Applied Nanoscience (v.8, #7)
The use of nanotechnology in cardiovascular disease by Meera Chandarana; Anthony Curtis; Clare Hoskins (1607-1619).
Cardiovascular diseases claim a number of lives globally; many of which are preventable. With the increase in diets that consist of high saturated fat, salt, and sugar, people often living sedentary lifestyles, and a rise in cases of obesity, the incidence of cardiovascular disease is increasing. These contributing factors, coupled with more advanced methods of diagnosis, have delivered statistics that clearly show that there is a rising trend in the prevalence of cardiovascular disease. Treatment for cardiovascular diseases is limited currently to oral medicines or invasive surgery. There is a huge gap in this area of medicine for novel therapeutics for improved patient outcomes. Nanotechnology may provide a solution to more effective treatment of disease, with better prognoses and a reduced side effect profile. This review will explore for potential solutions to the limited pharmacological therapies currently on the market and the future that lies ahead for the place of nanotechnology within cardiovascular medicine.
Keywords: Nanomedicine; Cardiovascular disease; Nanotechnology; Medical therapeutics
Comparison of experimental and first-principle results of band-gap narrowing of MgO nanostructures and their dependence on crystal structural parameters by N. Kamarulzaman; D. T. Mustaffa; N. F. Chayed; N. Badar; M. F. M. Taib; A. B. M. A. Ibrahim (1621-1628).
From experimental investigations of the bandgaps of magnesium oxide (MgO) nanostructures, the results show that band-gap narrowing occurred as the physical dimension of the MgO crystallites decrease. This is in contrast to other metal oxides such as ZnO. To obtain insights on this observed phenomenon, the first-principle studies using density functional theory were carried out. The strategy used here is different from the normal theoretical studies, such that information of the structural characterization obtained from experimental X-ray diffraction (XRD) data via the Rietveld method was used in the calculations. This is important, because nanostructures do not possess the same crystal parameters as the bulk and accurate real structural parameters should be used in the calculations. Based on these values, the crystal structures were simulated and the electronic band structures were calculated within the density functional theory (DFT). Results from the density of state (DOS) studies shows that the band-gap narrowing is due to the shifting of the valence and conduction bands. From our theoretical results, we can conclude that the narrowing of the bandgaps of MgO nanostructures is a consequence of the increase of their lattice parameters. The calculated results exhibit this trend and are in good agreement with the experimental results.
Keywords: MgO; First principle; Bandgap; DFT; Lattice parameter
Tolnaftate–graphene composite-loaded nanoengineered electrospun scaffolds as efficient therapeutic dressing material for regimen of dermatomycosis by Shashi Kiran Misra; Pramod W. Ramteke; Sandip Patil; Avinash C. Pandey; Himanshu Pandey (1629-1640).
Graphene “The novel carbon nano-trope” tailors auspicious platform for designing antimicrobial regimen by virtue of its conspicuous molecular interaction with the microorganism. In this work, Tolnaftate (Tf), an antifungal drug, was mingled with Graphene nanoplatelets (Gn) to develop composite (Tf–Gn) via the wet chemical route, embedded in a biocompatible polymeric blend of Eudragit RL100/Eudragit RS100 (EuRL100/EuRS100) and subjected to electrospinning to obtain nonwoven nanoengineered scaffolds (nanofibers) for enhanced anti-dermatophytic virtue. Pursuing cluster of optimization experiments, 20% w/v EuRL100/EuRS 100 was found to be adequate for formation of smooth, defect-free, and regular fibers. Field emission electron microscopy (FESEM) acknowledged zestfully fabrication of smooth, shiny, nano-range, and mesh-like architecture, comprising distinct pockets within their structure. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) conceded formation of the composite Tf–Gn, its physical compatibility with polymers, and improved thermal behavior. Exceptional swelling capacity, significant hydrophilicity, and immense drug entrapment efficiency were obtained of nanofibers fabricated from 3:1 ratio of EuRL100/EuRS100 polymers blend owing to relatively higher permeability which gratified essential benchmark for fabrication of nanofibrous scaffold to alleviate fungal infections caused by dermatophytes. In vitro drug release interpreted controlled liberation of Tf in dissolution media, following Korsmeyer–Peppas model kinetics, and suggested a diffusion-based mechanism. Microdilution broth method was performed for in vitro antifungal efficacy against extremely devastating dermatophytes, i.e., anthropophilic Trichophyton rubrum and zoophilic Microsporum canis, exhibited preeminent growth inhibition against T.rubrum and scanty for M.canis. Findings revealed the superior antifungal activity of Tf–Gn-loaded nanofibers as compared to Tf-loaded nanofibers and recommended potential dressing materials for an effective regimen of dermatomycosis.
Keywords: Graphene; Tolnaftate; Composite; Dermatomycosis; Dressing materials
Electrochemical study of UV erosion of Au nanorods by silver nanoclusters (NCs) allows the construction of a NC-sensitized photovoltaic cell by Kallol Mohanta; Yasser Attia Attia; David Buceta; Ángel M. Pérez-Mariño; M. Carmen Blanco Varela; M. Arturo López-Quintela; José Rivas (1641-1648).
It was reported that gold nanorods (Au NRs), synthesized by the conventional seed-mediated method, show unusual photoresponse to UV illumination due to the presence of silver nanoclusters (Ag NCs) which etch away Au NRs to slowly shred them and make them shorter in length. Here we report the electrochemical experiments supporting this atypical behavior. These studies show that a redox reaction is taking place on the surface of Au NRs in the presence of excited Ag NCs. The excitation energy of Ag NCs can be released in the system as the flow of free charges and it can be utilized for a photosensitive electronic application. A NC-sensitized photovoltaic cell shows the possibility of conversion (with 0.17% efficiency) from UV radiation to electrical energy based on Ag NCs.
Keywords: Au nanorods; Electrochemistry; UV radiation; Corrosion; Photochemical
Silica nanocomposites based on silver nanoparticles-functionalization and pH effect by M. Zienkiewicz-Strzałka; A. Deryło-Marczewska; R. B. Kozakevych (1649-1668).
Current reports in the field of nanotechnology indicate that the properties of metal nanoparticles are determined by their features such as size, shape, composition as well as a degree of crystallinity and stability. These, in turn, may depend heavily on their preparation way, treatment during and after synthesis and finally on properties of the supports and matrices. The goal of presented work was to determine the shape, size, and distribution of silver nanoparticles depending on preparation conditions. In particular, the issues of the formation of silver nanostructures (AgNP) with various shapes and sizes depending on functionalized silica surface as well as on the conditions of the impregnation step by noble metal ions (especially pH) were considered. In particular, the comprehensive approach to determine the impact of pH conditions on the properties of metallic nanoparticles is laid down in this work. Three types of fumed silica materials were selected as the supports of silver nanostructures (Aerosil 150, Aerosil 300 and Silochrom C-120). Silica materials were chemically functionalized by thiol and amine groups and treated with diamminesilver(I) ions [Ag(NH3)2]+. As a result of their reduction silicas adorned with silver nanostructures were obtained. In this work, the AgNP in the form of very small nanoparticles, longitudinal and spherical forms and greater structures with nondescript shape were successfully received and characterized through changing the form of functional groups on the solid surface by adjusting the pH conditions. It turns out that protonation and deprotonation of thiol, amino, and hydroxyl groups can be responsible for possible interactions between noble metal ions and functional groups in the form of both attractive and repulsive electrostatic interactions. The Ag nanoparticle/silica nanocomposites were investigated by X-ray diffraction, atomic force microscopy, potentiometric titration and X-ray photoelectron spectroscopy.
Keywords: Silver nanoparticle; Size control; Fumed silica; Impregnation; Ammine complex
Phase transformations and numerical modelling in simulated HAZ of nanostructured P91B steel for high temperature applications by Modassir Akhtar; Akhil Khajuria; Jitendra K. Sahu; J. Swaminathan; Rajneesh Kumar; Raman Bedi; Shaju K. Albert (1669-1685).
This paper critically assesses phase transformations occurring after welding and subsequent post weld heat treatments in simulated sub-heat affected zones (HAZ) of P91B steel. Samples for weld-HAZ simulation were produced corresponding to grain-coarsened HAZ, grain-refined HAZ and inter-critical HAZ. Analyses revealed diverse phase transformation mechanisms (for GCHAZ = pipe-diffusion and for GR/ICHAZ = GB-diffusion) owing to manipulation in grain size and boron-enriched nanosized particles as regards virgin steel after welding. However, after PWHT, same phase transformation mechanism (interface diffusion) in all simulated sub-HAZs is observed. Hardness evaluations and prior austenite grain boundaries dissolution confirm GB embrittlement after welding. Boron segregation, the presence of borides and boron-enriched particles heads to ~ 50% drop in hardness deviations enhancing GB hardening after PWHT. Particle refinement is observed after PWHT which is further validated by numerical modelling. In addition, particle evolution during cooling from peak temperature of weld thermal cycle and isothermal holding of PWHT is analysed. Apparent activation energy of nucleation/growth follows descending order, i.e. GC/GR/ICHAZ for nanosized particles during welding.
Keywords: P91B steel; Simulated sub-HAZ; Phase transformation; Effect of boron; Apparent activation energy
Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics by Kameron R. Hansen; J. Ryan Peterson; Alessandro Perego; Micah Shelley; Cameron R. Olsen; Luis D. Perez; Heather L. Hogg; Richard K. Watt; John S. Colton (1687-1699).
We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method.
Keywords: Lead sulfide; Ferritin; Nanoparticles; Quantum dots; Solar cells; Photovoltaics
Surfactant-free nanoencapsulation using reactive oligomers obtained by reversible addition fragmentation chain transfer polymerization of styrene and maleic anhydride by Sidhharth Sirohi; Manjeet Jassal; Ashwini K. Agrawal (1701-1710).
Reactive oligomers of styrene–maleic anhydride having controlled architecture were prepared using reversible addition fragmentation chain transfer (RAFT) polymerization. The co-oligomers were characterized by FTIR, Raman, NMR and GPC. The arrangement of co-monomers (i.e. the architecture) in the co-oligomeric RAFT agents could be controlled by changing the molar feed ratio of styrene to maleic anhydride in the range of 1–5.25 under controlled polymerization conditions. Non-alternating (homopolymer) blocks of styrene could be suppressed even at high mole ratios > 1 and the resultant co-oligomeric RAFT agents consisting of mainly alternating (SMS) and semi-alternating (SSM) sequences of styrene and maleic anhydride were obtained. These macro RAFT agents behaved as efficient reactive surfactants and their self-aggregation behavior was greatly influenced by their architecture. These could be successfully used for surfactant-free nanoencapsulation of active hydrophobic materials, such as n-octadecane, indicating their suitability for various applications.
Keywords: RAFT polymerization; Nanoencapsulation; Co-oligomers; Self aggregation
The experimental study to examine the stable dispersion of the graphene nanoparticles and to look at the GO–H2O nanofluid flow between two rotating disks by Taza Gul; Kiran Firdous (1711-1727).
The nanofluid analysis has been carried out as a function of temperature and this idea is utilized to study the graphene oxide (GO) water-based nanofluid from both experimental and numerical perspectives. Various spectral investigations were used to endorse the successful synthesis of graphene oxide. The obtained GO exhibits large size platelet morphology with stable dispersion in water. The experimental procedure of the preparation of nanofluid and its outputs has been analyzed with numerical data. The obtained results from the Chebyshev spectral scheme were transformed into a mathematical model considering the 3D flow of the dispersed GO nanofluid between two parallel rotating disks using the governing Navier–Stokes equations and energy equation with the utilization of Von Karman similarity transformations. The obtained nonlinear differential equations have been examined through a recently fashionable analytic approximation method called the Optimal Homotopy Analysis Method (OHAM). Opposite and same direction rotational effects have been conferred on the flow characteristics. To analyze how the velocities, pressure and temperature fields are affected by various parameters, plots have been displayed. Convergence of the obtained results has been authenticated with residual errors physically and numerically. Moreover, the physical parameters impact, such as local Nusselt number and skin friction coefficients are obtained through numerical data and inspect.
Keywords: Synthesis of graphene oxide; Three-dimensional GO–H2O nanofluid flow; Rotating disks; Heat transfer; OHAM; Error analysis for convergence
Preparation, physicochemical properties and antimicrobial activity of η-modification of titanium(IV) oxide intercalated with poly(N-vinylcaprolactam) by Olesya I. Timaeva; Irina P. Chihacheva; Galina M. Kuzmicheva; Lidiya V. Saf’yanova; Ratibor G. Chumakov; Raisa P. Terekhova (1729-1741).
PVCL-intercalated samples containing nano-dimensional phases with η-modification of the TiO2−x ·nH2O composition are obtained by hydrolysis of TiOSO4·xH2SO4·yH2O or TiOSO4·xH2O in the presence of poly(N-vinylcaprolactam) (PVCL). The incorporation of PVCL with water molecules into the interlayer space of the structure of the η-phase—TiO2−x ·(PVCL nH2O)—is established by the X-ray diffraction study while the presence of PVCL in the sample composition is confirmed by the X-ray photoelectron and IR spectroscopy CHNS analysis and X-ray spectral microanalysis. Intercalated samples manifest the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. It is shown that the sample composition (the content of hydrated titanium dioxide) the composition of the η-phase (the presence of PVCL and H2O or the water content in the interlayer space of the structure), and the surface composition (S in the form of SO4 2− groups O in the form of adsorbed water and OH groups) affect the antimicrobial activity in the dark.
Keywords: Titanium(IV) oxide; Intercalation; Antimicrobial activity; Nanoparticles; Polymer
Chemically reactive flow and heat transfer of magnetite Oldroyd-B nanofluid subject to stratifications by A. S. Alshomrani; M. Irfan; A. Salem; M. Khan (1743-1754).
As an emerging technology owing to countless worthy properties, nanofluids have been concerned by numerous scientists and developed a very energetic arena. Nanofluids, a colloidal assortment of nanoparticles and widespread analysis have disclosed applications of heat transfer because of their intensified aspects of thermal conductivity. The present article explores the nanofluid characteristics on MHD flow of an Oldroyd-B liquid. The convective and stratification mechanisms in the manifestation of thermal radiation and chemical reaction have been utilized for heat and mass transfer features. Additionally, the phenomenon of heat sink/source is accounted. The mathematical relation is established by means of usual boundary layer estimates. Homotopic approach has been utilized for the computation of resultant non-linear ODEs. Thermophysical properties of numerous somatic parameters on velocity, temperature and concentration are scheduled in plots as well as in tabular form. The present interruption reports that the liquid temperature declines for thermal stratification parameter, although conflicting trend is being noted for radiation parameter and thermal Biot number on temperature of Oldroyd-B fluid. The mass Biot number and chemical reaction parameter displays diminishing tendency on concentration field. Additionally, for authentication of current derived elucidations an assessment table of skin friction coefficient is prepared in restrictive cases.
Keywords: Oldroyd-B fluid; Magnetic field effects; Brownian and thermophoresis nanoparticles; Thermal radiation; Double stratification; Combined convective conditions
High responsivity, self-powered carbon–zinc oxide hybrid thin film based photodetector by H. Ahmad; T. Tamil (1755-1765).
A self-powered n-Si/C–ZnO/SiO2/p-Si heterojunction photodetector (PD) which comprises of carbon (C) and zinc oxide (ZnO) nanostructures on a n-type silicon (n-Si) substrate was prepared via vapor phase transport method. Excellent photodetection under 468 nm light illumination for powers ranging from 2.78 to 2910 µW delivered a quick response of about 9.5 µs. A high photoresponsivity of 2.082/AW and external quantum efficiency about 551% were obtained. The mechanism involved for the generation of a photocurrent at a zero bias voltage was discussed for future energy efficient optoelectronics devices. The morphology and composition of C, Zn and O were confirmed by field emission scanning electron microscope, energy dispersive X-ray and Raman scattering analysis. The formation of ZnO nanowires range from 10 to 100 nm, aided by the photoconduction mechanism. The Raman E 2 high mode of 437/cm of ZnO and the presence of D and G bands show the formation of a hybrid C–ZnO thin film. The calculated rectifying ratio is found to shift as the direct current bias voltage and light power increased. The deposition of C particles on the ZnO surface creates point defects and sub-energy levels in the ZnO bandgap which favour fast responsivity in the PD.
Keywords: Self-powered; Photodetector; Carbon; Zinc oxide; Responsivity
Carbon nanotubes grown on oil palm shell powdered activated carbon as less hazardous and cheap substrate by Abdullah Al Mamun; Mohammed A. AlSaadi; Md. Zahangir Alam; Iis Sopyan (1767-1779).
Multiwall carbon nanotubes were synthesised using fixed catalyst in a chemical vapor deposition reactor. The reactor system was locally built and used to grow carbon nanotubes (CNTs) on oil palm shell powdered activated carbon (PAC). The PAC was impregnated with Fe3+ catalyst through sonication process. The nano-micro composite produced in this study was named as “CNT-PAC”. Acetylene (C2H2) gas was used as carbon source compared to the use of toxic hydrocarbons such as benzene (C6H6). Synthesis parameters such as gas flow rates, temperature and reaction time were varied for high yield of the CNTs on powdered activated carbon. The CNT-PAC samples were characterized using field emission electron microscope and transmission electron microscope to confirm the growth of CNT as well as to study the morphology of the nano product. Selected well-grown CNT-PAC were further characterized using Fourier transform infrared spectroscopy, thermal gravimetric analysis and BET surface area measurement. The results showed that BET surface area was improved from 101.1 to 974.9 m2/g. The Zeta potential was − 46.1 mV. The zeta potential of the nano-micro composite indicated that the material will be in good dispersion in aqueous solution. The CNT-PAC product was also oxidized using KMnO4 to functionalise various radicals on the surfaces. The product could be potential as an adsorbent for gaseous and aqueous pollutants due to its high surface area and the presence of various functional groups.
Keywords: Adsorbent; Catalyst impregnation; Chemical vapor deposition; Functional groups; Nanotechnology; Powdered activated carbon
Tracking the effect of binder length on colloidal stability and bioconjugation of gold nanoparticles by J. P. Oliveira; W. J. Keijok; A. R. Prado; M. C. C. Guimarães (1781-1790).
Understanding the organization of self-assembled monolayers (SAMs) on gold nanoparticles (AuNPs) as protective coatings is a key role of biological applications of nanomaterials. Here, we report the influence on the stability of the surface coverage of three mercaptocarboxylic lingands onto AuNPs, mercaptopropanoic acid (MPA), mercaptoundecanoic acid (MUA) and mercaptopropionic acid (MHA) under different conditions. In addition, we optimized a bioconjugation route using bovine serum protein (BSA) as a protein model. AuNPs and successful binding of ligands and BSA on the AuNPs were analyzed by UV–Vis, TEM, FTIR, RAMAN, DLS and zeta potential. The size of as-synthesized AuNPs was 18 ± 1,2 nm with surface plasmon resonance (SPR) peak at 522 nm. The magnitude of the bathochromic shift of AuNPs with MPA, MUA and MHA was determined by UV–Vis and the SPR band position of AuNP shifts to 1.5, 3 and 5 nm longer. Moreover, the data show the influence of chain length on colloidal stability and covalent and non-covalent coupling steps with nanomaterials. We demonstrate a method for quantitative determination of the coatings on gold nanoparticles and open new perspectives in understanding the influence of monolayer thickness on the generation of nanobioconjugates for biological applications.
Keywords: Gold nanoparticles; Colloidal stability; Thiol ligands; Bioconjugation
Photocatalytic and biological properties of porous titanium aminophosphate by G. Gnanamoorthy; T. Dhanasekaran; S. Munusamy; A. Padmanaban; A. Stephen; V. Narayanan (1791-1807).
Titanium aminophosphate was synthesized by a simple chemical method and characterized by XRD, DRS–UV, FT-IR, Raman, FE-SEM, elemental mapping with EDX, HRTEM, contact angle and TG–DTA analyses. Ti–O phase of synthesized material was confirmed by X-ray diffraction patterns. Different vibrational bands of metal oxides and aminophosphate were carried out by Raman spectroscopy. The bandgap energy was determined by a diffuse reflectance UV–visible spectroscopy. FE-SEM with EDX were used to analyze the material size, morphology and elements. Hydrophilic studies were carried out by contact angle meter (CA). In the present study, we have evaluated the effective applications of titanium aminophosphate in biological and photocatalytic activities. The titanium aminophosphate functional groups were confirmed (Ti–O and Ti–O–Ti) by FT-IR spectroscopy. N–H groups were confirmed by elemental analyzer (CHN). Human lung adenocarcinoma (A549) cell line was used to examine cytotoxicity of titanium aminophosphate. The synthesized aminophosphate and titanium aminophosphate were tested against two Gram-positive and two Gram-negative bacteria and titanium aminophosphate exhibits higher antibacterial activity. Photocatalytic activity of titanium aminophosphate was determined by malachite green dye degradation process, which was performed using halogen lamp at 500 nm. The synthesized material shows high photocatalytic activity under visible light irradiation.
Keywords: Titanium aminophosphate; Photocatalytic activity; A549 cell line; Antibacterial activity; Malachite green dye
Bacillus lipopeptides: powerful capping and dispersing agents of silver nanoparticles by Vivek Rangarajan; Gunaseelan Dhanarajan; Pinaki Dey; Dipankar Chattopadhya; Ramkrishna Sen (1809-1821).
This study demonstrates the use of Bacillus lipopeptides as both capping and stabilizing agents in the single-step synthesis of silver nanoparticles (Ag-NPs). With the aim to achieve a stable Ag-NP suspension, two methods of synthesis procedures, methods A and B, were tested and compared. In method A, the excess reactant sodium borohydride (NaBH4) was added to the limiting reactant silver nitrate (AgNO3), while in method B the limiting reactant was added to the excess reactant. It was found that, in both methods, the lipopeptide concentration significantly influenced the morphology and size of Ag-NPs. In case of method A, at low lipopeptide concentrations, Ag-NPs of uniform size distribution were synthesized, whereas at high concentration, incipient small nano-spheres of Ag-NPs were found concentrated at the vesicular surfaces during initial stage of reaction. However, at later stages, the smaller spherical particles radically changed into varied shapes and sizes and eventually detached from the vesicles completely. Ag-NPs of method B showed narrow size distribution. Stability studies revealed that Ag-NP suspension remained stable up to the sodium chloride, NaCl, concentration of 25 g/L. Steric and depletion types of stabilization were found to be the predominant mechanisms that imparted stability to the Ag-NPs. The particles were found to be stable up to test period of 6 months. Antimicrobial studies revealed that the lipopeptide-conjugated Ag-NPs with low lipopeptide were sensitive against all the tested organisms.
Keywords: Lipopeptide; Silver nanoparticles; Capping agents; Nanoparticle stability; Antimicrobial activity
Facile, seedless and surfactant-free synthesis of ZnO nanostructures by wet chemical bath method and their characterization by Ramkumar Chandran; Archana Mallik (1823-1830).
In the present work, we report on the synthesis of ZnO nanostructures by a facile, surfactant-free and seedless growth by wet chemical route. The reported route is simplistic and versatile as by only varying the reaction time we were able to synthesize ZnO nanostructures of various morphologies such as pure sheets, rod-embedded sheets, pure rods and petal-shaped rods. A possible mechanism for the formation of ZnO sheets and its transformation to rods shaped morphology has been put forward. In the present study, we have carried out the structural, optical, photoelectrochemical and electronic properties only for the ZnO nanorods. The as-synthesized ZnO nanorods with wurtzite crystal structure exhibit high crystallinity with mean size of 1.28 µm × 287 nm. The nanorods exhibit a strong near-band edge emission at 388 nm which indicates the presence of shallow nitrogen acceptor defects in ZnO. The n-type conductivity of the nanorods was further confirmed by photoelectrochemical (PEC) and scanning tunneling spectroscopy studies. The synthesized ZnO nanorods exhibited PEC properties due to the reduced oxygen-related defects. The scanning tunneling spectroscopy measurements revealed a little shrink in the bandgap due to the nitrogen doping which was in good agreement with the emission spectroscopy results.
Keywords: ZnO; Nitrogen doping; PEC studies and scanning tunneling spectroscopy
Cu@nano-bio-MOF-7 composite: having more potential for in vitro drug adsorption/release and photocatalytic water splitting as compared to its parent nano-bio-MOF-7 by Tabinda Sattar (1831-1841).
Nano-bio-MOF-7 and its metal/composite material Cu@nano-bio-MOF-7 were synthesized. Both these materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron-dispersive X-rays (EDX) studies to know their morphology. Mass spectrometric studies of both the materials were conducted to estimate the molar masses. BET surface area measurements and pore size determination of nano-bio-MOF-7 and its composite Cu@ nano-bio-MOF-7 were determined by nitrogen adsorption isotherms. In vitro drug adsorption studies of both these materials were conducted using a drug trimetazidine dihyrochloride (vastarel). Powder X-ray diffraction (PXRD) analysis both in pure form and after drug loading were recorded. The amounts of adsorbed drug and its release after intervals from both these materials were estimated through high-performance liquid chromatography (HPLC). The amounts of hydrogen generation by both these materials were calculated through photocatalytic reactions. The results show a better behavior of Cu@nano-bio-MOF-7 as compared to its parent MOF material nano-bio-MOF-7, both for in vitro drug adsorption/release and photocatalytic hydrogen generation.
Keywords: Bio-MOFs; Nano-bio-MOFs; Nano-bio-MOFs composites; In vitro drug adsorption/release; Photocatalytic hydrogen generation
Dual gold nanostructure-based electrochemical immunosensor for CA125 detection by Nitin Kumar; Shivesh Sharma; Seema Nara (1843-1853).
With an aim to develop a sensitive immunoassay for ovarian cancer detection that has linearity over a broad range, we hereby report a dual gold nanostructure-based electrochemical immunosensor to detect ovarian cancer biomarker carcinoma antigen 125 (CA125) in serum. Gold nanorods (GNRs) are coated on indium tin oxide (ITO) and used as working electrode after immobilizing capture anti-CA125 on it. Second, gold nanoparticles (GNPs) tagged with cadmium ion (Cd2+) and another CA125 antibody is used as a probe for signal generation. A sandwich between gold nanorod-modified working electrode and GNP-based probe is formed through CA125 antigen. Direct detection of probe bound on the surface of immunosensor was done by differential pulse voltammetry (DPV) and the peak signals were directly proportional to the CA125 antigen concentration. The developed sensor has shown a detection limit of 3.4 U mL−1 with a broad linear detection range of 20–100 U mL−1. The immunosensor is stable, reproducible and has a good correlation coefficient of 0.97 for the clinical serum samples tested with the developed immunosensor and enzyme-linked immunosorbent assay (ELISA). It has the potential to detect CA125 in clinical samples which show abnormally high or low levels of CA125 in serum.
Keywords: CA125; Gold nanorods; Gold nanoparticles; Electrochemical immunosensor
Photocatalytic activity of Bi2S3 enlargement by decoration of silver for visible light thiophene degradation by I. A. Mkhalid (1855-1864).
Bi2S3 nanofibers were prepared via a hydrothermal technique and a photoassisted deposition way was applied to prepare silver-decorated Bi2S3 nanocomposites. Bi2S3 nanofibers and silver-decorated Bi2S3 nanocomposites were investigated using many characterization tools such as X-ray diffraction, field-emission scanning electron microscopy, photoluminescence emission spectra, X-ray photoelectron spectroscopy, ultraviolet and visible spectroscopy, and BET surface area. Photocatalytic destruction of thiophene was selected to determine the photocatalytic performance of Bi2S3 nanofibers and silver-decorated Bi2S3 nanocomposites. XRD results confirm the formation of Bi2S3 nanofibers. FSEM results reveal Bi2S3 nanofiber structure and silver was decorated on surface of Bi2S3 nanofibers. XPS results reveal that state of decorated silver is metallic. Decoration of Bi2S3 nanofibers by silver decreases electron–hole recombination rat, decreases bandgap, and increases photocatalytic activity. 0.3 wt% Ag/Bi2S3 photocatalyst has the top photocatalytic activity by which 100% thiophene was degraded within 60 min using 1.6 g/l photocatalyst dose. 0.3 wt% Ag/Bi2S3 photocatalyst has photocatalytic stability for five times use.
Keywords: Bi2S3 ; Nanofiber; Silver decoration; Visible photocatalyst; Thiophene destruction