Biodegradable Nanohybrid Materials as Candidates for Self-Sanitizing Filters Aimed at Protection from SARS-CoV-2 in Public Areas.

The COVID-19 pandemic has raised the problem of efficient, low-cost materials enabling the effective protection of people from viruses transmitted through the air or via surfaces. Nanofibers can be a great candidate for efficient air filtration due to their structure, although they cannot protect from viruses. In this work, we prepared a wide range of nanofibrous biodegradable samples containing Ag (up to 0.6 at.%) and Cu (up to 20.4 at.%) exhibiting various wettability. By adjusting the magnetron current (0.3 A) and implanter voltage (5 kV), the deposition of TiO2 and Ag+ implantation into PCL/PEO nanofibers was optimized in order to achieve implantation of Ag+ without damaging the nanofibrous structure of the PCL/PEO. The optimal conditions to implant silver were achieved for the PCL-Ti0.3-Ag-5kV sample. The coating of PCL nanofibers by a Cu layer was successfully realized by magnetron sputtering. The antiviral activity evaluated by widely used methodology involving the cultivation of VeroE6 cells was the highest for PCL-Cu and PCL-COOH, where the VeroE6 viability was 73.1 and 68.1%, respectively, which is significantly higher compared to SARS-CoV-2 samples without self-sanitizing (42.8%). Interestingly, the samples with implanted silver and TiO2 exhibited no antiviral effect. This difference between Cu and Ag containing nanofibers might be related to the different concentrations of ions released from the samples: 80 µg/L/day for Cu2+ versus 15 µg/L/day for Ag+. The high antiviral activity of PCL-Cu opens up an exciting opportunity to prepare low-cost self-sanitizing surfaces for anti-SARS-CoV-2 protection and can be essential for air filtration application and facemasks. The rough cost estimation for the production of a biodegradable nanohybrid PCL-Cu facemask revealed ~$0.28/piece, and the business case for the production of these facemasks would be highly positive, with an Internal Rate of Return of 34%.

How subtle differences in polymer molecular weight affect doxorubicin-loaded PLGA nanoparticles degradation and drug release.

Aims: To evaluate the influence of minor differences in molecular weights of commercially available low molecular weight PLGA grades on the kinetics of doxorubicin release from the nanoparticles.Methods: Three low-molecular weight 50/50 PLGA polymers were thoroughly characterised concerning intrinsic viscosity, molecular weight (Mw), acid value, and residual monomer content. The doxorubicin-loaded nanoparticles prepared using these polymers were evaluated concerning the kinetics of drug release and hydrolytic degradation.Results: The Mw of the polymers were slightly different: 10.2, 10.3, and 4.7 kDa. The nanoparticles obtained from the polymer with Mw of 4.7 kDa exhibited considerably higher rates of drug release and polymer degradation.Conclusion: In the case of low molecular weight PLGA grades even a few kilodaltons could be important for the batch-to-batch reproducibility of the nanoformulation parameters. These results bring forward the importance of in-house characterisation of the polymers to be used for the nanoparticle preparation.

Antibacterial, UV-Protective, Hydrophobic, Washable, and Heat-Resistant BN-Based Nanoparticle-Coated Textile Fabrics: Experimental and Theoretical Insight.

The use of nanoparticles (NPs) to modify the surface of cotton fabric is a promising approach to endowing the material with a set of desirable characteristics that can significantly expand the functionality, wear comfort, and service life of textile products. Herein, two approaches to modifying the surface of hexagonal boron nitride (h-BN) NPs with a hollow core and a smooth surface by treatment with maleic anhydride (MA) and diethylene triamine (DETA) were studied. The DETA and MA absorption on the surface of h-BN and the interaction of surface-modified h-NPs with cellulose as the main component of cotton were modeled using density functional theory with the extended Perdew-Burke-Ernzerhof functional. Theoretical modeling showed that the use of DETA as a binder agent can increase the adhesion strength of BN NPs to textile fabric due to the simultaneous hydrogen bonds with cellulose and BN. Due to the difference in zeta potentials (-38.4 vs -25.8 eV), MA-modified h-BN NPs form a stable suspension, while DETA-modified BN NPs tend to agglomerate. Cotton fabric coated with surface-modified NPs exhibits an excellent wash resistance and high hydrophobicity with a water contact angle of 135° (BN-MA) and 146° (BN-DETA). Compared to the original textile material, treatment with MA- and DETA-modified h-BN NPs increases heat resistance by 10% (BN-MA fabric) and 15% (BN-DETA fabric). Cotton fabrics coated with DETA- and MA-modified BN NPs show enhanced antibacterial activity against Escherichia coli U20 and Staphylococcus aureus strains and completely prevent the formation of an E. coli biofilm. The obtained results are important for the further development of fabrics for sports and medical clothing as well as wound dressings.