Algorítimo para detecção de insulina em fluidos biológicos baseado em componentes salivares detectados por meio de espectroscopia FTIR para utilização como plataforma diagnóstica

Abstract

Introduction: Currently the insulin measurements is performed by invasive procedure, painful and costly. Consequently, the search for a cheaper method of measuring insulin (without the use of reagents), non-invasive and painfulless is of great interest. Objective: This study aim to identify vibrational modes detected by infrared spectroscopy with Fourier transform of attenuated total reflection (ATR-FTIR) of saliva to be used in the insulin detection in biological fluids. Materials and Methods: It was used an algorithm able to quantify the concentration of insulin in biological fluids detected by spectroscopy. We used 2 µL of each sample with insulin in different concentrations (0 U/µL;1.5 x 10-3U/µL; 6.25 x 10-3 U/µL; 50 x 10-3 U/µl and 100 x 10-3U/µL) that were placed on the ATR crystal and dry with compressed air during 3 min. The penetration depth of the sample ranged between 0.1 and 2 μm and depended on the wavelength, angle of incidence of the beam and the index of refraction of the ATR crystal material. It was used the Pearson correlation with statistical analysis of the comparison between the known concentrations of insulin with the application of measurement of insulin by FTIR after the implementation of the algorithm. Results: It was found that there was the development of the algorithm with the use of the average spectrum of artificial saliva without insulin, of artificial saliva with growing solutions of insulin and insulin breeding in the spectrum between 1750-1500 cm-1. Conclusion: Whereas there is no description of this methodology in other studies and there is not this method by FTIR, it was concluded that this algorithm has the potential to be used as a complementary tool for fast, painless and non-invasive measurement insulin in biological fluids such as saliva, urine and cerebrospinal fluid.