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By considering the importance of water and its purity, herein, a powerful adsorbent has been developed for the adsorption of two toxic contaminants that commonly exist in water, viz., divalent mercury and hexavalent chromium. The efficient adsorbent, CNTs–PLA–Pd, was prepared by covalent grafting polylactic acid to carbon nanotubes and subsequent deposition of palladium nanoparticles. The CNTs–PLA–Pd could adsorb Hg(II), and Cr(VI) entirely exists in water. The adsorption rate for Hg(II) and Cr(VI) was rapid at initial stage, followed by gradual decrease, and attained the equilibrium. The Hg(II) and Cr(VI) adsorption was perceived within 50 min and 80 min, respectively with CNTs–PLA–Pd,. Further, experimental data for Hg(II) and Cr(VI) adsorption was analyzed, and kinetic parameters were estimated using pseudo–first and second–order models. The adsorption process of Hg(II) and Cr(VI) followed the pseudo–second–order kinetics, and the rate–limiting step in the adsorption was chemisorption. The Weber−Morris intraparticle pore diffusion model revealed that the Hg(II) and Cr(VI) adsorption over CNTs–PLA–Pd occurs through multiple phases. The experimental equilibrium parameters for the Hg(II) and Cr(VI) adsorption were estimated by Langmuir, Freundlich, and Temkin isotherms models. All three models were well suited and demonstrated that Hg(II) and Cr(VI) adsorption over CNTs–PLA–Pd transpires through monolayer molecular covering and chemisorption. [ABSTRACT FROM AUTHOR]

A multimode, dual functional nanomaterial, CNTs-Ag2S, comprised of carbon nanotubes (CNTs) and silver sulfide (Ag2S) nanoparticles, was prepared through the facile hydrothermal process. Before the deposition of Ag2S nanoparticles, hydrophobic CNTs were modified to become hydrophilic through refluxing with a mixture of concentrated nitric and sulfuric acids. The oxidized CNTs were employed to deposit the Ag2S nanoparticles for their efficient immobilization and homogenous distribution. The CNTs-Ag2S could adsorb toxic Cd(II) and completely degrade the hazardous Alizarin yellow R present in water. The adsorption efficiency of CNTs-Ag2S was evaluated by estimating the Cd(II) adsorption at different concentrations and contact times. The CNTs-Ag2S could adsorb Cd(II) entirely within 80 min of the contact time, while CNTs and Ag2S could not pursue it. The Cd(II) adsorption followed the pseudo-second-order, and chemisorption was the rate-determining step in the adsorption process. The Weber−Morris intraparticle pore diffusion model revealed that intraparticle diffusion was not the sole rate-controlling step in the Cd(II) adsorption. Instead, it was contributed by the boundary layer effect. In addition, CNTs-Ag2S could completely degrade alizarin yellow R in water under the illumination of natural sunlight. The Langmuir-Hinshelwood (L-H) model showed that the degradation of alizarin yellow R proceeded with pseudo-first-order kinetics. Overall, CNTs-Ag2S performed as an efficient adsorbent and a competent photocatalyst. [ABSTRACT FROM AUTHOR]

Cancer is a current dreadful disease and the leading cause of death. Next to cardiovascular diseases, cancer is the most severe threat to human life and health. Breast cancer is the most common invasive cancer diagnosed in women. Each year about 2.3 million women are diagnosed with breast cancer. In consideration of the severity of breast cancer, herein we designed the biocompatible nanomaterials, CNTs-HAP and GR-HAP, through grafting of hydroxyapatite (HAP) to carbon nanotubes (CNTs) and graphene (GR) nanosheets. CNTs-HAP and GR-HAP have been tested for their cytotoxicity, growth and motility inhibitory effects, and their effects on the mesenchymal markers. All these demonstrated significant dose-dependent and time-dependent in vitro cytotoxicity against SUM-159 and MCF-7 breast cancer cell lines. The cell viability assay showed that the CNTs-HAP was more effective over SUM-159 cells than MCF-7 cells. It found that the increase in the concentration of GR-HAP has inhibited the clonogenic ability of breast cancer cells. The GR-HAP exhibited a substantial inhibitory effect on the cell motility of SUM-159 cell lines. It was investigated that the expression of vimentin (mesenchymal marker) was majorly reduced in SUM-159 cells by GR-HAP. [ABSTRACT FROM AUTHOR]

An efficient adsorbent, CNTs–PAMAM–Ag, was prepared by grafting fourth-generation aromatic poly(amidoamine) (PAMAM) to carbon nanotubes (CNTs) and successive deposition of Ag nanoparticles. The FT–IR, XRD, TEM and XPS results confirmed the successful grafting of PAMAM onto CNTs and deposition of Ag nanoparticles. The absorption efficiency of CNTs–PAMAM–Ag was evaluated by estimating the adsorption of two toxic contaminants in water, viz., Pb(II) and As(III). Using CNTs–PAMAM–Ag, about 99 and 76% of Pb(II) and As(III) adsorption, respectively, were attained within 15 min. The controlling mechanisms for Pb(II) and As(III) adsorption dynamics were revealed by applying pseudo-first and second-order kinetic models. The pseudo-second-order kinetic model followed the adsorption of Pb(II) and As(III). Therefore, the incidence of chemisorption through sharing or exchanging electrons between Pb(II) or As(III) ions and CNTs–PAMAM–Ag could be the rate-controlling step in the adsorption process. Further, the Weber–Morris intraparticle pore diffusion model was employed to find the reaction pathways and the rate-controlling step in the adsorption. It revealed that intraparticle diffusion was not a rate-controlling step in the adsorption of Pb(II) and As(III); instead, it was controlled by both intraparticle diffusion and the boundary layer effect. The adsorption equilibrium was evaluated using the Langmuir, Freundlich, and Temkin isotherm models. The kinetic data of Pb(II) and As(III) adsorption was adequately fitted to the Langmuir isotherm model compared to the Freundlich and Temkin models. [ABSTRACT FROM AUTHOR]

Herein, we present the rational synthesis of a multimode photothermal agent, NGO–FA–CuS, for the advancement of photothermal therapy of cancer. The hierarchical architecture created in NGO–FA–CuS was attained by the covalent conjugation of folic acid (FA) to nanographene oxide (NGO) through amide bonding, followed by the hydrothermal deposition of CuS nanoflowers. In this approach, instead of mere mixing or deposition, FA was covalently bonded to NGO, which helped in retaining their intrinsic properties after binding and allowed to access them in the resulting hybrid nanostructure. In this specifically designed photothermal agent, NGO–FA–CuS, each component has an explicit task, i.e., NGO, FA and CuS act as the quencher, cancer cell-targeting moiety and photothermal transduction agent, respectively. Prior to the grafting of FA molecules and the deposition of CuS nanoflowers, sulfonic acid groups were introduced into NGO to provide stability under physiological conditions. Under irradiation using a 980 nm laser, NGO–FA–CuS was able to attain a temperature of 63.1 °C within 5 min, which is far beyond the survival temperature for cancer cells. Therefore, the resulting temperature recorded for NGO–FA–CuS was sufficient to induce hyperthermia in cancer cells to cause their death. When coming into contact with cancer cells, NGO–FA–CuS can cause a rapid increase in the temperature of their nucleus, destroy the genetic substances, and ultimately lead to exhaustive apoptosis under illumination using a near-infrared (NIR) laser. An excellent photothermal efficiency of 46.2% under illumination using a 980 nm laser and outstanding cytotoxicity against HeLa, SKOV3 and KB cells were attained with NGO–FA–CuS. Moreover, NGO–FA–CuS displays exceptional persistent photo-stability without photo-corrosiveness. The photothermal effect of NGO–FA–CuS was found to be dependent on its concentration and the power density of the laser source. It was found that its cytotoxicity toward cancer cells was enhanced with an increase in the concentration of NGO–FA–CuS and the incubation period. [ABSTRACT FROM AUTHOR]

The carbon nanotubes (CNTs) have been successfully modified to absorb in near‐infrared (NIR) region by synergetic functionalization with an important biopolymer, polylactic acid (PLA) and subsequent in‐situ deposition of Pd nanoparticles. This process has also extended the absorption ability of Pd nanoparticles towards NIR region apart from its classical absorption in UV and visible regions. Thus fabricated CNTs‐PLA‐Pd demonstrated excellent photothermal effect under exposure to 980 nm laser and significant stability against photo‐bleaching and corrosiveness. A stepwise increment in the photothermal effect of CNTs was attained by covalent grafting of PLA and successive deposition of Pd nanoparticles. The photothermal effect of CNTs‐PLA‐Pd was proportional to its concentration level and photothermal conversion efficiency calculated for CNTs‐PLA‐Pd was 26.5 %. The photothermal effect of CNTs‐PLA‐Pd under illumination to 980 nm laser was higher than that of 808 nm laser. The temperature attained during photothermal effect for CNTs‐PLA‐Pd was beyond 60 °C, which far exceeds the temperature survival level of cancer cells. Overall, the rational integration of CNTs, PLA and Pd nanoparticles in CNTs‐PLA‐Pd by reported strategy could offer a suitable avenue for advancement of cancer therapy. [ABSTRACT FROM AUTHOR]

Naturally available diatomaceous earth (DE) microparticles are ideal candidates for drug delivery due to their excellent features like biocompatibility, non-toxicity, porosity, high surface area and ease of surface modification. On the other hand, they have some limitations, especially in drug delivery applications, such as poor drug loading capacity and a very high initial burst release. In order to address these drawbacks, we have surface modified the diatoms with silica xerogel, which forms a novel hybrid material. The modification process was carried out by a facile sol–gel method, the silica xerogel decorated DE microparticles were extensively characterized by SEM, BET, ATR-IR spectroscopy and XRD in order to confirm the covalent linkage of the new material on the surface of the DE microparticles. The prepared hybrid material DE-XER (xerogel) acts as a pH-sensitive micro drug carrier for diclofenac sodium (DS) drug. The results indicate that surface modification plays a critical role, enhancing the drug loading capacity in comparison with neat DE microparticles, achieving effective controlled release. Furthermore, the obtained drug release data were fitted to the zero order model to understand the drug release mechanism. [ABSTRACT FROM AUTHOR]

Pristine aluminum (Al) has received great deal of attention on fabrication of nanoporous anodized alumina (NAA) with arrays of nanosized uniform pores with controllable pore sizes and lengths by the anodization process. There are many applications of NAA in the field of biosensors due to its numerous key factors such as ease of fabrication, high surface area, chemical stability and detection of biomolecules through bioconjugation of active molecules, its rapidness, and real-time monitoring. Herein, we reviewed the recent trends on the fabrication of NAA for high sensitive biosensor platforms like bare sensors, gold coated sensors, multilayer sensors, and microfluidic device supported sensors for the detection of various biomolecules. In addition, we have discussed the future prospectus about the improvement of NAA based biosensors for the detection of biomolecules. [ABSTRACT FROM AUTHOR]

The synthesis of polyaniline (PANI) nanospheres using a simple template-free method is described. The polymerization of aniline in aqueous medium was accomplished using ammonium persulfate without any protonic acid. The UV-visible spectrum of the PANI nanospheres displayed the characteristic absorption peak of the π-π* transition of the benzenoid ring at 355 nm. The oxidation state of the PANI nanospheres was identified with Fourier transform infrared spectroscopy by comparing the two bands at 1582 cm−1 (ring stretching in quinoid unit) and 1498 cm−1 (ring stretching in bezenoid unit). X-ray diffraction patterns demonstrated the low crystallinity of the PANI nanospheres. The morphology of the PANI nanospheres was spherical and their mean diameter was found to be in the range 3-12 nm. The thermal behavior of the PANI nanospheres was studied using thermogravimetric analysis. The effect of doping of HCl and H2SO4 on the PANI nanospheres was studied by measuring the current as a function of time of exposure. A high electrical conductivity of 6 × 10−2 S cm−1 was obtained for the PANI nanospheres doped with 100 ppm HCl, their optimum doping state. Copyright © 2011 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The title compound, [Er(C5H7O2)3(C12H8N2)], is a mixed-ligand metal–organic precursor for chemical vapour deposition, with the Er atom being eight-coordinate. The coordination polyhedron, described as a distorted square anti­prism, is formed by three bidentate (chelating) acetyl­acetonate residues and a phenanthroline ligand in the apical positions. Mol­ecular assembly via C—H⋯O hydrogen bonds generates a sheet structure in the ac plane. Weak co-operative C—H⋯π inter­actions form mol­ecular dimers and contribute to the stability of the inter­sheet packing. The supra­molecular assembly contains voids which form hydro­phobic porous channels, surrounded by a cluster of dimers. [ABSTRACT FROM AUTHOR]