Functional Bio-integrated Electronics research team observed the the chemical stability of ultrathin films of thermally grown silicon dioxide in aqueous solutions with different combinations of chemistries that are present in biofluids. These findings establish foundational data of relevance to predicting lifetimes of implantable devices that use silicon dioxide as biofluid barriers, and of other classes of systems, such as environmental monitors, where encapsulation against water penetration is important. The National Research Foundation supported this research. The new findings are published in ACS Applied Materials & Interfaces.