Electrical stimulation therapy and rotary jet-spinning scaffold to treat bone defects.

The combination of electrical stimulation (ES) and bone tissue engineering (BTE) has been successful in treatments of bone regeneration. This study evaluated the effects of ES combined with PCL + ß-TCP 5% scaffolds obtained by rotary jet spinning (RJS) in the regeneration of bone defects in the calvaria of Wistar rats. We used 120 animals with induced bone defects divided into 4 groups (n = 30): (C) without treatment; (S) with PCL+ ß-TCP 5% scaffold; (ES) treated with ES (10 µA/5 min); (ES + S) with PCL + ß-TCP 5% scaffold. The ES occurred twice a week during the entire experimental period. Cell viability (in vitro: Days 3 and 7) and histomorphometric, histochemical, and immunohistochemical (in vivo; Days 30, 60, and 90) analysis were performed. In vitro, ES + S increased cell viability after Day 7 of incubation. In vivo, it was observed modulation of inflammatory cells in ES therapy, which also promoted blood vessels proliferation, and increase of collagen. Moreover, ES therapy played a role in osteogenesis by decreasing ligand kappa B nuclear factor-TNFSF11 (RANKL), increasing alkaline phosphatase (ALP), and decreasing the tartarate-resistant acid phosphatase. The combination of ES with RJS scaffolds may be a promising strategy for bone defects regeneration, since the therapy controlled inflammation, favored blood vessels proliferation, and osteogenesis, which are important processes in bone remodeling.

Polycaprolactone/Beta-Tricalcium Phosphate Scaffolds Obtained via Rotary Jet-Spinning: in vitro and in vivo Evaluation.

This study aimed to evaluate in vitro and in vivo polymeric membranes obtained by a rotary jet-spinning process for the repair of critical bone defects in the calvaria of Wistar rats, for future use in tissue engineering. Experimental sample collections were performed on the 30, 60 and 90th postoperative days, and the analyses performed were histomorphometric, immunohistochemistry, and western blotting. Reducing inflammatory infiltrate in all groups and experimental periods, angiogenesis on the 30th day did not show any difference between the groups, on the 60th day, 5% polycaprolactone/beta-tricalcium phosphate(PCL/ß-TCP) was high compared to control (C), and on the 90th day, the same group reduced when compared to C and 10% PCL/ß-TCP. The fibroplasia presented oscillations in every segment; on the 30th and 60th day, there was an increase in 5% PCL/ß-TCP, which decreased by the 90th day compared to group C. 10% PCL/ß-TCP decreased compared to C on the 60th and 90th day. The percentage of the collagen area remained high in all groups and all experimental periods. Immunohistochemistry quantifications showed variations in bone metabolism suggesting new bone formation. The 5 and 10% PCL/ß-TCP scaffold were promising for the bone regeneration process because they participated in the modulation of inflammation, angiogenesis, fibroplasia, and collagenosis.

The monomeric formulation optimization of dental composite: mechanical and kinetic studies.

The optimization of the monomer composition, using a polymerization kinetic study and the mechanical behavior study of the composites, was the principal objective of this work. The monomeric mixture analyzed is a part of the composite that has been in development at the University of Campinas, Brazil. Parameters such as initiator, accelerator, and macro-components composition were optimized. The infrared spectroscopy was the analytical technique used in the kinetic study. On the mechanical characterization, the stress strain, flexure stress and its modulus, were the properties analyzed. The dependency between the polymeric reaction and the physical behavior of the composites and the monomer composition was observed and studied. Finally, the monomer optimum composition was determined.

Bioreabsorbable polymer scaffold as temporary meniscal prosthesis.

Menisci have an important role in load bearing, shock absorption, knee joint stability, and joint lubrication. Meniscal lesions and meniscectomy are followed by osteoarthritis in a high percentage of patients. At present, there is no ideal prosthesis for meniscal substitution. In this work, a bioreabsorbable polymer scaffold made of poly(L-lactic acid) (PLLA) and poly(p-dioxanone) (PPD) blend was developed to be used as a temporary meniscal prosthesis to stimulate the formation of an in situ meniscal replication while the scaffold is reabsorbed by the organism. Total meniscectomy of medial meniscus and arthrotomy was made in both back knees of 34 adult New Zealand white rabbits by medial parapatellar incision. The scaffolds were sutured in one of the knees, and other was used as a control. A meniscal replica was developed, suggesting that this material has great potential to be used as a meniscal prosthesis, especially because the new meniscus promoted a significant protection of cartilage, and cartilage degeneration in the control condyles was observed.