Mostrar registro simples

dc.contributor.advisorRocha, Tatiana Louise Avila de Campos
dc.contributor.authorMoraes, Duane da Silva
dc.date.accessioned2022-07-06T16:35:11Z
dc.date.accessioned2022-09-22T19:52:41Z
dc.date.available2022-07-06T16:35:11Z
dc.date.available2022-09-22T19:52:41Z
dc.date.issued2022-01-14
dc.identifier.urihttps://hdl.handle.net/20.500.12032/66037
dc.description.abstractThe gold nanoparticles (GNPs) have become strong candidates for applications in biosensors, as they have high electrical conductivity and catalytic activity, corrosion resistance, biocompatibility, low cytotoxicity, high stability in biological fluids and easy functionalization. One of the most consolidated methodologies in the literature for the synthesis of GNPs is the chemical reduction of Au3+ ions in metallic gold through chemical reducing agents, and any change in the synthesis parameters, as well as the insertion of stabilizing reagents influence the shape and size of the nanoparticles. Considering the above, the objective of this work is to study the synthesis of gold nanoparticles, aiming its application in biosensors. The methodological process was divided into three stages: the first stage consists of the study of the most suitable reducing agent for the synthesis of GNPs, in which the agents Sodium Citrate and Sodium Borohydride were evaluated; in the second stage, other synthesis parameters were evaluated, such as stirring speed, reduction agent addition speed and molar ratio between the reducing agent and precursor; in the third step, the GNPs solution chosen as the promising synthesis was functionalized with Polyethyleneimine to activate its surface and enable the bioreceptor coupling. All syntheses performed showed the characteristic band of metallic gold between 500 and 550 nm in the UV-visible analysis, confirming the formation of gold nanoparticles. The colloidal solutions synthesized with Sodium Citrate showed more intense coloration, the experimental method is simpler and requires less reaction time, compared to GNPs produced with Sodium Borohydride. The characterization analyzes of the samples from the second stage revealed that the higher the stirring speed of the system, the greater the diffusion speed of the chemical species in solution and the smaller the size of the gold nanoparticles. Regarding the molar ratio between precursor and reducing reagents added to the synthesis, it can be concluded that there is an ideal molar ratio and that higher or lower concentrations of the reducing agent in the solution contribute to an increase in the size of GNPs. Finally, regarding the addition speed of the reducing agent in the reaction medium, it can be inferred that a slower addition causes the production of larger nanoparticles, with variability of sizes and agglomerates. The results of the third stage of the work presented the possibility of functionalizing the gold nanoparticles with Polyethyleneimine, which interacts with GNPs by Van der Waals forces. The electrochemical characterization of commercial electrodes modified with functionalized gold nanoparticles revealed a significant reduction in charge transfer resistance when compared to the unmodified device, due to the conductive capacity of GNPs, contributing to the increased sensitivity of the electrodes in detecting chemical/biological reactions. Thus, it is concluded that it is possible to apply the solution of functionalized gold nanoparticles produced in this work in the construction of biosensors and that the next step of the study should focus on the bioreceptor coupling, which will depend, in turn, on the target biomarker for the diagnosis.en
dc.description.sponsorshipUNISINOS - Universidade do Vale do Rio dos Sinospt_BR
dc.languagept_BRpt_BR
dc.publisherUniversidade do Vale do Rio dos Sinospt_BR
dc.rightsopenAccesspt_BR
dc.subjectNanopartículas de ouropt_BR
dc.subjectPolietilenoiminaen
dc.titleSíntese de solução coloidal de nanopartículas de ouro para aplicação em dispositivos de detecção de biomarcadorespt_BR
dc.typeDissertaçãopt_BR


Arquivos deste item

ArquivosTamanhoFormatoVisualização
Duane da Silva Moraes_.pdf7.530Mbapplication/pdfVisualizar/Abrir

Este item aparece na(s) seguinte(s) coleção(s)

Mostrar registro simples


© AUSJAL 2022

Asociación de Universidades Confiadas a la Compañía de Jesús en América Latina, AUSJAL
Av. Santa Teresa de Jesús Edif. Cerpe, Piso 2, Oficina AUSJAL Urb.
La Castellana, Chacao (1060) Caracas - Venezuela
Tel/Fax (+58-212)-266-13-41 /(+58-212)-266-85-62

Nuestras redes sociales

facebook Facebook

twitter Twitter

youtube Youtube

Asociaciones Jesuitas en el mundo
Ausjal en el mundo AJCU AUSJAL JESAM JCEP JCS JCAP