Magnetically sensitive nanocomposites for targeted antitumor therapy with application of gemcitabine

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.

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Cytotoxicity induced by new spiral mesoporous silica nanorods via specific surface area and ROS accumulation in HeLa cells

Materials Advances ◽

10.1039/d0ma00199f ◽

2020 ◽

Vol 1 (9) ◽

pp. 3556-3564

Author(s):

Lan She ◽

Miao Sun ◽

Xinfang Li ◽

Anfeng Kang ◽

Feng Yang ◽

...

Keyword(s):

Oxidative Stress ◽

Mesoporous Silica ◽

Cell Viability ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Hela Cells ◽

Ros Accumulation ◽

Silica Nanorods

Results indicated that the effect of MSNRs on cell viability and cellular oxidative stress was related to specific surface area.

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

Materials ◽

10.3390/ma14040843 ◽

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.

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

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2017.0046 ◽

2017 ◽

Vol 376 (2112) ◽

pp. 20170046 ◽

Cited By ~ 3

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’.

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

Water Science & Technology ◽

10.2166/wst.2016.492 ◽

2016 ◽

Vol 75 (1) ◽

pp. 94-105 ◽

Cited By ~ 10

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.

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Relationship between Synthesis Conditions and Photocatalytic Activity of Nanocrystalline TiO2

Journal of Nanomaterials ◽

10.1155/2012/427453 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 17

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.

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

Catalysts ◽

10.3390/catal10060637 ◽

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.

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Moisture adsorption capacity and surface area as deduced from vapour pressure isotherms in relation to hygroscopic water of soils

Biologia ◽

10.2478/s11756-009-0073-z ◽

2009 ◽

Vol 64 (3) ◽

Cited By ~ 3

Author(s):

Abdel-monem Amer

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Saline Soil ◽

Alluvial Soil ◽

Calcareous Soils ◽

Adsorbed Layer ◽

Soil Profiles ◽

Moisture Adsorption ◽

Hygroscopic Water

AbstractSix calcareous and alluvial soil profiles differing in their texture, CaCO3 and salinity were chosen from west and middle Nile Delta for the present study. The 1st and 2nd profiles from Borg El-Arab area were sandy loam in texture and > 30% CaCO3, while the 3rd and 4th profiles (from Nubaria area) were sandy clay loam and < 30% CaCO3. The 2nd and 4th profiles were taken from cultivated area with maize. The 5th profile from Epshan area was non-saline clay alluvial soil and the 6th from El-Khamsen was saline clay alluvial soil. The relation between soil moisture content (W%) and water vapour pressure (P/P o) was established for the mentioned soils. Data showed that the specific surface area (S) values were 34–53 and 44–60 m2/g for calcareous soils of Borg El-Arab and Nubaria areas, 206–219 and 206–249 m2/g for non-saline and saline clay alluvial soils of Epshan and El-Khamsen areas, respectively. The corresponding values of the external specific surface area (S e) were 16–21, 14–22, 72–86 and 92–112 m2/g. Submitting W m+W me as an adsorption boundary of moisture films (W c) (where W m is mono-adsorbed layer of water vapour on soil particles and W me is the external mono-adsorbed layer), the maximum water adsorption capacity (W a) was found to be W c + W me or W m + 2W me. It was ranged from 1.88 to 2.70%, 1.97 to 2.95%, 9.70–10.70% and 10.80 to 13.12% while the maximum hygroscopic water (M H) values were 2.43–3.78%, 2.91–4.65%, 16–17% and 18.30–21.9% for the studied soil profiles respectively. The residual moisture content (θ r) at pF 7 and P/P o = 0 was ranged from 0.0005–0.0010%, 0.0007–0.0019% and 0.0043–0.0048% in Borg El-Arab, Nubaria and Epshan soil profiles, respectively.The inter-relations between the surface area and the hygroscopic moisture parameters of the soils under investigation were as followsCalcareous soils; W m = 0.40 M H, W c = 0.55 M H, W a = 0.70 M H, S = 14 M HNon-saline soil; W m = 0.35 M H, W c = 0.49 M H, W a = 0.63 M H, S = 13 M HSaline soil; W m = 031 M H, W c = 0.45 M H, W a = 0.59 M H, S = 12 M HThese relations give possibility to deduce the soil moisture adsorption capacities and specific surface area via maximum hygroscopic water, which can be obtained through the experimental determination of water vapor adsorption isotherms.

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