Bio-inspired metal-coordination: Using more of nature’s tricks to assemble hydrogel materials with multi-functional properties

A variety of dynamic bonds have been employed as reversible crosslinks in polymer materials in efforts to obtain desirable properties such as stimuli-response, self-healing and shape-memory. Many dynamic bonds utilized so far however, have poor compatibility with aqueous solvents, thereby limiting their use in polymer materials intended for environmental, medical and personal care applications. Inspired by marine biological materials, we have been exploring metal-coordinate dynamic crosslinks that allow unique control over metal-binding polymer network properties in aqueous conditions. These early bio-mimetic explorations revealed that certain metal-ligand coordination complexes allow aqueous polymer solutions to be finely tuned between fluids and strong viscoelastic gels, simply by the choice of the coordinating metal ion. More recently we have begun exploring stimuli-responsive properties of metal-coordinate polymer networks and have found that temperature, pH, magnetic and mechanical stimuli all can induce strong responses in metal-ligand coordinate crosslink dynamics. These demonstrations open the door to design of multi-stimuli-response controlled polymer hydrogel materials. Early lessons from this pursuit will be presented

Experiences with energy drink consumption among Norwegian adolescents

The objective of the present study was to describe adolescents’ habits and experiences with energy drink (ED) consumption and the relation to the amount of ED consumed. We used the national cross-sectional study Ungdata, conducted in 2015–16 in Norway. A total of 15 913 adolescents aged 13–19 years answered questions about ED consumption related to the following topics: reasons for, experiences with, habits and parental attitudes. The sample comprised only adolescents reporting to be ED consumers. We estimated the association between the responses and the average daily consumption of ED in multiple regression models. Those who consumed ED ‘to concentrate’ or ‘to perform better in school’ consumed on average 73⋅1 (CI 65⋅8, 80⋅3) and 112⋅0 (CI 102⋅7, 121⋅2) ml more daily, respectively, than those who did not consume ED for these reasons. Up to 80 % of the adolescents reported that ‘my parents think it is OK that I drink energy drink’, but at the same time almost 50 % reported that ‘my parents say that I shouldn't drink energy drink’. Apart from increased endurance and feeling stronger, both desired and adverse effects of ED consumption were reported. Our findings indicate that the expectation created by the ED companies have great influence on the adolescents’ consumption rate and that parental attitudes towards ED have little to no influence on the adolescents’ consumption rate.publishedVersio

Control of hierarchical polymer mechanics with bioinspired metal-coordination dynamics.

In conventional polymer materials, mechanical performance is traditionally engineered via material structure, using motifs such as polymer molecular weight, polymer branching, or block copolymer design. Here, by means of a model system of 4-arm poly(ethylene glycol) hydrogels crosslinked with multiple, kinetically distinct dynamic metal-ligand coordinate complexes, we show that polymer materials with decoupled spatial structure and mechanical performance can be designed. By tuning the relative concentration of two types of metal-ligand crosslinks, we demonstrate control over the material's mechanical hierarchy of energy-dissipating modes under dynamic mechanical loading, and therefore the ability to engineer a priori the viscoelastic properties of these materials by controlling the types of crosslinks rather than by modifying the polymer itself. This strategy to decouple material mechanics from structure is general and may inform the design of soft materials for use in complex mechanical environments. Three examples that demonstrate this are provided

Current outcomes of live-born children with double outlet right ventricle in Norway

Objectives: This population-based, comprehensive, retrospective study presented the clinical outcomes of all children born in Norway between 2003 and 2017 with double outlet right ventricle (DORV). Methods: All children born with DORV between 2003 and 2017 were identified in the Oslo University Hospital registry. Patients' characteristics, interventions, complications and deaths were recorded. Echocardiographic data were reviewed for classification according to current standards. We investigated time-dependent surgical reintervention and mortality using Kaplan-Meier analyses and determinants of treatment complications, reintervention and death using regression analyses. Results: Ninety-three children with DORV represented an annual median prevalence of 1.18 per 10 000 births in Norway. Six children received palliative care. With an intention to treat, a surgical route with the primary biventricular repair was followed for 62 children, staged biventricular repair for 15 and univentricular repair for 10 children. Major complications occurred in 1.0% and 6.2% of children following catheter or surgical intervention, respectively. No significant determinants of the complications were identified. Overall survival following treatment was 91.9%, 90.8%, 89.5% and 89.5% and corresponding freedom from surgical reintervention was 88.0%, 79.0%, 74.9% and 69.4% at 1, 2, 5 and 10 years, respectively. The presence of atrioventricular septal defect predicted an increased risk of mortality (hazard ratio: 7.16) but did not increase the risk of surgical reintervention. Conclusions: In Norway, most children receive tailored treatment for DORV with low rates of complications, surgical reinterventions and mortality. However, atrioventricular septal defect remains a potential determinant of postoperative death. Keywords: Biventricular; Complication; DORV; Double outlet right ventricle; Reintervention; Univentricular. © The Author(s) 2022. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.publishedVersio

Mucins trigger dispersal of Pseudomonas aeruginosa biofilms

Mucus is a biological gel that lines all wet epithelia in the body, including the mouth, lungs, and digestive tract, and has evolved to protect the body from pathogenic infection. However, microbial pathogenesis is often studied in mucus-free environments that lack the geometric constraints and microbial interactions in physiological three-dimensional mucus gels. We developed fluid-flow and static test systems based on purified mucin polymers, the major gel-forming constituents of the mucus barrier, to understand how the mucus barrier influences bacterial virulence, particularly the integrity of Pseudomonas aeruginosa biofilms, which can become resistant to immune clearance and antimicrobial agents. We found that mucins separate the cells in P. aeruginosa biofilms and disperse them into suspension. Other viscous polymer solutions did not match the biofilm disruption caused by mucins, suggesting that mucin-specific properties mediate the phenomenon. Cellular dispersion depended on functional flagella, indicating a role for swimming motility. Taken together, our observations support a model in which host mucins are key players in the regulation of microbial virulence. These mucins should be considered in studies of mucosal pathogenesis and during the development of novel strategies to treat biofilms