The combination of a supported UF membrane having low non-specific binding (NSB) and high protein retention of the tested chemical entity (CE) in a device that is SBS complaint. The membrane is heat sealed to form one or more integral wells that are used to reduce NSB and improve protein retention and provides a simple, flexible way to reduce CE, such as drug and drug candidate (and other small molecule) NSB so that drug binding studies may more closely predict the behavior of these compounds in vivo.