Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected human cell through ACE2. This study is developing a Pd nano-thin film electrode for electrochemical impedance spectroscopy. This invention can quantify neutralize antibody too. The detection platform can be used to screen 1 microliter anti-virus infection drug sample within 21 mins. Compare to SPR standard, our invention only needs 1/10000 concentration of ACE2reaction volume is ~1/30 than SPR. This invention can be adapted in detection of cancer markers,other emergency infection diseasestherapeutic drugs, too.