Investigation of bioactivity, biocompatibility and thermal behavior of sol-gel silica glass containing a high PEG percentage

A Comprehensive Review on the Thermal Stability Assessment of Polymers and Composites for Aeronautics and Space Applications

This review article provides an exhaustive survey on experimental investigations regarding the thermal stability assessment of polymers and polymer-based composites intended for applications in the aeronautical and space fields. This review aims to: (1) come up with a systematic and critical overview of the state-of-the-art knowledge and research on the thermal stability of various polymers and composites, such as polyimides, epoxy composites, and carbon-filled composites; (2) identify the key factors, mechanisms, methods, and challenges that affect the thermal stability of polymers and composites, such as the temperature, radiation, oxygen, and degradation; (3) highlight the current and potential applications, benefits, limitations, and opportunities of polymers and composites with high thermal stability, such as thermal control, structural reinforcement, protection, and energy conversion; (4) give a glimpse of future research directions by providing indications for improving the thermal stability of polymers and composites, such as novel materials, hybrid composites, smart materials, and advanced processing methods. In this context, thermal analysis plays a crucial role in the development of polyimide-based materials for the radiation shielding of space solar cells or spacecraft components. The main strategies that have been explored to improve the processability, optical transparency, and radiation resistance of polyimide-based materials without compromising their thermal stability are highlighted. The combination of different types of polyimides, such as linear and hyperbranched, as well as the incorporation of bulky pendant groups, are reported as routes for improving the mechanical behavior and optical transparency while retaining the thermal stability and radiation shielding properties. Furthermore, the thermal stability of polymer/carbon nanocomposites is discussed with particular reference to the role of the filler in radiation monitoring systems and electromagnetic interference shielding in the space environment. Finally, the thermal stability of epoxy-based composites and how it is influenced by the type and content of epoxy resin, curing agent, degree of cross-linking, and the addition of fillers or modifiers are critically reviewed. Some studies have reported that incorporating mesoporous silica micro-filler or microencapsulated phase change materials (MPCM) into epoxy resin can enhance its thermal stability and mechanical properties. The mesoporous silica composite exhibited the highest glass transition temperature and activation energy for thermal degradation among all the epoxy-silica nano/micro-composites. Indeed, an average activation energy value of 148.86 kJ/mol was recorded for the thermal degradation of unfilled epoxy resin. The maximum activation energy range was instead recorded for composites loaded with mesoporous microsilica. The EMC-5p50 sample showed the highest mean value of 217.6 kJ/mol. This remarkable enhancement was ascribed to the polymer invading the silica pores and forging formidable interfacial bonds.

Tailoring/Tuning Properties of Polyester Urea-Urethanes through Hybridization with Titania Obtained Using the Sol-Gel Process

Hybrid materials have been studied because in these materials the properties of organic components, such as elasticity and biodegradability, could be combined with the properties of inorganic components, such as good biological response, thereby transforming them into a single material with improved properties. In this work, Class I hybrid materials based on polyester-urea-urethanes and titania were obtained using the modified sol-gel method. This was corroborated using the FT-IR and Raman techniques which highlighted the formation of hydrogen bonds and the presence of Ti-OH groups in the hybrid materials. In addition, the mechanical and thermal properties and degradability were measured using techniques, such as Vickers hardness, TGA, DSC, and hydrolytic degradation; these properties could be tailored according to hybridization between both organic and inorganic components. The results show that Vickers hardness increased by 20% in hybrid materials as compared to polymers; also, the surface hydrophilicity increases in the hybrid materials, improving their cell viability. Furthermore, cytotoxicity in vitro test was carried out using osteoblast cells for intended biomedical applications and they showed non-cytotoxic behavior.

A novel thermosensitive persulfate controlled-release hydrogel based on agarose/silica composite for sustained nitrobenzene degradation from groundwater

The increasing risk of organic contamination of groundwater poses a serious threat to the environment and human health, causing an urgent need to develop long-lasting and adaptable remediation materials. Controlled-release materials (CRMs) are capable of encapsulating oxidants to achieve long-lasting release properties in aquifers and considered to be effective strategies in groundwater remediation. In this study, novel hydrogels (ASGs) with thermosensitive properties were prepared based on agarose and silica to achieve controlled persulfate (PS) release. By adjusting the composition ratio, the gelation time and internal pore structure of the hydrogels were regulated for groundwater application, which in turn affected the PS encapsulated amount and release properties. The hydrogels exhibited significant temperature responsiveness, with 6.8 times faster gelation rates and 2.8 times longer controlled release ability at 10 ℃ than at 30 ℃. The ASGs were further combined with zero-valent iron to achieve long-lasting degradation of the typical nitrobenzene compound 2,4-dinitrotoluene (2,4-DNT), and the degradation performance was maintained at 50 % within 14 PV, which was significantly improved compared with that of the PS/ZVI system. This study provided new concepts for the design of controlled-release materials and theoretical support for the remediation of organic contamination.

Biocompatible Silica-Polyethylene Glycol-Based Composites for Immobilization of Microbial Cells by Sol-Gel Synthesis

Biocatalysts based on the methylotrophic yeast Ogataea polymorpha VKM Y-2559 immobilized in polymer-based nanocomposites for the treatment of methanol-containing wastewater were developed. The organosilica composites with different matrix-to-filler ratios derived from TEOS/MTES in the presence of PEG (SP_EG-composite) and from silicon-polyethylene glycol (STP_EG-composite) differ in the structure of the silicate phase and its distribution in the composite matrix. Methods of fluorescent and scanning microscopy first confirmed the formation of an organosilica shell around living yeast cells during sol-gel bio-STP_EG-composite synthesis. Biosensors based on the yeast cells immobilized in STP_EG- and SP_EG-composites are characterized by effective operation: the coefficient of sensitivity is 0.85 ± 0.07 mgO₂ × min^-1 × mmol^-1 and 0.87 ± 0.05 mgO₂ × min^-1 × mmol^-1, and the long-term stability is 10 and 15 days, respectively. The encapsulated microbial cells are protected from UV radiation and the toxic action of heavy metal ions. Biofilters based on the developed biocatalysts are characterized by high effectiveness in the utilization of methanol-rich wastewater-their oxidative power reached 900 gO₂/(m³ × cycle), and their purification degree was up to 60%.

Poly (Methyl Methacrylate)-Containing Silver-Phosphate Glass Exhibits Potent Antimicrobial Activity without Deteriorating the Mechanical and Biological Properties of Dental Prostheses

Poly (methyl methacrylate) (PMMA) is a commonly used denture material with poor antimicrobial effects. This study investigated the antimicrobial effects of PMMA-containing silver-phosphate glass. We fabricated a novel material comprising PMMA-containing silver-phosphate glass. Then, microhardness, flexural strength, and gloss unit were analyzed. Antimicrobial activity against Streptococcus mutans and Candida albicans was investigated. Colony-forming units were counted, and antimicrobial rates were measured. Biocompatibility tests were performed using a colorimetric MTT assay for evaluating cell metabolic activity. The microhardness, flexural strength, and gloss unit of the experimental groups (with silver-phosphate glass) were not significantly different from those of the control group (no silver-phosphate glass) (P > 0.05), which showed clinically valid values. With increasing proportions of silver-phosphate glass, the antimicrobial activity against the two microorganisms increased (P < 0.05). Furthermore, S. mutans showed more than 50% antimicrobial activity in 4%, 6%, and 8% experimental groups, C. albicans showed more than 50% antimicrobial activity in 6% and 8% groups, and a statistically significant difference in antimicrobial activity was observed compared to the control (P < 0.05). The cell viability of the experimental groups was not significantly different from that of the control group (P > 0.05). Both control and experimental groups showed approximately 100% cell viability. These results suggest that silver-phosphate glass is a promising antimicrobial material in dentistry.

Surface Interactions between Ketoprofen and Silica-Based Biomaterials as Drug Delivery System Synthesized via Sol–Gel: A Molecular Dynamics Study

Biomaterial-based drug delivery systems for a controlled drug release are drawing increasing attention thanks to their possible pharmaceutical and biomedical applications. It is important to control the local administration of drugs, especially when the drug exhibits problems diffusing across biological barriers. Thus, in an appropriate concentration, it would be released in situ, reducing side effects due to interactions with the biological environment after implantation. A theoretical study based on Molecular Mechanics and Molecular Dynamics methods is performed to investigate possible surface interactions between the amorphous SiO₂ surface and the ketoprofen molecules, an anti-inflammatory drug, considering the role of drug concentration. These theoretical results are compared with experimental data obtained by analyzing, through Fourier transform infrared spectroscopy (FT-IR), the interaction between the SiO₂ amorphous surface and two percentages of the ketoprofen drug entrapped in a silica matrix obtained via the sol–gel method and dried materials. The loaded drug in these amorphous bioactive material forms hydrogen bonds with the silica surface, as found in this theoretical study. The surface interactions are essential to have a new generation of biomaterials not only important for biocompatibility, with specific structural and functional properties, but also able to incorporate anti-inflammatory agents for release into the human body.

Antibacterial and Chemical Characterization of Silica-Quercetin-PEG Hybrid Materials Synthesized by Sol-Gel Route

This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus).

Cellulose-Chitosan-Nanohydroxyapatite Hybrid Composites by One-Pot Synthesis for Biomedical Applications

The development of organic–inorganic hybrid materials deserves special interest for bone tissue engineering applications, where materials must have properties that induce the survival and activation of cells derived from the mesenchyme. In this work, four bio-nanocomposites based on cellulose and variable content of chitosan, from 15 to 50 w% based on cellulose, with nanohydroxyapatite and β-Glycerophosphate as cross-linking agent were synthesized by simplified and low-energy-demanding solvent exchange method to determine the best ratio of chitosan to cellulose matrix. This study analyzes the metabolic activity and survival of human dermal fibroblast cells cultivated in four bio-nanocomposites based on cellulose and the variable content of chitosan. The biocompatibility was tested by the in vitro cytotoxicity assays Live/Dead and PrestoBlue. In addition, the composites were characterized by FTIR, XRD and SEM. The results have shown that the vibration bands of β-Glycerophosphate have prevailed over the other components bands, while new diffraction planes have emerged from the interaction between the cross-linking agent and the biopolymers. The bio-nanocomposite micrographs have shown no surface porosity as purposely designed. On the other hand, cell death and detachment were observed when the composites of 1 and 0.1 w/v% were used. However, the composite containing 10 w% chitosan, against the sum of cellulose and β-Glycerophosphate, has shown less cell death and detachment when used at 0.01 w/v%, making it suitable for more in vitro studies in bone tissue engineering, as a promising economical biomaterial.

Synthesis, Structural, Morphological and Thermal Characterization of Five Different Silica-Polyethylene Glycol-Chlorogenic Acid Hybrid Materials

The present study investigated the structure, morphology, thermal behavior, and bacterial growth analysis of novel three-component hybrid materials synthesized by the sol-gel method. The inorganic silica matrix was weakly bonded to the network of two organic components: a well-known polymer such as polyethylene glycol (PEG, average molar mass of about 4000 g/mol), and an antioxidant constituted by chlorogenic acid (CGA). In particular, a first series was made by a 50 wt% PEG-based (CGA-free) silica hybrid along with two 50 wt% PEG-based hybrids containing 10 and 20 wt% of CGA (denoted as SP50, SP50C10 and SP50C20, respectively). A second series contained a fixed amount of CGA (20 wt%) in silica-based hybrids: one was the PEG-free material (SC20) and the other two contained 12 and 50 wt% of PEG, respectively (SP12C20 and SP50C20, respectively), being the latter already included in the first series. The X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images of freshly prepared materials confirmed that all the materials were amorphous and homogeneous regardless of the content of PEG or CGA. The thermogravimetric (TG) analysis revealed a higher water content was adsorbed into the two component hybrids (SP50 and SC20) because of the availability of a larger number of H-bonds to be formed with water with respect to those of silica/PEG/CGA (SPC), where silica matrix was involved in these bonds with both organic components. Conversely, the PEG-rich materials (SP50C10 and SP50C20, both with 50 wt% of the polymer) retained a lower content of water. Decomposition of PEG and CGA occurred in almost the same temperature interval regardless of the content of each organic component. The antibacterial properties of the SiO₂/PEG/CGA hybrid materials were studied in pellets using either Escherichia coli and Enterococcus faecalis, respectively. Excellent antibacterial activity was found against both bacteria regardless of the amount of polymer in the hybrids.

Characterization of Hybrid Materials Prepared by Sol-Gel Method for Biomedical Implementations. A Critical Review

The interaction between tissues and biomaterials (BM) has the purpose of improving and replacing anatomical parts of the human body, avoiding the occurrence of adverse reactions in the host organism. Unfortunately, the early failure of implants cannot be currently avoided, since neither a good mixture of mechanical and chemical characteristics of materials nor their biocompatibility has been yet achieved. Bioactive glasses are recognized to be a fine class of bioactive substances for good repair and replacement. BM interact with living bones through the formation of a hydroxyapatite surface layer that is analogous to bones. Bioglasses' composition noticeably affects their biological properties, as does the synthesis method, with the best one being the versatile sol-gel technique, which includes the change of scheme from a 'sol' fluid into a 'gel'. This process is widely used to prepare many materials for biomedical implants (e.g., hip and knee prostheses, heart valves, and ceramic, glassy and hybrid materials to serve as carriers for drug release). Nanoparticles prepared by the sol-gel method are interesting systems for biomedical implementations, and particularly useful for cancer therapy. This review provides many examples concerning the synthesis and characterization of the above-mentioned materials either taken from literature and from recently prepared zirconia/polyethylene glycol (PEG) hybrids, and the corresponding results are extensively discussed.

Sol⁻Gel Synthesis of Silica-Based Materials with Different Percentages of PEG or PCL and High Chlorogenic Acid Content

Implanted biomedical devices can induce adverse responses in the human body, which can cause failure of the implant-referred to as implant failure. Early implant failure is induced numerous factors, most importantly, infection and inflammation. Natural products are, today, one of the main sources of new drug molecules due to the development of pathogenic bacterial strains that possess resistance to more antibiotics used currently in various diseases. The aim of this work is the sol⁻gel synthesis of antibacterial biomedical implants. In the silica matrix, different percentages (6, 12, 24, 50 wt %) of polyethylene glycol (PEG) or poly(ε-caprolactone) (PCL) were embedded. Subsequently, the ethanol solutions with high amounts of chlorogenic acid (CGA 20 wt %) were slowly added to SiO₂/PEG and SiO₂/PCL sol. The interactions among different organic and inorganic phases in the hybrid materials was studied by Fourier transform infrared (FTIR) spectroscopy. Furthermore, the materials were soaked in simulated body fluid (SBF) for 21 days and the formation of a hydroxyapatite layer on their surface was evaluated by FTIR and XRD analysis. Finally, Escherichia coli and Pseudomonas aeruginosa were incubated with several hybrids, and the diameter of zone of inhibition was observed to assessment the potential antibacterial properties of the hybrids.

Influence of the Heat Treatment on the Particles Size and on the Crystalline Phase of TiO₂ Synthesized by the Sol-Gel Method

Titanium biomaterials’ response has been recognized to be affected by particles size, crystal structure, and surface properties. Chemical and structural properties of these nanoparticle materials are important, but their size is the key aspect. The aim of this study is the synthesis of TiO₂ nanoparticles by the sol-gel method, which is an ideal technique to prepare nanomaterials at low temperature. The heat treatment can affect the structure of the final product and consequently its biological properties. For this reason, the chemical structure of the TiO₂ nanoparticles synthesized was investigated after each heat treatment, in order to evaluate the presence of different phases formed among the nanoparticles. FTIR spectroscopy and XRD have been used to evaluate the different structures. The results of these analyses suggest that an increase of the calcination temperature induces the formation of mixed-crystalline-phases with different content of anatase and rutile phases. The results obtained by SEM measurements suggest that an increase in the particles size accompanied by a noticeable aggregation of TiO₂ nanoparticles is due to high temperatures achieved during the thermal treatments and confirmed the presence of different content of the two crystalline phases of titanium dioxide.

Drug Release of Hybrid Materials Containing Fe(II)Citrate Synthesized by Sol-Gel Technique

The use of oral iron integration is commonly recommended for the treatment of iron deficiency, nevertheless the diagnosis and treatment of this disease could clearly be improved. The aim of this work was the synthesis of therapeutic systems, iron (II) based, by sol-gel method. In an SiO₂ matrix, we embedded different weight percentages of polyethylene glycol (PEG6, 12, 24 wt%) and ferrous citrate (Fe(II)C5, 10, 15 wt%) for drug delivery applications. Fourier Transform Infrared (FTIR) spectroscopy was used to study the interactions among different components in the hybrid materials. Release kinetics in a simulated body fluid (SBF) were investigated and the amount of Fe2+ released was detected by Ultraviolet⁻Visible spectroscopy (UV-VIS) after reaction with ortho-phenantroline. Furthermore, the biological characterization was carried out. The bioactivity of the synthesized hybrid materials was evaluated by the formation of a layer of hydroxyapatite on the surface of samples soaked in SBF using FTIR spectroscopy. Finally, also, the potential antibacterial properties of the different materials against two different bacteria, E. coli and P. aeruginosa, were investigated.

Magnetic bioinspired micro/nanostructured composite scaffold for bone regeneration

Magnetic-responsive materials are promising for applications in various biomedical fields. Especially, superparamagnetic nanoparticles are widely used in magnetic system for bone tissue engineering owing to superior biocompatibility and long term stability. Based on the idea of in situ bionics, we successfully incorporate the nano-hydroxyapatite (nHAP) and Fe₃O₄ nanoparticles which were prepared by in situ crystallization and freeze-drying technique into the chitosan/collagen (CS/Col) organic matrix to achieve the uniform dispersion of inorganic substrate with nanometer-scale. The in vitro results of the physicochemical and biocompatibility tests showed that CS/Col/Fe₃O₄/nHAP magnetic scaffold possessed superior structural and mechanical performance for cell adhesion and proliferation, as well as the osteogenic differentiation. Mineralization experiments showed better bioactive and good ability of in situ biomimetic mineralization. Moreover, from the in vivo model of SD rats' skull defects proved that the CS/Col/Fe₃O₄/nHAP hybrid scaffold had a better tissue compatibility and higher bone regeneration ability when implanted into the skull defects comparing to control group. Herein, the magnetic hybrid micro/nanostructured scaffold showed a potential application for bone defect repair.

Sol-gel bioglasses in dental and periodontal regeneration: A systematic review

Due to their osteoconductive and osteoinductive abilities, bioglasses (BGs) have attracted attention in tissue engineering, especially for mineralized tissue. The aim of this study is to review the current state of the art on the effects of BGs produced by sol-gel on cells for dental and periodontal regeneration. The study also discusses associated antibacterial properties. The research was performed by considering the Preferred Reporting Items for Systematic Reviews and the Meta-Analyses (PRISMA) statement. The research ranged 5 years' window time (from January, 01, 2012, to August, 31, 2017) and the relevant studies were identified based on the inclusion/exclusion criteria. A total of 45 articles were selected from 244 initial returns, plus seven further articles coming from other sources were selected for the same purpose. From this systematic study, it is revealed that only 13 of the 52 articles have proved both the ability of BGs to differentiate dental cells at genetic level and their ability of triggering cell-mediated mineralization, but only six of them showed, along with cells, the antibacterial properties of the glasses. This review shows that sol-gel BGs are not toxic, can sustain cell proliferation and differentiation at a genetic level, and can keep the bacterial population under control. Moreover, a standard methodology and an ideal material are suggested. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1210-1227, 2019.

A canine in vitro model for evaluation of marrow-derived mesenchymal stromal cell-based bone scaffolds

Tissue engineered bone grafts based on bone marrow mesenchymal stromal cells (MSCs) are being actively developed for craniomaxillofacial (CMF) applications. As for all tissue engineered implants, the bone-regenerating capacity of these MSC-based grafts must first be evaluated in animal models prior to human trials. Canine models have traditionally resulted in improved clinical translation of CMF grafts relative to other animal models. However, the utility of canine CMF models for evaluating MSC-based bone grafts rests on canine MSCs (cMSCs) responding in a similar manner to scaffold-based stimuli as human MSCs (hMSCs). Herein, cMSC and hMSC responses to polyethylene glycol (PEG)-based scaffolds were therefore compared in the presence or absence of osteoinductive polydimethylsiloxane (PDMS). Notably, the conjugation of PDMS to PEG-based constructs resulted in increases in both cMSC and hMSC osteopontin and calcium deposition. Based on these results, cMSCs were further used to assess the efficacy of tethered bone morphogenic protein 2 (BMP2) in enhancing PEG-PDMS scaffold osteoinductivity. Addition of low doses of tethered BMP2 (100 ng/mL) to PEG-PDMS systems increased cMSC expression of osterix and osteopontin compared to both PEG-PDMS and PEG-BMP2 controls. Furthermore, these increases were comparable to effects seen with up to five-times higher BMP2 doses noted in literature. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2382-2393, 2018.

Sol-Gel Synthesis, Spectroscopic and Thermal Behavior Study of SiO₂/PEG Composites Containing Different Amount of Chlorogenic Acid

In this work, new phenol-based materials have been synthesized by the sol-gel method, in which different amounts of the phenolic antioxidant chlorogenic acid (CGA) (from 5 wt % to 20 wt %) were embedded in two different silica matrices: pure silica and silica-based hybrids materials, containing 50 wt % of polyethylene glycol (PEG). The incorporation of CGA in different sol-gel matrices might protect them from degradation, which could cause the loss of their properties. The two series of materials were chemically characterized by Fourier transform infrared (FTIR) spectroscopy. In addition, the thermal behavior of both series of materials containing CGA was studied by thermogravimetry under both air and inert N₂ flowing gas atmosphere. The bioactivity was evaluated by soaking the synthesized hybrids in a simulated body fluid, showing that the bioactivity of the silica matrix is not modified by the presence of PEG and CGA.

Thermal Behavior and Structural Study of SiO₂/Poly(ε-caprolactone) Hybrids Synthesized via Sol-Gel Method

SiO₂-based organic-inorganic hybrids (OIHs) are versatile materials whose properties may change significantly because of their thermal treatment. In fact, after their preparation at low temperature by the sol-gel method, they still have reactive silanol groups due to incomplete condensation reactions that can be removed by accelerating these processes upon heating them in controlled experimental conditions. In this study, the thermal behavior of pure SiO₂ and four SiO₂-based OIHs containing increasing amount (6, 12, 24 and 50 wt %) of poly(ε-caprolactone) (PCL) has been studied by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC). The FTIR analysis of the gas mixture evolved at defined temperatures from the samples submitted to the TG experiments identified the mechanisms of thermally activated processes occurring upon heating. In particular, all samples already release ethanol at low temperature. Moreover, thermal degradation of PCL takes place in the richest-PCL sample, leading to 5-hexenoic acid, H₂O, CO₂, CO and ε-caprolactone. After the samples' treatment at 450, 600 and 1000 °C, the X-ray diffraction (XRD) spectra revealed that they were still amorphous, while the presence of cristobalite is found in the richest-PCL material.

Synthesis of Bioactive Chlorogenic Acid-Silica Hybrid Materials via the Sol-Gel Route and Evaluation of Their Biocompatibility

Natural phenol compounds are gaining a great deal of attention because of their potential use as prophylactic and therapeutic agents in many diseases, as well as in applied science for their preventing role in oxidation deterioration. With the aim to synthetize new phenol-based materials, the sol-gel method was used to embed different content of the phenolic antioxidant chlorogenic acid (CGA) within silica matrices to obtain organic-inorganic hybrid materials. Fourier transform infrared (FTIR) measurements were used to characterize the prepared materials. The new materials were screened for their bioactivity and antioxidant potential. To this latter purpose, direct DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid) methods were applied: radical scavenging capability appeared strongly dependent on the phenol amount in investigated hybrids, and became pronounced, mainly toward the ABTS radical cation, when materials with CGA content equal to 15 wt% and 20 wt% were analyzed. The in vitro biocompatibility of the synthetized materials was estimated by using the MTT assay towards fibroblast NIH 3T3 cells, human keratinocyte HaCaT cells, and the neuroblastoma SH-SY5Y cell line. As cell viability and morphology of tested cell lines seemed to be unaffected by new materials, the attenuated total reflectance (ATR)-FTIR method was applied to deeply measure the effects of the hybrids in the three different cell lines.

Novel non-cytotoxic, bioactive and biodegradable hybrid materials based on polyurethanes/TiO2 for biomedical applications

Titanium compounds have demonstrated great interfacial properties with biological tissues whereas a wide variety of polyurethanes have also been successfully probed in medical applications. However, studies about hybrids based on polyurethanes/TiO₂ for medical applications are scarce. The aim of this work is to design novel biodegradable hybrid materials based on polyurethanes/TiO₂ (80% organic-20% inorganic) and to perform a preliminary study of the potential applications in bone regeneration. The hybrids have been prepared by a sol-gel reaction using titanium isopropoxide as precursor of the inorganic component and polyurethane as the organic one. A series of polyurethanes has been prepared using different polyesters glycol succinate as soft segment, and 1,6-diisocyanatohexane (HDI) and butanediol (BD) as linear hard segment. The spectroscopy techniques used allow to confirm the formation of the required polyurethanes by the identification of bands related to carboxylic groups (COOH), and the amine groups (NH), and also the TiOH bonds and the bonds related to the interconnected network between the inorganic and the organic components from hybrids. The results from SEM/EDS show a homogeneous distribution of the inorganic component into the organic matrix. The nontoxic character of the hybrid (H400) was probed using MG-63 cell line with over 90% of cell viability. Finally, the formation of a hydroxyapatite layer in the material surface after 21days of soaking in SBF shows the bioactive character.

Characterization and Cytotoxicity Analysis of a Ciprofloxacin Loaded Chitosan/Bioglass Scaffold on Cultured Human Periodontal Ligament Stem Cells: a Preliminary Report

AIM:

The aim of this study was to analyze the cytotoxicity of ciprofloxacin (CIP) loaded on chitosan bioactive glass scaffold on human periodontal ligament stem cells (PLSCs) in vitro.

MATERIALS AND METHODS:

PLSCs obtained from human third molars, cultures treated with medium containing 15 x 15 mm chitosan/bioactive glass scaffolds without/with different concentration 0, 5, 10, and 20 % of CIP. A total of 15 x 10^3 cells were plated in 6 well plates. The attached cells of each group were harvested from the plates after 1, 4 and 8 days of culture to detect the viability of cells. The cell number was determined using a hemocytometer and the trypan blue dye-exclusion assay. Data was analyzed using normality using Shapiro-Wilk test. Comparisons between groups were made using One-way ANOVA complemented by Tukey’s test.

RESULTS:

When comparing the proliferation rate of cells in the four groups, no statistically significant difference was found (P = 0.633). With regards to cell viability, no statistical difference was found between the 0, 5, and 10 % CIP concentrations, while the 20 % CIP concentration demonstrated the least viability with a high statistically significant difference (P = 0.003).

CONCLUSION:

Twenty percentages CIP demonstrated the least proliferation rate and viability.