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Aflatoxin B 1 (AF-B 1 ) are toxins secreted by secondary metabolites of molds that have adverse effects on humans and animals resulting in huge economic losses. Here we report on field useable, cost effective and direct electrochemical sensor based on conducting polymer composite electrode, Poly (3,4-ethylenedioxythiophene): polystyrene sulphonic acid (PEDOT-PSS) for label-free detection of AF-B 1 . Structural and morphological characterization of composite electrodes were carried out using XRD and SEM. We compared two different electroanalytical techniques namely, transient capacitance and differential pulse voltammetry, to select the most prominent technique for analyzing the mycotoxin easily. For direct detection of AF-B 1 , transient capacitance measurement at 77 and 1000 Hz was employed wherein sensor showed linearity in 18.18-300.0 ng mL -1 range at 77 Hz for AF-B 1 . Best limit of detection (LOD) for AF-B 1 was 55.41 ng mL -1 (369 pM) at 77 Hz with very good repeatability. DPV showed linearity in the range 18.18-342.85 ng mL -1 with LOD 435 pM. For demonstration of application of this sensor directly using minimum sample preparation, AF-B 1 sensing has been confirmed successfully using white button mushrooms and okra stored at ambient conditions. Sensor response with real samples suggest usefulness of sensor to monitor stored farm products easily., Competing Interests: Declaration of competing interest The authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest in the subject matter or materials discussed in this manuscript., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The evaluation of electrochemical sensing activity of hydrothermally derived PPy-MoS 2 -based nanocomposites subjected to 90 MeV C 6+ ion beam with fluence ranging, 1.0 × 10 10 -1.0 × 10 13 ions/cm 2 , is reported. Cross-linking, chain scissioning, and ion track formation could occur in the irradiated systems, as revealed from Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) studies. Electrochemical studies, viz., cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed in 0.1 M phosphate buffer solution (PBS) containing 5 mM K 3 [Fe(CN) 6 ] as redox probe. High redox activity, lower charge transfer resistance (R ct  = 490 Ω) and larger electroactive area (A = 0.4485 cm 2 ) were obtained in case of the composite system irradiated with a fluence of 3.5 × 10 11 ions/cm 2 . Immunosensor fabrication was executed via immobilization of mouse IgG over the pristine and post-irradiated electrodes. Afterwards, differential pulse voltammetry (DPV) was performed within the potential window - 0.2 to + 0.6 V (vs. Ag/AgCl) for the detection of specific analyte. Noticeably, the electrode system irradiated with a fluence of 3.5 × 10 11 ions/cm 2 is characterized by a lower limit of detection (LOD) of 0.203 nM and a higher sensitivity value of 10.0 µA mL ng -1  cm -2 . The energetic particle irradiation at a modest fluence can offer beneficial effects to the PPy-MoS 2 -based nanohybrid system providing immense scope as advanced electrochemical biosensor., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

In this study, we have stated the green biosynthesis of gold nanoparticles (AuNPs) by utilizing the extract of Monstera deliciosa leaves (MDL) as a reducing agent. Biosynthesized flat, thin, and single-crystalline gold nanotriangles obtained through centrifugation are then analyzed by different characterization techniques. The UV - visible absorption spectra of AuNPs exhibited maxima bands in the range of 500-590 nm, indicating a characteristic of AuNPs. XRD analysis revealed the formation of the (111)-oriented face-centered cubic (FCC) phase of AuNPs. ATR-IR spectra showed signatures of stretching vibrations of O-H, C-H, C=C, C=O, C-O, and C-N, accompanied by CH 3 rocking vibrations present in functional groups of biomolecules. FESEM images confirmed spherical nanoparticles with an average diameter in the range of 53-66 nm and predominantly triangular morphology of synthesized AuNPs within the size range of 420-800 nm. NMR, GC-MS, and HR-MS studies showed the presence of different biomolecules, including phenols, flavonoids, and antioxidants in MDL extracts, which play a crucial role of both, reducing as well as stabilizing and capping agents to form stable AuNPs by a bottom-up approach. They were then investigated for their antibacterial assay against Gram-positive ( S. aureus, B. subtilis ) and Gram-negative ( E. coli, P. aeruginosa ) microorganisms, along with testing of antifungal potential against various fungi ( Penicillium sp., Aspergillus flavus, Fusarium oxysporum, Rhizoctonia solani ) using the well diffusion method. Here, biosynthesized AuNPs showed non-antimicrobial properties against all four used bacteria and fungi, showing their suitability as a contender for biomedical applications in drug delivery ascribed to their inert and biocompatible nature., Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03898-0., (© King Abdulaziz City for Science and Technology 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)

Electrochemically deposited bimetallic copper-gold nanoparticles on indium tin oxide (Cu-AuNPs on ITO) glass are demonstrated to be a sensitive and reproducible surface-enhanced Raman scattering (SERS) platform. An optimal signal enhancement with reasonably good degree of homogeneity was obtained by tuning the deposition parameters of the electrochemical setup. For Raman active analytes such as malachite green (MG) and rhodamine 6G (R6G), the developed SERS platform yields a limit of detection (LOD) of 0.75 nM. The usability of the proposed SERS platform has been realized through detection of two important antibiotics namely sulfamethoxazole (SFZ) and tetracycline hydrochloride (TCH) commonly used in egg farms. Furthermore, a machine learning (ML)-based model coupled with a dimensionality reduction technique-principal component analysis (PCA)-has been implemented to classify the targeted analytes in egg samples., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

The uses of highly luminescent perovskite quantum dots in real analytical detection were limited by their supersensitive nature. Here, we have designed a CsPbBr 3 perovskite based fluorometric sensor by integrating them with a zeolitic imidazole framework (ZIF-8) via an in situ one step technique and established its stability in aqueous and other polar solvents. The CsPbBr 3 @ZIF-8 luminescence sensor functioned excellently for the trace detection of 4-nitroaniline and rhodamine blue dye molecules with a detection limit value of 8.367 ppb and 0.088 ppm, respectively. A comprehensive investigation found that the quenching of the fluorescence signal occurred via fluorescence resonance energy transfer (FRET) for rhodamine blue dye and a H-bonding interaction induced trap density mediated quenching mechanism was responsible for 4-NA detection. The potential of this suggested sensor as a cheap portable test paper probe for analyte detection was also explored. This study introduces CsPbBr 3 as a cutting-edge sensing platform for industrial pollutants such as dye molecules and nitroaromatics.

The self avoiding walk (SAW) model of the polymer has been extended to study the equilibrium properties of double stranded DNA (dsDNA) where two strands of the dsDNA are modeled by two mutually attracting self-avoiding walks (MASAWs) in the presence of an attractive surface. We study simultaneous adsorption and force induced melting transitions and explore different phases of DNA. It is observed that melting is entropically dominated, which can be substantially reduced under the application of an applied force. We consider three scenarios, where the surface is weakly, moderately and highly attractive. For both weakly and moderately attractive surfaces, the DNA desorbs from the surface in a zipped form and acquires the conformation of a melted state with the rise in temperature. However, for a strongly attractive surface, the force applied at one end of the strand (strand-II) results in unzipping, while the other strand (strand-I) remains adsorbed on the surface. We identify this as adsorption-induced unzipping, where the force applied on a single strand (strand-II) can unzip the dsDNA if the surface interaction energy exceeds a specific threshold. We also note that at a moderate surface attraction, the desorbed-zipped DNA melts with an increase in temperature and the free strand (strand-I) gets re-adsorbed onto the surface.

The equilibrium organization of two polymers in strong confinement has been extensively investigated in the scope of simple models in the recent past, after it was suggested that the entropic repulsion between polymers could be a mechanism for chromosome separation in living cells. Despite many efforts, how solvent quality can manipulate separation or compaction for the formation of domains in a two-polymer model system within symmetric or asymmetric confinement still remains elusive. This paper presents some important findings for a two-polymer system within box-like (symmetric) and triangle-like (asymmetric) confinement with equal areas, in terms of structural transitions such as from a single globule to individual globules, non-monotonic change in polymer size, variation in the free-energy barrier with separation, etc. By using the exact enumeration method on a two-dimensional self-avoiding walk model of polymers, our results reveal that the polymers have a greater preference to form individual globules rather than a 'micelle'-like single globule in triangular confinement compared to box-like confinement. Additionally, our results suggest that asymmetric confinement can act as an ideal tool to trap polymers in poor solvents due to the large free-energy barrier.

In this paper, we present a novel, one-step synthesis of SnO 2 nanoparticle-CeO 2 nanorod sensing material using a surfactant-mediated hydrothermal method. The bifunctional utility of the synthesized sensing material toward room-temperature sensing of CO gas and low-concentration optosensing of arsenic has been thoroughly investigated. The CeO 2 -SnO 2 nanohybrid was characterized using sophisticated analytical techniques such as transmission electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and so forth. The CeO 2 -SnO 2 nanohybrid-based sensor exhibited a strong response toward CO gas at room temperature. Under a low concentration (3 ppm) of CO gas, the CeO 2 -SnO 2 sensing material showed an excellent response time of 21.1 s for 90% of the response was achieved with a higher recovery time of 59.6 s. The nanohybrid sensor showed excellent low-concentration (1 ppm) sensing behavior which is ∼6.7 times higher than that of the pristine SnO 2 sensors. The synergistically enhanced sensing properties of CeO 2 -SnO 2 nanohybrid-based sensors were discussed from the viewpoint of the CeO 2 -SnO 2 n-n heterojunction and the effect of oxygen vacancies. Furthermore, the SnO 2 -CeO 2 nanoheterojunction showed luminescence centers and prolonged electron-hole recombination, thereby resulting in quenching of luminescence in the presence of arsenate ions. The photoluminescence of CeO 2 -SnO 2 is sensitive to the arsenate ion concentration in water and can be used for sensing arsenate with a limit of detection of 4.5 ppb in a wide linear range of 0 to 100 ppb., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

We study dsDNA (double strand DNA) melting in detail within varying strip-like confinement in a two-dimensional lattice model. The interplay between reduced configurational entropy and attractive base-pairing energy results in a non-monotonic melting profile of DNA. Structural transitions associated with confined DNA melting reveal a stretched or extended state for very strong confinement. By using the exact enumeration method, we investigate the emergence of a local denatured zone e.g. bubbles during DNA melting. The survival time of a single bubble within varying strip width is studied from the Fokker-Planck formalism by considering the bubble size as a reaction co-ordinate. We show that a simple lattice model can capture the sequence heterogeneity effect on DNA melting and bubble dynamics within the strip. Different time scales of bubble zipping for different DNA sequences are found, which may have potential applications in denaturation mapping.

By employing the exact enumeration technique on the lattice model of a polymer, we study the migration of the polymer chain across an entropic trap in a quasiequilibrium condition and explore the effect of solvent gradient present in the entropic trap which acts both parallel and perpendicular to the direction of migration. The Fokker-Planck formalism utilizes the free energy landscape of a polymer chain across the channel in the presence of the entropic trap to calculate the migration time. It is revealed that the migration is fast when the solvent gradient acts along the migration axis (i.e., x axis) inside the channel in comparison to the channel having the entropic trap. We report here for the first time that the entropic trap makes the migration faster at a certain value of solvent gradient. We also study the effect of transverse solvent gradient (along the y axis) inside the trap and investigate the structural changes of the polymer during migration through the channel. We observe the nonmonotonic dependence of migration time on the solvent gradient.

Herein, Fe 3 O 4 -SnO 2 nanoheterojunction has been synthesized and successfully encapsulated in gC 3 N 4 matrix using a novel hydrothermal technique. The synthesized material was characterized using sophisticated analytical methods like XRD, TEM, BET, UV-Vis, VSM and XPS to evaluate structural, morphological, optical, magnetic and surface chemical properties. The hybrid nanostructure Fe 3 O 4 -SnO 2 -gC 3 N 4 has been utilized for the LED light-induced photocatalytic degradation of carbofuran. The catalyst exhibited notable photocatalytic performance under visible light with an efficiency of ~89% and pseudo first order rate constant of 0.015 min -1 . The result of change in variables like catalyst dose, pollutant concentration, pH and contact time on the photodegradation efficiency and degradation kinetics was studied. The incorporation of Fe 3 O 4 improved the magnetic separation of the catalyst after several cycles of operation, thereby improving the practical utility of the catalyst system to tackle organic pollutants., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Herein, we have developed a novel synthetic strategy for the fabrication of Au-SnO 2 -CdS ternary nano-heterojunction catalyst and its utility towards LED light derived photocatalytic degradation of imidacloprid has been evaluated. The synthesized ternary nanocomposite was characterized using sophisticated analytical techniques to evaluate the catalyst's morphological, structural and surface chemical properties. The photocatalytic activity of the ternary catalyst towards the degradation of imidacloprid was evaluated under LED irradiation. Approximately 95% of the degradation efficiency was achieved with a pseudo-first-order reaction rate of 15.6 × 10 -3 min -1 . The degradation efficiency of Au-SnO 2 -CdS nano-catalyst was found to be ~1.2, 1.4 and 2.1 times to that of the pristine Au, CdS and SnO 2 nanomaterials under similar experimental conditions. The effect of variation of parameters like contact time, initial pollutant concentration and pH on degradation efficiency has also been investigated. Moreover, the identification of various degradation products and reactive intermediates were made with high-performance liquid chromatography and electron spin resonance techniques., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In this work, a nanohybrid of CuO/Mn 3 O 4 /ZnO was generated through a simple hydrothermal based procedure. The CuO/Mn 3 O 4 /ZnO nanohybrid has been characterized using X-ray diffraction, transmission electron microscopy high resolution transmission electron microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. UV-visible spectrophotometry and photoluminescence techniques allowed evaluation of optical properties that additionally suggested the prevalence of strong interfacial interaction between the three moieties of the nanohybrid and suppressed electron-hole recombination. The hybrid photocatalyst brought on ~ 97.02 ± 1.15% disintegration of rabeprazole when illuminated with visible light. The progress of the photodegradation was in conformity with pseudo-first order kinetic model and had a velocity constant of 0.07773 min -1 . Additionally, ~ 84.45% of total organic carbon removal was achieved while chemical oxygen demand was reduced by ~ 73.01%. Using high resolution liquid chromatograph mass spectrometry technique, identification of the degraded products was made and accordingly the mechanistic route of the aforesaid degradation was proposed., (© 2021. The Author(s).)

Herein, a novel synthetic strategy has been proposed to prepare engineered SnO 2 @ZIF-8/gC 3 N 4 nanohybrids for electrochemical sensing of p-nitrophenol (p-NP). The electrochemical properties were investigated using cyclic voltammetry (CV), chronoamperometry (CA), and differential pulse voltammetry (DPV). The developed nanohybrid sensor displayed an excellent electrochemical performance towards sensing of p-NP with a detection limit of 0.565 μM. The sensitivity of the prepared nanohybrid was found to be 2.63 μAcm -2 μM -1 . Moreover, the newly fabricated sensor exhibited remarkable selectivity (over tenfold excess) in the presence of common interferents. The simultaneous detection of isomers of nitrophenol is difficult using the developed sensor. However, other common interferents, such as phenol and aminophenol have negligible effects on the sensitivity of SnO 2 @ZIF-8/gC 3 N 4 towards the detection of p-nitrophenol. Further, the newly developed sensor showed consistency of sensing response up to 30 days. Thus, implementation of SnO 2 @ZIF-8/gC 3 N 4 nanohybrids as a p-NP electrochemical sensor offers the advantages of simplicity, selectivity, and stability., (Copyright © 2021 Elsevier Inc. All rights reserved.)

With the advancement of nanotechnology, the nano-sized particles make an imprint on our daily lives.The present investigation revealed that biomolecules present in seed exudates of Vigna radiata are responsible for the synthesis of AuNPs, confirmed by the routine characterization techniques. Anticancer efficacy showed by AuNPs might be due to the release of phytochemicals in the exudate which is being adsorbed on the surface of AuNPs referencing their anticancer efficacy against the tested breast cancer cell lines. Inhibition of clonogenicity and cell cycle arrest at G2/M phase then apoptosis of AuNPs was also observed, but found nontoxic to the human PBMC cells which further confirms its biocompatible property Among the various physicochemical study, present AuNPs shows unique information, they show photoluminescent property which may be used for bioimaging purposes. However, further molecular analysis needs to be explored to understand the underlying mechanism for therapeutic and biomedical application., Competing Interests: Authors declared no conflict of Interest., (© 2021 The Authors.)

Herein, we have developed Au-SnO 2 -rGO ternary nanoheterojunction catalyst for photocatalytic degradation of clothianidin under UV-LED irradiation. Au nanoparticles (Au NPs) were decorated with quantum sized SnO 2 nanoparticles (SnO 2 NPs) and embedded in the reduced graphene oxide (rGO) matrix. The synthesized photocatalyst was characterized using common instrumentation techniques to evaluate the morphological, structural and surface chemical properties of the catalyst. The photocatalytic property of the as-synthesized nanocomposite was investigated by studying the degradation of clothianidin under UV-LED irradiation. Approximately 97% of the degradation was achieved in 120 min with pseudo first-order reaction rate of 0.0309 min -1 . The effect of various parameters like contact time, catalyst dose, initial concentration, pH, irradiation source and interfering ions on the degradation performance has also been investigated. Identification of various intermediates in the degradation process was done with high performance liquid chromatography- mass spectral (LC/HRMS) technique. The reactive intermediates responsible for the degradation have also been identified with electron spin resonance (ESR) technique and complete mechanism of the degradation process has been proposed with the help of photo luminescence (PL) quenching studies., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background & Objectives: For detection and molecular characterization of Babesia microti in laboratory mice from India., Methods: A total of 625 mice were screened by peripheral blood smear examination and subsequently was confirmed by PCR using a piroplasm conserved primer set (Piro A/B). Nested PCR was done using a species-specific primer targeting the gene encoding the small subunit ribosomal RNA (18S rRNA). The PCR products were cloned, purified and sequenced. A total of 12 isolates were obtained. The sequences were aligned and phylogenetic trees were prepared with other published Babesia spp. sequences., Results: B. microti was detected with a total infection rate of 8.80%. The higher rate of infection was observed by species specific PCR (8.80%) than examined by blood smear (7.20%). Sequence and phylogenetic analysis showed that Babesia species detected in mice were genetically identical to the genotypes of B. microti and can be easily distinguished from other genotypes of Babesia parasites by neighbour joining and maximum likelihood method. Intra-species analysis indicated that all the twelve isolates from six North-Eastern states of India have a close identity but inter-species showed genetic reservoir host for transmission of babesial infection to humans., Interpretation & Conclusion: The detection of Babesia microti may suggest that laboratory mice may serve as potential reservoir host for human infection and possibility of innovative way of diagnosing and control of human babesiosis., Competing Interests: None

Tender coconut water is a pure and nutritious drink which play important role as nutraceuticals and pharmaceuticals contributes to the rapid growth of the functional food industry. In the mean-time the safety and shelf-life of the food is crucial for the both product as well as consumers. The intervention or application of nanotechnology gives immense a solution for the prolonged sustainability of the food products. This work reports on the nature of physiological changes of coconut liquid endosperm along with the interaction of its DNA with green route synthesized Ag nanoparticles (AgNPs) using Garuga pinnata leaf, an important ethnomedicinal plant. The physical and nutritional study of the coconut water were carried by UV-visible, XRD, NMR analysis whereas the synthesized Ag nanoparticles (AgNPs) were characterized by UV-Visible spectrophotometer, Raman Spectroscopy, DLS, AFM and FE-SEM analysis. The pH of the endosperm was found to decrease from 6.31 to 4.01, following an exponential decay trend and giving a decay constant of ~8.8 h. The broad absorption peak at ~310 nm gradually turns featureless with elapse of time. The proton nuclear magnetic resonance (H 1 -NMR) spectrum essentially revealed the presence of esters or organic acids, confirming a sudden fall in the rate of intensity in the immature coconut endosperms as compared to the matured coconut cases. While the pentosyl methyl group (~1.4-1.5 ppm) concentration is observably lowered, free amino acid (~1 ppm) is apparently suppressed in the former specimen. Gel electrophoresis of 10 kb DNA with Ag nanoparticles (AgNPs) showed a gradual decrease of band intensity for a concentration varying between 3:1 and 1:1. The less intense band was due to the lack of migration of DNA into the micropores of the gel as a consequence of interaction of negatively charged DNA with negatively charged AgNPs. The study of DNA interaction with AgNPs could help identifying and addressing the nature of degradation process while considering prevention from microbial attack and make the coconut water as potential functional food entity., Competing Interests: Authors declares no any conflicts of interest related to the publication of the manuscript., (© 2020 The Authors.)

In this work, we report manifested optical, optoelectronic and spin-spin relaxation features of a few layered tungsten disulphide (WS 2 ) nanosheets subjected to energetic γ-photons (∼1.3 MeV) emitted from a Co 60 source. Upon intense irradiation (dose = 96 kGy), a slight departure from the pure hexagonal phase was realized with the introduction of the trigonal phase at large. Moreover, in the Raman spectra, as a consequence of the radiation-induced effect, an apparent improvement of the E-to-A mode intensity and a reduction in phonon lifetimes have been realized, with the latter being dependent on the linewidths. The emergence of the new peak (D) maxima observable at ∼406 cm -1 in the Raman spectra and ∼680 nm in the photoluminescence (PL) spectra can be attributed to the introduction of defect centres owing to realization of sulphur vacancies (V S ) in the irradiated nanoscale WS 2 . Additionally, neutral exciton to charged exciton (trion) conversion is anticipated in the overall PL characteristics. The PL decay dynamics, while following bi-exponential trends, have revealed ample improvement in both the fast parameter (0.39 ± 0.01 ns to 1.88 ± 0.03 ns) and the slow parameter (2.36 ± 0.03 ns to 12.1 ± 0.4 ns) after γ-impact. We attribute this to the finite band gap expansion and the incorporation of new localized states within the gap, respectively. A declining exciton annihilation rate is also witnessed. The isotropic nature of the electron paramagnetic resonance spectra as a consequence of γ-exposure would essentially characterize a uniform distribution of the paramagnetic species in the system, while predicting a three-fold improvement of relative spin density at 96 kGy. Exploring defect dynamics and spin dynamics in 2D nanoscale systems does not only strengthen fundamental insight but can also offer ample scope for designing suitable components in the areas of miniaturized optoelectronic and spintronic devices.

Biodegradable starch-pectin‑titanium oxide nanoparticles (TiO 2 - NPs) blend edible films were developed by casting filmogenic solution of sweet potato starch and lemon waste pectin incorporated with TiO 2 nanoparticles. The effect of incorporating different concentration of TiO 2 nanoparticle (0.5-4% wt) on the different properties of starch and pectin based edible film was evaluated. Surface color measurement, light transmission, scanning electron microscopy, fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis techniques were used to characterize the developed films. Increasing the level of TiO 2 -NPs led to significant decreases in the moisture content, solubility, and moisture uptake of the films. Addition of low concentration of TiO 2 - NPs into starch-pectin films significantly improved the mechanical and moisture barrier properties. SEM analysis also revealed that good particles dispersion could be obtained when nano-TiO 2 particles content was low (0.5-2% wt). The glass transition temperatures (Tg) shifted to higher temperature with increasing the TiO 2 concentrations and the thermal stability of the films was increased. The transmittance percentage was also decreased with increasing the TiO 2 concentrations which revealed that with UV prevention capacity, the developed films can be used as food grade UV screening biodegradable packaging material., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Carbon nanotubes (CNTs) are a class of carbon allotropes with interesting properties that make them productive materials for usage in various disciplines of nanotechnology such as in electronics equipments, optics and therapeutics. They exhibit distinguished properties viz., strength, and high electrical and heat conductivity. Their uniqueness can be attributed due to the bonding pattern present between the atoms which are very strong and also exhibit high extreme aspect ratios. CNTs are classified as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) on the basis of number of sidewalls present and the way they are arranged spatially. Application of CNTs to improve the performance of many products, especially in healthcare, has led to an occupational and public exposure to these nanomaterials. Hence, it becomes a major concern to analyze the issues pertaining to the toxicity of CNTs and find the best suitable ways to counter those challenges. This review summarizes the toxicity issues of CNTs in vitro and in vivo in different organ systems (bio interphases) of the body that result in cellular toxicity., (© 2019 Xi'an Jiaotong University. Production and hosting by Elsevier B.V.)

Herein, we described a biogenic, additive fee, eco-friendly synthesized SnO 2 -CNT nanohybrid as an efficient, re-collectable and reusable material for onsite water remediation. We demonstrated that the SnO 2 -CNTs can provide a one stop solution for water remediation as it effectively accomplished the major treatment tasks like adsorption, catalytic transformation/degradation and disinfection. The structural, morphological, surface chemical compositions of the nanocomposite and the adsorption, catalytic and antimicrobial properties were investigated using common characterization and instrumental techniques. The results revealed the brilliant efficiency of SnO 2 -CNT nanoadsorbent towards As (III) and a maximum Langmuir adsorption capacity of 106.95 mg/g was observed at high arsenite concentration (C 0  = 1 mg/L). The nanoadsorbent was also found to be equally efficient in low arsenite concentration ranges (C 0  = 100 μg/L) as it could bring down the arsenic concentration below maximum permissible limit. Moreover, using model pollutants like p-nitrophenol, Alizarin red S, Metronidazole, bacterial strains (Bacillus subtilis, Escherichia coli, Streptococcus pneumonia etc.), and fungal strains (Aspergillus niger and Candida albicans), the multifunctional capability of SnO 2 -CNT towards water decontamination has been established. Our results suggested the promising potential of hierarchical nano-heterojunctions for engineering efficient water treatment processes.

Aims: Canine demodicosis is a parasitic condition affecting the skin of dogs. The present study was designed to characterize chitin synthase gene of Demodex canis. The molecular technique was used for better understanding of this gene., Methods: A total of 75 dogs which are reared as pets with or without showing any skin lesions were examined during the study period. Skin scrapings were examined by indirect method using 10% potassium hydroxide solution under 10 × microscope. DNA samples were extracted from positive skin samples and were subjected to PCR for molecular identification., Results: A total of 25 dogs irrespective of age, sex, breed or coat showed positive result for D. canis. The PCR revealed a single amplified product of 339 bp length which exactly matched with D. canis. The chitin synthase gene was amplified by PCR, subsequently cloned, sequenced, and compared with available data in GenBank for the particular gene of D. canis. Only one single nucleotide polymorphism (SNP) was noticed at 231 position of the chitin synthase gene sequence when compared to other isolates., Conclusion: The molecular technique confirms with the morphological identity of D. canis. This report signifies the value of peculiar tool to identify 'follicular mite' even from apparently healthy skin.

Monohydric alcohols, such as methanol (MEH), ethanol (ETH) and 2,2,2-trifluoroethanol (TFE), have significant effects on biological processes including the protein folding-unfolding phenomenon. Among the several monohydric alcohols, TFE, a fluorine-substituted alcohol, is known to induce a helical structure in proteins. In this work, we report the heterogeneous unfolding phenomenon of a small protein Chymotrypsin Inhibitor 2 in various concentrations of methanol, ethanol and TFE solutions by performing atomistic molecular dynamics simulation studies. Our study reveals that the unfolding phenomenon of CI2 under thermal stress majorly depends on the concentration and the nature of the alcohol. The presence of alcohols in general has been noted to accelerate the unfolding process compared to pure water and TFE, among them all, has been found to speed up the unfolding time scale at low concentrations. The molecular contact frequency between protein and alcohol follows the trend, MEH < ETH < TFE at low concentrations, whereas the trend becomes MEH ∼ ETH > TFE at more concentrated solutions. The differential water-mediated and self-clustering phenomena of alcohols, diverse protein-alcohol hydrogen bond strengths and the concentration dependent restricted inhomogeneous protein-water as well as protein-alcohol hydrogen bond dynamics suggest that TFE, a well known α-helix stabilizer, could be a good competitor among its class of denaturants.

A small number of key-residues in a protein sequence play vital roles in the function, stability, and folding of the protein. The nonuniform conformational disorder of a small protein Chymotrypsin Inhibitor 2 (CI2) and its secondary segments has been quantified in the ethanol governed temperature induced unfolding process by estimating its change in configurational entropy in several water-ethanol mixed solutions. Such calculations further assist us in identifying the key-residues, from where the unfolding of the protein was initiated. Our findings match well with the reported experimental results. We then make an attempt to explore the properties of the solvent water and ethanol around the key-residues of the protein in its folded and unfolded forms at ambient temperature to identify the individual role of ethanol and water in the protein unfolding. We find that the key-residues of the unfolded protein are in good contact with both water and ethanol as compared to those of the folded protein. In the presence of ethanol, water molecules are noticed to form a rigid structurally bound solvation layer around the key-residues of the protein, irrespective of its conformational state. The restricted translational motion and prominent caging effect of the water and ethanol molecules present around the key-residues of the unfolded protein are a signature of the existence of a rigid mixed water-ethanol layer as compared to that around the folded protein. Furthermore, comparable restricted structural relaxation of the key-residue-water and key-residue-ethanol hydrogen bonds in the unfolded protein as compared to that in the folded one implies that the formation of a strong long-lived hydrogen bonding environment nourishes the unfolding process. We believe that our findings will shed light to several co-solvent governed unfolding processes of a protein in general.

Semiconducting nanomaterials are very important by means of their stability and wide band gap tunability. Visible light induced photoelectrocatalytic water oxidation based on these material are challenging as they have large band gap energies. Herein, we report that MnO doping can activate wide band gap semiconductors like SnO 2 towards visible light induced water oxidation. Rutile SnO 2 nanoparticles (band gap 3.6eV), usually absorbing at UV region, was capable of harvesting visible light when doped with MnO thereby minimizing the energy requirement for photoelctrocatalytic water splitting. The system was characterized using UV-Vis, TEM and XPS. Photoelectrocatalytic activity was examined by LSV and CPE. The highly stable catalyst showed very good photoelectrocatalytic activity for the oxidation of water under alkaline condition with low overpotential of ∼370mV at 1.0mAcm -2 ., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The molecular mechanism of ethanol governed unfolding of an enzymatic protein, chymotrypsin inhibitor 2 (CI2), in water-ethanol mixed solutions has been studied by using combined molecular dynamics simulations and ONIOM study. The residue specific solvation of the unfolded protein and the interactions between the individual amino acid residues of the protein with ethanol as well as water have been investigated. The results are compared with that obtained from the folded state of the protein. Further, emphasis has been given to explore the residue's preferential site of attraction toward the nature of the solvents. The heterogeneous structuring of water and ethanol around the hydrophobic and hydrophilic surfaces of the protein is found to correlate well with their available surface areas to the solvents. Both hydrophobic and hydrophilic interactions are found to have important contributions in rupturing protein's secondary structural segments. Further, residue-water as well as residue-ethanol binding energies show significant involvement of the hydrogen bonding environment in the unfolding process; particularly, residue-water hydrogen bonds are found to play an indispensable role.

The present study reports on biogenic-synthesised silver nanoparticles (AgNPs) derived by treating Ag ions with an extract of Cassia fistula leaf, a popular Indian medicinal plant found in natural habitation. The progress of biogenic synthesis was monitored time to time using a ultraviolet-visible spectroscopy. The effect of phytochemicals present in C. fistula including flavonoids, tannins, phenolic compounds and alkaloids on the homogeneous growth of AgNPs was investigated by Fourier-transform infrared spectroscopy. The dynamic light scattering studies have revealed an average size and surface Zeta potential of the NPs as, -39.5 nm and -21.6 mV, respectively. The potential antibacterial and antifungal activities of the AgNPs were evaluated against Bacillus subtilis, Staphylococcus aureus, Candida kruseii and Trichophyton mentagrophytes . Moreover, their strong antioxidant capability was determined by radical scavenging methods (1,1-diphenyl-2-picryl-hydrazil assay). Furthermore, the AgNPs displayed an effective cytotoxicity against A-431 skin cancer cell line by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, with the inhibitory concentration (IC 50 ) predicted as, 92.2 ± 1.2 μg/ml. The biogenically derived AgNPs could find immense scope as antimicrobial, antioxidant and anticancer agents apart from their potential use in chemical sensors and translational medicine.

A series of atomistic molecular dynamics (MD) simulations of a small enzymatic protein Chymotrypsin Inhibitor 2 (CI2) in water-ethanol mixed solutions were carried out to explore the underlying mechanism of ethanol driven conformational changes of the protein. Efforts have been made to probe the influence of ethanol concentrations ranging from 0% to 75% (v/v) at ambient condition (300 K (T1)) and at elevated temperatures (375 K (T2) and 450 K (T3)) to investigate the temperature induced conformational changes of the protein further. Our study showed that the effect of varying ethanol concentrations on protein's structure is almost insignificant at T1 and T2 temperatures whereas at T3 temperature, partial unfolding of CI2 in 10% ethanol solution followed by full unfolding of the protein at ethanol concentrations above 25% occurs. However, interestingly, at T3 temperature CI2's native structure was found to be retained in pure water (0% ethanol solution) indicating that the cosolvent ethanol do play an important role in thermal denaturation of CI2. Such observations were quantified in the light of root-mean-square deviations (RMSDs) and radius of gyration. Although higher RMSD values of β-sheet over α-helix indicate complete destruction of the β-structure of CI2 at high ethanol concentrations, the associated time scale showed that the faster melting of α-helix happens over β-sheet. Around 60%-80% of initial native contacts of the protein were found broken with the separation of hydrophobic core consisting eleven residues at ethanol concentrations greater than 25%. This leads protein to expand with the increase in solvent accessible surface area. The interactions between protein and solvent molecules showed that protein's solvation shell preferred to accommodate ethanol molecules as compared to water thereby excluded water molecules from CI2's surface. Further, concentration dependent differential self-aggregation behavior of ethanol is likely to regulate the replacement of relatively fast diffused water by low diffused ethanol molecules from protein's surface during the unfolding process.

In eukaryotes, the heat shock factors (HSFs) are recognized as the master regulator of the heat shock response. In this respect, the genes encoding the heat shock factors seem to be important for adaptation to thermal stress in organisms. Despite this, only few mammalian HSFs has been characterized. In this study, four major heat shock factor genes viz. HSF-1, 2, 4, and 5 were studied. The main objective of the present study was to characterize the cDNA encoding using conserved gene specific primers and to investigate the expression status of these buffalo HSF genes. Our RT-PCR analysis uncovered two distinct variants of buffalo HSF-1 and HSF-2 gene transcripts. In addition, we identified a variant of the HSF5 transcript in buffalo lacking a DNA-binding domain. In silico analysis of deduced amino acid sequences for buffalo HSF genes showed domain architecture similar to other mammalian species. Changes in the gene expression profile were noted by quantitative real-time PCR (qRT-PCR) analysis. We detected the transcript of buffalo HSF genes in different tissues. We also evaluated the seasonal changes in the expression of HSF genes. Interestingly, the transcript level of HSF-1 gene was found upregulated in months of high and low ambient temperatures. In contrast, the expression of the HSF-4 and 5 genes was found to be downregulated in months of high ambient temperature. This suggests that the intricate balance of different HSFs is adjusted to minimize the effect of seasonal changes in environmental conditions. These findings advance our understanding of the complex, context-dependent regulation of HSF gene expression under normal and stressful conditions.

Combining fluorescence and magnetic features in a non-iron based, select type of quantum dots (QDs) can have immense value in cellular imaging, tagging and other nano-bio interface applications, including targeted drug delivery. Herein, we report on the colloidal synthesis and physical and biophysical assessment of wurtzite-type manganese selenide (MnSe) QDs in cell culture media. Aiming to provide a suitable colloidal system of biological relevance, different concentrations of reactants and ligands (e.g., thioglycolic acid, TGA) have been considered. The average size of the QDs is ∼7 nm, which exhibited a quantum yield of ∼75% as compared to rhodamine 6 G dye(®). As revealed from time-resolved photoluminescence (TR-PL) response, the near band edge emission followed a bi-exponential decay feature with characteristic times of ∼0.64 ns and 3.04 ns. At room temperature, the QDs were found to exhibit paramagnetic features with coercivity and remanence impelled by TGA concentrations. With BSA as a dispersing agent, the QDs showed an improved optical stability in Dulbecco's Modified Eagle Media(®) (DMEM) and Minimum Essential Media(®) (MEM), as compared to the Roswell Park Memorial Institute(®) (RPMI-1640) media. Finally, the cell viability of lymphocytes was found to be strongly influenced by the concentration of MnSe QDs, and had a safe limit upto 0.5 μM. With BSA inclusion in cell media, the cellular uptake of MnSe QDs was observed to be more prominent, as revealed from fluorescence imaging. The fabrication of water soluble, nontoxic MnSe QDs would open up an alternative strategy in nanobiotechnology, while preserving their luminescent and magnetic properties intact.

In this work, we explore the nature of ion-channel-like conductance fluctuations across a reconstituted phospholipid bilayer due to insertion of ∼100 nm sized, streptavidin-linked magnetite nanoparticles under static magnetic fields (SMFs). For a fixed bias voltage, the frequency of current bursts increases with the application of SMFs. Apart from a closed conductance state G(0) (≤14 pS), we identify four major conductance states, with the lowest conductance level (G(1)) being ∼126 pS. The number of channel events at G(1) is found to be nearly doubled (as compared to G(0)) at a magnetic field of 70 G. The higher-order open states (e.g., 3G(1), 5G(1)) are generally observable at larger values of biasing voltage and magnetic field. When the SMF of 145 G is applied, the multiconductance states are resolved distinctly and are assigned to the simultaneous opening and closing of several independent states. The origin of the current bursts is due to the instantaneous mechanical actuation of streptavidin-linked MNP chains across the phospholipid bilayer. The voltage-controlled, magnetogated ion channels are promising for diagnoses and therapeutic applications of excitable membranes and other biological systems.

Nanoscale tungsten oxide (WO3) particles were synthesized via a user-friendly solvothermal cum reduction route using sodium tungstanate (Na2WO4) and cetyl trimethyl ammonium bromide (C19H42NBr) as reactants. The X-ray diffraction and transmission electron microscopy studies have revealed monoclinic phase of WO3 with an average crystallite size of 40 nm and competitive crystallographic orientation along (002), (020), (200) planes. After extracting human genomic DNA from human blood by a standard protocol (Qiagen-Kit method), they were conjugated with nanoscale WO3 particles in varying molar concentrations. The biophysical interaction of DNA bound nanoparticles were characterized by Fourier transform infra-red spectroscopy, photoluminescence spectroscopy, agarose gel-electrophoresis and polymerase chain reaction. Understanding physical and biophysical aspects of unconjugated and DNA conjugated WO3 would provide scope for biosensing applications.