Hollow mesoporous silica nanoparticles as delivery vehicle of foot-and-mouth disease virus-like particles induce persistent immune responses in guinea pigs

Recent Updates on Multifunctional Nanomaterials as Antipathogens in Humans and Livestock: Classification, Application, Mode of Action, and Challenges

Pathogens cause infections and millions of deaths globally, while antipathogens are drugs or treatments designed to combat them. To date, multifunctional nanomaterials (NMs), such as organic, inorganic, and nanocomposites, have attracted significant attention by transforming antipathogen livelihoods. They are very small in size so can quickly pass through the walls of bacterial, fungal, or parasitic cells and viral particles to perform their antipathogenic activity. They are more reactive and have a high band gap, making them more effective than traditional medications. Moreover, due to some pathogen's resistance to currently available medications, the antipathogen performance of NMs is becoming crucial. Additionally, due to their prospective properties and administration methods, NMs are eventually chosen for cutting-edge applications and therapies, including drug administration and diagnostic tools for antipathogens. Herein, NMs have significant characteristics that can facilitate identifying and eliminating pathogens in real-time. This mini-review analyzes multifunctional NMs as antimicrobial tools and investigates their mode of action. We also discussed the challenges that need to be solved for the utilization of NMs as antipathogens.

Virus-Bionic Mesoporous Silica Nanoplatform for Malignant Tumor Inhibition via Effective Cellular Uptake and Precise Drug Delivery

Over the past few decades, sophisticated nanomaterials have been used as carries for the targeted delivery of therapeutics to solid tumors. However, the low efficiency of intracellular internalization of nanocarriers in current use restricts their biomedical application. In this work, we demonstrate that novel virus-bionic mesoporous-silica-based nanocarriers can be successfully prepared for programmed precise drug delivery. These unique viral mimic nanovesicles not only present virus bionic counterparts and nanostructures, but also have infectious virus-like properties toward tumor cells and tumor tissues. Encouragingly, their large surface area (322.1 m2 /g) endows them with high loading capacity for therapeutic agents, especially, they have more effective gene transfection properties than the commercially available LipoGeneTM transfection reagent. Thanks to their virus-inspired morphology, they exhibit outstanding cellular uptake efficiency with living tumor cells and the ability to invade cells in large quantities with incubation times as short as 5 min, which is much faster than traditional mesoporous silica nanoparticles (mSN) with smooth appearance. Importantly, after doxorubicin (DOX) loading and surface modification of tumor recognition motifs, RGD (Arg-Gly-Asp, vMN@DOX-RGD), the bionic drug-loaded viral mimics elicit potent tumor cell elimination both in vitro and in vivo, greatly exceeding the mSN-based group. Our work paves the way toward virus bionic nanocarrier design for malignant tumor suppression in the clinic.

Periodic Mesoporous Organosilica as a Nanoadjuvant for Subunit Vaccines Elicits Potent Antigen-Specific Germinal Center Responses by Activating Naive B Cells

Infection diseases such as AIDS and COVID-19 remain challenging in regard to protective vaccine design, while adjuvants are critical for subunit vaccines to induce strong, broad, and durable immune responses against variable pathogens. Here, we demonstrate that periodic mesoporous organosilica (PMO) acts as a multifunctional nanoadjuvant by adsorbing recombinant protein antigens. It can effectively deliver antigens to lymph nodes (LNs), prolong antigen exposure, and rapidly elicit germinal center (GC) responses by directly activating naive B cells via the C-type lectin receptor signaling pathway. In mice, both the gp120 trimer (HIV-1 antigen) and the receptor-binding domain (SARS-CoV-2 antigen) with the PMO nanoadjuvant elicit potent and durable antibodies that neutralize heterologous virus strains. LN immune cells analysis shows that PMO helps to effectively activate the T-follicular helper cells, GC B cells, and memory B cells and eventually develop broad and durable humoral responses. Moreover, the PMO nanoadjuvant elicits a strong cellular immune response and shapes this immune response by eliciting high levels of effector T helper cell cytokines. This study identifies a promising nanoadjuvant for subunit vaccines against multiple pathogens.

Nanoadjuvants: Promising Bioinspired and Biomimetic Approaches in Vaccine Innovation

Adjuvants are the important part of vaccine manufacturing as they elicit the vaccination effect and enhance the durability of the immune response through controlled release. In light of this, nanoadjuvants have shown unique broad spectrum advantages. As nanoparticles (NPs) based vaccines are fast-acting and better in terms of safety and usability parameters as compared to traditional vaccines, they have attracted the attention of researchers. A vaccine nanocarrier is another interesting and promising area for the development of next-generation vaccines for prophylaxis. This review looks at the various nanoadjuvants and their structure-function relationships. It compiles the state-of-art literature on numerous nanoadjuvants to help domain researchers orient their understanding and extend their endeavors in vaccines research and development.

Irregular particle morphology and membrane rupture facilitate ion gradients in the lumen of phagosomes

Localized fluxes, production, and/or degradation coupled to limited diffusion are well known to result in stable spatial concentration gradients of biomolecules in the cell. In this study, we demonstrate that this also holds true for small ions, since we found that the close membrane apposition between the membrane of a phagosome and the surface of the cargo particle it encloses, together with localized membrane rupture, suffice for stable gradients of protons and iron cations within the lumen of the phagosome. Our data show that, in phagosomes containing hexapod-shaped silica colloid particles, the phagosomal membrane is ruptured at the positions of the tips of the rods, but not at other positions. This results in the confined leakage at these positions of protons and iron from the lumen of the phagosome into the cytosol. In contrast, acidification and iron accumulation still occur at the positions of the phagosomes nearer to the cores of the particles. Our study strengthens the concept that coupling metabolic and signaling reaction cascades can be spatially confined by localized limited diffusion.

Nano dimensions/adjuvants in COVID-19 vaccines

A favorable outcome of the COVID-19 crisis might be achieved with massive vaccination. The proposed vaccines contain several different vaccine active principles (VAP), such as inactivated virus, antigen, mRNA, and DNA, which are associated with either standard adjuvants or nanomaterials (NM) such as liposomes in Moderna's and BioNTech/Pfizer's vaccines. COVID-19 vaccine adjuvants may be chosen among liposomes or other types of NM composed for example of graphene oxide, carbon nanotubes, micelles, exosomes, membrane vesicles, polymers, or metallic NM, taking inspiration from cancer nano-vaccines, whose adjuvants may share some of their properties with those of viral vaccines. The mechanisms of action of nano-adjuvants are based on the facilitation by NM of targeting certain regions of immune interest such as the mucus, lymph nodes, and zones of infection or blood irrigation, the possible modulation of the type of attachment of the VAP to NM, in particular VAP positioning on the NM external surface to favor VAP presentation to antigen presenting cells (APC) or VAP encapsulation within NM to prevent VAP degradation, and the possibility to adjust the nature of the immune response by tuning the physico-chemical properties of NM such as their size, surface charge, or composition. The use of NM as adjuvants or the presence of nano-dimensions in COVID-19 vaccines does not only have the potential to improve the vaccine benefit/risk ratio, but also to reduce the dose of vaccine necessary to reach full efficacy. It could therefore ease the overall spread of COVID-19 vaccines within a sufficiently large portion of the world population to exit the current crisis.

Innovative vaccine platforms against infectious diseases: Under the scope of the COVID-19 pandemic

While classic vaccines have proved greatly efficacious in eliminating serious infectious diseases, innovative vaccine platforms open a new pathway to overcome dangerous pandemics via the development of safe and effective formulations. Such platforms play a key role either as antigen delivery systems or as immune-stimulators that induce both innate and adaptive immune responses. Liposomes or lipid nanoparticles, virus-like particles, nanoemulsions, polymeric or inorganic nanoparticles, as well as viral vectors, all belong to the nanoscale and are the main categories of innovative vaccines that are currently on the market or in clinical and preclinical phases. In this paper, we review the above formulations used in vaccinology and we discuss their connection with the development of safe and effective prophylactic vaccines against SARS-CoV-2.

Evaluation of the Effect of Inactivated Transmissible Gastroenteritis Virus Vaccine with Nano Silicon on the Phenotype and Function of Porcine Dendritic Cells

A transmissible gastroenteritis virus (TGEV) is a porcine enteropathogenic coronavirus, causing acute swine enteric disease especially in suckling piglets. Mesoporous silica nanoparticles (MSNs) are safe vaccine adjuvant, which could enhance immune responses. Our previous research confirmed that nano silicon had immune-enhancing effects with inactivated TGEV vaccine. In this study, we further clarified the immune-enhancing mechanism of the inactivated TGEV vaccine with MSNs on porcine dendritic cells (DCs). Our results indicated that the inactivated TGEV vaccine with MSNs strongly enhanced the activation of the DCs. Expressions of TLR3, TLR5, TLR7, TLR9, and TLR10, cytokines IFN-α, IL-1β, IL-6, IL-12, and TNF-α, cytokine receptor CCR-7 of immature DCs were characterized and showed themselves to be significantly higher in the inactivated TGEV vaccine with the MSN group. In summary, the inactivated TGEV vaccine with MSNs has effects on the phenotype and function of porcine DCs, which helps to better understand the immune-enhancing mechanism.

In Vivo Sustained Release of Peptide Vaccine Mediated by Dendritic Mesoporous Silica Nanocarriers

Mesoporous silica nanoparticles have drawn increasing attention as promising candidates in vaccine delivery. Previous studies evaluating silica-based vaccine delivery systems concentrated largely on macromolecular antigens, such as inactivated whole viruses. In this study, we synthesized dendritic mesoporous silica nanoparticles (DMSNs), and we evaluated their effectiveness as delivery platforms for peptide-based subunit vaccines. We encapsulated and tested in vivo an earlier reported foot-and-mouth disease virus (FMDV) peptide vaccine (B₂T). The B₂T@DMSNs formulation contained the peptide vaccine and the DMSNs without further need of other compounds neither adjuvants nor emulsions. We measured in vitro a sustained release up to 930 h. B₂T@DMSNs-57 and B₂T@DMSNs-156 released 23.7% (135 µg) and 22.8% (132 µg) of the total B₂T. The formation of a corona of serum proteins around the DMSNs increased the B₂T release up to 61% (348 µg/mg) and 80% (464 µg/mg) for B₂T@DMSNs-57 and B₂T@DMSNs-156. In vitro results point out to a longer sustained release, assisted by the formation of a protein corona around DMSNs, compared to the reference formulation (i.e., B₂T emulsified in Montanide). We further confirmed in vivo immunogenicity of B₂T@DMSNs in a particle size-dependent manner. Since B₂T@DMSNs elicited specific immune responses in mice with high IgG production like the reference B₂T@Montanide™, self-adjuvant properties of the DMSNs could be ascribed. Our results display DMSNs as efficacious nanocarriers for peptide-based vaccine administration.

Nano-based approaches in the development of antiviral agents and vaccines

Outbreaks and the rapid transmission of viruses, such as coronaviruses and influenza viruses, are serious threats to human health. A major challenge in combating infectious diseases caused by viruses is the lack of effective methods for prevention and treatment. Nanotechnology has provided a basis for the development of novel antiviral strategies. Owing to their large modifiable surfaces that can be functionalized with multiple molecules to realize sophisticated designs, nanomaterials have been developed as nanodrugs, nanocarriers, and nano-based vaccines to effectively induce sufficient immunologic memory. From this perspective, we introduce various nanomaterials with diverse antiviral mechanisms and summarize how nano-based antiviral agents protect against viral infection at the molecular, cellular, and organismal levels. We summarize the applications of nanomaterials for defense against emerging viruses by trapping and inactivating viruses and inhibiting viral entry and replication. We also discuss recent progress in nano-based vaccines with a focus on the mechanisms by which nanomaterials contribute to immunogenicity. We further describe how nanotechnology may improve vaccine efficacy by delivering large amounts of antigens to target immune cells and enhancing the immune response by mimicking viral structures and activating dendritic cells. Finally, we provide an overview of future prospects for nano-based antiviral agents and vaccines.

Mesoporous silica nanoparticles: synthesis methods and their therapeutic use-recent advances

Mesoporous silica nanoparticles (MSNPs) are a particular example of innovative nanomaterials for the development of drug delivery systems. MSNPs have recently received more attention for biological and pharmaceutical applications due to their capability to deliver therapeutic agents. Due to their unique structure, they can function as an effective carrier for the delivery of therapeutic agents to mitigate diseases progress, reduce inflammatory responses and consequently improve cancer treatment. The potency of MSNPs for the diagnosis and management of various diseases has been studied. This literature review will take an in-depth look into the properties of various types of MSNPs (e.g. shape, particle and pore size, surface area, pore volume and surface functionalisation), and discuss their characteristics, in terms of cellular uptake, drug delivery and release. MSNPs will then be discussed in terms of their therapeutic applications (passive and active tumour targeting, theranostics, biosensing and immunostimulative), biocompatibility and safety issues. Also, emerging trends and expected future advancements of this carrier will be provided.

Hollow Silica Particles: Recent Progress and Future Perspectives

Hollow silica particles (or mesoporous hollow silica particles) are sought after for applications across several fields, including drug delivery, battery anodes, catalysis, thermal insulation, and functional coatings. Significant progress has been made in hollow silica particle synthesis and several new methods are being explored to use these particles in real-world applications. This review article presents a brief and critical discussion of synthesis strategies, characterization techniques, and current and possible future applications of these particles.

Advances and challenges in nanocarriers and nanomedicines for veterinary application

To ensure success in the development and manufacturing of nanomedicines requires forces of an interdisciplinary team that combines medicine, engineering, chemistry, biology, material and pharmaceutical areas. Numerous researches in nanotechnology applied to human health are available in the literature. Althought, the lack of nanotechnology-based pharmaceuticals products for use exclusively in veterinary pharmacotherapy creates a potential area for the development of innovative products, as these animal health studies are still scarce when compared to studies in human pharmacotherapy. Nano-dosage forms can ensure safer and more effective pharmacotherapy for animals and can more be safer for the consumers of livestock products, once they can offer higher selectivity and smaller toxicity associated with lower doses of the drugs. In addition, the development and production of nanomedicines may consolidate the presence of pharmaceutical laboratories in the global market and can generate greater profit in a competitive business environment. To contribute to this scenario, this article provides a review of the main nanocarriers used in nanomedicines for veterinary use, with emphasis on liposomes, nanoemulsions, micelles, lipid nanoparticles, polymeric nanoparticles, mesoporous silica nanoparticles, metallic nanoparticles and dendrimers, and the state of the art of application of these nanocarriers in drug delivery systems to animal use. Finnaly, the major challenges involved in research, scale-up studies, large-scale manufacture, analytical methods for quality assessment, and regulatory aspects of nanomedicines were discussed.

Hollow mesoporous silica nanoparticles as delivery vehicle of foot-and-mouth disease virus-like particles induce persistent immune responses in guinea pigs

Foot‐and‐mouth disease (FMD) is an acute and febrile infectious disease, which can cause great economic losses. Virus‐like particles (VLPs) as an advantageous antigen can induce significant specific immune response. To improve immunity of VLPs, especially, make it induce persistent immune response, the hollow mesoporous silica nanoparticles (HMSNs) as a potential nano‐adjuvant were synthesized and loaded the FMD virus (FMDV) VLPs. They were injected into guinea pigs and the specific immune response was detected. The results confirmed that HMSNs/VLPs can induce persistent humoral immunity with high‐level antibody titer for more than three months. HMSNs also improve the T‐lymphocyte proliferation and IFN‐γ induced by FMDV VLPs, and provides the ideal protection against FMDV challenge. These consequences indicated that HMSNs were good protein delivery vehicle and potential nano‐adjuvant of vaccines.

We synthesized Hollow mesoporous silica nanoparticles (HMSNs), as a delivery vehicle, are ideal candidate and have many unique structural features, including relatively larger surface areas, and controlled release capability, especially, good biocompatibility compared to golden nanoparticles as adjuvant.

VLPs are composed of one or more structural proteins of virus, and without viral genetic material. As a new type of safe vaccine, FMDV VLPs can induce excellent immune response as traditional vaccines.

To improve specific and persistent immune responses of FMDV VLPs, It is first time that HMSN was used as delivery of FMDV VLPs.

The results confirmed that HMSNs can improve specific and persistent immune responses of FMDV VLPs, as new generation adjuvant.