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17 pages, 2661 KiB

Open AccessArticle

Biomimetic Silica Particles with Self-Loading BMP-2 Knuckle Epitope Peptide and Its Delivery for Bone Regeneration

by Mi-Ran Ki, Thi Khoa My Nguyen, Tae-In Park, Hae-Min Park and Seung Pil Pack

Pharmaceutics 2023, 15(4), 1061; https://doi.org/10.3390/pharmaceutics15041061 - 25 Mar 2023

Cited by 8 | Viewed by 2712

Biomimetic silica deposition is an in-situ immobilization method for bioactive molecules under biocompatible conditions. The osteoinductive P4 peptide derived from the knuckle epitope of bone morphogenetic protein (BMP), which binds to BMP receptor-II (BMPRII), has been newly found to contain silica formation ability. [...] Read more.

Biomimetic silica deposition is an in-situ immobilization method for bioactive molecules under biocompatible conditions. The osteoinductive P4 peptide derived from the knuckle epitope of bone morphogenetic protein (BMP), which binds to BMP receptor-II (BMPRII), has been newly found to contain silica formation ability. We found that the two lysine residues at the N-terminus of P4 played a vital role in silica deposition. The P4 peptide co-precipitated with silica during P4-mediated silicification, yielding P4/silica hybrid particles (P4@Si) with a high loading efficiency of 87%. P4 was released from P4@Si at a constant rate for over 250 h, representing a zero-order kinetic model. In flow cytometric analysis, P4@Si showed a 1.5-fold increase in the delivery capacity to MC3T3 E1 cells than the free form of P4. Furthermore, P4 was found anchored to hydroxyapatite (HA) through a hexa-glutamate tag, followed by P4-mediated silicification, yielding P4@Si coated HA. This suggested a superior osteoinductive potential compared to silica or P4 alone coated HA in the in vitro study. In conclusion, the co-delivery of the osteoinductive P4 peptide and silica by P4-mediated silica deposition is an efficient method for capturing and delivering its molecules and inducing synergistic osteogenesis. Full article

(This article belongs to the Special Issue Functional Polymers in Drug Delivery)

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12 pages, 4396 KiB

Open AccessArticle

Cytotoxic Potential of Bio-Silica Conjugate with Different Sizes of Silver Nanoparticles for Cancer Cell Death

by Mohamed S. Hamdy, Serag Eldin I. Elbehairi, Ali A. Shati, Hisham S. M. Abd-Rabboh, Mohammad Y. Alfaifi, Khaled F. Fawy, Hala A. Ibrahium, Saad Alamri and Nasser S. Awwad

Materials 2022, 15(12), 4074; https://doi.org/10.3390/ma15124074 - 8 Jun 2022

Cited by 4 | Viewed by 1928

Abstract

Well-defined silver nanoparticles were doped into bio-based amorphous silica (Ag-b-SiO₂) with different silver contents (from 2 to 20 wt%) by a solvent-free procedure. The four as-synthetized samples were hydrogenated at 300 °C to ensure the formation of zero-valent Ag nanoparticles. The [...] Read more.

Well-defined silver nanoparticles were doped into bio-based amorphous silica (Ag-b-SiO₂) with different silver contents (from 2 to 20 wt%) by a solvent-free procedure. The four as-synthetized samples were hydrogenated at 300 °C to ensure the formation of zero-valent Ag nanoparticles. The prepared samples were characterized by X-ray powder diffraction (XRD), elemental analysis, N₂ sorption measurements, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM). The characterization data confirmed the formation of well-defined zero-valent silver nanoparticles in the range of 3–10 nm in the low-loading samples, while in high-loading samples, bulky particles of silver in the range of 200–500 nm were formed. The in vitro cytotoxic activities of the Ag-b-SiO₂ samples were tested against the tumor cell lines of breast (MCF-7), liver (HepG2), and colon (HCT 116) over a concentration range of 0.01 to 1000 g. The prepared samples exhibited a wide range of cytotoxic activities against cancer cells. An inverse relationship was observed between the silver nanoparticles’ size and the cytotoxic activity, while a direct relationship between the silver nanoparticles’ size and the apoptotic cell death was noticed. Full article

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13 pages, 5347 KiB

Open AccessArticle

Dispersion Tailoring and Four-Wave Mixing in Silica Microspheres with Germanosilicate Coating

by Maria P. Marisova, Alexey V. Andrianov, Gerd Leuchs and Elena A. Anashkina

Photonics 2021, 8(11), 473; https://doi.org/10.3390/photonics8110473 - 24 Oct 2021

Cited by 5 | Viewed by 2304

Abstract

Optical whispering gallery mode microresonators with controllable parameters in the telecommunication range are demanded for diverse applications. Controlling group velocity dispersion (GVD) in microresonators is an important problem, as near-zero GVD in a broad wavelength range could contribute to the development of new [...] Read more.

Optical whispering gallery mode microresonators with controllable parameters in the telecommunication range are demanded for diverse applications. Controlling group velocity dispersion (GVD) in microresonators is an important problem, as near-zero GVD in a broad wavelength range could contribute to the development of new microresonator-based light sources. We demonstrated theoretically near-zero dispersion tailoring in the SCL-band in combination with free-spectral range (FSR) optimization for FSR = 200 GHz and 300 GHz in silica glass microspheres with micron-scale germanosilicate coating. As an illustration of a possible application of such a GVD, we also performed a theoretical study of degenerate four-wave mixing (FWM) processes in the proposed microresonators for pumping in the SCL-band. We found that in some cases the generation of two or even three pairs of waves–satellites in a FWM process is possible in principle due to the specific GVD features. We also determined optimal microresonator configurations for achieving gradual change in the satellite frequency shift for the pump wavelengths in the SCL-, S-, CL-, C-, and L-bands. The maximum obtained FWM satellite tunability span was ~78 THz for a pump wavelength change of ~30 nm, which greatly exceeds the results for a regular silica microsphere without coating. Full article

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13 pages, 1042 KiB

Open AccessReview

Sustainability-Based Characteristics of Abrasives in Blasting Industry

by Iskandar Zulkarnain, Nor Adila Mohamad Kassim, M. I. Syakir, Azhar Abdul Rahman, Mohamad Shaiful Md Yusuff, Rosdin Mohd Yusop and Ng Oon Keat

Sustainability 2021, 13(15), 8130; https://doi.org/10.3390/su13158130 - 21 Jul 2021

Cited by 9 | Viewed by 6197

Abstract

The abrasive blasting industry is identified as the most unsafe operation in terms of potential exposure to airborne crystalline silica. This is due to the free silica content in the common abrasives that are used for blasting activities. This paper will identify a [...] Read more.

The abrasive blasting industry is identified as the most unsafe operation in terms of potential exposure to airborne crystalline silica. This is due to the free silica content in the common abrasives that are used for blasting activities. This paper will identify a sustainability-based or green blasting media to replace free silica content abrasives for blasting activities. The characteristics of sustainability-based abrasives are determined based on systematic review procedure. The combination keywords of “Abrasive blasting”, “Garnet’’, “Free Silica Media”, “Sustainable blasting”, “Eco-friendly blasting”, “Glass Bead blasting” and “Green blasting” were used to collect the existing studies on abrasive blasting operations. Six characteristics of green abrasives were identified: (1) zero content of free silica, (2) high efficiency and productivity, (3) low consumption media (4) low amount of waste generation and emission potentials (5) high recyclability and (6) environmentally friendly in line with sustainable development goals SDG3, SDG12, SDG13, SDG14 and SDG15. The application of green abrasives as substitution to free silica media is therefore important not only for safety and health reasons, but also for the environmental protection and sustainable business operations. Full article

(This article belongs to the Special Issue Plant-Based Resources as a Green Alternative for a Sustainable Future)

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15 pages, 3088 KiB

Open AccessArticle

The Effect of Polydimethylsiloxane-Ethylcellulose Coating Blends on the Surface Characterization and Drug Release of Ciprofloxacin-Loaded Mesoporous Silica

by Adrianna Skwira, Adrian Szewczyk and Magdalena Prokopowicz

Polymers 2019, 11(9), 1450; https://doi.org/10.3390/polym11091450 - 4 Sep 2019

Cited by 15 | Viewed by 4376

Abstract

In this study, we obtained novel solid films composed of ciprofloxacin-loaded mesoporous silica materials (CIP-loaded MCM-41) and polymer coating blends. Polymer coating blends were composed of ethylcellulose (EC) with various levels of polydimethylsiloxane (PDMS, 0, 1, 2% (v/v)). The [...] Read more.

In this study, we obtained novel solid films composed of ciprofloxacin-loaded mesoporous silica materials (CIP-loaded MCM-41) and polymer coating blends. Polymer coating blends were composed of ethylcellulose (EC) with various levels of polydimethylsiloxane (PDMS, 0, 1, 2% (v/v)). The solid films were prepared via the solvent-evaporation molding method and characterized by using scanning electron microscopy (SEM), optical profilometry, and wettability analyses. The solid-state of CIP present in the solid films was studied using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The release profiles of CIP were examined as a function of PDMS content in solid films. The surface morphology analysis of solid films indicated the progressive increase in surface heterogeneity and roughness with increasing PDMS content. The contact angle study confirmed the hydrophobicity of all solid films and significant impact of both PDMS and CIP-loaded MCM-41 on surface wettability. DSC and XRD analysis confirmed the presence of amorphous/semi-crystalline CIP in solid films. The Fickian diffusion-controlled drug release was observed for the CIP-loaded MCM-41 coated with PDMS-free polymer blend, whereas zero-order drug release was noticed for the CIP-loaded MCM-41 coated with polymer blends enriched with PDMS. Both the release rate and initial burst of CIP decreased with increasing PDMS content. Full article

(This article belongs to the Special Issue Functional Polymer Solutions and Gels–Physics and Novel Applications)

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8 pages, 2847 KiB

Open AccessArticle

Effect of Wet Expansion Behavior on Polyimide Membrane Diffractive Lens

by Guohan Gao, Danbo Mao, Bin Fan and Chunlin Guan

Coatings 2019, 9(9), 559; https://doi.org/10.3390/coatings9090559 - 2 Sep 2019

Cited by 12 | Viewed by 2640

Abstract

Optical polyimide (PI) membrane is a potential substrate to fabricate a diffractive primary lens in large aperture space-borne telescope. In this paper, we investigated the wet expansion behavior of PI via a strain gauge method and measured the coefficient of wet expansion (CWE) [...] Read more.

Optical polyimide (PI) membrane is a potential substrate to fabricate a diffractive primary lens in large aperture space-borne telescope. In this paper, we investigated the wet expansion behavior of PI via a strain gauge method and measured the coefficient of wet expansion (CWE) of PI membrane supported by different fixtures. The CWE of silica-fixed, ring-fixed, and free state PI membrane were near zero, 5 ppm/%, and 10 ppm/% respectively. It is found that Fresnel zone lens (FZL), based on PI membrane with lower CWE, achieve a better imaging quality with smaller wave-front errors. The underlying mechanisms and methods to improve imaging quality of ring-fixed FZL are discussed. This work provides direction in fabricating a flexible membrane diffractive lens with applicable imaging quality. Full article

(This article belongs to the Special Issue Design, Manufacturing and Measurement of Optical Film Coatings)

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12 pages, 2083 KiB

Open AccessArticle

Computing Free Energies of Hydroxylated Silica Nanoclusters: Forcefield versus Density Functional Calculations

by Antoni Macià Escatllar, Piero Ugliengo and Stefan T. Bromley

Inorganics 2017, 5(3), 41; https://doi.org/10.3390/inorganics5030041 - 29 Jun 2017

Cited by 3 | Viewed by 5038

Abstract

We assess the feasibility of efficiently calculating accurate thermodynamic properties of (SiO₂)_n·(H₂O)_m nanoclusters, using classical interatomic forcefields (FFs). Specifically, we use a recently parameterized FF for hydroxylated bulk silica systems (FFSiOH) to calculate zero-point energies and [...] Read more.

We assess the feasibility of efficiently calculating accurate thermodynamic properties of (SiO₂)_n·(H₂O)_m nanoclusters, using classical interatomic forcefields (FFs). Specifically, we use a recently parameterized FF for hydroxylated bulk silica systems (FFSiOH) to calculate zero-point energies and thermal contributions to vibrational internal energy and entropy, in order to estimate the free energy correction to the internal electronic energy of these nanoclusters. The performance of FFSiOH is then benchmarked against the results of corresponding calculations using density functional theory (DFT) calculations employing the B3LYP functional. Results are reported first for a set of (SiO₂)_n·(H₂O)_m clusters with n = 4, 8 and 16, each possessing three different degrees of hydroxylation (R = m/n): 0.0, 0.25 and 0.5. Secondly, we consider five distinct hydroxylated nanocluster isomers with the same (SiO₂)₁₆·(H₂O)₄ composition. Finally, the free energies for the progressive hydroxylation of three nanoclusters with R = 0–0.5 are also calculated. Our results demonstrate that, in all cases, the use of FFSiOH can provide estimates of thermodynamic properties with an accuracy close to that of DFT calculations, and at a fraction of the computational cost. Full article

(This article belongs to the Special Issue Inorganic Nanoclusters: Advances in Understanding Structure and Properties)

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30 pages, 6188 KiB

Open AccessFeature PaperArticle

Modeling Time-Dependent Behavior of Concrete Affected by Alkali Silica Reaction in Variable Environmental Conditions

by Mohammed Alnaggar, Giovanni Di Luzio and Gianluca Cusatis

Materials 2017, 10(5), 471; https://doi.org/10.3390/ma10050471 - 28 Apr 2017

Cited by 80 | Viewed by 8306

Abstract

Alkali Silica Reaction (ASR) is known to be a serious problem for concrete worldwide, especially in high humidity and high temperature regions. ASR is a slow process that develops over years to decades and it is influenced by changes in environmental and loading [...] Read more.

Alkali Silica Reaction (ASR) is known to be a serious problem for concrete worldwide, especially in high humidity and high temperature regions. ASR is a slow process that develops over years to decades and it is influenced by changes in environmental and loading conditions of the structure. The problem becomes even more complicated if one recognizes that other phenomena like creep and shrinkage are coupled with ASR. This results in synergistic mechanisms that can not be easily understood without a comprehensive computational model. In this paper, coupling between creep, shrinkage and ASR is modeled within the Lattice Discrete Particle Model (LDPM) framework. In order to achieve this, a multi-physics formulation is used to compute the evolution of temperature, humidity, cement hydration, and ASR in both space and time, which is then used within physics-based formulations of cracking, creep and shrinkage. The overall model is calibrated and validated on the basis of experimental data available in the literature. Results show that even during free expansions (zero macroscopic stress), a significant degree of coupling exists because ASR induced expansions are relaxed by meso-scale creep driven by self-equilibriated stresses at the meso-scale. This explains and highlights the importance of considering ASR and other time dependent aging and deterioration phenomena at an appropriate length scale in coupled modeling approaches. Full article

(This article belongs to the Special Issue Numerical Analysis of Concrete using Discrete Elements)

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