RESUMEN
A cortisol biosensor was developed based on double-conducting polymer nanowires, which exhibits excellent conductivity, resistance to biological contamination, and outstanding sensing performance. The biosensor employs dual-mode electrochemical techniques, namely, differential pulse voltammetry (DPV) and chronoamperometry (CA), for the sensitive and low fouling detection of the glucocorticoid hormone cortisol. Experimental results demonstrated that the linear detection range of the biosensor in DPV mode was 1.0 × 10-14-1.0 × 10-8 M, with a detection limit of 0.131 × 10-14 M. In CA mode, the biosensor exhibited a detection range of 1.0 × 10-13-1.0 × 10-7 M and a detection limit of 0.313 × 10-13 M. The biosensor was successfully utilized for the rapid detection of cortisol in human saliva. The combination of a high-specificity cortisol aptamer and functionalized double-conducting polymer nanowires ensured the exceptional specificity and sensitivity of the biosensor in detecting real biological samples.
Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Técnicas Electroquímicas , Hidrocortisona , Límite de Detección , Nanocables , Polímeros , Saliva , Saliva/química , Hidrocortisona/análisis , Nanocables/química , Técnicas Biosensibles/métodos , Humanos , Técnicas Electroquímicas/métodos , Técnicas Electroquímicas/instrumentación , Polímeros/química , Aptámeros de Nucleótidos/química , Conductividad EléctricaRESUMEN
MicroRNA, as a distinctive biomarker, plays a crucial role in the early prognosis and diagnosis of numerous severe diseases. However, due to its inherent properties such as low abundance, small size, and high sequence similarity, the sensitive and accurate detection of microRNA remains a major challenge. Herein, a dual-mode electrochemical biosensing platform was developed for microRNA detection, based on poly(3,4-ethylenedioxythiophene) (PEDOT) doped with graphene oxide-Fe3O4 (GO-Fe3O4) nanocomposite. The GO-Fe3O4/PEDOT composite demonstrated a porous microstructure, outstanding conductivity, and robust catalytic activity towards nitrite. It was electrodeposited onto the electrode surface in a one-step process using the cyclic voltammetry method (CV). The microRNA biosensor was obtained by anchoring DNA with amino groups to the GO-Fe3O4/PEDOT layer through the formation of amide bonds. The designed dual-mode microRNA biosensor demonstrated a broad linear range spanning from 10-15 M to 10-6 M, with low detection limits of 5.18 × 10-15 M and 7.36 × 10-15 M when using chronocoulometry (CC) and amperometric i-t curve (i-t) modes, respectively. Furthermore, a dual-mode electrochemical biosensor has been successfully developed and utilized for the detection of microRNA in human serum, demonstrating its potential for precise and sensitive microRNA detection and its practical application value in clinical medicine.
Asunto(s)
Técnicas Biosensibles , Compuestos Bicíclicos Heterocíclicos con Puentes , Técnicas Electroquímicas , Grafito , Límite de Detección , MicroARNs , Nanocompuestos , Polímeros , MicroARNs/sangre , MicroARNs/análisis , Técnicas Biosensibles/métodos , Nanocompuestos/química , Grafito/química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Polímeros/química , Técnicas Electroquímicas/métodos , HumanosRESUMEN
Excessive fat accumulation is a common phenomenon in cultured fish, which can cause metabolic disease such as fatty liver. However, the relative regulatory approach remains to be explored. Based on this, two feeding trials were conducted. Firstly, fish were fed either a normal-fat diet (NFD) or a high-fat diet (HFD) for eight weeks and sampled at the 2nd, 4th, 6th, and 8th week after feeding (Experiment I). In the first four weeks, fish fed an HFD grew faster than those fed an NFD. Conversely, the body weight and weight gain were higher in the NFD group at the 6th and 8th weeks. Under light and transmission electron microscopes, fat accumulation of the liver was accompanied by an obvious endoplasmic reticulum (ER) swell. Accordingly, the expressions of atf-6, ire-1, perk, eif-2α, atf-4, grp78, and chop showed that ER stress was activated at the 6th and 8th weeks. In Experiment II, 50 mg/kg 4-PBA (an ERs inhibitor) was supplemented to an HFD; this was named the 4-PBA group. Then, fish was fed with an NFD, an HFD, and a 4-PBA diet for eight weeks. As the result, the excessive fat deposition caused by an HFD was reversed by 4-PBA. The expression of ER stress-related proteins CHOP and GRP78 was down-regulated by 4-PBA, and the transmission electron microscope images also showed that 4-PBA alleviated ER stress induced by the feeding of an HFD. Furthermore, 4-PBA administration down-regulated SREBP-1C/ACC/FAS, the critical pathways of fat synthesis. In conclusion, the results confirmed that ER stress plays a contributor role in the fat deposition by activating the SREBP-1C/ACC/FAS pathway. 4-PBA as an ER stress inhibitor could reduce fat deposition caused by an HFD via regulating ER stress.