Anthocyanin-induced color changes in bacterial cellulose nanofibers for the accurate and selective detection of Cu(II) in water samples

A novel ratiometric fluorescent sensor from modified coumarin-grafted cellulose for precise pH detection in strongly alkaline conditions

Accurate and convenient monitoring of pH under extreme alkaline conditions is still a challenge. In this work, 4-(3-(7-hydroxy-2-oxo-2H-chromen-3-yl)-3-oxoprop-1-en-1-yl)benzamide (HCB), a coumarin derivative, was grafted onto dialdehyde cellulose (DAC) to obtain a sensor DAC-HCB, which exhibited a ratiometric fluorescent response to the pH of alkaline solutions, resulting in a significant fluorescent color change from yellow to blue (FI459 nm/FI577 nm) at pH 7.5-14. The structure of DAC-HCB was characterized through FT-IR, XRD, XPS, SEM. The pKa of sensor DAC-HCB was 13.16, and the fluorescent intensity ratio FI459 nm/FI577 nm possessed an excellent linear characteristic with pH in the scope of 9.0-13.0. Meanwhile, sensor DAC-HCB showed good selectivity, anti-interference, and fast response time to basic pH, which is an effective fluorescent sensor for examination of pH in alkali circumstance. The recognition mechanism of DAC-HCB to OH- was elucidated with HRMS and density-functional theory (DFT) computational analyses. Sensor DAC-HCB was successfully used for precise detection of environmental water samples pH. This work furnished a new protocol for test strips as a convenient and highly efficient pH detection tool for the high pH environment, and it has great potential for application in environmental monitoring.

Production of Bacterial Exopolysaccharides: Xanthan and Bacterial Cellulose

Recently, degradable biopolymers have become increasingly important as potential environmentally friendly biomaterials, providing a wide range of applications in various fields. Bacterial exopolysaccharides (EPSs) are biomacromolecules, which due to their unique properties have found applications in biomedicine, foodstuff, textiles, cosmetics, petroleum, pharmaceuticals, nanoelectronics, and environmental remediation. One of the important commercial polysaccharides produced on an industrial scale is xanthan. In recent years, the range of its application has expanded significantly. Bacterial cellulose (BC) is another unique EPS with a rapidly increasing range of applications. Due to the great prospects for their practical application, the development of their highly efficient production remains an important task. The present review summarizes the strategies for the cost-effective production of such important biomacromolecules as xanthan and BC and demonstrates for the first time common approaches to their efficient production and to obtaining new functional materials for a wide range of applications, including wound healing, drug delivery, tissue engineering, environmental remediation, nanoelectronics, and 3D bioprinting. In the end, we discuss present limitations of xanthan and BC production and the line of future research.

Covalently phenolated-β-lactoglobulin-pullulan as a green halochromic biosensor efficiency monitored Barramundi fish's spoilage

The effect of the covalent binding between anthocyanins extracted from purple potato peels and beta-lactoglobulin (β-Lg) on its ability to fabricate a green/smart halochromic biosensor combined with pullulan (Pul) was studied. The physical, mechanical, colorimetry, optical, morphological, stability, functionality, biodegradability, and applicability of β-Lg/Pul/Anthocyanin biosensors to monitor the Barramundi fish's freshness during storage were entirely evaluated. The docking and multispectral results proved that β-Lg could be successfully phenolated with anthocyanins and subsequently interacted with Pul via H-bonding and other forces which mainly subsequently form the smart biosensors. Phenolation with anthocyanins significantly heightened the mechanical, moisture resistance, and thermal steadiness of β-Lg/Pul biosensors. Anthocyanins also nearly duplicated the bacteriostatic and antioxidant activities of β-Lg/Pul biosensors. The biosensors changed the color associated with the loss in freshness of the Barramundi fish, mostly due to the ammonia production and pH-alteration throughout fish deterioration. Most importantly, β-Lg/Pul/Anthocyanin biosensors are biodegradable and decomposed within ∼30 d of simulated environmental circumstances. Overall, β-Lg/Pul/Anthocyanin smart biosensors could minimize the usage of plastic packaging materials and employ to monitor the freshness of stored fish and fish-stuffs.