Lipid-coated mesoporous silica nanoparticles for anti-viral applications via delivery of CRISPR-Cas9 ribonucleoproteins.

Emerging and re-emerging viral pathogens present a unique challenge for anti-viral therapeutic development. Anti-viral approaches with high flexibility and rapid production times are essential for combating these high-pandemic risk viruses. CRISPR-Cas technologies have been extensively repurposed to treat a variety of diseases, with recent work expanding into potential applications against viral infections. However, delivery still presents a major challenge for these technologies. Lipid-coated mesoporous silica nanoparticles (LCMSNs) offer an attractive delivery vehicle for a variety of cargos due to their high biocompatibility, tractable synthesis, and amenability to chemical functionalization. Here, we report the use of LCMSNs to deliver CRISPR-Cas9 ribonucleoproteins (RNPs) that target the Niemann-Pick disease type C1 gene, an essential host factor required for entry of the high-pandemic risk pathogen Ebola virus, demonstrating an efficient reduction in viral infection. We further highlight successful in vivo delivery of the RNP-LCMSN platform to the mouse liver via systemic administration.

Lipid-Coated Mesoporous Silica Nanoparticles for the Delivery of the ML336 Antiviral to Inhibit Encephalitic Alphavirus Infection.

Venezuelan equine encephalitis virus (VEEV) poses a major public health risk due to its amenability for use as a bioterrorism agent and its severe health consequences in humans. ML336 is a recently developed chemical inhibitor of VEEV, shown to effectively reduce VEEV infection in vitro and in vivo. However, its limited solubility and stability could hinder its clinical translation. To overcome these limitations, lipid-coated mesoporous silica nanoparticles (LC-MSNs) were employed. The large surface area of the MSN core promotes hydrophobic drug loading while the liposome coating retains the drug and enables enhanced circulation time and biocompatibility, providing an ideal ML336 delivery platform. LC-MSNs loaded 20 ± 3.4 µg ML336/mg LC-MSN and released 6.6 ± 1.3 µg/mg ML336 over 24 hours. ML336-loaded LC-MSNs significantly inhibited VEEV in vitro in a dose-dependent manner as compared to unloaded LC-MSNs controls. Moreover, cell-based studies suggested that additional release of ML336 occurs after endocytosis. In vivo safety studies were conducted in mice, and LC-MSNs were not toxic when dosed at 0.11 g LC-MSNs/kg/day for four days. ML336-loaded LC-MSNs showed significant reduction of brain viral titer in VEEV infected mice compared to PBS controls. Overall, these results highlight the utility of LC-MSNs as drug delivery vehicles to treat VEEV.

Nanoporous silica-water interfaces studied by sum-frequency vibrational spectroscopy.

Using sum-frequency vibrational spectroscopy, we found that water structure at nanoporous silica/water interfaces depended on the nanoporous film structure. For a periodic, self-assembled nanoporous film with monosized 2 nm pores occupying 20% of the top surface area, the surface vibrational spectrum was dominated by water in contact with silica, bare or covered by silane, at the top surface. It resembled the spectral characteristic of the hydrophilic water/silica or the hydrophobic water/silane interface. For a fractal nanoporous film with pores ranging from 5 to 50 nm in size occupying 90% of the top surface, the spectrum for a trimethyl silane-coated superhydrophobic porous film resembled largely that of a water/air interface. Only when the silane was completely removed would the spectrum revert to that characteristic of a hydrophilic water/silica interface. The surface charging behaviors of the bare nanoporous films in water with different pH were monitored by spectroscopic measurements and atomic force microscopy force measurements. The point of zero charge for the periodic porous film is around pH 2, similar to that of the flat silica surface. The point of zero charge could only be determined to be pH<6 for the fractal porous film because the thin fractal solid network limited the amount of surface charge and therefore, the accuracy of the measurements.

Responsive periodic mesoporous polydiacetylene/silica nanocomposites.

Responsive PMO materials have been synthesized through co-assembly of bridged diacetylenic silsesquioxane and surfactant. The spatially defined polydiacetylenic component, mesoporous network, and the covalent proximity of polydiacetylene to silica endow the PMO with mechanical robustness, reversible chromatic responses, improved thermal stability, and faster responses to chemical stimuli. This research also provides an efficient molecular design and assembly paradigm to fabricate a family of conjugated optoelectronic materials, creating novel platforms for sensors, actuators, and other device applications.