Lactoferrin-Functionalized Noble Metal Nanoparticles as New Antivirals for HSV-2 Infection

(1) Background: Lactoferrin has been recognized as a potent inhibitor of human herpetic viruses, such as herpes simplex type 1 (HSV-1) and 2 (HSV-2). In this work, we tested if silver and gold nanoparticles modified with lactoferrin (LF-Ag/AuNPs) can become novel microbicides with additional adjuvant properties to treat genital herpes infection. (2) Methods: The antiviral and cytotoxic activities of LF-Ag/AuNPs were tested in human skin HaCaT and vaginal VK-2-E6/E7 keratinocytes. Viral titers and immune responses after treatment with LF-Ag/AuNPs were tested in murine vaginal HSV-2 infection. (3) Results: LF-Ag/AuNPs inhibited attachment and entry of HSV-2 in human keratinocytes much better than lactoferrin. Furthermore, pretreatment with LF-AgNPs led to protection from infection. Infected mice treated intravaginally with LF-Ag/AuNPs showed lower virus titers in the vaginal tissues and spinal cords in comparison to treatment with lactoferrin. Following treatment, vaginal tissues showed a significant increase in CD8+/granzyme B + T cells, NK cells and dendritic cells in comparison to NaCl-treated group. LF-Ag/AuNPs-treated animals also showed significantly better expression of IFN-γ, CXCL9, CXCL10, and IL-1β in the vaginal tissues. (4) Conclusions: Our findings show that LF-Ag/AuNPs could become effective novel antiviral microbicides with immune-stimulant properties to be applied upon the mucosal tissues.

Plasmonic Spherical Nanoparticles Coupled with Titania Nanotube Arrays Prepared by Anodization as Substrates for Surface-Enhanced Raman Spectroscopy Applications: A Review

As surface-enhanced Raman spectroscopy (SERS) continues developing to be a powerful analytical tool for several probes, four important aspects to make it more accessible have to be addressed: low-cost, reproducibility, high sensibility, and recyclability. Titanium dioxide nanotubes (TiO2 NTs) prepared by anodization have attracted interest in this field because they can be used as safe solid supports to deposit metal nanoparticles to build SERS substrate nanoplatforms that meet these four desired aspects. TiO2 NTs can be easily prepared and, by varying different synthesis parameters, their dimensions and specific features of their morphology can be tuned allowing them to support metal nanoparticles of different sizes that can achieve a regular dispersion on their surface promoting high enhancement factors (EF) and reproducibility. Besides, the TiO2 photocatalytic properties enable the substrate’s self-cleaning property for recyclability. In this review, we discuss the different methodological strategies that have been tested to achieve a high performance of the SERS substrates based on TiO2 NTs as solid support for the three main noble metal nanoparticles mainly studied for this purpose: Ag, Au, and Pt.

Preparing and Applying Silver Nanoparticles in Conductive Ink and Inkjet Painting

Noble metal nanoparticles have special properties in optical, electronic, and physical chemistry due to their high surface area and volume. With the development of electronic printing technology, inkjet printing has gradually replaced traditional spin coating and blade coating, since it leads to more material savings and a faster batch production, and the pattern can be easily designed by a computer. In this study, Ag nanoparticles were prepared by a chemical reduction method. Non-toxic, environment-friendly agents were selected to fabricate a single-shape, uniform-size, crystal-form, and monodisperse product. The effects of the reducing agent ratio and the stabilizer ratio on the size, shape, and stability of the nanoparticles are discussed. The silver nanoparticles were characterized by an ultraviolet-visible spectrophotometer (UV-vis) and a transmission electron microscope (TEM). In addition, in order to prepare conductive ink that can stably disperse for a long time and that can be applied to inkjet printing on a PET flexible substrate at a lower sintering temperature, a sintering agent and a commercial surfactant were added. The experimental results show that the best addition ratio of the precursor to the reducing agent and the stabilizer is 1:6:1. The conductive silver ink was printed and treated by a70 mM NaCl solution, and the electric resistivity was 5.17×10−4 Ω· cm.