US 12,326,415 B2
Antibody-free rapid detection of bacteria
Yaser Abdi, Tehran (IR); Shahrzad Molavi, Tehran (IR); and Ali Bozorg, Tehran (IR)
Assigned to University of Tehran, (IR)
Filed by Yaser Abdi, Tehran (IR); Shahrzad Molavi, Tehran (IR); and Ali Bozorg, Tehran (IR)
Filed on Jun. 20, 2022, as Appl. No. 17/844,341.
Claims priority of provisional application 63/274,015, filed on Nov. 1, 2021.
Prior Publication US 2022/0326176 A1, Oct. 13, 2022
Int. Cl. G01N 27/414 (2006.01)
CPC G01N 27/4145 (2013.01) [G01N 27/4148 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for detecting a species of bacteria in a sample solution, comprising:
putting the sample solution in contact with an array of zinc oxide (ZnO) nanorods grown on a gate region of a field effect transistor (FET) biosensor, the sample solution comprising a solution suspected to contain bacteria;
applying an alternating current (AC) voltage at a set of frequencies of 500 Hz to 2 MHz between a source electrode within a source region of the FET biosensor and a drain electrode within a drain region of the FET biosensor;
applying a first direct current (DC) voltage of V1 to the sample solution on the gate region;
measuring a first set of electrical impedance values (Z1) between the source region and the drain region responsive to the applied AC voltage and the applied V1, the Z1 comprising a first set of real part magnitude of electrical impedance respective to the set of frequencies;
calculating, utilizing one or more processors, a first impedance difference set (ΔZ1) by calculating a difference between each electrical impedance value of the Z1 measured at a respective frequency (fi) of the set of frequencies and a respective electrical impedance value of a first initial set of electrical impedance values (Z10) associated with a bacteria-free reference solution measured at the same frequency fi, calculating each first impedance difference being done using a relation defined by:
(ΔZ1)fi=(Z1)fi−(Z10)fi;
determining, utilizing the one or more processors, bacteria indicative factors, comprising:
detecting a first impedance difference peak value (ΔZ1m) of the ΔZ1; and
determining a peak frequency (fm) of the set of frequencies respective to the ΔZ1m; and
detecting a presence of a first species of bacteria in the sample solution based on the bacteria indicative factors.