Detection of Kallikrein-Related Peptidase 4 with a
Label-free Electrochemical Impedance Biosensor Based on a Zinc(II)
Phthalocyanine Tetracarboxylic Acid-Functionalized Disposable Indium
Tin Oxide Electrode
posted on 2021-02-15, 06:03authored byElif Burcu Aydın, Muhammet Aydın, Abdulcelil Yuzer, Mine Ince, Kasim Ocakoğlu, Mustafa Kemal Sezgintürk
A new impedimetric biosensing system
based on kallikrein-related
peptidase 4 (KLK 4) antigen-specific antibodies and a zinc(II) phthalocyanine
tetracarboxylic acid (Zn-PcTCa) matrix material was developed for
the first time in this study. First, a Zn-PcTCa-coated indium tin
oxide surface was used as an interface matrix material for the immobilization
of anti-KLK 4 antibodies, and they bound to the platform via amide
bonds. In the presence of KLK 4 antigens, the anti-KLK 4 antibodies
specifically captured these antigens and caused changes in the electrochemical
properties of the system. Randles equivalent circuit was utilized
to evaluate the impedimetric signal, which was measured with the help
of an electrochemical impedance spectroscopy method. After the specific
interaction, the electron transfer resistance (Rct) was remarkably increased and displayed a linear relationship
with the level of the KLK 4 antigen in the range of 0.02–15
pg/mL, with a a detection limit of 6.8 fg/mL. The designed biosensor
was able to detect a KLK 4 antigen with good sensitivity, excellent
specificity, and high stability. In addition, because of having a
low-cost and robust procedure for fabrication, it could be repeatedly
used in several areas including clinical diagnosis.