Magnetic copper silicate and boronic acid-conjugated AuNCs@keratin-based electrochemical/fluorescent dual-sensing for carcinoembryonic antigen

Co, Fe Dual-Doped MoS2 Nanosheets on Polypyrrole Microtubes as Effective Peroxidase Mimics for Glutathione Sensing

Heteroatom doping is considered an effective way to enhance the catalytic activity of MoS2 nanosheets (NSs). In the paper, dual-metal doping was proposed to incorporate Fe and Co into hierarchical MoS2 ultrathin NSs, which grew directly on polypyrrole microtubes (Fe, Co-MoS2@PPy), for the enhanced enzyme-like catalytic reaction. The particular hollow tubular structure realized effective electron transfer. The doped Fe and Co tuned the electronic architecture of the MoS2 NSs to enhance the enzyme-like catalytic activity. The abundant exposed void spaces facilitated ion diffusion/penetration between the PPy interlayer and Fe-Co doped MoS2 shell, leading to heterostructured synergistic effects. Therefore, the synthesized Fe and Co-MoS2@PPy composites showed remarkable catalytic activity. The high catalytic efficiency of Fe and Co-MoS2@PPy was confirmed with the reaction of tetramethylbenzidine (TMB) and H2O2 for visible detection. The blue color disappeared after adding glutathione (GSH). Thus, this procedure was used as a convenient way to detect GSH with a detection limit of 0.76 μM. The dual-metal-doped strategy was confirmed to improve the performance of MoS2 nanocomposites and could be used as a promising matrix for other applications, such as electrochemical energy conversion, medical diagnosis, and others.

Simultaneous Assay of CA 72-4, CA 19-9, CEA and CA 125 in Biological Samples Using Needle Three-Dimensional Stochastic Microsensors

Two-needle 3D stochastic microsensors based on boron- and nitrogen-decorated gra-phenes, modified with N-(2-mercapto-1H-benzo[d]imidazole-5-yl), were designed and used for the molecular recognition and quantification of CA 72-4, CA 19-9, CEA and CA 125 biomarkers in biological samples such as whole blood, urine, saliva and tumoral tissue. The NBGr-2 sensor yielded lower limits of determination. For CEA, the LOD was 4.10 × 10-15 s-1 g-1 mL, while for CA72-4, the LOD was 4.00 × 10-11 s-1 U-1 mL. When the NBGr-1 sensor was employed, the best results were obtained for CA12-5 and CA19-9, with values of LODs of 8.37 × 10-14 s-1 U-1 mL and 2.09 × 10-13 s-1 U-1 mL, respectively. High sensitivities were obtained when both sensors were employed. Broad linear concentration ranges favored their determination from very low to higher concentrations in biological samples, ranging from 8.37 × 10-14 to 8.37 × 103 s-1 U-1 mL for CA12-5 when using the NBGr-1 sensor, and from 4.10 × 10-15 to 2.00 × 10-7 s-1 g-1 mL for CEA when using the NBGr-2 sensor. Student's t-test showed that there was no significant difference between the results obtained utilizing the two microsensors for the screening tests, at a 99% confidence level, with the results obtained being lower than the tabulated values.