A poloxamer 407 (P407)—Casein hydrogel was chosen to carry polycaprolactone nanoparticles carrying terbinafine (PCL-TBH-NP). In this study, terbinafine hydrochloride (TBH) was encapsulated into polycaprolactone (PCL) nanoparticles, which were further incorporated into a poloxamer-casein hydrogel in a different addition order to evaluate the effect of gel formation. Nanoparticles were prepared by the nanoprecipitation technique and characterized by evaluating their physicochemical characteristics and morphology. The nanoparticles had a mean diameter of 196.7 ± 0.7 nm, PDI of 0.07, negative ζ potential (−0.713 mV), high encapsulation efficiency (>98%), and did not show cytotoxic effects in primary human keratinocytes. PCL-NP modulated terbinafine was released in artificial sweat. Rheological properties were analyzed by temperature sweep tests at different addition orders of nanoparticles into hydrogel formation. The rheological behavior of nanohybrid hydrogels showed the influence of TBH-PCL nanoparticles addition in the mechanical properties of the hydrogel and a long-term release of the nanoparticles from it.

The effects of neuroinvasion by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) become clinically relevant due to the numerous neurological symptoms observed in Corona Virus Disease 2019 (COVID‐19) patients during infection and post‐COVID syndrome or long COVID. This study reports the biofabrication of a 3D bioprinted neural‐like tissue as a proof‐of‐concept platform for a more representative study of SARS‐CoV‐2 brain infection. Bioink is optimized regarding its biophysical properties and is mixed with murine neural cells to construct a 3D model of COVID‐19 infection. Aiming to increase the specificity to murine cells, SARS‐CoV‐2 is mouse‐adapted (MA‐SARS‐CoV‐2) in vitro, in a protocol first reported here. MA‐SARS‐CoV‐2 reveals mutations located at the Orf1a and Orf3a domains and is evolutionarily closer to the original Wuhan SARS‐CoV‐2 strain than SARS‐CoV‐2 used for adaptation. Remarkably, MA‐SARS‐CoV‐2 shows high specificity to murine cells, which present distinct responses when cultured in 2D and 3D systems, regarding cell morphology, neuroinflammation, and virus titration. MA‐SARS‐CoV‐2 represents a valuable tool in studies using animal models, and the 3D neural‐like tissue serves as a powerful in vitro platform for modeling brain infection, contributing to the development of antivirals and new treatments for COVID‐19.

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Electrospinning technology was used to produced polyvinylpyrrolidone (PVP)-copper salt composites with structural differences, and their virucidal activity against coronavirus was investigated. The solutions were prepared with 20, 13.3, 10, and 6.6% w/v PVP containing 3, 1.0, 0.6, and 0.2% w/v Cu (II), respectively. The rheological properties and electrical conductivity contributing to the formation of the morphologies of the composite materials were observed by scanning electron microscopy (SEM). SEM images revealed the formation of electrospun PVP-copper salt ultrafine composite fibers (0.80 ± 0.35 µm) and electrosprayed PVP-copper salt composite microparticles (1.50 ± 0.70 µm). Energy-dispersive X-ray spectroscopy (EDS) evidenced the incorporation of copper into the produced composite materials. IR spectra confirmed the chemical composition and showed an interaction of Cu (II) ions with oxygen in the PVP resonant ring. Virucidal composite fibers inactivated 99.999% of coronavirus within 5 min of contact time, with moderate cytotoxicity to L929 cells, whereas the virucidal composite microparticles presented with a virucidal efficiency of 99.999% within 1440 min of exposure, with low cytotoxicity to L929 cells (mouse fibroblast). This produced virucidal composite materials have the potential to be applied in respirators, personal protective equipment, self-cleaning surfaces, and to fabric coat personal protective equipment against SARS-CoV-2, viral outbreaks, or pandemics.

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