A detection method for a sensor membrane formed of EuTixOy as part of a biosensor by using PNIPAAm for wrapping enzymes is provided with adding 1.0 g of NIPAAm powder to 20 ml water, heating same at 60° C. to form NIPAAm solution, and cooling the NIPAAm solution; adding 200 μl of 98.7 wt % of APS and 50 μl of 99 wt % of TEMED to the NIPAAm solution, uniformly mixing same, and reacting the mixture for 30 hours to prepare a transparent, gel PNIPAAm; adding 5 mg enzymes to 100 μl of 1× PBS buffer solution, uniformly mixing same, adding 100 μl of PNIPAAm to the buffer solution, and uniformly mixing the buffer solution; placing a biosensor on a heater for heating at a constant temperature of 37° C. wherein the biosensor is an EIS sensor having a sensor membrane formed of EuTixOy; and taking a measurement.