This work proposes a feasible, reproducible, and low-cost modified method to manufacture chitosan, chitosan/IgG-protein-loaded, and trimethylated chitosan nanoparticles, using microfluidics combined with the microemulsion technique, which differs from the traditional batch process of chitosan-based nanoparticles. The synthesis process consists of generating microreactors of chitosan-based polymer in a poly-dimethylsiloxane ψ-shaped microfluidic device and then crosslinking with sodium tripolyphosphate outside the cell. Transmission electron microscopy demonstrates an improvement in size control and distribution of the solid-shape chitosan nanoparticles (~80 nm) compared to the batch synthesis. Regarding chitosan/IgG-protein-loaded nanoparticles, these presented a core-shell morphology having a diameter of close to 15 nm. Raman and X-ray photoelectron spectroscopies confirmed the ionic crosslinking between the amino groups of chitosan and the phosphate groups of sodium tripolyphosphate in the fabricated samples and the total encapsulation of IgG protein during the fabrication of chitosan/IgG-loaded nanoparticles. Then, an ionic crosslinking and nucleation-diffusion process of chitosan-sodium tripolyphosphate was carried out during the nanoparticle formation, with and without IgG protein loading. The use of N-trimethyl chloride chitosan nanoparticles in vitro on human-keratinocyte-derived cell line HaCaT did not show side effects independently of its concentration from 1 to 10 μg/mL. Therefore, the proposed materials could be used as potential carrier-delivery systems.

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Background: The rapidly widespread SARS-CoV-2 infection has affected millions worldwide, thus becoming a global health emergency. Although vaccines are already available, there are still new COVID-19 cases daily worldwide, mainly due to low immunization coverage and the advent of new strains. Therefore, there is an utmost need for the discovery of lead compounds to treat COVID-19. Objective: Considering the relevance of the SARS-CoV-2 MPRO in viral replication and the role of the isoquinoline moiety as a core part of several biologically relevant compounds, this study aimed to identify isoquinoline-based molecules as new drug-like compounds, aiming to develop an effective coronavirus inhibitor. Method: 274 isoquinoline derivatives were submitted to molecular docking interactions with SARS-CoV-2 MPRO (PDB ID: 7L0D) and drug-likeness analysis. The five best-docked isoquinoline derivatives that did not violate any of Lipinski's or Veber's parameters were submitted to ADMET analysis and molecular dynamics (MD) simulations. Results < Discussion: The selected compounds exhibited docking scores similar to or better than chloroquine and other isoquinolines previously reported. The fact that the compounds interact with residues that are pivotal for the enzyme's catalytic activity, and show the potential to be orally administered makes them promising drugs for treating COVID-19. Conclusion: Ultimately, MD simulation was performed to verify ligand-protein complex stability during the simulation period.

Cerium polymeric composites have novel applications in fuel cells, optical devices, gas sensors, catalysis, ultraviolet absorbers, hydrogen storage materials, and biomedicines. This study reports the fabrication of low-cost electrospun single and core-shell polyethylene oxide (PEO) doped with Cerium fibers fabricated in two moisture ambients. Scanning electron microscopy and atomic force microscopy revealed that obtaining the thinnest average fiber diameter requires 47-52 %RH and 2 % Cerium dopant. Using a PEO capping (shell fiber) allows the increment of Cerium in the inner matrix (core-fiber) to produce non-beading continuous fibers with 3.5% of the dopant. The undoped single or core-shell fibers presented a 52.7 to 54.2 % crystallinity, indecently of relative humidity used during the fabrication process. In contrast, the use of Cerium dopant up to 2% induces an increase in their crystallinity due to the formation of Ce-O species, enhancing their thermal properties, regardless of the moisture during manufacturing as was found with Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis.

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