Bumpy structured nanofibrous membrane as a highly efficient air filter with antibacterial and antiviral property.

Recently, the pandemic infectious diseases caused by coronavirus have prompted the development of air filter membranes to against infectious agents and protect human health. This research focuses on air filter membrane with antibacterial and antiviral property for high-efficiency particulate matter (PM) removal. Herein, polyamide-6 electrospun nanofibers were anchored with silver nanoparticles through hydrogen-bond. Bumpy nanorough surface and multilevel structure contribute to improve capture capacity, and silver nanoparticles provide a strong ability to inactivate bacteria and virus. In conclusion, this membrane exhibits high PM2.5 filtration efficiency of 99.99% and low pressure drop of 31 Pa; simultaneous removal of multiple aerosol pollutants, e.g., SOx, NOx, methylbenzene, L-Nicotine; superior antibacterial performance against Escherichia coli (Gram negative bacteria) and Staphylococcus aureus (Gram positive bacteria), antiviral property against Porcine Deltacoronavirus and not significant cytotoxicity. Research of air filtration material is important to remove air pollutants and to prevent infection and spread of respiratory infectious diseases.

NAC-loaded electrospun scaffolding system with dual compartments for the osteogenesis of rBMSCs in vitro.

PURPOSE: In this study, we aimed to develop a unique N-acetyl cysteine (NAC)-loaded polylactic-co-glycolic acid (PLGA) electrospun system with separate compartments for the promotion of osteogenesis. MATERIALS AND METHODS: We first prepared solutions of NAC-loaded mesoporous silica nanoparticles (MSNs), PLGA, and NAC in N, N-dimethylformamide and tetrahydrofuran for the construction of the electrospun system. We then fed solutions to a specific injector for electrospinning. The physical and chemical properties of the scaffold were characterized through scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The release of NAC and Si from different PLGA scaffolds was estimated. The cell viability, cell growth, and osteogenic potential of rat bone marrow-derived stroma cell (rBMSCs) on different PLGA scaffolds were evaluated through MTT assay, live/dead staining, phalloidin staining, and Alizarin red staining. The expression levels of osteogenic-related markers were analyzed through real-time PCR (qRT-PCR). RESULTS: NAC was successfully loaded into MSNs. The addition of MSNs and NAC decreased the diameters of the electrospun fibers, increased the hydrophilicity and mechanical property of the PLGA scaffold. The release kinetic curve indicated that NAC was released from (PLGA + NAC)/(NAC@MSN) in a biphasic pattern, that featured an initial burst release stage and a later sustained release stage. This release pattern of NAC encapsulated on the (PLGA + NAC)/(NAC@MSN) scaffolds enabled to prolong the high concentrations of release of NAC, thus drastically affecting the osteogenic differentiation of rBMSCs. CONCLUSION: A PLGA electrospun scaffold was developed, and MSNs were used as separate nanocarriers for recharging NAC concentration, demonstrating the promising use of (PLGA + NAC)/(NAC@MSN) for bone tissue engineering.

Bactericidal efficacy of three parameters of Nd:YAP laser irradiation against Enterococcus faecalis compared with NaOCl irrigation.

The success of endodontic treatment depends on the thorough removal of microorganisms from the root canal system. The search for new ways to eliminate the microorganisms is therefore justified. Nd:YAP is a laser that uses yttrium aluminum perovskite, doped with neodymium crystal, as active laser medium. We used the Nd:YAP laser in an in vitro experiment to evaluate the bactericidal effect of three parameters of Nd:YAP laser-activated irrigation on biofilms of Enterococcus faecalis in root canals. The canals of 45 extracted human single-root teeth were prepared on a #35 Mtwo instrument and contaminated with E. faecalis for 14 days. Forty infected single-root teeth were then randomly divided into four groups according to the irrigation agitation protocols as follows: 5.25% sodium hypochlorite (NaOCl), Nd:YAP laser (180 mJ) + NaOCl, Nd:YAP laser (280 mJ) + NaOCl, and Nd:YAP laser (360 mJ) + NaOCl. The remaining bacteria were counted immediately using the cell count method. Teeth were firstly spilt and one half examined by scanning electron microscopy (SEM). The other half involved examination of bacterial colonization in dentinal tubules using confocal laser scanning microscopy (CLSM). Nd:YAP laser (280 mJ) + NaOCl and Nd:YAP laser (360 mJ) + NaOCl completely removed the E. faecalis biofilms from the root canal walls and made it the cleanest among the treatment groups. Bacterial reductions in the treatment groups for dentinal tubules are presented in a descending order as follows: Nd:YAP laser (360 mJ) (53.7%), Nd:YAP laser (280 mJ) (51.5%) > Nd:YAP laser (180 mJ) (45.3%) > 5.25% NaOCl (31.9%) > control (19.3%) (p < 0.05). Nd:YAP laser of 280 mJ and 360 mJ showed effective bactericidal effect in removing E. faecalis biofilm from the root canal walls and dentinal tubules.

Flexible Hydrophobic Antifouling Coating with Oriented Nanotopography and Nonleaking Capsaicin.

Incorporating natural product antifoulants (NPAs) into coatings with controlled surface topography is considered a promising way to suppress marine fouling. However, the rapid leakage of NPAs and the relatively complicated process of constructing well-patterned topography remain unresolved problems for practical applications. In this work, capsaicin bonded to CoFe2O4/gelatin magnetic nanoparticles was mixed with a polydimethylsiloxane (PDMS)-based block copolymer. When applied together by a simple spray-coating method, these materials formed a film. The leakage of capsaicin was restrained by the chemical bonds with the CoFe2O4/gelatin nanospheres. The primary nanorough structure was constructed by the phase separation of the PDMS-based copolymer. The secondary nanorough structure was formed by the incorporation of capsaicin-loaded CoFe2O4/gelatin nanospheres, which were demonstrated to improve the orientation of the PDMS-based block copolymer chains. The combination of oriented nanotopography and nonleaking capsaicin endows the coating with enhanced, long-lasting antifouling ability.

Hydrophilic Magnetofluorescent Nanobowls: Rapid Magnetic Response and Efficient Photoluminescence.

Multifunctional integration based on a single nanostructure is emerging as a promising paradigm to future functional materials. In this paper, novel magnetofluorescence nanobowls built with ferroferric mandrel and quantum dots exoderm is reported. Magnetic mandrels are stacked into nanobowls though hydrophobic primary Fe3O4 nanocrystals dragged into anion polyelectrolyte aqueous solution via forced solvent evaporation. Bright luminescence core/shell/shell CdSe/CdS/ZnS quantum dots (QDs) are modified with cationic hyperbranched polyethylenimine (PEI). Through electrostatic interactions, positively charged PEI-coated QDs are anchored on the surface of magnetic mandrel. Under this method, the luminescence of QDs is not quenched by magnetic partners in the resultant magnetoflurescence nanobowls. Such magnetoflurescence nanobowls exhibit high saturation magnetization, superparamagnetic characteristics at room temperature, superior water dispersibility, and excellent photoluminescence properties. The newly developed magnetoflurescence nanobowls open a new dimension in efforts toward multimodal imaging probes combining strong magnetization and efficient fluorescence in tandem for biosensors and clinical diagnostic imaging.