Banca de DEFESA: VALCILAINE TEIXEIRA BARBOSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : VALCILAINE TEIXEIRA BARBOSA
DATE: 11/07/2022
TIME: 08:00
LOCAL: Ambiente virtual
TITLE:

Bioactive primary dressings of silver nanoparticles obtained by biogenic synthesis with red propolis from Alagoas

KEY WORDS:

Electrospinning, Films, Wounds, Polycaprolactone, Antimicrobial activity

PAGES: 115
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Skin lesions are still considered a major challenge in the health area, considering that current dressings are, to a large extent, imported and expensive. Dressings can be primary, when used in direct contact with the injured tissue, and bioactive, with a role in the healing cascade. Thus, this work aims to develop bioactive primary dressings with polymeric matrix of polycaprolactone (PCL), containing silver nanoparticles (AgNP-P) obtained by biogenic synthesis with red propolis from Alagoas. For this, the synthesized and dried nanoparticles were incorporated in different concentrations (1, 2 and 5%) in fixed polymer concentration (9%). The dressings were prepared using casting and electrospinning techniques, resulting in films and fibers, respectively. In the case of fibers, they were optimized with the aid of scanning electron microscopy (SEM), in which average fiber diameter and porosity were seen. For the characterization of the materials were utilized techniques of X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), as well as essays of water contact angle, swelling, silver release by inductively coupled plasma optical emission spectrometry (ICP-OES), antimicrobial activity, cytotoxicity and mechanical activity. As a result, the best conditions for the fibers were a voltage of 15kV, 12 cm distance between needle-collector and needle of 1.2 mm in diameter, leading to a nanofibers porosity of approximately 85%. The crystalline planes of metallic silver visualized by XRD confirmed the presence of AgNP-P. TG curves showed a decomposition of products similar to the pure polymer, while DSC allowed observing a decrease in the melting temperature corroborated by the crystallinity of the compounds that was also reduced due to the increase in the concentration of AgNP-P. FTIR spectras revealed that AgNP-P seems to be impregnated only by physical interaction with the polymer in both production techniques. The products obtained by electrospinning showed a higher swelling and silver release capacity compared to the films. Consequently, the nanofibers with the highest concentration of silver (E-5%) showed bacterial inhibition with a release of only 0.0833 µg/mL in 24h against the evaluated bacteria, being, therefore, the product of choice for the next analyses. Finally, E-5% showed no toxicity against L929 cells, similar to fibroblasts, and exhibited properties of elasticity and resistance suitable for use as dressings. Thus, it was possible to conclude that the electrospinning processing demonstrated better results in the properties of the dressings and the use of nanoparticles biosynthesized with propolis was essential for a product with antimicrobial activity without presence of toxicity.

BANKING MEMBERS:
Externo à Instituição - HELVÉCIO VINÍCIUS ANTUNES ROCHA - Fiocruz - RJ
Interna - 1543737 - ADRIANA SANTOS RIBEIRO
Presidente - 1527220 - CAMILA BRAGA DORNELAS
Externo à Instituição - JOHNNATAN DUARTE DE FREITAS - IFAL
Interna - 3066401 - LIGIA MARIA MANZINE COSTA
Externo ao Programa - 1348288 - MARIO ROBERTO MENEGHETTI