Host-Directed Virus-Mimicking Particles Interacting with the ACE2 Receptor Competitively Block Coronavirus SARS-CoV-2 Entry.

Herein, we fabricate host-directed virus-mimicking particles (VMPs) to block the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into host cells through competitive inhibition enabled by their interactions with the angiotensin-converting enzyme 2 (ACE2) receptor. A microfluidic platform is developed to fabricate a lipid core of the VMPs with a narrow size distribution and a low level of batch-to-batch variation. The resultant solid lipid nanoparticles are decorated with an average of 231 or 444 Spike S1 RBD protrusions mimicking either the original SARS-CoV-2 or its delta variant, respectively. Compared with that of the nonfunctionalized core, the cell uptake of the functionalized VMPs is enhanced with ACE2-expressing cells due to their strong interactions with the ACE2 receptor. The fabricated VMPs efficiently block the entry of SARS-CoV-2 pseudovirions into host cells and suppress viral infection. Overall, this study provides potential strategies for preventing the spread of SARS-CoV-2 or other coronaviruses employing the ACE2 receptor to enter into host cells.

Customer perceptions of COVID-19 countermeasures on passenger ships during the pandemic.

The COVID-19 pandemic devastated substantial portions of the tourism industry; the cruise industry particularly suffered from negative publicity as the virus spread rapidly on cruise ships. The pandemic is a disaster that the industry has been forced to adapt to. This study illustrates, through a mixed-methods research design, what factors cruiseferry operators considered in their responses to the pandemic, whether the implemented countermeasures increased their customers' sense of security, and what countermeasures customers would agree to follow before boarding a ship. The study thereby provides insights into which countermeasures are likely to decrease customers' perceived health risks and which they are ready to accept or not on cruises during pandemics.

Immunogenic SARS-CoV-2 Epitopes: In Silico Study Towards Better Understanding of COVID-19 Disease-Paving the Way for Vaccine Development.

The emergence of the COVID-19 outbreak at the end of 2019, caused by the novel coronavirus SARS-CoV-2, has, to date, led to over 13.6 million infections and nearly 600,000 deaths. Consequently, there is an urgent need to better understand the molecular factors triggering immune defense against the virus and to develop countermeasures to hinder its spread. Using in silico analyses, we showed that human major histocompatibility complex (MHC) class I cell-surface molecules vary in their capacity for binding different SARS-CoV-2-derived epitopes, i.e., short sequences of 8-11 amino acids, and pinpointed five specific SARS-CoV-2 epitopes that are likely to be presented to cytotoxic T-cells and hence activate immune responses. The identified epitopes, each one of nine amino acids, have high sequence similarity to the equivalent epitopes of SARS-CoV virus, which are known to elicit an effective T cell response in vitro. Moreover, we give a structural explanation for the binding of SARS-CoV-2-epitopes to MHC molecules. Our data can help us to better understand the differences in outcomes of COVID-19 patients and may aid the development of vaccines against SARS-CoV-2 and possible future outbreaks of novel coronaviruses.

Quantitative bioimage analytics enables measurement of targeted cellular stress response induced by celastrol-loaded nanoparticles.

The cellular stress response, which provides protection against proteotoxic stresses, is characterized by the activation of heat shock factor 1 and the formation of nuclear stress bodies (nSBs). In this study, we developed a computerized method to quantify the formation and size distribution of nSBs, as stress response induction is of interest in cancer research, neurodegenerative diseases, and in other pathophysiological processes. We employed an advanced bioimaging and analytics workflow to enable quantitative detailed subcellular analysis of cell populations even down to single-cell level. This type of detailed analysis requires automated single cell analysis to allow for detection of both size and distribution of nSBs. For specific induction of nSB we used mesoporous silica nanoparticles (MSNs) loaded with celastrol, a plant-derived triterpene with the ability to activate the stress response. To enable specific targeting, we employed folic acid functionalized nanoparticles, which yields targeting to folate receptor expressing cancer cells. In this way, we could assess the ability to quantitatively detect directed and spatio-temporal nSB induction using 2D and 3D confocal imaging. Our results demonstrate successful implementation of an imaging and analytics workflow based on a freely available, general-purpose software platform, BioImageXD, also compatible with other imaging modalities due to full 3D/4D and high-throughput batch processing support. The developed quantitative imaging analytics workflow opens possibilities for detailed stress response examination in cell populations, with significant potential in the analysis of targeted drug delivery systems related to cell stress and other cytoprotective cellular processes.

Human dermal fibroblast proliferation controlled by surface roughness of two-component nanostructured latex polymer coatings.

In this study hierarchically-structured latex polymer coatings and self-supporting films were characterised and their suitability for cell growth studies was tested with Human Dermal Fibroblasts (HDF). Latex can be coated or printed on rigid or flexible substrates thus enabling high-throughput fabrication. Here, coverslip glass substrates were coated with blends of two different aqueous latex dispersions: hydrophobic polystyrene (PS) and hydrophilic carboxylated acrylonitrile butadiene styrene (ABS). The nanostructured morphology and topography of the latex films was controlled by varying the mixing ratio of the components in the latex blend. Thin latex-coatings retain high transparency on glass allowing optical and high resolution imaging of cell growth and morphology. Compared to coverslip glass surfaces and commercial well-plates HDF cell growth was enhanced up to 150-250 % on latex surfaces with specific nanostructure. Growth rates were correlated with selected roughness parameters such as effective surface area (Sq), RMS-roughness (Sdr) and correlation length (Scl37). High-resolution confocal microscopy clearly indicated less actin stress-fibre development in cells on the latex surface compared to coverslip glass. The results show that surface nanotopography can, by itself, passively modulate HDF cell proliferation and cytoskeletal architecture.

Sugar-decorated mesoporous silica nanoparticles as delivery vehicles for the poorly soluble drug celastrol enables targeted induction of apoptosis in cancer cells.

Cancerous cells have a rapid metabolism by which they take up sugars, such as glucose, at significantly higher rates than normal cells. Celastrol is a traditional herbal medicine known for its anti-inflammatory and anti-cancer activities. The poor aqueous solubility and lack of target selectivity of celastrol result in low therapeutic concentration of the drug reaching subcellular compartments of the target tissue, making it an interesting candidate for nanoparticulate delivery. The goal of this study was to utilize glucose as an affinity ligand decorated on mesoporous silica nanoparticles (MSNs), with the aim of delivering these celastrol-loaded MSNs with high specificity to cancer cells and inducing minimal off-target effects in healthy cells. MSNs were thus functionalized with sugar moieties by two different routes, either by conjugation directly to the MSN surface or mediated by a hyperbranched poly(ethylene imine), PEI layer; the latter to increase the cellular uptake by providing an overall positive surface charge as well as to increase the reaction sites for sugar conjugation. The effect of surface functionalization on the target-specific efficacy of the particles was assessed by analyzing the uptake in HeLa and A549 cells as cancer cell models, as compared to mouse embryonic fibroblasts (MEF) as a representative for normal cells. To this end a comprehensive analysis strategy was employed, including flow cytometry, confocal microscopy, and spectrophotometry. When the apoptotic effect of celastrol was evaluated, the anti-cancer activity of celastrol was shown to be significantly enhanced when it was loaded into the specifically designed MSNs. The particles themselves did not induce any toxicity, and normal cells displayed minimal off-target effects. In summary, we show that glucose-functionalized MSNs can be used as efficient carriers for targeted celastrol delivery to achieve specific induction of apoptosis in cancer cells.