High Ionic Strength Enhances the Anti-Pepsin Activity of Titanium Dioxide Nanoparticles

Gastro-esophageal reflux disease (GERD) is a state that evolves when there is a return of acid and pepsin enzyme into the esophagus. Inhibition of pepsin enzyme is one of the strategies used successfully for the treatment of GERD. Titanium dioxide nanoparticles (TiO2 NPs) are among the safest nanoparticles (NPs) that can be used inside the human body. The aim of the present study is to use TiO2 NPs as an inhibitor for the pepsin enzyme as a new treatment for GERD. The activity of pepsin before and after the addition of certain amounts of the NPs to the reaction mixture was measured spectrophotometrically. These experiments were repeated at different temperatures and different ionic strengths. The Michaelis constant (Km) and maximum velocity (Vmax) of the pepsin catalyzed reactions were calculated from the Lineweaver-Burke plots. The results revealed a significant reduction in the pepsin activity by TiO2 NPs. Both Km and Vmax are changed after inhibition indicating a mixed inhibition of pepsin activity. The result also showed that the combination of high ionic strength and TiO2 NPs causes a complete inhibition of pepsin activity. It can be concluded that the best condition for inhibition of pepsin activity is by using a combination of TiO2 NPs and high concentration NaCl at 37℃

Anti-pepsin activity of silicon dioxide nanoparticles

SiO2NPs as an inhibitor of pepsin enzyme for treatment of gastro-esophageal reflux disease (GERD) was used. Silicon dioxide nanoparticles (pepsin coated SiO2NPs) are among the safest nanoparticles that can be used inside the human body. The activity of pepsin before and after the addition of certain amounts of the NPs to the reaction mixture was measured spectrophotometrically. Furthermore, these experiments were repeated at different temperatures, different weights of NPs, and different ionic strengths. The kinetic aparameters (Km and Vmax) of the pepsin catalyzed reactions were calculated from the Lineweaver-Burke plots. The results showed that there is a significant reduction of pepsin activity by SiO2NPs (Vmax of free pepsin = 4.82 U and Vmax of the immobilizedpepsin = 2.90 U). The results also indicated that the presence of ionic strength causes remarkable reduction of pepsin activity. It can be concluded the best condition for inhibition of pepsin activity is by using a combination of SiO2NPs and high concentration NaCl at 37 °C.Se usaron nanopartículas de dióxido de silicio como inhibidores de la pepsina para el tratamiento del reflujo gastroesofágico (GERD). Estas nanopartículas (SiO2NPs recubiertas de pepsina) son unas de las más seguras y pueden usarse en el cuerpo humano. Se midió a través de espectrofotometría la actividad de la pepsina antes y después de añadir cierta cantidad de NPs a la mezcla reactante. Adicionalmente, se repitieron estas pruebas a diferentes temperaturas, variando el peso de las NPs y la fuerza iónica. Se calcularon los parámetros cinéticos (Km y Vmax) de las reacciones catalizadas con pepsina a través de las gráficas de Lineweaver-Burke. Los resultados mostraron que, usando SiO2NPs (Vmax de pepsina libre = 4.82 U y Vmax de pepsina inmovilizada = 2.90 U) y a través de la presencia de fuerza iónica, la actividad enzimática se reduce significativamente. Se concluye que la mejor condición para inhibir la actividad enzimática es usando una combinación de SiO2NPs y una alta concentración de NaCl a 37 °C