Poly(2-oxazoline) glycopolymers with tunable LCST behavior

A series of thermo-responsive glyco-poly(2-oxazoline)s based on 2-ethyl-2-oxazoline and 2-(dec-9-enyl)-2-oxazoline were prepared. To study the effect of the sugar content on the solution behavior in water, two sets of copolymers with constant monomer-to-initiator ratios of 20 and 50 and varying amounts of the hydrophobic alkene functionalized monomer were synthesized. The glycopolymers were obtained by the photoaddition of 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glycopyranose onto the double bonds followed by deacetylation of the saccharide residues. Turbidimetry measurements of the respective glycopolymers revealed a decreasing cloud point temperature with increasing amount of sugar moieties, proposed to be caused by hydrogen bonding between the sugars and the polymer amide groups, which is enabled by the flexibility of the long decyl spacer. Due to the linear relationship between cloud point temperatures and the sugar content, the cloud points can be easily tailored for specific applications

A sugar decorated macrornolecular bottle brush by carbohydrate-initiated cationic ring-opening polymerization

The capability of a range of protected glucose- (Glc), galactose- (Gal), and fructose- (Fm) based tosylates and triflates to initiate the living cationic ring-opening polymerization of 2-ethy1-2-oxazoline (EtOx) was investigated by detailed kinetic studies utilizing (1)H and (19)F NMR spectroscopy and SEC as well as MALDI and ESI TOF mass spectrometry. The Glc and Gal tosylates and a sterically hindered Fm triflate revealed slow and incomplete initiation, whereas the Glc and Gal triflates resulted in living polymerizations. Well-defined Glc as well as Gal alpha-end-functionalized PEtOx was obtained after deprotection. Functionalization of the living oxazolinium chain ends with methacrylate anions resulted in a macromonomer that was applied for RAFT polymerization. Deprotection resulted in a comb polymer that is selectively functionalized with Glc at the ends of all side chains (DP(backbone) = 13, DP(side) (chains) = 10, PDI = 1.11)

Internationally lost COVID-19 cases

BACKGROUND: With its epicenter in Wuhan, China, the COVID-19 outbreak was declared a pandemic by the World Health Organization (WHO). While many countries have implemented flight restrictions to China, an increasing number of cases with or without travel background to China are confirmed daily. These developments support concerns on possible unidentified and unreported international COVID-19 cases, which could lead to new local disease epicenters. METHODS: We have analyzed all available data on the development of international COVID-19 cases from January 20th, 2020 until February 18th, 2020. COVID-19 cases with and without travel history to China were divided into cohorts according to the Healthcare Access and Quality Index (HAQ-Index) of each country. Chi-square and Post-hoc testing were performed. RESULTS: While COVID-19 cases with travel history to China seem to peak for each HAQ-cohort, the number of non-travel related COVID-19 cases seem to continuously increase in the HAQ-cohort of countries with higher medical standards. Further analyses demonstrate a significantly lower proportion of reported COVID-19 cases without travel history to China in countries with lower HAQ (HAQ I vs. HAQ II, posthoc p < 0.01). CONCLUSIONS: Our data indicate that countries with lower HAQ-index may either underreport COVID-19 cases or are unable to adequately detect them. Although our data may be incomplete and must be interpreted with caution, inconsistencies in reporting COVID-19 cases is a serious problem which might sabotage efforts to contain the virus

Impact of PEG and PEG-b-PAGE modified PLGA on nanoparticle formation, protein loading and release.

The effect of modifying the well-established pharmaceutical polymer PLGA by different PEG-containing block-copolymers on the preparation of ovalbumin (OVA) loaded PLGA nanoparticles (NPs) was studied. The used polymers contained poly(d,l-lactic-co-glycolic acid) (PLGA), polyethylene glycol (PEG) and poly(allyl glycidyl ether) (PAGE) as building blocks. The double emulsion technique yielded spherical NPs in the size range from 170 to 220nm (PDI<0.15) for all the differently modified polymers, allowing to directly compare protein loading of and release. PEGylation is usually believed to increase the hydrophilic character of produced particles, favoring encapsulation of hydrophilic substances. However, in this study simple PEGylation of PLGA had only a slight effect on protein release. In contrast, incorporating a PAGE block between the PEG and PLGA units, also eventually enabling active targeting introducing a reactive group, led to a significantly higher loading (+25%) and release rate (+100%), compared to PLGA and PEG-b-PLGA NPs

Analytical and synthesis details from Determination of ω-end functionalities in tailored poly(2-alkyl-2-oxazoline)s by liquid chromatography and mass spectrometry

The in-depth analytical characterization of polymers, in particular regarding intended biomedical applications, is becoming increasingly important to elucidate their structure–property relationships. Specifically, end group analysis of, e.g. polymers featuring a ‘stealth effect’ towards the immune system is of particular importance because of their use in coupling reactions to bioactive compounds. Herein, we established a liquid chromatography (LC) protocol to analyse bicyclo[6.1.0]nonyne-functionalised poly(2-alkyl-2–oxazoline)s (POx)s as promising functional polymers that can be applied in strain-promoted click reactions. This work involved the synthesis of poly(2-methyl-2-oxazoline) (PMeOx) and poly(2-ethyl-2-oxazoline) (PEtOx) by living cationic ring-opening polymerization (CROP) with different molar masses ranging from 2 up to 17.5 kDa and, to our knowledge, the first liquid chromatographic analysis of PMeOx. The developed analytical protocol enables the quantitative determination of post-polymerization reaction sequences with respect to the conversion of the ω-end groups. All synthesized polymers were straightforwardly analysed on a C18-derivatized silica monolithic column under reversed-phase chromatographic conditions with a binary mobile phase gradient comprising a mixture of acetonitrile and water. Subsequent mass spectrometry of collected elution fractions enabled the confirmation of the desired ω-end group functionalities and the identification of synthetic by-products

Novel insights into the enterotoxigenic potential and genomic background of Staphylococcus aureus isolated from raw milk

In this study, 53 Staphylococcus (S.) aureus strains were typed by 16S–23S rDNA intergenic spacer region (ISR) typing and staphylococcal enterotoxin gene (SEg) typing for all the staphylococcal enterotoxin (se) and sta- phylococcal enterotoxin-like toxin (sel) genes known to date, revealing a higher discriminatory power than that of multi locus sequence typing. Six strains, one of each ISR- and SEg-type, were genome sequenced and the ability to produce some classical and new SEs when growing in milk was investigated. The manual analysis of the six genomes allowed us to confirm, correct and expand the results of common available genomic data pipelines such as VirulenceFinder. Moreover, it enabled us to (i) investigate the actual location of se and sel genes, even for genes such as selY, whose location (in the core genome) was so far unknown, (ii) find novel allelic variants of se and sel genes and pseudogenes, (iii) correctly annotate se and sel genes and pseudogenes, and (iv) discover a novel type of enterotoxin gene cluster (egc), i.e. the egc type 5 in strains 356P and 364P, while S. argenteus MSHR1132 harbored the egc type 6. Four of the six S. aureus strains produced sufficient amounts of SEA, SEC, SED and SEH in milk to cause staphylococcal food poisoning (SFP), with S. aureus 372 P being the highest producer of SED in milk found to date, producing as much as ca. 47,300 ng/mL and 49,200 ng/mL of SED, after 24 and 48 h of incubation in milk at 37 °C, respectively. S. aureus 372 P released a low amount of SER in milk, most likely because the seR gene was present as a pseudogene, putatively encoding only 51 amino acids. These findings confirm that not only the classical SEs, but also the new ones can represent a potential hazard for the consumers’ health if produced in foods in sufficient amounts. Therefore, the detection of SEs in foods, especially if involved in SFP cases, should focus not only on classical, but also on all the new SEs and SEls known to date. Where reference methods are unavailable, the presence of the relevant genes, by using the conventional and real time PCR protocols we exhaustively provided herein, and their nucleotide sequences, should be investigated

Optimized Encapsulation of the FLAP/PGES-1 Inhibitor BRP-187 in PVA-Stabilized PLGA Nanoparticles Using Microfluidics

The dual inhibitor of the 5-lipoxygenase-activating protein (FLAP) and the microsomal prostaglandin E2 synthase-1 (mPGES-1), named BRP-187, represents a promising drug candidate due to its improved anti-inflammatory efficacy along with potentially reduced side effects in comparison to non-steroidal anti-inflammatory drugs (NSAIDs). However, BRP-187 is an acidic lipophilic drug and reveals only poor water solubility along with a strong tendency for plasma protein binding. Therefore, encapsulation in polymeric nanoparticles is a promising approach to enable its therapeutic use. With the aim to optimize the encapsulation of BRP-187 into poly(lactic-co-glycolic acid) (PLGA) nanoparticles, a single-phase herringbone microfluidic mixer was used for the particle preparation. Various formulation parameters, such as total flow rates, flow rate ratio, the concentration of the poly(vinyl alcohol) (PVA) as a surfactant, initial polymer concentration, as well as presence of a co-solvent on the final particle size distribution and drug loading, were screened for best particle characteristics and highest drug loading capacities. While the size of the particles remained in the targeted region between 121 and 259 nm with low polydispersities (0.05 to 0.2), large differences were found in the BRP-187 loading capacities (LC = 0.5 to 7.29%) and drug crystal formation during the various formulations