Banca de DEFESA: ANDERSON DIAS VIANA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDERSON DIAS VIANA
DATE: 02/12/2019
TIME: 14:00
LOCAL: auditório do Química III
TITLE:

SILVER NANOPARTICLES STABILIZED BY RICINOLEIC ACID AND ITS EPOXIDED FORM APPLIED AS A CYSTEINE SENSOR AND ANTIMICROBIAL AGENT

KEY WORDS:

Silver Nanoparticles; Ricinoleic Acid; Cysteine sensor; Bactericidal Effect

PAGES: 95
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Eletroquímica
SUMMARY:

Nanoparticles have been applied for their large surface area, their reactivity and the new properties that do not exist in the bulk phase. New syntheses using natural products have been used to make the process more ecofriendly. However, the use of raw natural product requires high temperatures or a long synthesis time. In this work we use ricinoleic acid extracted from castor oil, due to its biodegradability, higher water solubility and availability, as it is a characteristic plant of Brazilian northeastern. Ricinoleic acid epoxidation was done to increase the reducing capacity. In this work, the synthesis of silver nanoparticles with ricinoleic acid surfactant (AgSAR) and its epoxidized form (AgSEAR) was optimized to be applied as cysteine sensors and antibacterial agents. Maximum UV-Vis absorbances of 420 nm for AgSAR and 405 nm for AgSEAR were obtained, indicating nanoparticle formation. The optimal design of the experiment was the concentration of 0.5 mmol∙L^-1 Ag⁺ and 20 mmol∙L^-1 of surfactant in AgSAR synthesis and 0.3 mmol∙L^-1 of Ag⁺ and 20 mmol∙L^-1 of the surfactant in AgSEAR synthesis. Synthesis time decreased from 10 days  with AgSAR to 6 hours with AgSEAR. The average nanoparticle size was 16.70 nm for AgSAR and 17.80 nm for AgSEAR, while for EDL 75.42 nm for AgSAR and 82.10 nm for AgSEAR size diameter were obtained. This size difference indicates that surfactants are found as micelles around the nanoparticle. The nanoparticles were elective to cysteine with a detection limit of 3.49 μmol∙L^-1 for AgSAR and 16.67 μmol∙L^-1 for AgSEAR. In the antibacterial application, there was total inhibition of growth at a concentration of 18 mg/L for AgSAR and 11 mg/L for AgSEAR.

BANKING MEMBERS:
Presidente - 1958858 - LUIZ HENRIQUE DA SILVA GASPAROTTO
Interno - 1198847 - JOSE LUIS CARDOZO FONSECA
Externo ao Programa - 063.531.844-09 - RAFAEL DA SILVA FERNANDES - UFRN
Externo à Instituição - JOSÉ ROBERTO SIQUEIRA JUNIOR - UFTM
Externo à Instituição - SEVERINO ALVES JUNIOR - UFPE