pH Initiated Site Specific Drug Release

Abstract

Studies have shown that unhealthy cells can have more acidic conditions in the cytoplasm. A medical application for this is to target unhealthy cells with vesicles containing a drug and then lyse when exposed to a more acidic environment. To demonstrate acidic pH-initiated cell lysing, sodium laurate was integrated into a dimyristoylphosphatidylcholine (DMPC) bilayer by sonicating the two organic compounds at a 1:1 ratio in a phenol red solution. Newly made vesicles contained phenol red, a chromophoric pH indicator that appears red in basic solutions, but yellow in acidic solutions. Vesicles will lyse as surrounding solution becomes more acidic, protonating sodium laurate to become lauric acid, and collapsing the bilayer. The expected results would be a delayed increase in absorbance at 420 nm when compared to phenol red alone being exposed to an acidic environment.