Structural Insights into the Mechanism of Heat‐Set Gel Formation of Polyisocyanopeptide Polymers

One of the key factors influencing the mechanical properties of natural and synthetic extracellular matrices (ECM) is how large‐scale 3D gel‐like structures emerge from the molecular self‐assembly of individual polymers. Here, structural characterization using small‐angle neutron scattering (SANS) of ECM‐mimicking polyisocyanopeptide (PIC) hydrogels are reported as a function of background ions across the Hofmeister series. More specifically, the process of polymer assembly is examined by probing the structural features of the heat‐set gels and correlating them with their rheological and micro‐mechanical properties. The molecular parameters obtained from SANS clearly show changes in polymer conformation which map onto the temperature‐induced changes in rheological and micro‐mechanical behavior. The formation of larger structures are linked to the formation of cross‐links (or bundles), whilst the onset of their detection in the SANS is putatively linked to their concentration in the gel. These insights provide support for the ‘hot‐spot’ gelation mechanism of PIC heat‐set gels. Finally, it is found that formation of cross‐links and heat‐set gelling properties can be strongly influenced by ions in accordance with Hofmeister series. In practice, these results have significance since ions are inherently present in high concentration during cell culture studies; this may therefore influence the structure of synthetic ECM networks

1H-1,2,3-triazole: from structure to function and catalysis

The heterocyclic family of azoles have recently become one of the most widely used members of the N-heterocycles; the most prominent one being 1H-1,2,3-triazole and its derivatives. The sudden growth of interest in this structural motif was sparked by the advent of click chemistry, first described in the early 2000s. From the early days of click chemistry, when the accessibility of triazoles made them into one of the most versatile linkers, interest has slowly turned to the use of triazoles as functional building blocks. The presence of multiple N-coordination sites and a highly polarized carbon atom allows for metal coordination and the complexation of anions by both hydrogen and halogen bonding. Exploitation of these multiple binding sites makes it possible for triazoles to be used in various functional materials, such as metallic and anionic sensors. More recently, triazoles have also shown their potential in catalytic systems, thus increasing their impact far beyond the initial purpose of click chemistry. This report gives an overview of the structure, functionalities, and use of triazoles with a focus on their use in catalytic systems

Sequential Determination of Total Arsenic and Cadmium in Concentrated Cadmium Sulphate Solutions by Flow-Through Stripping Chronopotentiometry after Online Cation Exchanger Separation

Flow-through stripping chronopotentiometry with a gold wire electrode was used for the determination of total arsenic and cadmium in cadmium sulphate solutions for cadmium production. The analysis is based on the online separation of arsenic as arsenate anion from cadmium cations by means of a cation exchanger. On measuring arsenate in the effluent, the trapped cadmium is eluted by sodium chloride solution and determined in a small segment of the effluent by making use of the same electrode. The elaborated protocol enables a full automatic measurement of both species in the same sample solution. The accuracy of the results was confirmed by atomic absorption spectrometry. The LOD and LOQ for Arsenic were found to be 0.9 μg dm-3 and 2.7 μg dm-3, respectively. A linear response range was observed in the concentration range of 1 to 300 μg dm-3 for sample volumes of 4 mL. The repeatability and reproducibility were found to be 2.9% and 5.2%, respectively. The linear response range for cadmium was found to be 0.5 to 60 g/L. The method was tested on samples from a cadmium production plant

Structural insights into the mechanism of heat-set gel formation of polyisocyanopeptide polymers

One of the key factors influencing the mechanical properties of natural and synthetic extracellular matrices (ECM) is how large-scale 3D gel-like structures emerge from the molecular self-assembly of individual polymers. Here, structural characterization using small-angle neutron scattering (SANS) of ECM-mimicking polyisocyanopeptide (PIC) hydrogels are reported as a function of background ions across the Hofmeister series. More specifically, the process of polymer assembly is examined by probing the structural features of the heat-set gels and correlating them with their rheological and micro-mechanical properties. The molecular parameters obtained from SANS clearly show changes in polymer conformation which map onto the temperature-induced changes in rheological and micro-mechanical behavior. The formation of larger structures are linked to the formation of cross-links (or bundles), whilst the onset of their detection in the SANS is putatively linked to their concentration in the gel. These insights provide support for the ‘hot-spot’ gelation mechanism of PIC heat-set gels. Finally, it is found that formation of cross-links and heat-set gelling properties can be strongly influenced by ions in accordance with Hofmeister series. In practice, these results have significance since ions are inherently present in high concentration during cell culture studies; this may therefore influence the structure of synthetic ECM networks

Sensor devices inspired by the five senses: a review

Wearable devices (wearables) have recently gained significant traction and are predicted to dominate many areas of research over the next 5 years. Many wearables contain a host of sensors that feedback vital bodily parameters to a central system. Although many artificial sensors exist, the biggest challenge to medical wearables is to interface and harness the “big data” set from the human bodies own complex sensor network to better allow early diagnosis and/or treatment and prevention of diseases that have a huge economic burden on society such as type II diabetes. Cybernetics and medicine are joining their forces to overcome the new challenges in developing smarter, more intuitive and smaller sensors that interface with the human sensory system. This review is focused on the interface of devices to ion-mediated transduction pathways both through G-Coupled Protein Receptors and direct or mechanically transduced ion pathways