Engineered reaction containers that can be physically and chemically defined to control the flux of molecules of different sizes and charge are disclosed. Methods for constructing small volume reaction containers through a combination of etching and deposition are also disclosed. The methods allow for the fabrication of multiple devices that possess features on multiple length scales, specifically small volume containers with controlled porosity on the nanoscale.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the U.S. Department of Energy. The government has certain rights in the invention.