Biosensors are powerful analytical tools used to identify and detect target molecules. Electrochemical biosensors, which combine biosensing with electrochemical analysis techniques, are efficient analytical instruments that translate concentration signals into electrical signals, enabling the quantitative and qualitative analysis of target molecules. Electrochemical biosensors have been widely used in various fields of detection and analysis due to their high sensitivity, superior selectivity, quick reaction time, and inexpensive cost. However, the signal changes caused by interactions between a biological probe and a target molecule are very weak and difficult to capture directly by using detection instruments. Therefore, various signal amplification strategies have been proposed and developed to increase the accuracy and sensitivity of detection systems. This review serves as a reference for biosensor and detector research, as it introduces the research progress of electrochemical signal amplification strategies in olfactory and taste evaluation. It also discusses the latest signal amplification strategies currently being employed in electrochemical biosensors for nanomaterial development, enzyme labeling, and nucleic acid amplification techniques, and highlights the most recent work in using cell tissues as biosensitive elements.

Neoagaro-oligosaccharides (NAOS) have health benefits that are related to their amount and degree of polymerization (DP). However, the current methods that are used to quantify enzymatically released NAOS are un-specific and time-consuming. Agar has been extracted from Gelidium amansii and has been degraded by AgaXa (a recombinant β-agarase). Polysaccharide analysis using carbohydrate gel electrophoresis (PACE) has been adapted in order to quantify NAOS. In addition, the anti-oxidant activity of the degraded samples has been assessed. We have found that the PACE method provided sensitive, precise, and accurate quantification for each of the six NAOS samples. PACE has revealed that the DP of the enzymatic products from the AgaXa digestion were mainly neoagaro-octaose and neoagaro-decaose. The degraded samples exhibited increased radical-scavenging activity towards 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline sulfonic acid) radicals. While the anti-oxidant activity may have been from NAOS activity and contributions from neoagaro-octaose and neoagaro-decaose. The adapted PACE method that has been presented here is promising for large sample analysis during quality control and for characterizing novel β-agarase degradation mechanisms.

It is unclear whether different processing methods change the biological functions of foods and how these functions are evaluated in the human body. Here, steamed bread and baked bread, the traditional staple foods in China and many Western countries, were made by steaming and baking, respectively, using one piece of fermented wheat dough and then consumed by 16 healthy young volunteers. By detecting 38 cytokines, 12 metabolic enzymes, glucose, lactate, and nicotinamide adenine dinucleotide (NADH) in the serum, the cytokine network and central metabolic pathway network were investigated to compare the effects of the two staple foods on immunity and metabolism. Compared with steamed bread, baked bread increased (p < 0.05) concentrations of fractalkine and macrophage-derived chemokine, decreased (p < 0.05) the concentration of interleukin-1RA, increased (p < 0.05) the expression level of phosphofructokinase, and decreased (p < 0.05) the expression level of glucose-6-phosphate dehydrogenase in the serum. Two network analyses indicated that baked bread, as compared to the steamed bread, enhanced communication between immune cells, increased catabolism, and decreased anabolism. Further, a correlation analysis of cytokines and metabolic enzymes suggested that the two staple foods may affect metabolism by regulating the secretion of cytokines. These findings highlight how the same raw food material processed by different methods may have different impacts on immunity and metabolism in humans.

The biosensor reflecting the linkage of the umami signal during conduction and amplification, and the study on the receptor–ligand recognition mechanism.