posted on 2023-12-04, 19:35authored byYucheng Zhou, Xuan Luo, Fei Yan, Yiping Mou
Prompt and accurate
detection of CA19-9 in human serum has great
clinical significance for the early diagnosis and disease monitoring
of cancer. Herein, we develop a convenient and antifouling electrochemical
sensor for CA19-9 determination by immobilization of both an electrochemical
redox probe [methylene blue (MB)] and immunorecognition element (CA19-9
antibody) on an electrostatic nanocage consisting of bipolar silica
nanochannel array (bp-SNA). bp-SNA is composed of a negatively charged
inner layer (n-SNA) and positively charged outer layer (p-SNA), which
could be stably prepared on indium tin oxide (ITO) in several seconds
using a two-step electrochemically assisted self-assembly approach
and display asymmetric surface charges for confinement and enrichment
of cationic MB into the inner n-SNA layer through electrostatic interaction.
Modification of the CA19-9 antibody on the top surface of bp-SNA confers
the sensing interface with specific recognition capacity. An antibody–antigen
complex formed at the as-prepared immunosensor causes the decreased
electrochemical signals of MB, achieving sensitive determination of
CA19-9 with a wider linear dynamic range from 10 μU/mL to 50
U/mL and a low detection limit (3 μU/mL). Furthermore, accurate
and feasible analysis of the CA19-9 amount in human serum samples
by our proposed probe-integrated electrochemical immunosensor is realized.