KCS

A number of patients who complain of laryngopharyngeal reflux disease (LPR) is on the gradual increase due to changes in climate, environment, and eating habits. LPR causes hoarseness, frequent throat clearing, bitter taste in the mouth, referred ear pain, chronic cough and even larynx cancer. However, the effective treatment of LPR is difficult because the treatment yet stay in the inhibition of gastric acid secretion as well as the symptoms persist after treatment. Therefore, appropriate treatment through accurate and rapid diagnosis is necessary. Since pepsin is proteolytic enzyme produced only in the stomach, detection techniques of pepsin in saliva is useful as a sensitive and non-invasive method for the reflux of stomach contents. Therefore, pepsin is one of the most important biomarkers to diagnose LPR. Herein, we report on a new approach to design an immunoassay based on the enzyme-linked immunosorbent assay (ELISA). Binding of antigen-antibody converts a colorless substrate to a colored product by using enzyme. Furthermore, to confirm the presence of pepsin in saliva resulting from LPR, we checked the pH of saliva through the color changes of various kinds of indicator. The general pH of saliva is about 6.7, but in the case of saliva which contains pepsin, the pH decreases. We compared the color between different pH of phosphate buffer and artificial saliva in acidic and basic condition of indicators. In this ways, we investigate the utility of colorimetric immunoassay to determine pepsin in biological samples (i.e., saliva).