RESUMO
In this study, polypyrrole nanotubes (PPy-NT) and gold nanoparticles (AuNPs) were electrochemically synthesized to form a hybrid material and used as an electroactive layer for the attachment of proteins for the construction of a high-performance biosensor. Besides the enhancement of intrinsic conductivity of the PPy-NT, the AuNPs act as an anchor group for the formation of self-assembly monolayers (SAMs) from the gold-sulfur covalent interaction between gold and Mercaptopropionic acid (MPA). This material was used to evaluate the viability and performance of the platform developed for biosensing, and three different biological approaches were tested: first, the Avidin-HRP/Biotin couple and characterizations were made by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), wherein we detected Biotin in a linear range of 100-900 fmol L-1. The studies continued with folate group biomolecules, using the folate receptor α (FR-α) as a bioreceptor. Tests with anti-FR antibody detection were performed, and the results obtained indicate a linear range of detection from 0.001 to 6.70 pmol L-1. The same FR-α receptor was used for Folic Acid detection, and the results showed a limit of detection of 0.030 nmol L-1 and a limit of quantification of 90 pmol L-1. The results indicate that the proposed biosensor is sensitive and capable of operating in a range of clinical interests.
Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Nanotubos , Ouro/química , Polímeros/química , Pirróis/química , Ácido Fólico , Biotina , Nanopartículas Metálicas/química , Técnicas Biossensoriais/métodos , Eletrodos , Técnicas Eletroquímicas , Limite de DetecçãoAssuntos
Humanos , Feminino , Pandemias , COVID-19 , Ansiedade/epidemiologia , Brasil/epidemiologia , Estudos Longitudinais , Depressão/epidemiologia , SARS-CoV-2 , MãesAssuntos
COVID-19 , Pandemias , Ansiedade/epidemiologia , Brasil/epidemiologia , Depressão/epidemiologia , Feminino , Humanos , Estudos Longitudinais , Mães , SARS-CoV-2RESUMO
BACKGROUND: Studies have shown that sexual initiation at earlier ages increases the risk of depressive symptoms in adolescents. However, little is known about its association with major depressive episode (MDE). METHODS: The association between age of sexual initiation and MDE at 18 years was assessed in the 1993 Pelotas Birth Cohort using multiple logistic regression. Sexual initiation characteristics (age and type of partner) were assessed at the 15- and 18-years follow-up. The age of sexual initiation was evaluated in categories (11-14, 15-16, 17+ years). The type of partner was categorized into: boyfriend/ girlfriend, casual partner and other. MDE was assessed using the Mini International Neuropsychiatric Interview (MINI). RESULTS: From the 4027 adolescents assessed, the prevalence of MDE was higher in females (10.1%) than in males (3.4%), and 66.7% of the males and 58.6% of the females reported sexual initiation up to 16 years (p < 0.001). Female adolescents who had sexual initiation <17 years had higher odds of MDE (15-16 years: OR 2.29; 11-14 years: OR 2.23), however no association was found for males. The type of partner in the first sexual intercourse was not associated to depression. LIMITATIONS: Possibility of recall bias on the age of sexual initiation, and low statistical power for some analyses. CONCLUSIONS: A positive association between age of sexual initiation and MDE was observed only in females. More investigation is needed to understand the mechanisms through which age of sexual initiation can affect the risk of depression and whether the association persists in adulthood.