Fabricación de biosensores piezoeléctricos para la lectura de interacciones antígeno-anticuerpo

Abstract

In recent years, quartz crystal microbalances (QCM) have aroused great interest in the scientific and industrial communities due to their potential applications in areas such as medicine, quality control, chemistry, and the pharmaceutical industry. They are part of a rapid monitoring technique, and also have a low cost, high reproducibility, and low detection limits of the substance of interest. The following research addresses the main steps for biosensors with fibrinogen (1.5 mg/ml) or bovine serum albumin (1.5 mg/ml) monolayers anchored to the gold electrode of quartz crystals fabrication, which are used for detecting the protein/protein interaction in the saturated solution of anti-fibrinogen and anti-bovine serum albumin (1.5 mg/ml). Gold electrodes were prepared by a sputtering technique using a high purity gold target to grow thin films onto the surfaces of quartz crystals until they presented a fundamental frequency of 20 MHz. The morphology, roughness, thickness, and crystallography were characterized using scanning electron microscopy, atomic force microscopy, profilometry, and X-ray diffraction, respectively. The amino-functionalization of the gold electrodes and fibrinogen and bovine serum albumin sensitive films manufacture were performed by using molecular self-assembly. Through experimental data, the Sauerbrey model obtained the adsorbed surface concentration of protein after protein/protein interaction. The protein surface coverage of fibrinogen/anti-fibrinogen and albumin/anti-albumin interactions were 3.20 $\mu $g/cm$^{2}$ and 2.02 $\mu $g/cm$^{2}$, respectively. On the other hand, the cases of low homology, which were present in the fibrinogen/albumin and albumin/anti-fibrinogen interactions, showed values of 0.37 $\mu $g/cm$^{2}$ and 0.08 $\mu $g/cm$^{2}$, respectively.