No abstract

Can Organic Solvent Nanofiltration (OSN) be considered green? Is OSN greener than other downstream processing technologies? These are the two main questions addressed critically in the present review. Further questions dealt with in the review are as follows: What is the carbon footprint associated with the fabrication and disposal of membrane modules? How much solvent has to be processed by OSN before the environmental burden of OSN is less than the environmental burden of alternative technologies? What are the main challenges for improving the sustainability of OSN? How can the concept of Quality by Design (QbD) improve and assist the progress of the OSN field? Does the scale have an effect on the sustainability of membrane processes? The green aspects of OSN membrane fabrication, processes development and scale-up as well as the supporting concept of QbD, and solvent recovery technologies are critically assessed and future research directions are given, in this review. Gyorgy Szekely Gyorgy received his MSc degree in Chemical Engineering from the Technical University of Budapest, and he earned his PhD degree in Chemistry under Marie Curie Actions from the Technical University of Dortmund. He worked as an Early Stage Researcher in Hovione PharmaScience and an IAESTE Fellow at the University of Tokyo. He is currently a Research Associate in Imperial College London. His multidisciplinary professional background covers supramolecular chemistry, organic and analytical chemistry, molecular recognition, molecular imprinting, process development, nanofiltration and pharmaceutical impurity scavenging. He is the Secretary General of the Marie Curie Fellows Association and a Member of the Royal Society of Chemistry.

Hydrogels are commonly studied for tissue engineering applications and controlled drug delivery. In order to evaluate their reliability as scaffolds and delivery devices, literature describes many release studies performed involving different analytical techniques. However, these experiments can be expensive, time-consuming, and often not reproducible. In this study, two injectable agar-carbomer-based hydrogels were studied, both being loaded with sodium fluorescein, a harmless fluorophore with a steric hindrance similar to many small drugs, such as for example steroids and other neuroprotecting agents. Starting from simple, traditional, and inexpensive release experiments, it was possible to indirectly estimate the self-diffusion coefficient (D) of loaded sodium fluorescein. Such a parameter was also directly measured in the gel matrix by means of high resolution magic angle spinning (HRMAS) diffusion-ordered spectroscopy NMR. Because of the agreement between the calculated values and those measured by HRMAS-NMR spectroscopy, the latter approach can be considered as a simple and fast alternative to long analytic procedures.

No abstract

Recent development of organic solvent nanofiltration (OSN) materials has been overwhelmingly directed toward tight membranes with ultrahigh permeance. However, emerging research into OSN applications is suggesting that improved separation selectivity is at least as important as further increases in membrane permeance. Membrane solutions are being proposed to improve selectivity, mostly by exploiting solute/solvent/membrane interactions and by fabricating tailored membranes. Because achieving a perfect separation with a single membrane stage is difficult, process engineering solutions, such as membrane cascades, are also being advocated. Here we review these approaches to the selectivity challenge, and to clarify our analysis, we propose a selectivity figure of merit that is based on the permselectivity between the two solutes undergoing separation as well as the ratio of their molecular weights.

Synthetic chemists have devoted tremendous effort towards the production of precision synthetic polymers with defined sequences and specific functions. However, the creation of a general technology that enables precise control over monomer sequence, with efficient isolation of the target polymers, is highly challenging. Here, we report a robust strategy for the production of sequence-defined synthetic polymers through a combination of liquid phase synthesis and selective molecular sieving. The polymer is assembled in solution with real time monitoring to ensure couplings go to completion, on a three-armed star-shaped macromolecule to maximise efficiency during the molecular sieving process. This approach is applied to the construction of sequence-defined polyethers, with sidearms at precisely defined locations that can undergo site-selective modification after polymerisation. Using this versatile strategy, we have introduced structural and functional diversity into sequence-defined polyethers, unlocking their potential for real-life applications in nanotechnology, healthcare and information storage.Natural macromolecules, such as nucleic acids and proteins, are heteropolymers with perfectly defined chain length, monomer sequence and chirality. This precise control of the primary sequence provides structural and functional diversity sufficient to generate the molecular complexity required by all living organisms 1,2 . Polymer chemists have employed strategies such as single monomer insertion 3,4 , tandem monomer addition 5 , kinetic control 6 , segregated templating 7,8 , and sequential growth polymerisation 9,10 , to provide polymers with narrowly disperse, but not uniform, chain lengths and approximately controlled sequences. Nevertheless, these sequence-controlled approaches cannot compete with the precision of nature. To prepare truly uniform sequence-defined polymers, iterative synthesis can afford the required nature-like degree of control over the final sequence. In iterative synthesis specific monomers are added one-at-a-time to the end of a growing polymer chain, reaction debris is then separated from the chain extended polymer, and the cycle is repeated using the next monomer in the sequence 11,12 . Solid-phase iterative synthesis 13 is the premiere method for preparation of sequence-defined polymers, mainly because of the simple reaction and purification processes (i.e. filtration and washing), as well as its ease of automation 14 . However, the insoluble solid supports are often expensive, and the purity of the growing polymer is not readily monitored during synthesis 7,12 . Furthermore, the rates of solid-phase coupling reactions are limited by diffusion into the solid support, ultimately leading to a decline in coupling yields and accumulation of deletion errors 15 . Moreover, solid-phase synthesis is generally difficult to scale up, precluding many industrial applications, particularly in materials science 7,10,12 .Consequently, liquid-phase iterative synthetic methods have long been proposed to ove...

No abstract

Considering that the authentication of food contents is one of the most important issues for the food quality sector, and given the increasing demand for transparency in the meat industry followed the horsemeat scandal in Europe, this study investigates processed-meat products from Italian markets and supermarkets using the mitochondrial cytochrome b gene qualitative PCR identification system in order to verify any species substitution or mislabeling. The results revealed a high substitution rate among the meat products, highlighting a mislabeling rate of 57 %, and consequently, considerable discordance with the indications on the labels, which raises significant food-safety and consumer-protection concerns.