based on a single DNA molecule guanine with a single walled carbon nanotube electrode has been investigated using density functional theory along with non‐equilibrium Green''s function based first principle approach. The semi‐empirical model of this single bio‐molecular switch has been operated at an ultra‐high 25 THz frequency in mid‐UV range. This single bio‐molecule comprises switching activity upon UV photo‐excitation. The influence of the highest occupied molecular orbital and lowest unoccupied molecular orbital gap and the quantum ballistic transmission into the switching activity are discussed in detail in this study. It has been observed that the maximum ON–OFF ratio, i.e. 327 is obtained at +0.8 V bias voltage. Theoretical results show that current through the twisted form is sufficiently larger than the straightened form, which recommends that this structure has smart prospective application in the future generation switching nanotechnology.Inspec keywords: molecular electronic states, density functional theory, ab initio calculations, DNA, organic compounds, molecular electronics, Green''s function methods, molecular biophysics, single‐wall carbon nanotubes, optical switches, orbital calculationsOther keywords: nonequilibrium Green''s function, semiempirical model, single bio‐molecular switch, UV photo‐excitation, lowest unoccupied molecular orbital gap, first principle study, single optical molecular switch, switching property, optical single molecular switch, single DNA molecule guanine, single walled carbon nanotube electrode, density functional theory, highest occupied molecular orbital gap, switching nanotechnology     

Multi‐scale approach for simulating time‐delay biochemical reaction systems

This study presents a multi‐scale approach for simulating time‐delay biochemical reaction systems when there are wide ranges of molecular numbers. The authors construct a new efficient approach based on partitioning into slow and fast subsets in conjunction with predictor–corrector methods. This multi‐scale approach is shown to be much more efficient than existing methods such as the delay stochastic simulation algorithm and the modified next reaction method. Numerical testing on several important problems in systems biology confirms the accuracy and computational efficiency of this approach.Inspec keywords: biochemistry, delays, biological techniques, predictor‐corrector methodsOther keywords: multiscale approach, time‐delay biochemical reaction systems, predictor–corrector methods, delay stochastic simulation algorithm, modified next reaction method, numerical testing, systems biology, method accuracy, computational efficiency     

Biogenic synthesis and thermo‐magnetic study of highly porous carbon nanotubes

Nanomaterials synthesis using natural sources is the technology to up come with advanced materials through extracts of plant, microorganisms, poultry waste etc. In this study, the authors report the synthesis of porous carbon nanotubes using high‐temperature decomposition technique facilitated by cobalt salt using chicken fats, a poultry waste as a precursor. Since chicken fats contain fatty acids which can decompose into short hydrocarbon chains and cobalt can act as the catalyst. The formation of carbon nanotubes was confirmed by Raman spectra, peaks at 1580 and 1350.46 cm⁻¹ confirmed the graphite mode G‐band and structural imperfections defect mode D‐band, respectively. Transmission electron microscopy showed the formation of tube‐like structures. Nitrogen adsorption–desorption studies showed the high‐surface area of 418.1 m² g⁻¹ with an estimated pore diameter of 8.1 nm. Thermogravimetry analysis–derivative thermogravimetric analysis–differential thermal analysis showed the instant weight loss at 517°C attributed to the rapid combustion of nanotubes. A vibrating‐sample magnetometer showed the paramagnetic nature of the so‐formed carbon nanotubes formed.Inspec keywords: transmission electron microscopy, infrared spectra, nanomagnetics, pyrolysis, decomposition, adsorption, desorption, carbon nanotubes, differential thermal analysis, thermal analysis, nanofabrication, Raman spectra, X‐ray diffraction, scanning electron microscopy, paramagnetic materialsOther keywords: biogenic synthesis, highly porous carbon nanotubes, microorganisms, high‐temperature decomposition technique, cobalt salt, chicken fats, fatty acids, short hydrocarbon chains, Raman spectra, graphite mode G‐band, structural imperfections defect mode D‐band, transmission electron microscopy, paramagnetic nature, thermo‐magnetic properties, poultry waste, nitrogen adsorption‐desorption studies, thermogravimetry analysis, differential thermal analysis, carbon nanotubes, temperature 517.0 degC, C     

Analysis and classification of DNA‐binding sites in single‐stranded and double‐stranded DNA‐binding proteins using protein information

Single‐stranded DNA‐binding proteins (SSBs) and double‐stranded DNA‐binding proteins (DSBs) play different roles in biological processes when they bind to single‐stranded DNA (ssDNA) or double‐stranded DNA (dsDNA). However, the underlying binding mechanisms of SSBs and DSBs have not yet been fully understood. Here, the authors firstly constructed two groups of ssDNA and dsDNA specific binding sites from two non‐redundant sets of SSBs and DSBs. They further analysed the relationship between the two classes of binding sites and a newly proposed set of features (residue charge distribution, secondary structure and spatial shape). To assess and utilise the predictive power of these features, they trained a classification model using support vector machine to make predictions about the ssDNA and the dsDNA binding sites. The author''s analysis and prediction results indicated that the two classes of binding sites can be distinguishable by the three types of features, and the final classifier using all the features achieved satisfactory performance. In conclusion, the proposed features will deepen their understanding of the specificity of proteins which bind to ssDNA or dsDNA.Inspec keywords: biology computing, DNA, molecular biophysics, molecular configurations, pattern classification, proteins, support vector machinesOther keywords: dsDNA binding sites, ssDNA binding sites, support vector machine, classiflcation model, spatial shape, secondary structure, residue charge distribution, binding mechanisms, biological process, protein information, double‐stranded DNA‐binding proteins, single‐stranded DNA‐binding proteins     

CdO nanoparticles,c‐MWCNT nanoparticles and CdO nanoparticles/c‐MWCNT nanocomposite fibres: in vitro assessment of anti‐proliferative and apoptotic studies in HeLa cancer cell line

A simple ultrasonic assisted chemical technique was used to synthesise cadmium oxide (CdO) nanoparticles (NPs) and CdO NPs/c‐Multiwalled carbon nanotube (c‐MWCNT) nanocomposite fibres.To confirm the physio‐chemico properties and to analyse surface morphology of the obtained nanomaterials X‐Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were performed. To evaluate the anti‐cancer property of CdO NPs, c‐MWCNT NPs and CdO NPs/c‐MWCNT nanocomposite fibres, an anti‐proliferative assay test (Methylthiazolyl diphenyl‐ tetrazolium bromide ‐ MTT assay) were performed on HeLa cells which further estimated IC50 value (Least concentration of sample in which nearly 50% of cells remain alive) under in‐vitro conditions. On comparison, CdONPs/c‐MWCNT based system was found to be superior by achieving 52.3% cell viability with its minimal IC50 value of 31.2 μg/ml. Lastly, the CdO NPs based system was taken up for an apoptotic study using DNA fragmentation assay for estimating its ability to cleave the DNA of the HeLa cells into internucleosomal fragments using the agarose gel electrophoresis method. In conclusion, based on our observations, CdO NPs/c‐MWCNT hybrid based system can be further used for the development of efficient drug delivery and therapeutic systems.Inspec keywords: drug delivery systems, electrophoresis, oxidation, toxicology, DNA, nanoparticles, drugs, field emission electron microscopy, scanning electron microscopy, nanofabrication, surface morphology, cancer, X‐ray diffraction, nanomedicine, cellular biophysics, filled polymers, biomedical materials, molecular biophysics, biochemistry, Fourier transform infrared spectra, multi‐wall carbon nanotubesOther keywords: c‐MWCNT nanoparticles, apoptotic study, HeLa cancer cell line, cadmium oxide nanoparticles, c‐MWCNT NPs, anti‐proliferative assay test [methyl thiazolyl diphenyl‐tetrazolium bromide assay], human epithelioid cervix carcinoma cells, live cells, CdO NP‐based system, IC50 concentration, HeLa cell line, cell deaths, CdO‐C     

Multi‐bit Boolean model for chemotactic drift of Escherichia coli

Dynamic biological systems can be modelled to an equivalent modular structure using Boolean networks (BNs) due to their simple construction and relative ease of integration. The chemotaxis network of the bacterium Escherichia coli (E. coli ) is one of the most investigated biological systems. In this study, the authors developed a multi‐bit Boolean approach to model the drifting behaviour of the E. coli chemotaxis system. Their approach, which is slightly different than the conventional BNs, is designed to provide finer resolution to mimic high‐level functional behaviour. Using this approach, they simulated the transient and steady‐state responses of the chemoreceptor sensory module. Furthermore, they estimated the drift velocity under conditions of the exponential nutrient gradient. Their predictions on chemotactic drifting are in good agreement with the experimental measurements under similar input conditions. Taken together, by simulating chemotactic drifting, they propose that multi‐bit Boolean methodology can be used for modelling complex biological networks. Application of the method towards designing bio‐inspired systems such as nano‐bots is discussed.Inspec keywords: cell motility, microorganisms, Boolean functionsOther keywords: multibit Boolean approach, conventional BNs, high‐level functional behaviour, steady‐state responses, chemoreceptor sensory module, drift velocity, chemotactic drifting, multibit Boolean methodology, complex biological networks, bio‐inspired systems, multibit Boolean model, chemotactic drift, dynamic biological systems, equivalent modular structure, Boolean networks, simple construction, chemotaxis network, bacterium Escherichia coli, biological systems     

Lamivudine‐conjugated and efavirenz‐loaded G2 dendrimers: Novel anti‐retroviral nano drug delivery systems

Infection with human immunodeficiency virus (HIV)‐1 causes immunological disorders and death worldwide which needs to be further assisted by novel anti‐retroviral drug delivery systems. Consequently, finding newer anti‐retroviral pharmaceuticals by using biocompatible, biodegradable nanomaterials comprising a nanoparticle as core and a therapeutic agent is of high global interest. In this experiment, a second generation of a negatively charged nano‐biopolymer linear globular G2 dendrimer was carefully conjugated and loaded with well‐known anti‐HIV drugs lamivudine and efavirenz, respectively. They were characterised by a variety of analytical methods such as Zetasizer, Fourier‐transform infrared spectroscopy, elemental analysis and liquid chromatography‐mass spectroscopy. Additionally, conjugated lamivudine and loaded efazirenz with globular PEGylated G2 dendrimer were tested on an HEK293 T cell infected by single‐cycle replicable HIV‐1 virion and evaluated using XTT test and HIV‐1 P24 protein load. The results showed that lamivudine‐conjugated G2 significantly decreased retroviral activity without any cell toxicity. This effect was more or less observed by efavirenz‐loaded G2. These nano‐constructs are strongly suggested for further in vivo anti‐HIV assays.     

Antimicrobial activity of functionalised carbon nanotubes against pathogenic microorganisms

Carbon nanotubes represent one of the best examples of novel nanostructures, exhibit a range of extraordinary physical properties, strong antimicrobial activity and can pierce bacterial cell walls. This investigation handles the antimicrobial activity of functionalised multiwall carbon nanotubes (F‐MWNTs) as an alternative antimicrobial material compared to the commercial antibiotics. Antibacterial activities of F‐MWNTs are investigated through two different kinds of bacteria, E. coli and S. aureus. The results demonstrate that the best concentration of F‐MWNTs for the maximum inhibition and antibacterial functionality is 80 and 60 μg/ml for E. coli and S. aureus, respectively. The transmission electron microscope reveals the morphological changes damage mechanism for the cellular reliability on these microorganisms. F‐MWNTs are capable of biologically isolating the cell from their microenvironment, contributing to the development of toxic substances and placing the cell under oxidative stress leading to cellular death. The efficiency of F‐MWNTs is compared with the common antibiotics and shows an enhancement in the inhibitory effect with percentages reaches 85%. To account for the bactericidal performance of F‐MWNTs towards these pathogens, the dielectric conductivity and the bacterial growth measurements are conducted. The present study endeavour that F‐MWNTs could be exploited in biomedical devices and altering systems for hospital and industrial cleaning applications.Inspec keywords: antibacterial activity, biomedical materials, microorganisms, cellular biophysics, toxicology, nanomedicine, multi‐wall carbon nanotubes, transmission electron microscopy, electrical conductivity, permittivityOther keywords: F‐MWNTs, pathogenic microorganisms, antimicrobial activity, bacterial cell walls, functionalised multiwall carbon nanotubes, antibacterial activity, E. coli, S. aureus, antimicrobial material, physical properties, transmission electron microscopy, morphological changes, damage mechanism, cellular reliability, microenvironment, toxic substances, oxidative stress, cellular death, bactericidal performance, dielectric conductivity, bacterial growth measurements, biomedical devices, C     

Ketoconazole‐conjugated ZnO nanoparticles based semi‐solid formulation and study their impacts on skin disease

In this study, the ketoconazole‐conjugated zinc oxide (ZnO) nanoparticles were prepared in a single‐step approach using dextrose as an intermediate compound. The physical parameters confirmed the drug conjugation with ZnO and their size was around 70–75 nm. The drug loading and in vivo drug release studies indicated that the –CHO group from the dextrose increase the drug loading up to 65% and their release kinetics were also studied. The anti‐fungal studies indicated that the prepared nanoparticles exhibit strong anti‐fungal activity and the minimum concentration needed is 10 mg/ml. The nanoparticles loaded semi‐solid gel was prepared using carbopol, methylparaben, propyl paraben and propylene glycol. The in vitro penetration of the ketoconazole‐conjugated nanoparticles was studied using the skin. The results indicated that the semi‐solid gel preparations influenced the penetration and also favoured the accumulation into the skin membrane. The veterinary clinical studies indicated that the prepared gel is highly suitable for treatment of Malassezia.Inspec keywords: II‐VI semiconductors, skin, biomedical materials, antibacterial activity, wide band gap semiconductors, drug delivery systems, nanomedicine, drugs, diseases, gels, nanofabrication, nanoparticles, zinc compounds, biomembranes, veterinary medicineOther keywords: strong anti‐fungal activity, propyl paraben, propylene glycol, semisolid gel preparations, skin membrane, veterinary clinical studies, semisolid formulation, skin disease, ketoconazole‐conjugated zinc oxide nanoparticles, single‐step approach, physical parameters, drug conjugation, drug loading, release kinetics, dextrose, in vivo drug release studies, carbopol, methylparaben, in vitro penetration, Malassezia, ZnO