Holographic Sensors in Biotechnology

As populations expand worldwide, medical care will need to diversify its data collection techniques to be able to provide adequate healthcare to global populations, this can be achieved through point-of-care analysis by wearable analytical devices. Holographic sensors are reusable optical biosensors with the capability to continuously monitor variations, generating the prospect of in vivo monitoring of patient homeostasis. Holographic optical sensors have emerged as an opportunity for low cost and real-time point-of-care analysis of biomarkers to be realized. This review aims to summarize the fundamentals and fabrications of holographic sensors; a key focus will be directed to examining the biotechnology applications in a variety of analytical settings. Techniques covered include surface relief gratings, inverse opals, metal nanoparticle and nanoparticle free holographic sensors. This article provides an overview of holographic biosensing in applications such as pH, alcohol, ion, glucose, and drug detection, alongside antibiotic monitoring. Details of developments in fabrication and sensitizing techniques will be examined and how they have improved the applicability of holographic sensors to point-of-care analytics. Although holographic sensors have made significant progress in recent years, the current challenges, and requirements for advanced holographic technology to fulfil their future potential applications in biomedical devices will be discussed.     

Characterization of the phenolic acid profile and in vitro bioactive properties of white beetroot products

The impact of boiling, baking and fermentation treatment on the phenolic acid profile, antioxidant capacity (AC) and angiotensin-1 converting enzyme (ACE) activity of white beetroot was investigated. The phenolic acids were analysed by liquid chromatography–mass spectrometry (micro-HPLC-MS/MS), while AC and ACE were determined by in vitro assays. Phenolic acids concentration was between 87.55 and 100.98 ng g⁻¹ d.m. Ferulic and p-coumaric acids were the main compounds among the nine phenolic acids identified. Boiling increased the phenolic acid content by 3%; however, baking and fermentation reduced the level of these acids by approximately 6% and 11%, respectively. A significant positive correlation was observed between the results of all AC assays and sinapic and caffeic acid content. The ACE inhibitory activity of white beetroot products may be attributable to the combined effect of the syringic, 4-hydroxybenzoic, ferulic and p-coumaric acids. Our study indicates that white beetroot as a novel product may be a valuable source of phenolic acids and functional properties.     

Site-Selective Peptide Macrocyclization

Cyclized peptides have seen a rise in popularity in the pharmaceutical industry as drug molecules. As such, new macrocyclization methodologies have become abundant in the last several decades. However, efficient methods of cyclization without the formation of side products remain a great challenge. Herein, we review cyclization approaches that focus on site-selective chemistry. Site selectivity in macrocyclization decreases the generation of side products, leading to a greater yield of the desired peptide macrocycles. We will also take an in-depth look at the new exclusively intramolecular N-terminal site-selective CyClick strategy for the synthesis of cyclic peptides. The CyClick method uses imine formation between an aldehyde and the N terminus. The imine is then trapped by a nucleophilic attack from the second amidic nitrogen in an irreversible site-selective fashion.     

Feeding strategy impacts heterologous protein production in Yarrowia lipolytica fed-batch cultures—Insight into the role of osmolarity

Fed-batch cultivation is the preferred bioprocessing strategy applied in microbial production of proteins. Feeding strategy is crucial parameters to be optimized upon development of a fed-batch process. In this study, we investigated impact of different feeding strategies on production of recombinant enzymatic protein in Yarrowia lipolytica cultures. From amongst tested strategies, comprising intermittent and continuous feedings, also in cascade with respiratory factors, intermittent feeding executed after complete exhaustion of glycerol from the medium, with moderate amplitude of osmolarity, was the most beneficial in terms of the secretory enzyme amount, its volumetric productivity and specific activity. Because adopted feeding strategies strongly modulated osmolarity of the cultures, the effect of osmotic pressure on production of the target heterologous protein was investigated in a series of batch cultivations with addition of osmoactive compounds (NaCl, sorbitol, sucrose, and glycerol) at different concentrations. Although obvious promoting effect of the osmoactive substances on the enzyme production was clear, no straightforward correlation between the medium osmolarity and the target enzyme's specific activity could be observed. These results suggest that not only the level of osmolarity but also chemical character of the osmoactive compound have both important impact on the production of secretory proteins in Y. lipolytica cultures.     

Ductile ultra high strength hot stamped steel obtained by Q&P treatments

Current hot stamped steels can offer ultra high strength (1500?MPa) with limited elongation (～5%). Research is ongoing to develop hot stamped steels with similar strength and improved ductility by using various microstructural approaches. The current work describes in depth the characterisation of microstructural features of a steel that was processed via a quenching and partitioning method in a modified hot stamping thermal cycle to deliver a good combination of strength and ductility. It was found that the microstructure thus produced is very complex comprising many different phases. As it is also beyond the ability of one single technique to fully characterise it, several techniques were employed in order to properly understand the various features of the different constituents of this microstructure.