Banca de QUALIFICAÇÃO: Marylene Sousa Guimarães Roma

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Marylene Sousa Guimarães Roma
DATE: 23/05/2023
TIME: 09:30
LOCAL: Auditório do IB
TITLE:

"DEVELOPMENT OF A SALIVA CORTISOL SENSOR WITH AN INTERDIGITATED ELECTRODE PLATFORM BASED ON BARIUM TITANATE NANOPARTICLES."

KEY WORDS:

Titanium; Nanoparticles; Electrode; Cortisol; Point-of-Care

PAGES: 97
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The stress caused by our lifestyle affects more than 90% of the world's population, promoting restrictive physiological and/or psychosomatic responses to patients. The hormone cortisol, essential for the maintenance of homeostasis, is known as a potential biomarker for the detection of stress. There is an increasing rise in patient self-monitoring technologies, using Point-of-Care devices, which apply sensors, in the detection of cortisol using nanoparticles and the Interdigitated Array Electrode arrangement capacitive, enabling noninvasive, accurate diagnosis, and screening in complex fluids. This study aims at determining the cortisol dosage in saliva samples using mesoporous titanium oxide and complex impedance spectroscopy. The characteristic TiBaO3 dielectric and high dielectric constant, was used for incorporation to the surface of the IDE. The synthesis of mesoporous particles of TiBaO3 were prepared by the colloidal precipitation method from titanium tetraisopropoxide (TTIP) IV, barium chloride and non-ionic copolymer Pluronic® P123 as structure directing agent, to obtain SBA-15 mesopore structure. The TTIP precursor underwent hydrothermal reaction of hydrolysis and condensation, the reaction was conducted by chemical reflux, and subsequently calcined at different temperatures. Where at the end of the reactions the surfactant P123 was removed from 270ºC. For the characterization of the TiBaO3 nanoparticle, analyses were employed by scanning electron microscopy (SEM), infrared spectroscopy with attenuated total reflectance (FTIR-ATR) and X-ray diffraction (XRD). A special gold interdigitated electrode platform of semiconducting mesoporous barium titanate oxide nanoparticles (TiBaO3) was developed. To increase the cortisol binding specificity in the complex samples, albumin was attached on mesoporous surface particles as a surface anti-binder agent. In the electrochemical cell construction, the interdigitated electrode was used as a support to the TiBaO3 power deposits. Different analytical cortisol standard samples were prepared and measured at a constant voltage of 5 mV; the nominal current of 40 nA was generated at 1 kHz. The complex impedance was recorded using a sinusoidal input voltage in the frequency range of 100 Hz to 2 kHz. Principal component analysis was used for data processing. Cortisol levels as low as 40 nanograms per milliliter were detected. Further studies are being conducted to use this method to quantify the cortisol in complex human saliva samples.

BANKING MEMBERS:
Externo à Instituição - Alessandro Pinheiro - IFB
Presidente - 1547480 - JOSE ANTONIO HUAMANI COAQUIRA
Externo ao Programa - 331970 - JOSE FELICIO DA SILVA
Externo ao Programa - 1892565 - LEONARDO GIORDANO PATERNO