RESUMO
Schistosomiasis is a neglected tropical disease with a worldwide prevalence. Neuroschistosomiasis is the most severe presentation of the disease and affects the central nervous system. In this work, Schistosoma mansoni detection was based on self-assembled layers of 3-mercaptopropyltrimethoxysilane (MPTS) and electrosynthesized gold nanoparticles (AuNPs). The DNA probe was chemisorbed onto AuNPs. The biosensor was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The impedimetric response of the MPTS-AuNPs-DNAprobe system indicates an effective modification of the electrode surface. Topographical atomic force microscopy images were used to characterize the self-assembled layers on the gold electrode surface. The proposed biosystem was able to recognize the S. mansoni genome sequence at different concentrations in samples of urine, cerebrospinal fluid, and serum. Several concentration ranges were evaluated: urine (27-50â¯pg⯵L-1), cerebrospinal fluid (25-60â¯pg⯵L-1), and serum (27-42â¯pg⯵L-1). The limit detection (LOD) of the biosensor was 0.6â¯pg⯵L-1. The developed label-free genosensor was able to detect small concentrations of S. mansoni DNA in complex biological fluids.
Assuntos
Sondas de DNA/química , DNA de Helmintos/análise , Nanopartículas Metálicas/química , Schistosoma mansoni/isolamento & purificação , Animais , Técnicas Biossensoriais/métodos , Sondas de DNA/genética , DNA de Helmintos/genética , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Humanos , Limite de Detecção , Hibridização de Ácido Nucleico , Compostos de Organossilício , Schistosoma mansoni/genética , Silanos/químicaRESUMO
Schistosomiasis is a neglected disease closely related to the low levels of social development and a serious public health problem. In this work, we performed an electrochemical detection of Schistosoma mansoni DNA with a self-assembled monolayer of mercaptobenzoic acid (MBA) immobilizing nanostructures composed of gold nanoparticles (AuNPs) and magnetite nanoparticles (Fe3O4_NPs). Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used to monitor the hybridization process. MBA-Fe3O4_NPs-AuNPs-DNAprobe system reveals an effective electrochemical response indicating the surface modification. The proposed biosystem was capable to recognize specific nucleotide sequence of S. mansoni present in cerebrospinal fluid (CFS) and serum samples at different genome DNA concentrations. The biorecognition resulted in an increase in the electron transfer resistance and a decrease of the current peaks at higher DNA concentrations during electrochemical measurements. The developed platform showed a DNA detection limit of 0.781 and 0.685pgµL-1 for serum and CFS, respectively. Therefore, the obtained biosensor can be considered as a useful tool for specific detection of S. mansoni at low concentrations in various biological fluids.