Morphological modifications and surface amorphization in ZnO sonochemically treated nanoparticles

The Local Release of Teriparatide Incorporated in 45S5 Bioglass Promotes a Beneficial Effect on Osteogenic Cells and Bone Repair in Calvarial Defects in Ovariectomized Rats

With the increase in the population's life expectancy, there has also been an increase in the rate of osteoporosis, which has expanded the search for strategies to regenerate bone tissue. The ultrasonic sonochemical technique was chosen for the functionalization of the 45S5 bioglass. The samples after the sonochemical process were divided into (a) functionalized bioglass (BG) and (b) functionalized bioglass with 10% teriparatide (BGT). Isolated mesenchymal cells (hMSC) from femurs of ovariectomized rats were differentiated into osteoblasts and submitted to in vitro tests. Bilateral ovariectomy (OVX) and sham ovariectomy (Sham) surgeries were performed in fifty-five female Wistar rats. After a period of 60 days, critical bone defects of 5.0 mm were created in the calvaria of these animals. For biomechanical evaluation, critical bone defects of 3.0 mm were performed in the tibias of some of these rats. The groups were divided into the clot (control) group, the BG group, and the BGT group. After the sonochemical process, the samples showed modified chemical topographic and morphological characteristics, indicating that the surface was chemically altered by the functionalization of the particles. The cell environment was conducive to cell adhesion and differentiation, and the BG and BGT groups did not show cytotoxicity. In addition, the experimental groups exhibited characteristics of new bone formation with the presence of bone tissue in both periods, with the BGT group and the OVX group statistically differing from the other groups (p < 0.05) in both periods. Local treatment with the drug teriparatide in ovariectomized animals promoted positive effects on bone tissue, and longitudinal studies should be carried out to provide additional information on the biological performance of the mutual action between the bioglass and the release of the drug teriparatide.

Effect of Topical PTH 1-34 Functionalized to Biogran® in the Process of Alveolar Repair in Rats Submitted to Orchiectomy

(1) Background: There are many therapies for osteoporosis control and bone maintenance; anabolic drugs such as teriparatide and bone grafts help in the repair process and stimulate bone formation. Thus, the aim of the present study was to evaluate the behavior of repaired bone in the presence of PTH (teriparatide) associated with Biogran^® (biomaterial) through a sonochemical procedure after extraction in rats. (2) Methods: The insertion of Biogran^® with PTH in the alveolus was performed 30 days after incisor extraction. Euthanasia occurred after 60 days. (3) Results: The use of local treatment of PTH loaded with Biogran® in healthy rats promoted good results for micro-CT, with an increase in percentage and bone volume, number and trabecular separation and less total porosity. Greater immunostaining for Wnt, β-Catenin and osteocalcin proteins and lower expression for Thrombospondin-Related Adhesive Protein (TRAP), which shows an increase in the number of osteoblasts and inhibition of osteoclast action. However, the treated orchiectomized groups did not obtain such expressive results. (4) Conclusion: The use of Biogran^® with PTH improved alveolar repair in rats. However, new researches with more efficient doses must be studied to collaborate effectively with the formation of a quality bone after the orchiectomy.

Frequency-Dependent Sonochemical Processing of Silicon Surfaces in Tetrahydrofuran Studied by Surface Photovoltage Transients

The field of chemical and physical transformations induced by ultrasonic waves has shown steady progress during the past decades. There is a solid core of established results and some topics that are not thoroughly developed. The effect of varying ultrasonic frequency is among the most beneficial issues that require advances. In this work, the effect of sonication of Si wafers in tetrahydrofuran on the photovoltage performance was studied, with the specific goal of studying the influence of the varying frequency. The applied ultrasonic transducer design approach enables the construction of the transducer operating at about 400 kHz with a sufficient sonochemical efficiency. The measurements of the surface photovoltage (SPV) transients were performed on p-type Cz-Si(111) wafers. Sonication was done in tetrahydrofuran, methanol, and in their 3:1 mixture. When using tetrahydrofuran, the enhanced SPV signal (up to ≈80%) was observed due to increasing sonication frequency to 400 kHz. In turn, the signal was decreased down to ≈75% of the initial value when the frequency is lowered to 28 kHz. The addition of methanol suppressed this significant difference. It was implied that different decay processes with hydrogen decomposed from tetrahydrofuran could be attempted to explain the mechanism behind the observed frequency-dependent behavior.

Sonochemical time standardization for bioactive materials used in periimplantar defects filling

The aim of this study was determinate the best sonochemical time in order to obtain better bone characteristics when a bioactive material (Biogran) is used in the filling periimplantar defects. In this study, 32 rats were submitted to surgical proceedings to create a periimplantar defect that was filled with Biogran receiving different sonochemical times: 15 (G1), 30 (G2), 45 (G3) or 90 min (G4). The biomaterial was characterized through X-ray diffraction and scanning electron microscopy (SEM). In vivo analysis was performed through micro CT, laser confocal microscopy, immunohistochemistry and evaluation of bone cytoarchitecture through hematoxylin and eosin (HE) staining. The data were submitted to statistical testing, considering a significance level of p < 0.05. Rx diffraction of pure bioglass showed that it is predominantly amorphous; otherwise, there are small peaks at 23° and 31°. SEM shows that the longer the sonochemical time, the less edges the biomaterial will present. Within the groups, G1 and G2 showed the best quantity and quality by micro CT (p > 0.05). The best bone turnover result was found in G1 and G2, otherwise the better results were related to neoformed bone area, bone mineral apposition rate and bone implant contact to G1 (p < 0.05). G1 had the best results in terms of bone cytoarchitectural evaluation and immunohistochemistry. It is possible to conclude that Biogran that received 15 min of sonochemical treatment (G1) presented periimplantar bone repair with the best extracellular matrix properties, including the best quality and quantity of vital bone.

Bone repair with raloxifene and bioglass nanoceramic composite in animal experiment

OBJECTIVE

This study proposes to evaluate, by means of microtomographic analysis, the topical potential of raloxifene combined with BioGran® through the sonochemical method in the repair of critical bone defects in the calvaria of rats. The hypothesis was that the homogenization of Raloxifene to Biogran at the 20% concentration would improve the bone repair at the grafted site.

MATERIALS AND METHODS

A 5-mm calvaria bone defect was induced in three groups: CTR (100% BioGran®); RAL10 (90% BioGran® and 10% raloxifene), and RAL20 (80% BioGran® and 20% raloxifene). The animals were euthanized after 30 days and the microCT analysis was then performed to evaluate the parameters bone volume (BV), bone volume percentage (BV/TV), trabecular bone thickness (Tb.Th), and the separation and number of trabeculae (Tb.Sp and Tb.N). The obtained results were compared using ANOVA and Tukey test (p < 0.05).

RESULTS

The best results were found for the CTR and RAL20 groups, in which the BV, BV/TV, Tb.Sp, and Tb.N parameters were statistically significant in comparison with RAL10 (p < 0.05).

CONCLUSIONS

In view of the results obtained in this experiment, we can conclude that BioGran® alone or in an 80/20 mass concentration with raloxifene can lead to favorable bone formation.

Ultrasound-assisted surface treatment of ZrO2 with BSA and incorporating in PVC to improve the properties of the obtained nanocomposites: Fabrication and characterization

This paper describes the preparation of poly(vinyl chloride) (PVC) nanocomposites (NCs) reinforced with modified zirconia (ZrO₂) nanoparticles (NPs). The ZrO₂ NPs were defined as efficient filler for PVC NCs. For achieving the best dispersion and improvement of properties, the surface of ZrO₂ NPs was modified by Bovine Serum Albumin (BSA). Carboxylic acids and amines are important functional groups of BSA which handle the grafting BSA on the surface of ZrO₂ NPs. The PVC/ZrO₂-BSA NCs were fabricated by incorporation of various amounts of the ZrO₂-BSA NPs (3, 6 and 9wt%) into PVC matrix. All the above processes were accomplished by ultrasonication asa green and environmentally-friendly method. Also, the magnetic and mechanical stirrer was used for the preparation of samples but the results are not suitable and the aggregation was observed which indicated the use of ultrasonic irradiation is the best method for the preparation of NC. The products were characterized by Fourier transform infrared spectroscopy, Transmission electron microscopy, Field emission scanning electron microscopy, X-ray diffraction, Thermogravimetric analysis, Ultraviolet-visible spectroscopy, photoluminescence spectroscopy, energy dispersive X-ray spectroscopy, wettability, and mechanical tests. The achieved PVC/ZrO₂-BSA NCs showed high thermal stability, good mechanical, optical and wettability properties compared to the pure PVC. In addition, among the obtained NCs, the PVC/ZrO₂-BSA NC 6wt% showed the best improvement.