Yarui An

Carbohydrate antigen 19–9 (CA19 - 9) can be used as a biomarker for pancreatic cancer. Measuring the concentration of CA19 - 9 in serum is essential for screening pancreatic cancer patients. In this paper, a dual-electric signal outputs biosensor based on ping pong chrysanthemum-like Bi-BiOI and ternary core–shell structured Pd@AuPt was constructed for ultra-sensitive detection of tumor marker CA19 - 9 using differential pulse voltammetry (DPV) and chronoamperometry (i-t). Ping pong Chrysanthemum-like Bi-BIOI was prepared via one-pot hydrothermal method. To realize the covalent bonding of bismuth-based materials with MWCNT, bismuth-based materials were functionalized by amino groups. MWCNT-NH₂-Bi-BIOI with large specific surface area and remarkable electrical conductivity was used as the sensing platform. Ternary core–shell structured Pd@AuPt with peroxide-like activity and enhanced biocompatibility immobilized massive antibodies through covalent Au–N and Pt–N bonds, thus broadening the linear range of the immunosensor. Based on the above materials, a dual-electric signal outputs biosensor was constructed for detecting CA19 - 9. Under optimal conditions, the detection range of DPV and i-t is 0.001–150 U/mL, the detection limit of DPV is 0.0003 U/mL, and that of i-t is 0.00024 U/mL. In addition, the dual-electric signal outputs immunoassay excels in anti-interference, splendid reproducibility and high recovery in actual sample detection, indicating that the immunosensor is a promising approach to be applied to the detection of CA19 - 9 in clinical diagnosis. Graphical abstract

The abnormal concentrations of human immunoglobulin G (hIgG) refers to many kinds of diseases. Analytical methods with the characteristics of rapid response, easy operation and high sensitivity should be designed to accurately determinate the hIgG levels in human serum. In this work, a label-free electrochemical immunosensor based on WSe₂/rGO was developed to sensitively detect human immunoglobulin G. First, the flower-like transition metal dichalcogenides (TMDCs) Tungsten Diselenide (WSe₂) with large effective specific surface area and porous structure was synthesized by hydrothermal synthesis. As a bio-matrix, the flower-like WSe₂ efficiently increased the active sites for loading antibodies. Meanwhile, reduced graphene oxide (rGO) obtained by tannic acid reduction was used to improve the current response of the sensing interface. WSe₂ was combined with rGO and the electrochemical active surface area (ECSA) of the sensing interface was enlarged to 2.1 times that of GCE. Finally, the combination of flower-like WSe₂ and rGO broadened the detection range and reduced the detection limit of the sensing platform. The immunosensor exhibited a high sensitivity with a wide linear range of 0.01–1000 ng/mL and low detection limit of 4.72 pg/mL. The real sample analysis of hIgG were conducted under optimal conditions, and the spiked recovery rates were between 95.5 and 104.1%. Moreover, satisfactory results were obtained by testing the stability, specificity and reproducibility of the immunosensor. Therefore, it can be concluded that the as-proposed immunosensor has the application potential of clinical analyze of hIgG in human serum. Graphical abstract

This work took advantage of 3D biomimetic hydrangea-like bismuth oxychloride (BiOCl) and PtNi nanocubes to fabricate a facile electrochemical immunosensor for the detection of CA19–9. Herein, APTES functionalized BiOCl (APTES-BiOCl) with large specific surface areas can provide eco-friendly microenvironment for biomolecules. The PtNi nanocubes prepared by the classic hydrothermal method have good conductivity, which can facilitate electron transfer highly efficient. Meanwhile, PtNi nanocubes can immobilize the anti-CA19–9 via covalent Pt-N bonds to anchor a great number of biomolecules more firmly. In addition, reduced graphene oxide (rGO) with excellent conductivity was implemented as a matrix, which greatly promoted electron transfer at the sensing interface. Under the optimal conditions, the proposed immunosensor can detect CA19–9 sensitively, from which a linear range of 0.01–150 U·ml ^–1 was derived accompanied with a low detection limit of 0.0034 U·ml ^–1 . The results illustrated that the designed immunosensor exhibited excellent specificity, good reproducibility, and satisfactory stability. Moreover, it can be applied in the detection of real samples, which indicated that the immunosensor has great potential for early screening and diagnosis of diseases.

Correction for ‘Accuracy improvement on quantitative analysis of the total iron content in branded iron ores by laser-induced breakdown spectroscopy combined with the double back propagation artificial neural network’ by Piao Su et al., Anal. Methods, 2022, 14, 427–437, DOI: 10.1039/D1AY01881G.

A label-free electrochemical immunosensor based on the biscuit-like bismuth nanosheets (BiNSs) and multi-wall carbon nanotubes–chitosan-gold nanoparticles (MWCNTs–Chit-AuNPs) was constructed for the detection of human immunoglobulin G (hIgG). The biscuit-like BiNSs prepared by one-step aqueous phase reduction method had a large electroactive surface area, 1.7 times that of bare glassy carbon electrode (GCE), which could load more antibodies and were used as a larger platform for the specific identification of antigens and antibodies. In addition, MWCNTs and AuNPs with good conductivity could be used to regulate the sensing interface, which promoted electron transfer greatly. Moreover, the AuNPs could stably anchor anti-hIgG by the affinity interaction between amine group of antibody and AuNPs, which greatly increased the number of anti-hIgG attached to the sensing platform. Under the optimal conditions, the proposed immunosensor exhibited excellent analytical performance for hIgG with a wide linear response of 0.01–1000 ng/mL and a low detection limit of 4.26 pg/mL. The electrochemical immunosensor exhibited favorable reproducibility, excellent specificity and high storage stability. Additionally, the immunosensor could be applied to determining hIgG in human serum samples as well. Considering these advantages, the electrochemical immunosensor has the potential application in clinical diagnosis. Graphical abstract