Hypoxanthine Biosensor Based on Immobilization of Xanthine Oxidase on Modified Pt Electrode and Its Application for Fish Meat

Review on recent advances in fabrication of enzymatic and chemical sensors for hypoxanthine

Hypoxanthine is an important product of the nucleotide degradation pathway. It has been considered as a potential marker for assessing meat freshness and clinical diagnosis. In the review, we focus on advancement made in the fabrication of hypoxanthine sensors. Several traditional methods are being utilized for the detection of hypoxanthine, but these methods are expensive, complex, require pretreatment of the sample which is time-consuming and trained persons to operate. Sensors have emerged as simple, rapid, economic, disposable, and portable tools for hypoxanthine detection in biological samples. In particular, the review describes the significant role of hypoxanthine in clinical and food applications. Classification of sensors into enzymatic and non-enzymatic sensors along with the different methods used for xanthine oxidase immobilization and type of transducers used for hypoxanthine detection are briefly explained.

Aldehyde oxidase assay by capillary electrophoresis: From off-line, online up to immobilized enzyme reactor

Capillary electrophoresis is a modern separation technique characterized by many benefits, which qualify it also for enzyme assays and the study of enzyme kinetics during drug development. Homogeneous or heterogeneous approaches can be followed for the enzymatic incubation. In this study, an immobilization procedure of aldehyde oxidase on magnetic particles was developed considering their integration with capillary electrophoresis. A number of magnetic nano/microparticle types were tested for this purpose, showing that aldehyde oxidase was most active when immobilized on bare silica magnetic nanoparticles. Primarily, the reusability of the enzyme immobilized on bare silica nanoparticles was tested. Three consecutive incubations with substrate could be performed, but the activity considerably dropped after the first incubation. One reason could be an enzyme detachment from the nanoparticles, but no release was detected neither at 4°C nor at 37°C during 5 h. The drop in enzymatic activity observed in consecutive incubations, could also be due to inactivation of the enzyme over time at given temperature. For the immobilized enzyme stored at 4°C, the activity decreased to 83% after 5 h, in contrast with a steep decrease at 37°C to 37%.

Enzymes in Fish and Seafood Processing

Enzymes have been used for the production and processing of fish and seafood for several centuries in an empirical manner. In recent decades, a growing trend toward a rational and controlled application of enzymes for such goals has emerged. Underlying such pattern are, among others, the increasingly wider array of enzyme activities and enzyme sources, improved enzyme formulations, and enhanced requirements for cost-effective and environmentally friendly processes. The better use of enzyme action in fish- and seafood-related application has had a significant impact on fish-related industry. Thus, new products have surfaced, product quality has improved, more sustainable processes have been developed, and innovative and reliable analytical techniques have been implemented. Recent development in these fields are presented and discussed, and prospective developments are suggested.