Split-type photoelectrochemical immunoassay for sensitive quantification of carcinoembryonic antigen based on target-induced in situ formation of Z-type heterojunction.

Carcinoembryonic antigen (CEA), a vital biomarker, plays a significant role in the early diagnosis and prognostic estimation of malignant tumors. In this study, a split-type photoelectrochemical immunoassay for the sensitive quantification of CEA has been successfully developed based on the target-induced in situ formation of a Z-type heterojunction. First, gold nanoparticle-decorated ZnIn2S4 (AuNPs/ZnIn2S4) composites were synthesized and used for the fabrication of photoelectrodes. Then, the detection antibody labeled with Ag nanoparticles was formed and applied for the biorecognition of CEA and subsequent liberation of Ag+ ions to induce the in situ formation of Ag2S/AuNPs/ZnIn2S4, a Z-type heterojunction, on the photoelectrode. The Z-type Ag2S/AuNPs/ZnIn2S4 heterojunction with effectively promoted separation of photogenerated charge carriers could lead to a markedly enhanced photocurrent response and highly sensitive quantification of CEA. Moreover, the three-dimensional spatial structure of ZnIn2S4 provides abundant active sites for the reaction and exhibits non-enzymatic properties, which are conducive to the further improvement of the analytical performance of CEA. The developed split-type photoelectrochemical immunoassay with good sensitivity, satisfactory selectivity, reliable stability, wide dynamic linear range (0.01-20 ng mL-1), and low detection limit (7.3 pg mL-1) offers valuable insights into the development of novel PEC biosensing models for the detection of tumor biomarkers and holds potential application value in the field of disease diagnosis.

Omnichannel integration strategy based on BOPS.

Technological innovation and the upgrading of consumer preferences have greatly accelerated the rapid development of the "new retail" omnichannel model. Meeting the personalized and seamless interactive experience expected by consumers requires integrating the advantages of both offline and online channels and expanding the integrated and intelligent omnichannel layout. This has emerged as a complex problem that the industry urgently needs to address. In order to tackle this issue, we conducted a study on a Buy-Online-and-Pick-up-in-Store (BOPS) pricing game between offline stores and e-commerce departments, considering factors such as match probability and network cost of return. Furthermore, we proposed the Buy-Online-and-Pick-up-in-Store-and-Return-Online (BORO) strategy and conducted an analysis on the variation in market share and revenue levels for both offline stores and e-commerce departments under this strategy. The results demonstrate that: (i) the omnichannel strategy of BOPS can increase the revenues of both offline stores and e-commerce departments only when the distance costs are moderate; (ii) the BORO strategy provides greater benefits to offline stores compared to e-commerce departments; and (iii) the effectiveness of the BORO strategy is influenced by factors such as match probability, distance cost, and product return. This research not only provides a theoretical foundation but also practical insights for the strategic channel management of omnichannel brand merchants.