scholarly journals How Surface Properties of Silica Nanoparticles Influence Structural, Microstructural and Biological Properties of Polymer Nanocomposites

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 843
Author(s):  
Łukasz Zych ◽  
Anna Maria Osyczka ◽  
Agnieszka Łacz ◽  
Agnieszka Różycka ◽  
Wiktor Niemiec ◽  
...  
Keyword(s):  
Specific Surface ◽  
Silica Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Roughness Parameter ◽  
Hydroxyl Groups ◽  
Type I ◽  
Chemical Action ◽  
Inorganic Particles ◽  
Surface Silica

The aim of this work was to study effect of the type of silica nanoparticles on the properties of nanocomposites for application in the guided bone regeneration (GBR). Two types of nanometric silica particles with different size, morphology and specific surface area (SSA) i.e., high specific surface silica (hss-SiO2) and low specific surface silica (lss-SiO2), were used as nano-fillers for a resorbable polymer matrix: poly(L-lactide-co-D,L-lactide), called PLDLA. It was shown that higher surface specific area and morphology (including pore size distribution) recorded for hss-SiO2 influences chemical activity of the nanoparticle; in addition, hydroxyl groups appeared on the surface. The nanoparticle with 10 times lower specific surface area (lss-SiO2) characterized lower chemical action. In addition, a lack of hydroxyl groups on the surface obstructed apatite nucleation (reduced zeta potential in comparison to hss-SiO2), where an apatite layer appeared already after 48 h of incubation in the simulated body fluid (SBF), and no significant changes in crystallinity of PLDLA/lss-SiO2 nanocomposite material in comparison to neat PLDLA foil were observed. The presence and type of inorganic particles in the PLDLA matrix influenced various physicochemical properties such as the wettability, and the roughness parameter note for PLDLA/lss-SiO2 increased. The results of biological investigation show that the bioactive nanocomposites with hss-SiO2 may stimulate osteoblast and fibroblast cells’proliferation and secretion of collagen type I. Additionally, both nanocomposites with the nanometric silica inducted differentiation of mesenchymal cells into osteoblasts at a proliferation stage in in vitro conditions. A higher concentration of alkaline phosphatase (ALP) was observed on the material modified with hss-SiO2 silica.

Microstructure Analysis of Xanthoceras Sorbifolia Shell Activated Carbon

2014 ◽  
Vol 941-944 ◽  
pp. 1051-1055
Author(s):  
Hong Zhi Zhu ◽  
Zhen Hua Xue
Keyword(s):  
Activated Carbon ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Type I ◽  
Bet Specific Surface Area ◽  
Strong Adsorption ◽  
Measurement Results ◽  
Isotherm Adsorption ◽  
Activating Agent

The Xanthoceras sorbifolia shell activated carbon which was prepared by using zinc chloride as activating agent has a strong adsorption performance of cationic adsorbate (methylene blue) 845.275mg/g and anionic adsorbate (iodine) 1584.96mg/g. Specific surface area study showed that: the adsorption isotherms of activated carbonsamples are type I isotherm adsorption, BET specific surface area was 1455.233m2/g. Displayed by pore specific surface analyzer's measurement results that the pore radius ratio of activated carbon in the range of 3.2-3.4Å is the largest. This proves that these holes are mainly micropores. Meanwhile, the conclusions obtained by the SEM further proof.

scholarly journals Magnetically sensitive nanocomposites for targeted antitumor therapy with application of gemcitabine

2020 ◽  
Vol 11 (4) ◽  
pp. 528-538
Author(s):  
N. M. Korniichuk ◽  
◽  
S. P. Turanska ◽  
A. L. Petranovska ◽  
M. V. Abramov ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Surface Condition ◽  
Adsorbed Layer ◽  
Cytostatic Activity ◽  
Hydroxyl Groups ◽  
Antitumor Therapy ◽  
Traditional Use

The aim of the work is synthesis and study on the properties of polyfunctional magnetosensitive nanocomposites (NC) and target-directed magnetic fluids (MF) based on physiological solution (PS), magnetite, gemcitabine (GEM) and HER2 antibodies (AB), promising for use in targeted antitumor therapy against MDA-MB-231 aggressive tumor cells of triple-negative human breast cancer (BC) with high proliferative and metastatic activity. The specific surface area (Ssp) of samples was determined by the method of thermal desorption of nitrogen using a device KELVIN 1042 of “COSTECH Instruments”. The size of nanoparticles (NP) has been estimated by the formula DBET = 6/(ρSBET), where ρ is the density of NC particle, SBET is the value of the specific surface area calculated by the polymolecular adsorption theory of Brunauer, Emmett and Teller (BET). The surface condition of nanodispersed samples was studied by IR spectroscopy (“Perkin Elmer” Fourier spectrometer, a model 1720X). To calculate the concentration of hydroxyl groups on the surface of nanostructures, the method of differential thermal analysis was used in combination with differential thermogravimetric analysis. The thermograms were recorded using a derivatograph Q-1500D of MOM firm (Hungary) in the temperature range of 20–1000 °C at a heating rate of 10 deg/min. X-ray phase analysis of nanostructures was performed using a diffractometer DRON-4-07 (CuKα radiation with a nickel filter in a reflected beam, the Bragg-Brentano focusing). The size and shape of NP were determined by electron microscopy (a transmission electron microscope (TEM) JEM-2100F (Japan)). The hysteresis loops of the magnetic moment of the samples were measured using a laboratory vibration magnetometer of Foner type at room temperature. Measurement of optical density, absorption spectra and GEM concentration in solutions was performed by spectrophotometric analysis (Spectrometer Lambda 35 UV/Vis Perkin Elmer Instruments). The amount of adsorbed substance on the surface of magnetite was determined using a spectrophotometer at λ = 268 nm from a calibration graph. The thickness of the adsorbed layer of GEM in the composition of Fe3O4@GEM NC was determined by magnetic granulometry. To study the direct cytotoxic/cytostatic effect of a series of experimental samples of MF based on PS, Fe3O4 NP, GEM, HER2 AB, as well as MF components in mono- or complex use, onto MDA-MB-231 cells in vitro, IC50 index was determined. MF were synthesized on the basis of single-domain Fe3O4 and PS, stabilized with sodium oleate (Ol.Na) and polyethylene glycol (PEG), containing GEM and HER2 (Fe3O4@GEM/Ol.Na/PEG/HER2+PS). The cytotoxic/cytostatic activity of MF against MDA-MB-231 cells was studied. It was found that as a result of application of synthesized MF composed of Fe3O4@GEM/Ol.Na/PEG/HER2+PS at the concentration of magnetite of 0.05 mg/mL, GEM - 0.004 mg/mL and HER2 AB - 0.013 μg/mL, a synergistic effect arose, with reduction of the amount of viable BC cells to 51 %. It has been proved that when using MF based on targeted Fe3O4/GEM/HER2 complex, the increased antitumor efficacy is observed compared to traditional use of the drug GEM, with a significant reduction (by four times) of its dose. The high cytotoxic/cytostatic activity of Fe3O4/GEM/HER2 complexes is explained by the fact that endogenous iron metabolism disorders play a significant role in the mechanisms of realization of the apoptotic program under the influence of nanocomposite. Thus, when the nanocomposite system contains Fe3O4/GEM/HER2 complexes in MDA-MB-231 cells, a significant increase is observed in the level of “free iron”, which favours formation of reactive oxygen species and causes oxidative stress (Fenton reaction). The consequences of oxidative stress are induction of apoptosis, enhancement of lipid peroxidation processes, as well as structural and functional rearrangement of biological membranes. The prospects have been shown of further studies of Fe3O4@GEM/Ol.Na/PEG/HER2+PS MF in order to create on their basis a magnetically carried remedy for use in targeted antitumor therapy.

scholarly journals Residual wood polymers facilitate compounding of microfibrillated cellulose with poly(lactic acid) for 3D printer filaments

2017 ◽  
Vol 376 (2112) ◽  
pp. 20170046 ◽  
Author(s):  
Armin Winter ◽  
Norbert Mundigler ◽  
Julian Holzweber ◽  
Stefan Veigel ◽  
Ulrich Müller ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Three Dimensional ◽  
High Specific Surface Area ◽  
Microfibrillated Cellulose ◽  
Poly Lactic Acid ◽  
Hydroxyl Groups ◽  
Surface Chemical

Microfibrillated cellulose (MFC) is a fascinating material with an obvious potential for composite reinforcement due to its excellent mechanics together with high specific surface area. However, in order to use this potential, commercially viable solutions to important technological challenges have to be found. Notably, the distinct hydrophilicity of MFC prevents efficient drying without loss in specific surface area, necessitating storage and processing in wet condition. This greatly hinders compounding with important technical polymers immiscible with water. Differently from cellulose, the chemistry of the major wood polymers lignin and hemicellulose is much more diverse in terms of functional groups. Specifically, the aromatic moieties present in lignin and acetyl groups in hemicellulose provide distinctly less polar surface-chemical functionality compared to hydroxyl groups which dominate the surface-chemical character of cellulose. It is shown that considerable advantages in the production of MFC-filled poly(lactic acid) filaments for three-dimensional printing can be obtained through the use of MFC containing residual lignin and hemicellulose due to their advantageous surface-chemical characteristics. Specifically, considerably reduced agglomerations of MFC in the filaments in combination with improved printability and improved toughness of printed objects are achieved. This article is part of a discussion meeting issue ‘New horizons for cellulose nanotechnology’.

scholarly journals Adsorption of phosphate ions from an aqueous solution by calcined nickel-cobalt binary hydroxide

2016 ◽  
Vol 75 (1) ◽  
pp. 94-105 ◽  
Author(s):  
Fumihiko Ogata ◽  
Erimi Ueta ◽  
Megumu Toda ◽  
Masashi Otani ◽  
Naohito Kawasaki
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Correlation Coefficients ◽  
Hydroxyl Groups ◽  
Order Model ◽  
Molar Ratios ◽  
Phosphate Ions ◽  
Increasing Temperature ◽  
Adsorption Desorption

Different molar ratios of a Ni/Co binary hydroxide (NiCo82, NiCo91, and Ni100) were prepared and calcined at 270 °C (NiCo82-270, NiCo91-270, and Ni100-270). The properties of the adsorbents and the amount of adsorbed phosphate ions were evaluated. The adsorbents calcined at 270 °C had a nickel oxide structure. The amount of adsorbed phosphate ions, the amount of hydroxyl groups, and the specific surface area of the calcined adsorbents at 270 °C were greater than those of the uncalcined adsorbents. The amount of adsorbed phosphate ions was related to the amount of hydroxyl groups and the specific surface area; the correlation coefficients were 0.966 and 0.953, respectively. The adsorption isotherm data for NiCo91 and NiCo91-270 were fit to both the Freundlich and Langmuir equations. The amount of adsorbed phosphate ions increased with increasing temperature. The experimental data fit the pseudo-second-order model better than the pseudo-first-order model. A neutral pH was optimal for phosphate ion adsorption. In addition, the phosphate ions that were adsorbed onto NiCo91-270 could be recovered using sodium hydroxide, and the adsorbent was useful for the repetitive adsorption/desorption of phosphate ions. Collectively, these results suggest that NiCo91-270 is prospectively useful for the adsorption of phosphate ions from aqueous solutions.

scholarly journals Relationship between Synthesis Conditions and Photocatalytic Activity of Nanocrystalline TiO2

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yosep Han ◽  
Hyung-Seok Kim ◽  
Hyunjung Kim
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Crystallite Size ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Synthesis Conditions

The degradation efficiency of methylene blue by TiO2nanoparticles, which were synthesized under different synthesis conditions (i.e., molar ratio of water and titanium tetraisopropoxide (TTIP), pH, and calcination temperature) in a sol-gel process, was systematically investigated. The results showed that increasing the molar ratio of water and TTIP led to the enhanced photocatalytic activity of TiO2nanoparticles, which were likely attributed to the increased specific surface area of TiO2nanoparticles synthesized with high molar ratio. The results were supported by the relative increase in the size of interaggregated pores of the aggregated TiO2nanoparticles. The best photocatalytic activity of TiO2nanoparticles was observed at acidic synthesis conditions; however, the results were not consistent with physical properties for the crystallinity and the crystallite size of TiO2nanoparticles but rather explained by the presence of abundant hydroxyl groups and water molecules existing on the surface of TiO2under acidic synthesis environments. Furthermore, methylene blue degradation experiments revealed that the photocatalytic activity of TiO2nanoparticles was maximized at the calcination temperature of 700°C. The trend was likely due to the combined effect of the anatase crystallinity which showed the highest value at 700°C and the crystallite size/specific surface area which did not excessively increase up to 700°C.

Fabrication of Chitosan-coated Mesoporous Silica Nanoparticles Bearing Rosuvastatin as Drug Delivery System

2021 ◽  
Vol 18 ◽  
Author(s):  
Mojdeh Rahnama Ghahfarokhi ◽  
Ghasem Dini ◽  
Behrooz Movahedi
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Mesoporous Silica ◽  
Specific Surface ◽  
Silica Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ph Value ◽  
Mesoporous Silica Nanoparticles ◽  
Molar Ratio

Aim: In this work, to improve the solubility and bioavailability of the rosuvastatin (RSV) drug, chitosan-coated mesoporous silica nanoparticles (CS-MSNs) as drug delivery systems were fabricated. Methods: To do this, first MSNs with a maximum specific surface area were synthesized from sodium silicate as silica source and different molar ratios of cethyl trimethylammonium bromide (CTAB) and pluronics (P123, PEO20PPO17PEO20) as surfactants via the sol-gel process. Then, the synthesized MSNs were coated by CS polymer with the help of (3-glycidoxypropyl)methyldiethoxysilane (GPTMS) as a linker between MSNs and CS. Subsequently, the RSV drug was loaded into the synthesized CS-coated MSNs. The products were characterized by different techniques, including X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR). The in vitro drug release profile of the fabricated DDS was evaluated in a typical phosphate-buffered saline (PBS) solution at different pH values (i.e., 4, 6, and 7.4) for 48 h. To assess the cytotoxicity, the viability of the human fibroblast cells exposed to the fabricated DDS was also examined. Results: The results showed that at an optimal molar ratio of P123/CTAB, the amorphous MSNs with a specific surface area of about 1080 m2/g, a pore diameter of 4 nm, a pore volume of 1.1 cm3/g, and an average size of about 30 nm were synthesized. Also, the presence of all the components, including the CS coating and the RSV drug, was confirmed in the structure of the fabricated DDS by FTIR analysis. Due to the pH-responsive feature of the CS coating, the RSV drug release from the fabricated DDS showed a reasonable environmental response; as the pH value of the PBS solution decreased, the degree of drug release increased. Conclusion: The CS coating enhanced the cytotoxicity of the fabricated DDS and led to sustainable drug release behavior, which would provide a beneficial approach for drug delivery technology.

scholarly journals Strategy for Modifying Layered Perovskites toward Efficient Solar Light-Driven Photocatalysts for Removal of Chlorinated Pollutants

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 637
Author(s):  
Monica Raciulete ◽  
Florica Papa ◽  
Catalin Negrila ◽  
Veronica Bratan ◽  
Cornel Munteanu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermal Analyses ◽  
Annealing Treatment ◽  
Solar Light ◽  
Hydroxyl Group ◽  
Layered Perovskite ◽  
Hydroxyl Groups ◽  
Layered Perovskites

We have explored an efficient strategy to enhance the overall photocatalytic performances of layered perovskites by increasing the density of hydroxyl group by protonation. The experimental procedure consisted of the slow replacement of interlayer Rb+ cation of RbLaTa2O7 Dion-Jacobson (DJ) perovskite by H+ via acid treatment. Two layered perovskites synthesized by mild (1200 °C for 18 h) and harsh (950 and 1200 °C, for 36 h) annealing treatment routes were used as starting materials. The successful intercalation of proton into D-J interlayer galleries was confirmed by FTIR spectroscopy, thermal analyses, ion chromatography and XPS results. In addition, the ion-exchange route was effective to enlarge the specific surface area, thus enhancing the supply of photocharges able to participate in redox processes involved in the degradation of organic pollutants. HLaTa_01 protonated layered perovskite is reported as a efficient photocatalyst for photomineralization of trichloroethylene (TCE) to Cl− and CO2 under simulated solar light. The enhanced activity is attributed to combined beneficial roles played by the increased specific surface area and high density of hydroxyl groups, leading to an efficiency of TCE mineralization of 68% moles after 5 h of irradiation.

scholarly journals MORPHOLOGY AND SIZE OF SILICA NANOPARTICLES OBTAINED BY LOW-TEMPERATURE PLASMA

2020 ◽  
Vol 22 (5) ◽  
pp. 153-159
Author(s):  
V. A. Vlasov ◽  
P. V. Kosmachev
Keyword(s):  
Specific Surface ◽  
Silica Nanoparticles ◽  
Surface Area ◽  
Specific Surface Area ◽  
Building Materials ◽  
Raw Materials ◽  
Particle Morphology ◽  
Nitrogen Adsorption ◽  
Temperature Plasma ◽  
Average Size

The paper presents the results of a comprehensive study of the particle morphology, size distribution, average size, specific surface area and agglomeration of SiO2 nanoparticles obtained by plasma technology from natural high-silica raw materials (quartzite). The dynamic light scattering, transmission electron microscopy, and nitrogen adsorption techniques are used. It is shown that using the plasma source, polydisperse silica nanoparticles with the distribution of 10–300 nm can be obtained with the average size of 30 ± 7 nm and specific surface area of 71 ± 4 m2/g from natural quartzite. The average agglomerate consists of about 10 particles. The zeta potential varies from –54 to 9 mV for the powder, which can be useful in planning multicomponent systems. The investigated powder can be used as a hardening additive for the manufacture of building materials with improved performance for the creation of specialpurpose objects.

scholarly journals Application of X-ray Diffraction (XRD) and Rock–Eval Analysis for the Evaluation of Middle Eastern Petroleum Source Rock

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6672
Author(s):  
Golam Muktadir ◽  
Moh’d Amro ◽  
Nicolai Kummer ◽  
Carsten Freese ◽  
Khizar Abid
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Source Rock ◽  
Specific Surface Area ◽  
Oxygen Index ◽  
Hydrogen Index ◽  
Type I ◽  
Type Ii ◽  
Kerogen Type ◽  
Rock Eval

In this study, collected samples of nine different wells from the Middle East are used for various geochemical analyses to determine the hydrocarbon generation potential. The determination is carried out following the grain density, specific surface area, XRD, and Rock–Eval pyrolysis analyses. Four different types of kerogen are plotted based on the Rock–Eval analysis result. Kerogen type I usually has high hydrogen index (e.g., HI > 700) and low oxygen index, which is considered oil-bearing. Kerogen Type II has hydrogen index between type I and type II and oxygen index higher than type I (e.g., 350 < HI < 700) and is also considered to have oil-bearing potential. Kerogen type III has a lower hydrogen index (e.g., HI < 350) and is considered to have a primarily gas-generating potential with terrigenous organic matter origination. Kerogen type IV has a very low hydrogen index and higher oxygen index (compared with other types of kerogen), which is considered the inert organic matter. The kerogen quality of the analyzed samples can be considered as very good to fair; the TOC content ranges from 1.64 to 8.37 wt% with most of them containing between 2 and 4 wt%. The grain density of these examined samples is in the range of 2.3–2.63 g/cc. The TOC and density of the samples have an inversely proportional relationship whereas the TOC and the specific surface area (BET) has a positive correlation. The specific surface area (BET) of the examined samples is in the range of 1.97 m2/g–9.94 m2/g. The examined samples are dominated by clay, primarily kaolinite and muscovite. Additionally, few samples have a higher proportion of quartz and calcite. The examined samples from the Middle East contain kerogen type III and IV. Only two samples (JF2-760 and SQ1-1340) contain type I and type II kerogen. Considering Tmax and Hydrogen Index (HI), all of the samples are considered immature to early mature. Rock–Eval (S2) and TOC plotting indicate that most of the samples have very poor source rock potential only with an exception of one (JF2-760), which has a fair-to-good source rock potential.

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