The moderating role of psychological resilience in the relationship between fear of COVID-19 and psychological distress, in a cohort of rural and regional healthcare workers. During major lockdowns in Victoria, Australia 2020-2021.

The emergence of the COVID-19 pandemic resulted in substantial pressures for healthcare workers across the world. The association between fear of COVID-19 and psychological distress, and the role of psychological resilience have gained research interest. The current study aimed to investigate the cross-sectional association between fear of COVID-19 and psychological distress, in Australian rural/regional healthcare workers and determine whether resilience modifies this association. Most participants were nurses (38.0%), mean age was 44.9 years, and 80.5% were female (N = 1313). An adjusted logistic regression analysis showed that the highest tertile of the Fear of COVID-19 scale was associated with higher odds of moderate to severe symptoms of anxiety (OR = 3.72, 95% CI = 2.27, 6.11; p < 0.001) and depression (OR = 3.48, 95% CI = 2.30, 5.28; p < 0.001). Healthcare workers with high level of fear of COVID-19 and low level of resilience were much more likely to report moderate to severe symptoms of anxiety (OR = 12.27, 95% CI = 6.65-22.65, p < 0.001) and depression (OR = 12.21, 95% CI = 6.93-21.50, p < 0.001) when compared to healthcare workers with low level of fear of COVID-19 and high level of resilience. A cross-sectional design was used and therefore cause and effect between fear of COVID-19 and psychological distress cannot be inferred. Longitudinal research is needed to investigate the possible causal relationship. These findings highlight the potential mental health effects of fear of COVID-19 on HCWs and demonstrate the importance of resilience as a possible moderator of these effects.

Mucins as multifunctional building blocks of biomaterials.

Mucins are large glycoproteins that are ubiquitous in the animal kingdom. Mucins coat the surfaces of many cell types and can be secreted to form mucus gels that assume important physiological roles in many animals. Our growing understanding of the structure and function of mucin molecules and their functionalities has sparked interest in investigating the use of mucins as building blocks for innovative functional biomaterials. These pioneering studies have explored how new biomaterials can benefit from the barrier properties, hydration and lubrication properties, unique chemical diversity, and bioactivities of mucins. Owing to their multifunctionality, mucins have been used in a wide variety of applications, including as antifouling coatings, as selective filters, and artificial tears and saliva, as basis for cosmetics, as drug delivery materials, and as natural detergents. In this review, we summarize the current knowledge regarding key mucin properties and survey how they have been put to use. We offer a vision for how mucins could be used in the near future and what challenges await the field before biomaterials made of mucins and mucin-mimics can be translated into commercial products.

Genetically Engineered Mucoadhesive Spider Silk.

Mucoadhesion is defined as the adhesion of a material to the mucus gel covering the mucous membranes. The mechanisms controlling mucoadhesion include nonspecific electrostatic interactions and specific interactions between the materials and the mucins, the heavily glycosylated proteins that form the mucus gel. Mucoadhesive materials can be used to develop mucosal wound dressings and noninvasive transmucosal drug delivery systems. Spider silk, which is strong, biocompatible, biodegradable, nontoxic, and lightweight would serve as an excellent base for the development of such materials. Here, we investigated two variants of the partial spider silk protein 4RepCT genetically engineered in order to functionalize them with mucoadhesive properties. The pLys-4RepCT variant was functionalized with six cationically charged lysines, aiming to provide nonspecific adhesion from electrostatic interactions with the anionically charged mucins, while the hGal3-4RepCT variant was genetically fused with the Human Galectin-3 Carbohydrate Recognition Domain which specifically binds the mucin glycans Galß1-3GlcNAc and Galß1-4GlcNAc. First, we demonstrated that coatings, fibers, meshes, and foams can be readily made from both silk variants. Measured by the adsorption of both bovine submaxillary mucin and pig gastric mucin, the newly produced silk materials showed enhanced mucin binding properties compared with materials of wild-type (4RepCT) silk. Moreover, we showed that pLys-4RepCT silk coatings bind mucins through electrostatic interactions, while hGal3-4RepCT silk coatings bind mucins through specific glycan-protein interactions. We envision that the two new mucoadhesive silk variants pLys-4RepCT and hGal3-4RepCT, alone or combined with other biofunctional silk proteins, constitute useful new building blocks for a range of silk protein-based materials for mucosal treatments.

Mucin-Inspired Lubrication on Hydrophobic Surfaces.

In the human body, high-molecular-weight glycoproteins called mucins play a key role in protecting epithelial surfaces against pathogenic attack, controlling the passage of molecules toward the tissue and enabling boundary lubrication with very low friction coefficients. However, neither the molecular mechanisms nor the chemical motifs of those biomacromolecules involved in these fundamental processes are fully understood. Thus, identifying the key features that render biomacromolecules such as mucins outstanding boundary lubricants could set the stage for creating versatile artificial superlubricants. We here demonstrate the importance of the hydrophobic terminal peptide domains of porcine gastric mucin (MUC5AC) and human salivary mucin (MUC5B) in the processes of adsorbing to and lubricating a hydrophobic PDMS surface. Tryptic digestion of those mucins results in removal of those terminal domains, which is accompanied by a loss of lubricity as well as surface adsorption. We show that this loss can in part be compensated by attaching hydrophobic phenyl groups to the glycosylated central part of the mucin macromolecule. Furthermore, we demonstrate that the simple biopolysaccharide dextran can be functionalized with hydrophobic groups which confers efficient surface adsorption and good lubricity on PDMS to the polysaccharide.