Loading...
Search for:
transmission-electron-microscopy
0.009 seconds
Total 433 records
Toward visual chiral recognition of amino acids using a wide-range color tonality ratiometric nanoprobe
, Article Analytica Chimica Acta ; Volume 1231 , 2022 ; 00032670 (ISSN) ; Fahimi Kashani, N ; Morad, R ; Jamshidi, Z ; Hormozi Nezhad, M. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Chiral recognition has long been a challenging issue to deal with in biological systems, drug design and food authentication. Implementing nanoparticle-based probes with intrinsic or induced chirality in this field has addressed several issues concerning sensitivity, reliability, rapidness and the cost of chiral sensing platforms. Yet, research into chiral nanoprobes that can be used for visual monitoring of chiral substances is still in its infancy. As part of this study, a visual chiral recognition platform has been developed in which a combination of blue-emitting carbon dots (BCDs) and mercaptopropionic acid-capped CdTe quantum dots (MPA-QDs) with inherent chiroptical activity were...
SPR-based assay kit for rapid determination of Pb2+
, Article Analytica Chimica Acta ; Volume 1220 , 2022 ; 00032670 (ISSN) ; Kamani, P ; Madaah Hosseini, H. R ; Sadrnezhaad, S. K ; Sharif University of Technology
Elsevier B.V
2022
Abstract
A recyclable optical nanosensor was developed by immobilizing L-tyrosine functionalized silver nanoparticles (AgNPs) on the polyethylene terephthalate (PET) substrate for rapid determination of Pb2+ ions. At first, the L-tyrosine functionalized AgNPs were assessed in the solution phase; the response time was lower than 15 s, and a limit of detection lower than 9 nM was obtained in the dynamic range of 1–1000 nM. For fabrication of the optical assay kit, the design of experiment (DOE) was used to optimize the immobilization efficiency of the nanoparticles on PET films by studying AgNO3 concentration and pH as two crucial parameters. The assay kit in optimal conditions showed a sharp localized...
Enhanced singlet oxygen production under nanoconfinement using silica nanocomposites towards improving the photooxygenation’s conversion
, Article Journal of Nanoparticle Research ; Volume 24, Issue 9 , 2022 ; 13880764 (ISSN) ; Kazemeini, M ; Sharif University of Technology
Springer Science and Business Media B.V
2022
Abstract
In this contribution, the effect of physical immobilization of methylene blue (MB) into silica nanocomposites was investigated on the conversion and selectivity of the photooxygenation of anthracene and dihydroartemisinic acid (DHAA). Physically immobilized photocatalysts were synthesized through a developed Stöber method and were thoroughly characterized by UV–Vis, FTIR, XRD, XPS, SEM, TEM, HR-TEM, BET-BJH, and EDX analyses. Based on the TEM and UV–Vis results, it was determined that enhancement of the MB concentration as an organocatalyst for the Stöber reaction led to an increase in the size of the nanoparticles from 54 to 183 nm and a 21 nm blue shift in their UV–Vis spectra. Moreover,...
Hyperbranched polyethylenimine functionalized silica/polysulfone nanocomposite membranes for water purification
, Article Chemosphere ; Volume 290 , 2022 ; 00456535 (ISSN) ; Jouyandeh, M ; Akhi, H ; Mousavi Khadem, S. S ; Ganjali, M. R ; Moradi, H ; Mirsadeghi, S ; Badiei, A ; Esmaeili, A ; Rabiee, N ; Habibzadeh, S ; Koyuncu, I ; Nouranian, S ; Formela, K ; Saeb, M. R ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Hyperbranched polyethyleneimine functionalized silica (PEI-SiO2) nanoparticles with considerable hydrophilicity were synthesized and incorporated into a polysulfone (PSF)/dimethylacetamide (DMA)/polyvinylpyrrolidone (PVP) membrane casting solution in five different ratios to fabricate PEI-SiO2/PSF nanocomposite membranes using nonsolvent-induced phase separation. The hydrophilic PEI-SiO2 nanoparticles were characterized by TEM, FTIR, TGA, and XPS analyses. Morphology, water contact angles, mean pore sizes, overall porosity, tensile strengths, water flux, antifouling and the dye separation performances of the PEI-SiO2/PSF membranes were also studied. The PEI-SiO2 nanoparticles were uniformly...
Simvastatin-loaded nano-niosomes confer cardioprotection against myocardial ischemia/reperfusion injury
, Article Drug Delivery and Translational Research ; Volume 12, Issue 6 , 2022 , Pages 1423-1432 ; 2190393X (ISSN) ; Mousavi Niri , N ; Akbarzade, I ; Sharifi, M ; Aboutaleb, N ; Sharif University of Technology
Springer
2022
Abstract
Although simvastatin (SIM) has been proven to be a powerful agent against myocardial ischemia/reperfusion (MI/R) injury, poor water solubility, short half-life, and low bioavailability have made it futile while using conventional drug delivery system. Hence, this study aims to investigate therapeutic efficacy of SIM-loaded nano-niosomes on MI/R injury. Surface active agent film hydration method was used to synthesize nano-niosomes. The physicochemical properties of nano-niosomes were characterized using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Moreover, niosomes were characterized in entrapment efficiency (EE) and releasing pattern. Male Wistar rats were...
Effective promotion of g–C3N4 photocatalytic performance via surface oxygen vacancy and coupling with bismuth-based semiconductors towards antibiotics degradation
, Article Chemosphere ; Volume 287 , 2022 ; 00456535 (ISSN) ; Moradi, M ; Aghaebrahimi Samani, S ; Kakavandi, B ; Rahman Setayesh, S ; Noorisepehr, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this research, the potential of bismuth chromate (BCO), a new bismuth-based semiconductor belongs to the family of Bi2XO6 (X = Mo, W, or Cr), was introduced by a novel 1D/2D structure consist of BCO nanobelts and N2-freezed ultra-wrinkled graphitic carbon nitride (N–CN) nanosheets. To enhance intimate contact between BCO and N–CN (BCO/N–CN composite), surface oxygen vacancy (VO) was created as an efficient electron transfer highway using a simple alkaline-treatment-assisted method. Various characterization techniques, including XRD, FT-IR, EPR, FE-SEM, TEM, BET, DRS, PL, EIS, and photocurrent transient analyses were conducted to elucidate the physicochemical aspects of catalysts. The...
Green porous benzamide-like nanomembranes for hazardous cations detection, separation, and concentration adjustment
, Article Journal of Hazardous Materials ; Volume 423 , 2022 ; 03043894 (ISSN) ; Fatahi, Y ; Asadnia, M ; Daneshgar, H ; Kiani, M ; Ghadiri, A. M ; Atarod, M ; Mashhadzadeh, A. H ; Akhavan, O ; Bagherzadeh, M ; Lima, E. C ; Saeb, M. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Green biomaterials play a crucial role in the diagnosis and treatment of diseases as well as health-related problem-solving. Typically, biocompatibility, biodegradability, and mechanical strength are requirements centered on biomaterial engineering. However, in-hospital therapeutics require an elaborated synthesis of hybrid and complex nanomaterials capable of mimicking cellular behavior. Accumulation of hazardous cations like K+ in the inner and middle ear may permanently damage the ear system. We synthesized nanoplatforms based on Allium noeanum to take the first steps in developing biological porous nanomembranes for hazardous cation detection in biological media. The...
Thermo- and pH-sensitive dendrosomes as bi-phase drug delivery systems
, Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 9, Issue 8 , 2013 , Pages 1203-1213 ; 15499634 (ISSN) ; Fard, A. K ; Abedi, F ; Chegeni, B. K ; Bani, F ; Sharif University of Technology
2013
Abstract
Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having β-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20-37. °C and pH7-8, but dissociated and released drug at temperatures lower than 20. °C or higher...
Design of pH-responsive nanoparticles of terpolymer of poly(methacrylic acid), polysorbate 80 and starch for delivery of doxorubicin
, Article Colloids and Surfaces B: Biointerfaces ; Volume 101 , January , 2013 , Pages 405-413 ; 09277765 (ISSN) ; Chan, H. K ; Raval, G ; Abdekhodaie, M. J ; Liu, Q ; Heerklotz, H ; Wu, X. Y ; Sharif University of Technology
2013
Abstract
This work focused on the design of new pH-responsive nanoparticles for controlled delivery of anticancer drug doxorubicin (Dox). Nanoparticles of poly(methacrylic acid)-polysorbate 80-grafted starch (PMAA-PS 80-g-St) were synthesized by using a one-pot method that enabled simultaneous grafting of PMAA and PS 80 onto starch and nanoparticle formation in an aqueous medium. The particles were characterized by FTIR, 1H NMR, TEM, DLS, and potentiometric titration. Dox loading and in vitro release from the nanoparticles were investigated. The FTIR and 1H NMR confirmed the chemical composition of the graft terpolymer. The nanoparticles were relatively spherical with narrow size distribution and...
Superparamagnetic iron oxide nanoparticles (SPIONs): Development, surface modification and applications in chemotherapy
, Article Advanced Drug Delivery Reviews ; Volume 63, Issue 1-2 , January–February , 2011 , Pages 24-46 ; 0169409X (ISSN) ; Sant, S ; Wang, B ; Laurent, S ; Sen, T ; Sharif University of Technology
2011
Abstract
At present, nanoparticles are used for various biomedical applications where they facilitate laboratory diagnostics and therapeutics. More specifically for drug delivery purposes, the use of nanoparticles is attracting increasing attention due to their unique capabilities and their negligible side effects not only in cancer therapy but also in the treatment of other ailments. Among all types of nanoparticles, biocompatible superparamagnetic iron oxide nanoparticles (SPIONs) with proper surface architecture and conjugated targeting ligands/proteins have attracted a great deal of attention for drug delivery applications. This review covers recent advances in the development of SPIONs together...
Structural characterization of a rhamnolipid-type biosurfactant produced by Pseudomonas aeruginosa MR01: Enhancement of di-rhamnolipid proportion using gamma irradiation
, Article Colloids and Surfaces B: Biointerfaces ; Volume 81, Issue 2 , 2010 , Pages 397-405 ; 09277765 (ISSN) ; Abassi, H ; Ahmadkhaniha, R ; Roostaazad, R ; Masoomi, F ; Zahiri, H. S ; Ahmadian, G ; Vali, H ; Noghabi, K. A ; Sharif University of Technology
2010
Abstract
We previously reported that MR01, an indigenous strain of Pseudomonas aeruginosa, was able to produce a rhamnolipid-type biosurfactant. Here, we attempted to define the structural properties of this natural product. The analysis of the extracted biosurfactant by thin-layer chromatography (TLC) revealed the presence of two compounds corresponding to those of authentic mono- and di-rhamnolipid. The identity of two structurally distinguished rhamnolipids was confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. Liquid chromatography/mass spectrometry (LC/MS) of extracted biosurfactant revealed up to seventeen different rhamnolipid congeners. Further quantification showed...
Nanostructured TiO2-CeO2 mixed oxides by an aqueous sol-gel process: Effect of Ce:Ti molar ratio on physical and sensing properties
, Article Sensors and Actuators, B: Chemical ; Volume 150, Issue 2 , 2010 , Pages 631-640 ; 09254005 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Nanostructured TiO2-CeO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and cerium chloride were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. The effect of Ce:Ti molar ratio was studied on the crystallisation behaviour of the products. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders crystallised at the low temperature of 500 °C, containing anatase-TiO2, rutile-TiO2 and cubic-CeO2 phases, as well as Ti 8O15, Ti3O5 and Ce 11O20 depending on annealing temperature and Ce:Ti molar...
Synthesis and characterisation of nanostructured neodymium titanium oxides by sol-gel process: Controlling the phase composition, crystal structure and grain size
, Article Materials Chemistry and Physics ; Volume 122, Issue 2-3 , 2010 , Pages 512-523 ; 02540584 (ISSN) ; Fray, D. J ; Sharif University of Technology
2010
Abstract
Nanocrystalline neodymium titanium oxide thin films and powders with different phase compositions with mesoporous structure were produced by a straightforward particulate sol-gel route. The sols were prepared in various Nd:Ti molar ratios and they showed a narrow particle size distribution in the range 20-26 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of Nd4Ti9O24, Nd2Ti4O11, Nd3Ti4O12 for titanium dominant powders (Nd:Ti ≤ 45:60), mixtures of Nd2TiO5 and Nd2O3 for neodymium dominant powders (Nd:Ti ≥ 75:25) and pure Nd3Ti4O12 phase for equal molar ratio of Nd:Ti, depending on the annealing temperature and Nd:Ti...
Multifunctional core-shell nanoplatforms (gold@graphene oxide) with mediated NIR thermal therapy to promote miRNA delivery
, Article Nanomedicine: Nanotechnology, Biology, and Medicine ; Volume 14, Issue 6 , 2018 , Pages 1891-1903 ; 15499634 (ISSN) ; Akhavan, O ; Adeli, M ; Razzazan, S ; Dinarvand, R ; Zanganeh, S ; Soleimani, M ; Dinarvand, M ; Atyabi, F ; Sharif University of Technology
Elsevier Inc
2018
Abstract
Recent insights into the nanomedicine have revealed that nanoplatforms enhance the efficacy of carrier in therapeutic applications. Here, multifunctional nanoplatforms were utilized in miRNA-101 delivery and NIR thermal therapy to induce apoptosis in breast cancer cells. Au nanorods (NRs) or nanospheres (NSs) covered with graphene oxide (GO) were prepared and functionalized with polyethylene glycol as a stabilizer and poly-L-arginine (P-L-Arg) as a targeting agent. In nanoplatforms, coupling Au@GO prepared stable structures with higher NIR reactivity. P-L-Arg substantially enhanced the cellular uptake and gene retardation of stuffs coated by them. However, rod-shape nanoplatforms indicated...
Effect of graphene oxide nanosheets on visible light-assisted antibacterial activity of vertically-aligned copper oxide nanowire arrays
, Article Journal of Colloid and Interface Science ; Volume 521 , 2018 , Pages 119-131 ; 00219797 (ISSN) ; Ashari Astani, N ; Rahighi, R ; Tayyebi, A ; Tayebi, M ; Khezri, J ; Hashemi, E ; Rothlisberger, U ; Simchi, A ; Sharif University of Technology
Academic Press Inc
2018
Abstract
In the present work, the effect of graphene oxide (GO) nanosheets on the antibacterial activity of CuO nanowire arrays under visible light irradiation is shown. A combined thermal oxidation/electrophoretic deposition technique was employed to prepare three-dimensional networks of graphene oxide nanosheets hybridized with vertically aligned CuO nanowires. With the help of standard antibacterial assays and X-ray photoelectron spectroscopy, it is shown that the light-activated antibacterial response of the hybrid material against gram-negative Escherichia coli is significantly improved as the oxide functional groups of the GO nanosheets are reduced. In order to explore the physicochemical...
Voltammetric studies of sumatriptan on the surface of pyrolytic graphite electrode modified with multi-walled carbon nanotubes decorated with silver nanoparticles
, Article Talanta ; Volume 80, Issue 1 , 2009 , Pages 31-38 ; 00399140 (ISSN) ; Shahrokhian, S ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
2009
Abstract
Multi-walled carbon nanotube decorated with silver nanoparticles (AgNPs-MWCNT) is used as an effective strategy for modification of the surface of pyrolytic graphite electrode (PGE). This modification procedure improved colloidal dispersion of the decorated MWCNTs in water, affording uniform and stable thin films for altering the surface properties of the working electrode. Robust electrode for sensing applications is obtained in a simple solvent evaporation process. The electrochemical behavior of sumatriptan (Sum) at the bare PGE and AgNPs-MWCNT modified PGE is investigated. The results indicate that the AgNPs-MWCNT modified PGE significantly enhanced the oxidation peak current of Sum. A...
Multi-walled carbon nanotubes with immobilised cobalt nanoparticle for modification of glassy carbon electrode: Application to sensitive voltammetric determination of thioridazine
, Article Biosensors and Bioelectronics ; Volume 24, Issue 11 , 2009 , Pages 3235-3241 ; 09565663 (ISSN) ; Ghalkhani, M ; Adeli, M ; Amini, M. K ; Sharif University of Technology
2009
Abstract
Multi-walled carbon nanotubes (MWCNTs) were immobilised with cobalt nanoparticles and analyzed by transmission electron microscopy. This modification procedure substantially improved colloidal dispersion of the immobilised MWCNTs in water and organic solvents, yielding uniform and stable thin films for modification of the glassy carbon electrode surface. The modified electrode showed an efficient catalytic role for the electrochemical oxidation of thioridazine (TR), leading to remarkable decrease in its oxidation overpotential of approximately 100 mV and enhancement of the kinetics of the electrode reaction, which can be confirmed by increasing in the peak current and sharpness of the peak....
Recent advances in the design and applications of amyloid-β peptide aggregation inhibitors for Alzheimer’s disease therapy
, Article Biophysical Reviews ; Volume 11, Issue 6 , 2019 , Pages 901-925 ; 18672450 (ISSN) ; Khazaei, S ; Behnammanesh, H ; Shamloo, A ; Erfani, M ; Beiki, D ; Bavi, O ; Sharif University of Technology
Springer
2019
Abstract
Alzheimer’s disease (AD) is an irreversible neurological disorder that progresses gradually and can cause severe cognitive and behavioral impairments. This disease is currently considered a social and economic incurable issue due to its complicated and multifactorial characteristics. Despite decades of extensive research, we still lack definitive AD diagnostic and effective therapeutic tools. Consequently, one of the most challenging subjects in modern medicine is the need for the development of new strategies for the treatment of AD. A large body of evidence indicates that amyloid-β (Aβ) peptide fibrillation plays a key role in the onset and progression of AD. Recent studies have reported...
Simultaneous controlled release of 5-FU, DOX and PTX from chitosan/PLA/5-FU/g-C3N4-DOX/g-C3N4-PTX triaxial nanofibers for breast cancer treatment in vitro
, Article Colloids and Surfaces B: Biointerfaces ; Volume 179 , 2019 , Pages 495-504 ; 09277765 (ISSN) ; Hosseini, S ; Mahboobnia, K ; Boloursaz, L. A ; Moradi, M ; Irani, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
In the present study, the tri-layer nanofibers were synthesized via triaxial electrospinning process to control the sustained delivery of Doxorubicin (DOX), Paclitaxel (PTX) and 5- fluorouracil (5-FU) anticancer drugs from nanofibers. The 5-FU molecules were incorporated into the core solution (chitosan/polyvinyl alcohol (CS/PVA)) to fabricate the CS/PVA/5-FU inner layer of nanofibers. The intermediate layer was prepared from poly(lactic acid)/chitosan (PLA/CS) nanofibers. The DOX and PTX molecules were initially loaded into the g-C3N4 nanosheets and following were incorporated into the PLA/CS solution to fabricate the outer layer of nanofibers. The synthesized nanosheets and nanofibers were...
Doxorubicin/cisplatin-loaded superparamagnetic nanoparticles as a stimuli-responsive Co-delivery system for chemo-photothermal therapy
, Article International Journal of Nanomedicine ; Volume 14 , 2019 , Pages 8769-8786 ; 11769114 (ISSN) ; Zamani, M ; Vossoughi, M ; Iraji zad, A ; Sharif University of Technology
Dove Medical Press Ltd
2019
Abstract
Introduction: To date, numerous iron-based nanostructures have been designed for cancer therapy applications. Although some of them were promising for clinical applications, few efforts have been made to maximize the therapeutic index of these carriers. Herein, PEGylated silica-coated iron oxide nanoparticles (PS-IONs) were introduced as multipurpose stimuli-responsive co-delivery nanocarriers for a combination of dual-drug chemotherapy and photothermal therapy. Methods: Superparamagnetic iron oxide nanoparticles were synthesized via the sonochemical method and coated by a thin layer of silica. The nanostructures were then further modified with a layer of di-carboxylate polyethylene glycol...