Immunodetection of 17β-estradiol in serum at ppt level by microcantilever resonators

► The immunodetection of 17β-estradiol by microcantilever resonators is here proposed. ► The method was tested in buffer solutions and extracted samples from spiked sera. ► The method exhibits a limit of detection of 20 ppt in extracted sera. ► A limited cross-reactivity with high concentrations (ppb) of testosterone was shown. ► The method was found more sensitive than a commercial ELISA test.