scholarly journals Chitosan-GPTMS-Silica Hybrid Mesoporous Aerogels for Bone Tissue Engineering

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2723
Author(s):  
María V. Reyes-Peces ◽  
A. Pérez-Moreno ◽  
Deseada María de-los-Santos ◽  
María del Mar Mesa-Díaz ◽  
Gonzalo Pinaglia-Tobaruela ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Sol Gel ◽  
Polymer Networks ◽  
Supercritical Drying ◽  
Hybrid Structure ◽  
Stress Fibers ◽  
Molar Ratio ◽  
Surface Areas ◽  
Silica Hybrid

This study introduces a new synthesis route for obtaining homogeneous chitosan (CS)-silica hybrid aerogels with CS contents up to 10 wt%, using 3-glycidoxypropyl trimethoxysilane (GPTMS) as coupling agent, for tissue engineering applications. Aerogels were obtained using the sol-gel process followed by CO2 supercritical drying, resulting in samples with bulk densities ranging from 0.17 g/cm3 to 0.38 g/cm3. The textural analysis by N2-physisorption revealed an interconnected mesopore network with decreasing specific surface areas (1230–700 m2/g) and pore sizes (11.1–8.7 nm) by increasing GPTMS content (2–4 molar ratio GPTMS:CS monomer). In addition, samples exhibited extremely fast swelling by spontaneous capillary imbibition in PBS solution, presenting swelling capacities from 1.75 to 3.75. The formation of a covalent crosslinked hybrid structure was suggested by FTIR and confirmed by an increase of four hundred fold or more in the compressive strength up to 96 MPa. Instead, samples synthesized without GPTMS fractured at only 0.10–0.26 MPa, revealing a week structure consisted in interpenetrated polymer networks. The aerogels presented bioactivity in simulated body fluid (SBF), as confirmed by the in vitro formation of hydroxyapatite (HAp) layer with crystal size of approximately 2 µm size in diameter. In vitro studies revealed also non cytotoxic effect on HOB® osteoblasts and also a mechanosensitive response. Additionally, control cells grown on glass developed scarce or no stress fibers, while cells grown on hybrid samples showed a significant (p < 0.05) increase in well-developed stress fibers and mature focal adhesion complexes.

Fabrication of Carbon Aerogels

2006 ◽  
Vol 11-12 ◽  
pp. 19-22 ◽  
Author(s):  
Y.N. Feng ◽  
Lei Miao ◽  
Yong Ge Cao ◽  
T. Nishi ◽  
Sakae Tanemura ◽  
...  
Keyword(s):  
Pore Size ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Limited Range ◽  
Molar Ratio ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Catalyst Content ◽  
Fabrication Parameters ◽  
Pyrolysis Processes

RF (Resorcinol-Formaldehyde) aerogels and carbon aerogels were prepared through the sol-gel method following the routes of polymerization, gelation, supercritical drying and pyrolysis processes. The influence of fabrication parameters on the textural structure of the samples, e.g., specific surface area, pore size, and pore size distribution, etc., were systematically investigated. With a decrease in the R/F molar ratio, or an increase in the catalyst content within a limited range, the porosity of the nanostructure materials increases. The optimal temperature of pyrolysis for RF aerogel was investigated by TGA (Thermogravimetric Analysis).

scholarly journals Cuttlefish Bone-Derived Biphasic Calcium Phosphate Scaffolds Coated with Sol-Gel Derived Bioactive Glass

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2711
Author(s):  
Ana S. Neto ◽  
Daniela Brazete ◽  
José M.F. Ferreira
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Calcium Phosphates ◽  
Sol Gel ◽  
Biological Properties ◽  
X Ray Diffraction ◽  
Bioactive Glasses ◽  
Hydrothermal Transformation

The combination of calcium phosphates with bioactive glasses (BG) has received an increased interest in the field of bone tissue engineering. In the present work, biphasic calcium phosphates (BCP) obtained by hydrothermal transformation of cuttlefish bone (CB) were coated with a Sr-, Mg- and Zn-doped sol-gel derived BG. The scaffolds were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The initial CB structure was maintained after hydrothermal transformation (HT) and the scaffold functionalization did not jeopardize the internal structure. The results of the in-vitro bioactivity after immersing the BG coated scaffolds in simulated body fluid (SBF) for 15 days showed the formation of apatite on the surface of the scaffolds. Overall, the functionalized CB derived BCP scaffolds revealed promising properties, but further assessment of the in-vitro biological properties is needed before being considered for their use in bone tissue engineering applications.

Synthesis of Monolithic Macroporous Carbon Xerogels from Phenol, m-Cresol, Furfural and Phosphoric Acid by Sol-Gel Approach

2013 ◽  
Vol 750-752 ◽  
pp. 1804-1811
Author(s):  
Rui Zhang ◽  
Zi Jun Hu ◽  
Shuang Ling Jin ◽  
Xia Shao ◽  
Ming Lin Jin
Keyword(s):  
Phosphoric Acid ◽  
Ambient Pressure ◽  
Sol Gel ◽  
Nitrogen Atmosphere ◽  
Molar Ratio ◽  
Surface Areas ◽  
Carbon Xerogels ◽  
Porous Properties ◽  
Macroporous Carbon

Mixtures of phenol and m-cresol in 1-propanol were first reacted with phosphoric acid and then with furfural to form gels, which were dried under ambient pressure and pyrolyzed under nitrogen atmosphere to form monolithic macroporous carbon xerogels. The molar ratio of m-cresol to phenol (m-C/P), phenol and m-cresol to furfural ((m-C+P)/F), phenol and m-cresol to phosphoric acid ((m-C+P)/H3PO4) was fixed at 1:5, 1:2 and 4.0 respectively while the m-C+P+F in 1-propanol was changed from 18 to 30 g/100ml to investigate the effect of the m-C+P+F concentrations on the porous properties of the monolithic carbon xerogels. It is found that the surface areas of the monolithic carbon xerogels are mainly contributed by micropores and their mesopore volumes are negligible. The monolithic carbon xerogels are rich in macropores whose sizes decrease from 4 to 0.22μm with increasing m-C+P+F concentrations. Moreover, the yields of the monolithic carbon xerogels are around 60%, which is higher than previous ones without phosphoric acid.

Synthesis of Biodegradable Polyester by Polycondensation with Tunable Properties

2015 ◽  
Vol 1119 ◽  
pp. 418-422
Author(s):  
Lee Xiau Yeen ◽  
Mat Uzir Wahit
Keyword(s):  
Drug Delivery ◽  
Tissue Engineering ◽  
Material Properties ◽  
Drug Delivery Systems ◽  
Molar Ratio ◽  
Cross Link ◽  
In Vitro Degradation ◽  
Broad Application ◽  
Dodecanedioic Acid

A biodegradable cross-linked polyester, poly (1, 8-octanediol-glycerol-dodecanedioate) (POGDA) was prepared from 1, 8-octanediol (Oct), glycerol (Gly) and dodecanedioic acid (DA) without any catalyst. One of the factors, molar ratio of monomers greatly affects the material properties of POGDA and the effect was evaluated. Result showed that the glycerol acts as cross-link agent. When the molar ratio of glycerol increased, the gel content of POGDA became higher. POGDA has a range of glass transition temperature (Tg) with different monomers’ molar ratio. Exist of melting point (Tm) indicated the crystallline region in the polymer. POGDA with low molar ratio of glycerol has high Tm due to the bigger region of crystal. In vitro degradation was performed to investigate the biodegradation behaviour of POGDA. The polymer with tunable material properties by tailoring monomers’ molar ratio is expected to have broad application in medical fields such as drug delivery systems and tissue engineering.

scholarly journals Comparison of the Effect of Sol-Gel and Coprecipitation Routes on the Properties and Behavior of Nanocomposite Chitosan-Bioactive Glass Membranes for Bone Tissue Engineering

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Elke M. F. Lemos ◽  
Sandhra M. Carvalho ◽  
Patrícia S. O. Patrício ◽  
Claudio L. Donnici ◽  
Marivalda M. Pereira
Keyword(s):  
Tissue Engineering ◽  
Cell Viability ◽  
Bioactive Glass ◽  
Bone Regeneration ◽  
Sol Gel ◽  
Composite Films ◽  
Maximum Tensile Stress ◽  
Control Group ◽  
Nanoparticle Dispersion

Recent studies in tissue engineering have highlighted the importance of the development of composite materials based on biodegradable polymers containing bioactive glasses, in particular, composites for high load support and excellent cell viability for potential application in bone regeneration. In this work, hybrid composite films were obtained by combining chitosan with bioactive glass in solution form and in nanoparticle dispersion form obtained by the two different synthesis routes: the sol-gel method and coprecipitation. The bioactive glass served both as a mechanical reinforcing agent and as a triggering agent with high bioactivity. The results ofin vitroassays with simulated body fluid demonstrated the formation of a significant layer of fibrils on the surface of the film, with a typical morphology of carbonated hydroxyapatite, reflecting induction of a favorable bioactivity. Maximum tensile stress increased from 42 to 80 MPa to the sample with 5% wt bioactive glass. In addition, samples containing 5% and 10% wt bioactive glass showed a significant increase in cell viability, 18 and 30% increase compared to the control group. The samples showed significant response, indicating that they could be a potential material for use in bone regeneration through tissue engineering.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2286-2289
Author(s):  
Fei He ◽  
Xiao Dong He ◽  
Yao Li
Keyword(s):  
Structural Change ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Molar Ratio

Low-density xSiO2-(1-x)Al2O3 xerogels with x=0.9, 0.8, 0.7, 0.6 (mole fractions) were prepared by sol-gel and non-supercritical drying. Silica alkogels, which were the framework of binary composite materials, formed from tetraethyl orthosilicate (TEOS) by hydrolytic condensation with a molar ratio of TEOS: H2O: alcohol: hydrochloric acid: ammonia =1: 4: 10: 7.5×10-4: 0.0375. Aluminum hydroxide derived from Al(NO3)3·9H2O and NH4OH acting in the alcohol solution under the condition of catalyst. After filtrating and washing, the precipitation was mixed into silica sols to form SiO2-Al2O3 mixed oxide gels with different silicon and aluminum molar ratio. The structural change and crystallization of the binary xerogels were investigated after heat treatment at 600 for 2 h by the means of X-ray diffraction. Nitrogen adsorption experiment was performed to estimate specific surface area, porous volume and pore size distribution. The structural change of xerogels was observed by FT-IR spectroscopy. The resulting mixed xerogels possess of mesoporous structure which is characteristic of cylindrical pores, high specific surface area of 596-863 m2/g and a relatively narrow pore distribution of 2.8-30 nm. Al2O3 is introduced into the SiO2 phase and some of Al-O-Si bonds form.

scholarly journals Hydroxyl Groups Induce Bioactivity in Silica/Chitosan Aerogels Designed for Bone Tissue Engineering. In Vitro Model for the Assessment of Osteoblasts Behavior

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2802
Author(s):  
Antonio Perez-Moreno ◽  
María de las Virtudes Reyes-Peces ◽  
Deseada María de los Santos ◽  
Gonzalo Pinaglia-Tobaruela ◽  
Emilio de la Orden ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Crystal Nucleation ◽  
Elastic Behavior ◽  
Molar Ratio ◽  
Apatite Crystal ◽  
Hydroxyl Groups ◽  
Oh Groups ◽  
Composite Aerogels ◽  
Hybrid Aerogels

Silica (SiO2)/chitosan (CS) composite aerogels are bioactive when they are submerged in simulated body fluid (SBF), causing the formation of bone-like hydroxyapatite (HAp) layer. Silica-based hybrid aerogels improve the elastic behavior, and the combined CS modifies the network entanglement as a crosslinking biopolymer. Tetraethoxysilane (TEOS)/CS is used as network precursors by employing a sol-gel method assisted with high power ultrasound (600 W). Upon gelation and aging, gels are dried in supercritical CO2 to obtain monoliths. Thermograms provide information about the condensation of the remaining hydroxyl groups (400–700 °C). This step permits the evaluation of the hydroxyl group’s content of 2 to 5 OH nm−2. The formed Si-OH groups act as the inductor of apatite crystal nucleation in SBF. The N2 physisorption isotherms show a hysteresis loop of type H3, characteristic to good interconnected porosity, which facilitates both the bioactivity and the adhesion of osteoblasts cells. After two weeks of immersion in SBF, a layer of HAp microcrystals develops on the surface with a stoichiometric Ca/P molar ratio of 1.67 with spherulite morphology and uniform sizes of 6 μm. This fact asserts the bioactive behavior of these hybrid aerogels. Osteoblasts are cultured on the selected samples and immunolabeled for cytoskeletal and focal adhesion expression related to scaffold nanostructure and composition. The initial osteoconductive response observes points to a great potential of tissue engineering for the designed composite aerogels.

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