Label-free sensing of thrombin based on quantum dots and thrombin binding aptamer

► Label-free aptamer based detection of thrombin is realized using CdTe QDs. ► Easy to operate as the complicated cross-linking reactions were eliminated. ► Turn-on sensing mode could reduce background signal and improve sensitivity. ► Serum sample analysis was achieved, requiring no pretreatment or separation. ► This work may offer a relatively general approach to other analytes detection.