Researchers determined that in CF mucus nanobeads have lower diffusion coefficient, and the elastic and viscous moduli are higher than in non-CF mucus. Also, they found that 25% correction of F508del mutation with lumacaftor is enough to improve significantly CF mucus properties. Surprisingly, also incubation with amiloride, a compound that reduces fluid absorption but not the secretion of bicarbonate, improved CF mucus properties. Regarding inhalation of bicarbonate by CF patients, a pilot clinical trial is planned. In conclusion, CF mucus properties can be recovered in vitro either improving the hydration of the airways or increasing the activity of the mutated protein with a corrector compound, probably by increasing bicarbonate secretion. The results of the clinical trial will permit to determine whether bicarbonate, a low cost and mutation-independent treatment, can improve the properties of CF sputums.