Mesoporous silica particles (MSP) have received increasing interest for various applications because of their unique features such as controlled pore size, low density, high chemical and thermal ...stability, and high surface area. In this study, MSP was applied as an additive in water-based drilling fluids (WBMs). The effect of MSP on the rheological, thermal, filtration, and structural properties of WBMs was investigated. The results were compared with those of analogous fluids containing conventional nonporous silica particles (SSP). Rheological assays showed shear-thinning and viscoelastic behavior, which were more noticeable for fluids including MSP. It was observed that low concentrations of MSP (0.25 %wt) can achieve the same rheological properties as the fluids with higher SSP content (up to 0.5 %wt). The rheological properties of SSP-containing fluids were not significantly affected by the presence of NaCl or aging tests. The theoretical Herschel–Bulkley model represents the rheological behavior of WBMs. The MSP-based WBMs exhibited better filtration properties before aging. The microstructures of the WBMs were analyzed using Scanning Electron Microscopy (SEM). A homogeneous distribution of SSP in the WBMs was observed, while particle agglomeration was observed in WBMs containing MSP. In addition, surface interactions were studied to elucidate the interactions between particles and fluid constituents. The surface interaction, assessed through ζ-potential and FTIR analysis, revealed that the binding affinities of BT, PAC, and XGD with MSP were augmented compared to their individual values. Based on the experimental results, MSP constitutes a promising alternative as an additive for the design of WBMs.
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•The effect of silica particles type on water-based drilling fluids (WBMs) performance was investigated.•Lower concentrations of MSP were required to achieve the same rheological properties of the fluids containing SSP.•The physicochemical properties of SSP and MSP had a different effect on the performance of WBMs.•The surface interactions mainly governed the rheological properties of WBMs.
The addition of hydrophilic components (CaCl2, poly-2-ethyl-2-oxazoline (PEOX) or mesoporous silica particles (MSP)) into Styrene-Butadiene-Styrene (SBS)/chloroform solution was shown to affect the ...resulting breath figure patterns in terms of pore size, pore shape and order. Honeycomb-patterned porous SBS polymer films were prepared by adding 30 wt% PEOX capped, CaCl2 loaded mesoporous silica particles into SBS solution. The long-range order observed with a pore diameter of ∼3.6 µm in the breath figure pattern at RT and 50–70% RH was attributed to the synergistic contributions of each component. CaCl2 promotes the condensation of water vapor and the nucleation of many water droplets on the polymer solution. When localized in a uniformly swollen layer of PEOX around MSP, easier nucleation together with stabilization of water droplets by MSP and PEOX leads to hexagonally-ordered breath figures. The results demonstrate the addition of hydrophilic components as an easy tool to tune breath figure patterns at relatively low humidity and their synergistic contributions.
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The sorption of poorly aqueous soluble active pharmaceutical ingredients (API) to mesoporous silica carriers is an increasingly common formulation strategy for dissolution rate ...enhancement for this challenging group of substances. However, the success of this approach for a particular API depends on an array of factors including the properties of the porous carrier, the loading method, or the attempted mass fraction of the API. At present, there is no established methodology for the rational selection of these parameters. In the present work, we report a systematic comparison of four well-characterised silica carriers and seven APIs loaded by the same solvent evaporation method. In each case, we find the maximum amorphization capacity by x-ray powder diffraction analysis and measure the in vitro drug release kinetics. For a selected case, we also demonstrate the potential for bioavailability enhancement by a permeation essay.
In this paper, we demonstrate that preparation by electrospray deposition of mesoporous SiO2 particles can be employed as additives to Aluminum/Poly (Vinylidene Fluoride) (Al/PVDF) to enhance ...reaction velocity. We find that the reaction velocity of Al/PVDF with 5 wt% SiO2 is 3× higher. The presence of meso‐SiO2 appears to accelerate the decomposition of PVDF, with a significant increase in HF release, resulting in higher heat release. We believe that hot‐spots around meso‐SiO2 may serve as multiple ignition points, with the multi‐layered structure promoting heat convection to increase the propagation rate.
With 5 wt% mesoporous silica, the burning rate of Al/PVDF film was 3× times higher. The meso‐SiO2 appears to highly accelerate the decomposition of PVDF, with a significant increase in HF release and higher heat release. Hot‐spots around meso‐SiO2 may serve as multiple ignition points and the multi‐layered structure promote the heat convection thus highly increase the spreading rate.
Novel hydrogel-based multifunctional systems prepared utilizing photocrosslinking and freeze-drying processes (PhotoCross/Freeze-dried) dedicated for bone tissue regeneration are presented. ...Fabricated materials, composed of methacrylated gelatin, chitosan, and chondroitin sulfate, possess interesting features including bioactivity, biocompatibility, as well as antibacterial activity. Importantly, their degradation and swellability might be easily tuned by playing with the biopolymeric content in the photocrosllinked systems. To broaden the potential application and deliver the therapeutic features, mesoporous silica particles functionalized with methacrylate moieties decorated with hydroxyapatite and loaded with the antiosteoporotic drug, alendronate, (MSP-MA-HAp-ALN) were dispersed within the biopolymeric sol and photocrosslinked. It was demonstrated that the obtained composites are characterized by a significantly extended degradation time, ensuring optimal conditions for balancing hybrids removal with the deposition of fresh bone. We have shown that attachment of MSP-MA-HAp-ALN to the polymeric matrix minimizes the initial burst effect and provides a prolonged release of ALN (up to 22 days). Moreover, the biological evaluation in vitro suggested the capability of the resulted systems to promote bone remodeling. Developed materials might potentially serve as scaffolds that after implantation will fill up bone defects of various origin (osteoporosis, tumour resection, accidents) providing the favourable conditions for bone regeneration and supporting the infections' treatment.
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Glabridin, a compound in the root extract of Glycyrrhiza glabra, has been identified as an effective tyrosinase inhibitor. Applied on skin, melanin synthesis is inhibited, making ...glabridin an interesting candidate for skin whitening or for the treatment of age spots. However, main obstaclefor its practical use is its low dermal bioavailability, caused by its poor water solubility. In this work smartPearls technology was used to increase the glabridins water solubility. smartPearls consist of silica particles with mesopores in which actives can be loaded. By this, actives are stabilized in amorphous state and simultaneously finely distributed in nm-range. Both amorphization and nanoization are well known approaches to increase saturation solubilities. In smartPearls these approaches are combined. In the first step, glabridin smartPearls formulation was developed, screening systematically the suitability of 4 different silicas varying in their pore sizes (3, 6, 10, 17 nm). Also, most suited filling level of glabridin was determined (25, 50, 80% referred to total pore volume of respective silica). Silica loading was performed by the immersion-evaporation method, resulting in pores filled with glabridin from bottom to top. By light microscopy, dynamic scanning calorimetry and X-ray diffraction the sample with 6 nm pore size and filling levels of 25% and 50% have been verified to be completely amorphous. Highest physical storage stability of 7 months up to now was obtained for the 25% filled sample. In the next step, concept of increased saturation solubility for smartPearls was proven. Dissolution profiles were recorded in situ for glabridin smartPearls and compared to glabridin raw drug powder. Both saturation solubility and dissolution velocity were remarkably improved. The water solubility for example increased by a factor of more than 4. This makes glabridin smartPearls promising for creating skin products with improved dermal bioavailability.
The incorporation of fluorescent nanoprobes into three dimensional (3D) matrixes is capable of enhancing the fluorescence properties of nanoprobes and greatly benefiting sensing application. In this ...work, N-acetyl-l-cysteine capped-copper nanoclusters (NAC-CuNCs) were incorporated into 3D mesoporous silica particles (M-SiO2) through electrostatic assembly. The assembly process takes only 2 min, and the fluorescence emission and quantum yield of NAC-CuNCs were significantly improved owing to the electrostatic confinement effect of M-SiO2. The prepared M-SiO2@NAC-CuNCs was further integrated with MnO2 nanosheets, a newly-emerged fluorescence nanoquencher with broad absorption spectrum. The emission intensity of M-SiO2@NAC-CuNCs was significantly decreased in the presence of MnO2 nanosheets by inner filter effect (IFE), and then recovered by ascorbic acid generated by the enzymolysis of l-ascorbic acid-2-phosphate (AAP) in the presence of acid phosphatase (ACP). On this basis, an enhanced emission platform was developed for “turn off-on” detection of ACP, a key indicator for diagnosis of prostate cancer. The detection limit for ACP activity was 0.47 U/L. Moreover, the approach was used to monitor ACP level in real serum samples with high accuracy, providing an attractive approach for clinical diagnosis of prostate cancer and other ACP-related diseases.
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•It is the first attempt to confine CuNCs in 3D M − SiO2 particles.•M − SiO2 can greatly improve the fluorescence performance of CuNCs through electrostatic confinement effect.•The preparation of M-SiO2@NAC-CuNCs composites can be completed within 2 min.•M-SiO2@NAC-CuNCs based “turn off-on” method for acid phosphatase activity detection is developed.
Folic acid (FA), a water-soluble vitamin (B9), is crucial for metabolic activities and regulatory processes of cells. Mammalian cells cannot synthesize any form of folate, thereby necessitating their ...exogenous supply. Further, FA is degraded by light, heat, oxidation, and external conditions. Therefore, the need for micro- and nano-encapsulation techniques for FA arises. The present work deals primarily with various encapsulation techniques for FA, including coacervation, electrospraying, electrospinning, nanoemulsions, biopolymer nanoparticles, nanohydrogels, and mesoporous silica particles from research studies, elaborately described with relevant justifications and other novel techniques. An overview of FA is provided and its structural aspects and factors affecting its degradation are discussed. The review also comprehensively discusses the controlled release mechanisms and factors affecting FA release from encapsulation systems. Pharmacokinetic studies conducted to assess the bioavailability of FA post oral administration are mentioned. The novel techniques with the highest encapsulation efficiency of FA were proliposomes, electrospinning, and double emulsification. Additionally, the highest FA serum concentration obtained in oral bioavailability studies was found in a novel desolvation process cum ultrafiltration encapsulation method using zein as the encapsulant. The positive impact of specific techniques and the future scope along with suggestions for FA encapsulation systems are examined.
The effect of the phosphoric acid addition on the nanostructures of the mesoporous silica (MPS) particles and the states of tris(8-hydroxyquinolinato)aluminum (Alq3) in the mesopores were ...investigated. It was found that the regularity of the mesopores of the MPS particles became irregular by the excessive addition of phosphoric acid. Furthermore, the phosphoric acid on the silica skeletons in the mesopores would strictly interact with the Alq3 molecules, so that the proportion of monomer components with less overlap among the π-π orbitals (i.e., δ-phase-like Alq3 molecules) increased with increasing the phosphoric acid, which was effectively monitored in the fluorescence spectra. It was suggested that the interactions between Alq3 and mesopores were formed not only by hydrogen bonds but also by electrostatic forces between P–O− and aluminum ion, and then the Alq3 molecules were planarly fixed on the surfaces, indicating the importance of the phosphoric acid addition for fixing the photofunctional species on the mesopores.
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•Phosphoric acid-containing mesoporous silica (PMPS) particles were synthesized.•Tris(8-hydroxyquinolinato)aluminum (Alq3) was adsorbed on the mesopores.•Characteristic nanostructures of the particles were analyzed and investigated.•Alq3 strongly interacted with the mesopores containing phosphoric acid.•The monomer component of Alq3 increased with increasing the phosphoric acid.
We report the engineering of poly(ethylene glycol) (PEG) hydrogel particles using a mesoporous silica (MS) templating method via tuning the PEG molecular weight, particle size, and the presence or ...absence of the template and investigate the cell association and biodistribution of these particles. An ex vivo assay based on human whole blood that is more sensitive and relevant than traditional cell-line based assays for predicting in vivo circulation behavior is introduced. The association of MS@PEG particles (template present) with granulocytes and monocytes is higher compared with PEG particles (template absent). Increasing the PEG molecular weight (from 10 to 40 kDa) or decreasing the PEG particle size (from 1400 to 150 nm) reduces phagocytic blood cell association of the PEG particles. Mice biodistribution studies show that the PEG particles exhibit extended circulation times (>12 h) compared with the MS@PEG particles and that the retention of smaller PEG particles (150 nm) in blood, when compared with larger PEG particles (>400 nm), is increased at least 4-fold at 12 h after injection. Our findings highlight the influence of unique aspects of polymer hydrogel particles on biological interactions. The reported PEG hydrogel particles represent a new class of polymer carriers with potential biomedical applications.
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