Biossensor magnetoelástico para diagnóstico de Sars-Cov-2

Abstract

Magnetoelastic biosensors, categorized as mass sensors, operate by detecting variations in the fundamental resonance frequency. Their standout feature lies in their targeted pathogen detection capability, achieved through precise surface functionalization. In this thesis, a magnetoelastic biosensor was developed to detect Sars-CoV-2. Extrinsic factors influencing the sensitivity of magnetoelastic sensors were evaluated, e.g. the influence of operating temperature, applied magnetic field, thermal treatments, and corrosive environment. A support made of aluminum was used as a heat sink to prevent resonance frequency shifts due to self-heating, and a polarization bias current source with field stability of 0.01% was implemented to eliminate the effects of current variations. This ensured that any changes in resonance frequency were solely attributable to an increase in mass. Applying thermal treatment before and after the coating process improved the homogeneity of the sensor response and increased the corrosion resistance. The sensor's surface was functionalized to make it specific for detecting the recombinant Sars-CoV-2 protein. ATR-FTIR confirmed the immobilization of biorecognition agents on the sensor surface. Using AuNPs to amplify the response signal allowed the detection of the Sars-CoV-2 recombinant protein. The biosensors used in this work present a mass sensitivity of 196 Hz/µg. Alternatives to improve the biosensor's mass sensitivity were evaluated through computational simulations of the sensors' vibration modes, as well as the frequency variation response as a function of the position and amount of mass loaded on the surface. From the results obtained, it was possible to carry out controlled functionalization of the biosensor surface to expand the response signal, taking into account only the regions with the highest vibration intensity and eliminating the blind spots in which the resonance frequency variation due to the adhered mass is practically zero. In summary, a magnetoelastic biosensor was developed and optimized for the specific detection of the recombinant Sars-CoV-2 protein. In addition to confirming the efficacy of the sensor surface functionalization and signal amplification using AuNPs, this work highlighted the importance of extrinsic factors on the device's sensitivity. Computational simulations allowed for the optimization of mass distribution on the sensor surface, maximizing sensitivity and eliminating blind spots. These advancements enable the biosensor to be used with greater precision and reliability, establishing it as a promising tool for diagnostic applications in virus detection. [resumo fornecidos pelo autor]