Photoelectrochemical detection of alpha-fetoprotein based on ZnO inverse opals structure electrodes modified by Ag2S nanoparticles

Abstract

In this work, a new photoelectrochemical biosensor based on Ag2S nanoparticles (NPs) modified macroporous ZnO inverse opals structure (IOs) was developed for sensitive and rapid detection of alpha fetal protein (AFP). Small size and uniformly dispersed Ag2S NPs were prepared using the Successive Ionic Layer Adsorption And Reaction (SILAR) method, which were adsorbed on ZnO IOs surface and frame work as matrix for immobilization of AFP. The composite structure of ZnO/Ag2S expanded the scope of light absorption to long wavelength, which can make full use of the light energy. Meanwhile, an effective matching of energy levels between the conduction bands of Ag2S and ZnO are beneficial to the photo-generated electrons transfer. The biosensors based on FTO (fluorine-doped tinoxide) ZnO/Ag2S electrode showed enough sensitivity and a wide linear range from 0.05 ng/mL to 200 ng/mL with a low detection limit of 8 pg/mL for the detection of AFP. It also exhibited high reproducibility, specificity and stability. The proposed method was potentially attractive for achieving excellent photoelectrochemical biosensor for detection of other proteins.

Ag-doped ZnO nanorods embedded reduced graphene oxide nanocomposite for photo-electrochemical applications

“…Owing to the excellent physical and chemical properties, such as high electrochemical stability, super oxidative capacity and low toxicity, ZnO is a promising material for the application of photocatalytic activity. Therefore, among the other metal oxides, ZnO is the first and widely used material in heterogeneous photocatalysis [7–10]. Although it has numerous advantages in the photocatalytic process, the fast recombination of photo-excited charge carriers in ZnO hinders the photocurrent generation and photocatalytic efficiency.…”

State-of-the-Art Optical Devices for Biomedical Sensing Applications—A Review

“…ZnO inverse opal and quantum dots were used on the photoelectrochemical electrode surface in this analysis [204]. In another study, an inverse opal biosensor based on inverse opal-Ag 2 S NPs was proposed for the detection of AFP [205]. The ZnO inverse opal/Ag 2 S composite resulted in the production of long-wavelength light absorption.…”

“…The LOD for AFP detection was 8 pg/mL, which was nearly 1.5 times higher than the former process. This outcome was due to better photo-generated electron conduction in ZnO inverse opal/Ag 2 S structures due to the successful matching of energy levels among the transmission bands of Ag 2 S and ZnO inverse opal [205]. Apart from the TiO 2 based inverse opal, IOH nonporous arrangements could be employed in label-free and selective recognition of the IgG antibodies [206].…”

Photonic crystal based biosensors: Emerging inverse opals for biomarker detection

“…5 c, the Abs were immobilized on chitosan/fluorine-TiO 2 /ZnO–IOs electrode surface and the composite of AFP-QDs-GOX were used as a tracer to enhance the sensitivity of immunosensor [ 87 ]. In the other work, they developed IO biosensor for detection of AFP using IOs–Ag 2 S NPs [ 116 ]. The ZnO IO/Ag 2 S composite led to the development of light absorption to long wavelengths.…”

“…AFP was detected with LOD of 8 pg/mL which was almost 1.5 times better than the previous method. This result is related to effective matching of energy levels among the transmission bands of Ag 2 S and ZnO IO which led to better photo-generated electrons conduction in ZnO IO/Ag 2 S structures [ 116 ].…”