Search

In this paper, ultra-low level selective detection of bovine serum albumin (BSA) has been demonstrated, based on chemically derived graphene i.e., reduced graphene oxide (RGO) nanosheets. The working principle of the sensor is based upon change in conductance of the RGO nanosheets with different concentration of BSA. The change in conductance is based on the charge transfer between BSA and functional groups of RGO. The morphological and structural characterizations of RGO nanosheets were carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Raman spectroscopy is performed to further validate the interaction between RGO sensing layer and BSA molecules. Electrical impedance spectroscopy is performed to observe the impedance variation when BSA interacts with RGO. The sensor device exhibits sensitivity of 10 nA/pM. The lower limit of detection (LOD) of the sensor is found to be 1 pM and response time around 35 s, confirming very high sensitivity for BSA. All electrical (current-voltage) measurements were carried out at 2 V bias for low power operation. The sensor exhibits highest sensitivity at 30 °C and for RGO thickness ~4 nm. The RGO based sensor device is selective towards BSA when compared to proteins like L-Histidine, HSA, BHB and Biotin. Our results suggest that RGO based devices are promising for low-cost, portable and real time detection of BSA at room temperature.

SARS-CoV2 entry is mediated by binding of viral spike-protein(S) to the transmembrane Angiotensin-Converting Enzyme-2 (ACE2) of the host cell. Thus, to prevent transmission of disease, strategies to abrogate the interaction are important. However, ACE2 cannot be blocked since its normal function is to convert the Angiotensin II peptide to Angiotensin(1-7) to reduce hypertension. This work reports a recombinant cell line secreting soluble ACE2-ectopic domain (MFcS2), modified to increase binding and production efficacy and fused to human immunoglobulin-Fc. While maintaining its enzymatic activity, the molecule trapped and neutralized SARS CoV2 virus in vitro with an IC50 of 64 nM. In vivo, with no pathology in the vital organs, it inhibited the viral load in lungs in SARS-CoV2 infected Golden-Syrian-hamster. The Intravenous pharmacokinetic profiling of MFcS2 in hamster at a dose of 5 mg/Kg presented a maximum serum concentration of 23.45 µg/mL with a half-life of 29.5 hrs. These results suggest that MFcS2 could be used as an effective decoy based therapeutic strategy to treat COVID19. This work also reports usage of a novel oral-cancer cell line as in vitro model of SARS-Cov2 infection, validated by over expressing viral-defence pathways upon RNA-seq analysis and over-expression of ACE2 and TMPRSS upon growth in hyperglycaemic condition.

Functionalized carbon nanotubes are recommended as potential drug-delivery tools due to their reduced toxicity and increased solubility or wettability. However, their applications are still restricted because of their dose- and time-dependent toxicity. The conflicting reports regarding toxicity assays of pristine and functionalized multiwalled carbon nanotubes (MWCNTs) in different in vivo and in vitro models inspired us to design a safe drug-releasing device and investigate its applicability in a widely used human-analogous in vivo model. We thereby propose a biocompatible drug-delivery vector that is nontoxic even at higher doses in the Caenorhabditis elegans nematode model. We further carried out a comparative analysis of the various biocompatibility assays of MWCNTs functionalized with inorganic and organic molecules. Synthetic single-stranded DNA (ssDNA) oligonucleotide (5′-GGG-GGG-GGG-G-3′)-functionalized MWCNTs were found to be the most biocompatible and nontoxic even at higher doses (320 µg/mL) of MWCNTs. In contrast, pristine and NH2-functionalized MWCNT were proven to be toxic at lower doses (20–160 µg/mL) of MWCNTs based on survival, locomotion, reproductive potential, and oxidative-stress-related endpoints. Thus, the order of cytotoxicity in animals was observed to be as follows: pristine MWCNTs > NH2-functionalized MWCNTs > ssDNA-functionalized MWCNT.

Tuberculosis (T.B.) is a disease that occurs due to infection by the bacterium

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.

SARS-CoV2 entry is mediated by binding of viral spike-protein (S) to the transmembrane Angiotensin-Converting Enzyme-2 (ACE2) of the host cell. Thus, to prevent transmission of disease, strategies to abrogate the interaction are important. However, ACE2 cannot be blocked since its normal function is to convert the Angiotensin II peptide to Angiotensin(1-7) to reduce hypertension. This work reports a recombinant cell line secreting soluble ACE2-ectopic domain (MFcS2), modified to increase binding and production efficacy and fused to human immunoglobulin-Fc. While maintaining its enzymatic activity, the molecule trapped and neutralized SARS-CoV2 virus in vitro with an IC50 of 64 nM. In vivo, with no pathology in the vital organs, it inhibited the viral load in lungs in SARS-CoV2 infected Golden-Syrian-hamster. The Intravenous pharmacokinetic profiling of MFcS2 in hamster at a dose of 5 mg/Kg presented a maximum serum concentration of 23.45 µg/mL with a half-life of 29.56 hrs. These results suggest that MFcS2 could be used as an effective decoy based therapeutic strategy to treat COVID19. This work also reports usage of a novel oral-cancer cell line as in vitro model of SARS-Cov2 infection, validated by over expressing viral-defence pathways upon RNA-seq analysis and over-expression of ACE2 and TMPRSS2 upon growth in hyperglycaemic condition.

SARS-CoV-2 is the virus responsible for causing COVID-19 disease in humans, creating the recent pandemic across the world, where lower production of Type I Interferon (IFN-I) is associated with the deadly form of the disease. Membrane protein or SARS-CoV-2 M proteins are known to be the major reason behind the lower production of human IFN-I by suppressing the expression of IFNβ and Interferon Stimulated Genes. In this study, 7,832 compounds from 32 medicinal plants of India possessing traditional knowledge linkage with pneumonia-like disease treatment, were screened against the Homology-Modelled structure of SARS-CoV-2 M protein with the objective of identifying some active phytochemicals as inhibitors. The entire study was carried out using different modules of Schrodinger Suite 2020-3. During the docking of the phytochemicals against the SARS-CoV-2 M protein, a compound, ZIN1722 from

At present, the potential role of the AgNPs/endo-fullerene molecule metal nano-composite has been evaluated over the biosystems in-vitro. The intra-atomic configuration of the fullerene molecule (C60) has been studied in-vitro for the anti-proliferative activity of human breast adenocarcinoma (MDA-MB-231) cell lines and antimicrobial activity against a few human pathogens that have been augmented with the pristine surface plasmonic electrons and antibiotic activity of AgNPs. Furthermore, FTIR revealed the basic vibrational signatures at ~3300 cm−1, 1023 cm−1, 1400 cm−1 for O-H, C-O, and C-H groups, respectively, for the carbon and oxygen atoms of the C60 molecule. NMR studies exhibited the different footprints and magnetic moments at ~7.285 ppm, explaining the unique underlying electrochemical attributes of the fullerene molecule. Such unique electronic and physico-chemical properties of the caged carbon structure raise hope for applications into the drug delivery domain. The in-vitro dose-dependent application of C60 elicits a toxic response against both the breast adenocarcinoma cell lines and pathogenic microbes. That enables the use of AgNPs decorated C60 endo fullerene molecules to design an effective anti-cancerous drug delivery and antimicrobial agent in the future, bringing a revolutionary change in the perspective of a treatment regime.

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.

Humidity sensors are of utmost importance in certain areas of life, in processing industries, in fabrication laboratories and in agriculture. Precise evaluation of humidity percentage in air is the need of various applications. Graphene and its composites have shown great potential in performing as humidity sensors owing to enormous surface area, very low electrical noise, high electrical conductivity, mechanical and thermal stability and high room temperature mobility. There is no such extensive review on graphene-based devices for humidity sensing applications. This review extensively discusses graphene-based devices intended towards sensing humidity, starting from the methods of synthesizing graphene, its electronic and mechanical properties favoring sensing behavior and different types of sensing mechanisms. The review also studies the performance and recent trends in humidity sensor based on graphene, graphene quantum dots, graphene oxide, reduced graphene oxide and various composite materials based on graphene such as graphene/polymer, graphene/metal oxide or graphene/metal. Discussions on the limitations and challenges of the graphene-based humidity sensors along with its future trends are made.

Recent advances in nanotechnology and nano biomaterials have attracted considerable attention in the field of cancer therapy. The development of biocompatible nanotherapeutics that selectively target cancer cells is a prime area of interest in current research. In the present study, graphene oxide nanosheets were synthesized using a modified Hummer’s method and characterized by using FTIR spectroscopy, Raman spectroscopy, and X-ray Diffraction analyses, FE-SEM, HR-TEM and AFM. FT-IR spectra revealed the presence of the characteristic wave-numbers of 1585 cm−1, 2841 cm−1, and 3443 cm−1 uncovering the presence of intrinsic functional groups predominantly C=C, C-O, and C=O bonds. The characteristic intrinsic defect proportions in the as-prepared GO sheets exhibited a portion of the ID/IG ratio of ~ 1.05, indicating thereby a lesser proportion of available defect quantity in our synthesized graphene oxide sheets. XRD studies uncovered an interesting characteristic value of (001) and (002) lattice planes at a diffraction angle of 30o, which indicated a crystalline nature of the as-prepared graphene sheets. Thermo Gravimetric analyses of the as-prepared sheets indicated that in the range of 300–900 ℃, the sheet exhibited a tremendous rate of thermal response at different applied temperatures, uncovering the underlying physico-chemical attributes of the sheets. It is observed from the DLS experimentation that GO sheets exhibited a zeta potential ζ-potential of − 9.3 mV, which is expected to be a most stable colloidal form. The lateral thickness of the graphene nanosheets was approximately 6.45 nm, which was corroborated by the TEM and AFM analyses, respectively. The potential biomedical application of graphene nanosheets was evaluated by assessing the cytotoxicity and antioxidant activity. The IC50 of H2O2 scavenging activity by GO sheets was determined to be 61.91 ± 1.14 µg/ml. The DPPH and H2O2 scavenging activity of the GO sheets increases with the increase with the dosage concentrations from 25 to 400 µg/ml, respectively. The in-vitro tests revealed that the GO sheets had a high level of cytotoxicity to the human breast cancer MDA-MB-231 cells that was concentration dependent. In contrast, the cytotoxicity of the GO sheets against the HaCaT normal cell line was marginal, suggesting that the graphene nanosheets could be safely used in cancer therapy.

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.

Two different morphological forms of graphene nanosheets: improved reduced graphene oxide (IRGO) and modified reduced GO (rGO) (MRGO) have been synthesised by improved and modified methods, respectively. Physical characterisations of these graphene nanosheets were carried out using X‐ray diffraction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Colloidal stability of these nanosheets toward a selected bacterium (e.g. Staphylococcus aureus) was ascertained by zeta potential. In the present study, the authors for the first time made an attempt to study and compare the potentialities of these two different forms of graphene nanosheets as efficient bactericidal agents. Field‐emission scanning electron microscopy and TEM with energy dispersive X‐ray spectroscopy (EDAX) studies of IRGO and MRGO have been carried out to explore their underlying mechanism of antibacterial responses through physical as well as chemical interactions with the selected bacterial species.

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.

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.

Bio‐ synthesis of silver nanoparticles (AgNPs) was made by using the aqueous leaf extract of Ardisia solanacea. Rapid formation of AgNPs was observed from silver nitrate upon treatment with the aqueous extract of A. solanacea leaf. The formation and stability of the AgNPs in the colloidal solution were monitored by UV–visible spectrophotometer. The mean particle diameter of AgNPs was calculated from the DLS with an average size ∼4 nm and ∼65 nm. ATR‐FTIR spectroscopy confirmed the presence of alcohols, aldehydes, flavonoids, phenols and nitro compounds in the leaf which act as the stabilizing agent. Antimicrobial activity of the synthesized AgNPs was performed using agar well diffusion and broth dilution method against the Gram‐positive and Gram‐negative bacteria. Further, robust anti‐oxidative potential was evaluated by DPPH assay. The highest antimicrobial activity of synthesized AgNPs was found against Pseudomonas aeruginosa (28.2 ± 0.52 mm) whereas moderate activity was found against Bacillus subtilis (16.1 ± 0.76), Candida kruseii (13.0 ± 1.0), and Trichophyton mentagrophytes (12.6 ± 1.52). Moreover, the potential wound healing activity was observed against the BJ‐5Ta normal fibroblast cell line. Current research revealed that A. solanacea was found to be a suitable source for the green synthesis of silver nanoparticles.

The present work reports on the physical and biophysical characterization of bismuth ferrite (BFO) nanorods fabricated on porous anodized alumina (AAO) templates. The diameter of the nanorods was quite large, which vary in the range of 20–100 nm. The BFO nanorods exhibited enhanced polarization and significant magnetic susceptibility. Moreover, an enhanced magnetoelectric coupling was evident from magnetocapacitance measurements, which exhibited a power law. Upon analyzing through optical, petri-plate and electron microscopy imaging, we observed that, the asymmetric structure of the nanorods gave rise to augmented antibacterial response against the chosen bacteria ( Staphylococcus aureus ). The x-ray photoelectron spectra (XPS) data have exhibited significant peak shifts upon interaction with bacterial cells owing to a change of Bi oxidation state from one to another. Thus potential redox reaction, which might take place at the material-bio interface, is ascertained for bacterial death. Apart from physical insights, understanding the interaction between the bacteria and the nanorods of BFO could pave the way in exploring the antibacterial potentiality of such anisotropic nanoscale systems.

In this chapter, the authors discuss the solution of spread of infectious diseases in terms of SI model in fuzzy environment, which is modelled in a typical discrete system. As the system is discrete in nature, the concept of difference equation has been embarked. In order to understand the underlying uncertainty perspective, they explored the fuzzy difference equations to study the problem.

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 (H1-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. Keywords: Liquid endosperm, Degradation, Green Ag nanoparticles, Spectroscopy, Electrophoresis

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 (IC50) 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.

Multi-walled carbon-nanotubes are considered as promising drug-delivery tool for their unique physicochemical properties. The aim of our study is to assess the biological impact of pristine MWCNT in an in vivo model using Caenorhabditis elegans since it shares 60-80% homologous genes with human genome. The toxicity of MWCNT was determined by evaluating survival assay and motility of C. elegans . Gradual increase in the concentration of pristine MWCNT imparted adverse effects on survival potential and motility of C. elegans gradually. Death rate of worms increased from 7%-17% after 24 hours and from14%-23% after 48 hours with increasing concentrations of MWCNT treatment.