Fe(2+) and Fe(3+) as a redox pair showing different effects on a water-soluble conjugated polymer PPESO(3) is definitely an interesting and useful phenomenon in view of signal transduction and has been utilized to develop sensitive assays of hydrogen peroxide and glucose.

A facile synthetic route for preparing fluorescent conjugated polymer PPESO 3 has been proposed. Compared with a commonly used synthetic procedure, not only is the newly developed procedure simplified but also the dealkylation step with BBr 3 is avoided. Therefore, the preparing difficulty and danger are reduced, which is obviously beneficial to the preparation and application of PPESO 3 and other PPEs with similar structure. Also, the nonspecific bindings between PPESO 3 and proteins were investigated. Encouraged by the results, a rather simple but effective sensor system to assay protease activity was developed. This sensor took advantage of the nonspecific interactions of the ionic conjugated polymers with proteins and the enzyme-catalyzed hydrolysis of proteins. It was known that bovine serum albumin (BSA) could enhance the fluorescence of PPESO 3 with an apparent blue shift of the peak emission wavelength. Such phenomena have been successfully utilized to monitor trypsin and pepsin activities in this study for the first time.

Okara is a white-yellow fibrous residue consisting of the insoluble fraction of the soybean seeds remaining after extraction of the aqueous fraction during the production of tofu and soymilk, and is generally considered a waste product. It is packed with a significant number of proteins, isoflavones, soluble and insoluble fibers, soyasaponins, and other mineral elements, which are all attributed with health merits. With the increasing production of soy beverages, huge quantities of this by-product are produced annually, which poses significant disposal problems and financial issues for producers. Extensive studies have been done on the biological activities, nutritional values, and chemical composition of okara as well as its potential utilization. Owing to its peculiar rich fiber composition and low cost of production, okara might be potentially useful in the food industry as a functional ingredient or good raw material and could be used as a dietary supplement to prevent varied ailments such as prevention of diabetes, hyperlipidemia, obesity, as well as to stimulate the growth of intestinal microbes and production of microbe-derived metabolites (xenometabolites), since gut dysbiosis (imbalanced microbiota) has been implicated in the progression of several complex diseases. This review seeks to compile scientific research on the bioactive compounds in soybean residue (okara) and discuss the possible prebiotic impact of this fiber-rich residue as a functional diet on eubiosis/dysbiosis condition of the gut, as well as the consequential influence on liver and kidney functions, to facilitate a detailed knowledge base for further exploration, implementation, and development.

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This article reports the synthesis, optical properties, and pH responses of a water-soluble poly(phenylene ethynylene) with pendant carboxylate groups. This conjugated polyelectrolyte, PPE-OBS, was prepared via a facile synthetic route, using 1,4-di(ethyl 4-oxy-butyrate)-2,5-diiodo-benzene as polymeric monomer and followed by the alkali induced saponification. PPE-OBS absorbs strongly in the blue region and emits a moderately intense fluorescence. However, it subjects to unstable emission in neutral aqueous media, which is believed to arise because the polymer tends to become more hydrophobic via protonation and to form much heavier aggregates (clusters). Subsequent studies on the interaction and stabilization of PPE-OBS with various surfactants indicate that its fluorescence stability can be largely improved in the presence of a small amount of surfactant. More interestingly, even at low pH, the surfactant-stabilized polyelectrolyte with its pendant groups being ACOOH rather than ACOO À remains water-soluble and emits efficiently, which is expected of great significance for the covalent linkage to bio-molecules. In addition, the sensitive pH response in emission spectrum of PPE-OBS/surfactant complex over a relatively wide range suggests surely a potential access to the fluorescent sensing of pH variation.