Biossensor eletroquímico de ureia com detector potenciométrico para monitoramento de doença renal causada pelo SARS-COV-2

Abstract

COVID-19 is known to cause widespread damage to the tiny air sacs in the lungs and acute respiratory failure, which can also affect the kidneys and result in Acute Renal Failure (ARF), a severe and potentially deadly condition. Early prevention and diagnosis are crucial, as many kidney issues only become apparent when more than half to three-quarters of kidney function is already compromised. Given these challenges, there has been significant research into developing biosensors for renal diagnosis. These devices enable early detection, allowing for better treatment and improving patients' outcomes. This study focuses on creating an electrochemical urea biosensor with a potentiometric detector to aid in monitoring renal failure associated with the SARS-CoV-2 virus. The biosensor was made using the screen-printing technique, forming two electrodes (sensor and reference) on a conductive copper tape. Antimony was then deposited on the electrodes, and silver paint containing the enzyme urease was applied to the sensor electrode. The urease enzyme, extracted from jack beans, was characterized by Fourier transform infrared spectroscopy (FTIR), enzyme activity/kinetic parameters and hydrogen potential (pH). The biosensors were characterized by optical microscopy (OM), X-ray diffraction (XRD), electrical resistance and conductivity, sensitivity and linearity range, stability period/response time and reproducibility. The potentiometric detector was developed using <Proteus= software and <Arduino IDE= software, which were then transferred to an Arduino nano microcontroller. Its housing was developed using the Shapr 3D software and printed on a 3D printer using the polymer polylactic acid (PLA), into which the electronic system and software necessary for its operation were inserted. The jack bean extract containing the urease enzyme showed absorption bands characteristic of the urease enzyme and Michaelis – Menten behavior, showing affinity with its substrate urea at maximum concentrations of 60mmol.L-1. The biosensors presented a smooth and flat structure under a certain orientation with effective electrodeposition of antimony over the entire copper surface and the presence of silver particles over the entire surface of the sensor electrode. In the XRD analysis, characteristic peaks of crystalline materials were observed, which favors the performance of the biosensors by maintaining their conductivity properties, essential for their functioning. The potentiometric response of the biosensor was analyzed in relation to different concentrations of urea solution, demonstrating a linear range and sensitivity at concentrations ranging between 15 and 75 mg/dL. The detection limit was investigated and established at 75 mg/dL. Furthermore, the response time of the biosensor was determined to be 60 seconds, showing good reproducibility. The potentiometric detector converted the potential difference obtained from the biosensor reaction into urea concentration in mg/dl, indicating the effectiveness of the methodology used in their development as an electrochemical urea biosensor.