The described subject matter includes techniques and components for minimally invasive, selective capture and release of analytes. An aptamer is selected for its binding affinity with a particular analyte(s). The aptamer is functionalized on a solid phase, for example, microbeads, polymer monolith, microfabricated solid phase, etc. The analyte is allowed to bind to the aptamer, for example, in a microchamber. Once the analyte has been bound, a temperature control sets the temperature to an appropriate temperature at which the captured analyte is released.