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Enhancement of bioactivity and bioavailability of curcumin with chitosan based materials
Khalid Mahmood Zia,Kashif Mahmood,Mohammad Zuber,Zill-i-Huma Nazli,Saima Rehman,Fatima Zia 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12
Curcumin (CUR) has been investigated for its poor accessibility to a site of action or absorption and rapid metabolism to cope with the limited medication and cure applications. This article reviews numerous approaches, such as encapsulated surfactant/polymeric micelles, liposomes, micro/nano-spheres, nano-suspensions/composites, nanocomplex, films, and hydrogels for effective transfer of CUR to target sites. Chitosan (CS), and chitosan derivatives have been found to enhance therapeutic efficacy of CUR. CS/modified-CS based alginate, cyclodextrin, starch, dextran sulfate, ZnO, phytosomes, and poly(butyl) cyanoacrylate drug delivery matrices improved bioavailability, prolonged drug loading and permeability, sustained release rate, improved solubility and stability (prevent metabolic degradation) of CUR, consequently promoting various clinical applications. CS based polysaccharide, protein, and metal oxide drug delivery nano formulations advantageously participated to improve biological activities of CUR. We have attempted to summarize these delivery approaches, and reviewed future trends/strategies to permit the introduction of CUR as practical therapeutic drug.
Khalid Mahmood,박승빈 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.2
Zinc oxide (ZnO) and Al-doped ZnO (AZO) thin films were prepared by electrostatic spray deposition method at atmospheric pressure followed by annealing. The effects of annealing and Al doping on the structural,electrical and optical properties of the films were investigated. The results show that films have random orientation with compact hexagonal wurtzite structure. It also implies that the annealing and the Al doping help to improve the electrical conductivity and optical properties as well. The minimum value of resistivity was 1.10 × 10−4 Ω cm for 0.5 at. % AZO film and transmittance was greater than 96% in the visible region. The present value of resistivity is comparable to the lowest values for AZO films reported in open literatures. All the films prepared by this method have a good crystalline structure and homogenous surface. We proposed that the substitution of Al in the ZnO lattice has positive effects in terms of increasing the free electron concentration. At atmospheric pressure, the electrospraying method was confirmed to be suitable for the preparation of AZO films with low resistivity and high transmittance.
Mahmood, Khalid,Swain, Bhabani Sankar,Han, Gill-Sang,Kim, Byeong-Jo,Jung, Hyun Suk American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.13
<P>The realization of arrays of high-aspect-ratio nitrogen-doped ZnO (NZO) nanorod is critical to the development of high-quality nanostructure-based optoelectronic and electronic devices. In this study, we used a solution-based method to grow arrays of vertically aligned high-aspect-ratio NZO nanorods on ZnO seed layer covered fluorine-doped tin oxide substrates. We investigated whether the diameters and aspect ratios of the nanorods were affected by the addition of polyethylenimine (PEI) to the precursor solution used as well as by variations in the growth temperature and the concentration of the precursor solution. The performances of dye-sensitized solar cells (DSSCs) in which the synthesized high-aspect-ratio NZO nanorods were used as the photoanode material were also studied. That the dopant, nitrogen, was introduced into the ZnO lattice was confirmed using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. It was seen that after the addition of PEI, the NZO and ZnO nanorod arrays increased in length and their diameters became smaller (i.e., their aspect ratios increased). This resulted in an increase in the amount of dye absorbed by them, leading to improvements in the DSSCs based on the nanorods. The structural, morphological, optical, and photovoltaic characteristics of ZnO and NZO nanorod arrays synthesized using different precursor concentrations and growth temperatures (160–190 °C) were also examined. We also investigated the effect of the use of PEI on these characteristics. The power conversion efficiency (PCE) of DSSCs fabricated using the NZO nanorod arrays was found to be significantly higher than that of DSSCs based on the pure ZnO nanorod arrays. This increase in efficiency could be attributed to the combined effects of the increase in the charge-carrier concentration, change in morphology, and increase in the Fermi energy levels of the nanorods, which resulted because of N doping. A PCE of 5.0% was obtained for a DSSC based on a film of arrays of NZO nanorods having an aspect ratio of ∼47 and synthesized using PEI.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-13/am500105x/production/images/medium/am-2014-00105x_0015.gif'></P>
Mahmood, Khalid,Kang, Hyun Wook,Park, Seung Bin,Sung, Hyung Jin American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.8
<P>Upright-standing nanoporous nanosheets of iodine-doped ZnO (ZnO:I) nanocrsytallites were grown hydrothermally at low temperature and studied as dye-sensitized solar-cell electrodes. The highest overall energy-conversion efficiency of ∼6.6% was achieved with the film consisted of nanosheets of ZnO:I nanocrystallites. This efficiency was significantly improved than the 3.2% achieved for ZnO:I films only including nanosized crystallites, and higher than the 2.4% for undoped ZnO nanosheet film. The nanosheets of ZnO:I nanocrsytallites were proven to be positive in causing light scattering in a broad wavelength region and, therefore, enhancing the light harvesting capability of the photoelectrode film and thus, promotes the solar cell performance. The fabricated cells exhibited highly durable cell performances, even after a month under atmospheric conditions. Electrochemical impedance spectroscopy (EIS) data confirmed that iodine doping was helpful to lower the recombination resistance and prolonged electron lifetime of the ZnO:I cells, hence diminishing the recombination process. The efficiency achieved for the best DSSC in this work was much better than ever reported for a ZnO-based DSSC.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-8/am303272g/production/images/medium/am-2012-03272g_0011.gif'></P>
Mahmood, Khalid,Swain, Bhabani Sankar,Jung, Hyun Suk The Royal Society of Chemistry 2014 Nanoscale Vol.6 No.15
<P>In this paper, ZnO and Al-doped ZnO films were deposited using the electrospraying method and studied for the first time as photoanodes for efficient perovskite solar cells. Effects of substrate temperature, deposition time, applied voltage, substrate-to-nozzle distance and flow rate (droplet size) on the morphology of ZnO were studied with the help of FE-SEM images. The major factors such as the droplet size of the spray, substrate temperature and substrate-to-nozzle distance at deposition control the film morphology. Indeed, these factors determine the density of the film, its smoothness and the flow of solution over the substrate. The droplet size was controlled by the flow rate of the spray. The substrate-to-nozzle distance and flow rate will both regulate the solution amount deposited on the surface of the substrate. The most favorable conditions for a good quality ZnO thin film were a long substrate-to-nozzle distance and lower solution flow rates. In situ droplet size measurement shows that the size and dispersion of particles were narrowed. The method was shown to have a high deposition rate and efficiency relative to well-established thin film deposition techniques such as chemical and physical vapor deposition. In addition, it also allows easy control of the microstructure and stoichiometry of the deposits. The pure ZnO film produced under optimum conditions (440 nm thick) demonstrated a high power conversion efficiency (PCE) of 10.8% when used as a photoanode for perovskite solar cells, owing to its high porosity, uniform morphology and efficient electron transport. For thicker films a drastic decrease in PCE was observed due to their low porosity. We also observed that the open-circuit voltage increases from 1010 mV to 1045 mV and also the PCE increases from 10.8% to 12.0% when pure ZnO films were doped with aluminum (Al). Under atmospheric pressure, the electrospraying system produces the reasonably uniform-sized droplets of smaller size, so the films have a smooth surface and are highly suited for optoelectronic applications.</P>
Khalid Mahmood Zia,Shahid Adeel,Fazal-ur- Rehman,Habiba Aslam,Muhammad Kaleem Khosa,Mohammad Zuber 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-
The current research presents the exploration of coloring potential of neem bark under the influence ofultrasonic treatment. It is found that good color strength is obtained when tannin from bark is extractedin acidified methanol medium and is used to dye irradiated cotton fabric. New shades and good ratings offastness were obtained when optimal fabric was mordanted with herbal biomolecules where excellentrating has been obtained after bio-mordanting the fabrics under optimal conditions. It is concluded thatUS treatment being green tool in natural dyeing has a great potential to isolate colorants from plantsources under mild conditions.