Biossensor com grade de período longo funcionalizada com GO e anticorpos: uma abordagem para detecção de IL-1β

Abstract

The development of biosensors with high sensitivity and selectivity is essential for the advancement of biomedical diagnostics. In this work, the fabrication and characterization of an optical biosensor based on long-period gratings (LPGs), functionalized with graphene oxide (GO) and anti-IL-1β antibodies, are presented for the detection of the pro-inflammatory cytokine interleukin-1β (IL-1β). The biosensor was functionalized with GO and antibodies through 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) activation chemistry and encapsulated in a microfluidic cartridge for liquid-phase testing. Morphological surface characterization was performed using SEM and Raman spectroscopy, confirming GO deposition and efficient biofunctionalization. The spectral response obtained with an optical spectrum analyzer revealed systematic shifts in the resonant attenuation bands as a function of IL-1β concentration. These shifts are associated with variations in charge density in the sensing layer, caused by antigen–antibody interactions and biomolecular mass accumulation, which modify the effective refractive index of the optical fiber. The developed biosensor exhibited estimated limits of detection (LOD) of 21.35 pg/mL and 6.36 pg/mL after regeneration, representing improvements of 3- and 10-fold compared to the most efficient sensor reported in the literature. The device also demonstrated high selectivity, showing a negligible response to the nonspecific analyte interleukin-10 (IL-10). These results demonstrate the potential of the proposed biosensor as a promising tool for clinical diagnostic applications, with the possibility of adaptation for other biomarkers and integration into multiplexed sensing systems.