Synthetic virus-like particles prepared via protein corona formation enable effective vaccination in an avian model of coronavirus infection

Silver nanoparticle-adjuvanted vaccine protects against lethal influenza infection through inducing BALT and IgA-mediated mucosal immunity

Most of current influenza virus vaccines fail to develop a strong immunity at lung mucosae (site of viral entry) due to sub-optimal vaccination protocols (e.g. inactivated virus administered by parenteral injections). Mucosal immunity could be improved by using locally-delivered vaccines containing appropriate adjuvants. Here we show, in a mouse model, that inclusion of silver nanoparticles (AgNPs) in virus-inactivated flu vaccine resulted in reduction of viral loads and prevention of excessive lung inflammation following influenza infection. Concomitantly, AgNPs enhanced specific IgA secreting plasma cells and antibodies titers, a hallmark of successful mucosal immunity. Moreover, vaccination in the presence of AgNPs but not with gold nanoparticles, protected mice from lethal flu. Compared with other commercial adjuvants (squalene/oil-based emulsion) or silver salts, AgNPs stimulated stronger antigen specific IgA production with lower toxicity by promoting bronchus-associated lymphoid tissue (BALT) neogenesis, and acted as a bona fide mucosal adjuvant.

Applications of Nanodiamonds in the Detection and Therapy of Infectious Diseases

We are constantly exposed to infectious diseases, and they cause millions of deaths per year. The World Health Organization (WHO) estimates that antibiotic resistance could cause 10 million deaths per year by 2050. Multidrug-resistant bacteria are the cause of infection in at least one in three people suffering from septicemia. While antibiotics are powerful agents against infectious diseases, the alarming increase in antibiotic resistance is of great concern. Alternatives are desperately needed, and nanotechnology provides a great opportunity to develop novel approaches for the treatment of infectious diseases. One of the most important factors in the prognosis of an infection caused by an antibiotic resistant bacteria is an early and rigorous diagnosis, jointly with the use of novel therapeutic systems that can specifically target the pathogen and limit the selection of resistant strains. Nanodiamonds can be used as antimicrobial agents due to some of their properties including size, shape, and biocompatibility, which make them highly suitable for the development of efficient and tailored nanotherapies, including vaccines or drug delivery systems. In this review, we discuss the beneficial findings made in the nanodiamonds field, focusing on diagnosis and treatment of infectious diseases. We also highlight the innovative platform that nanodiamonds confer for vaccine improvement, drug delivery, and shuttle systems, as well as their role in the generation of faster and more sensitive clinical diagnosis.

A health concern regarding the protein corona, aggregation and disaggregation

Nanoparticle (NP)-protein complexes exhibit the "correct identity" of NP in biological media. Therefore, protein-NP interactions should be closely explored to understand and modulate the nature of NPs in medical implementations. This review focuses mainly on the physicochemical parameters such as dimension, surface chemistry, morphology of NPs, and influence of pH on the formation of protein corona and conformational changes of adsorbed proteins by different kinds of techniques. Also, the impact of protein corona on the colloidal stability of NPs is discussed. Uncontrolled protein attachment on NPs may bring unwanted impacts such as protein denaturation and aggregation. In contrast, controlled protein adsorption by optimal concentration, size, pH, and surface modification of NPs may result in potential implementation of NPs as therapeutic agents especially for disaggregation of amyloid fibrils. Also, the effect of NPs-protein corona on reducing the cytotoxicity and clinical implications such as drug delivery, cancer therapy, imaging and diagnosis will be discussed. Validated correlative physicochemical parameters for NP-protein corona formation frequently derived from protein corona fingerprints of NPs which are more valid than the parameters obtained only on the base of NP features. This review may provide useful information regarding the potency as well as the adverse effects of NPs to predict their behavior in vivo.

Size-dependent neutralizing activity of gold nanoparticle-based subunit vaccine against dengue virus

Dengue results in substantial human morbidity and significant socio-economic impacts, but a specific dengue therapeutic is not available. The currently available dengue vaccine has low efficacy and high rate of adverse effects, necessitating different strategies for the development of a safer and more efficient vaccine against dengue virus. We describe here a hybrid combination of different-sized gold nanoparticles (AuNPs) and domain III of envelope glycoprotein derived from serotype 2 of dengue virus (EDIII) as dengue subunit vaccine. The efficacy of the EDIII-functionalized AuNPs (AuNP-E) to induce neutralizing antibody in BALB/c mice is evaluated. Obtained results show that AuNP-E induced a high level of antibody which mediates serotype-specific neutralization of dengue virus. More importantly, the level of antibody is dependent on both the size of AuNPs and the concentration of AuNP-E, implicating the possibility to modulate it through adjusting these parameters. These results represent an important step towards the development of tetravalent AuNP-based subunit dengue vaccine.

STATEMENT OF SIGNIFICANCE

This research presents a novel subunit vaccine against dengue virus using a hybrid comprising gold nanoparticles (AuNPs) and domain III of envelop protein (EDIII). We proved the neutralizing activity of anti-EDIII antibody induced in immunized mice on Dengue virus serotype 2 in an AuNP core size and concentration dependent manner. The hybrid concept behind this work could also be adopted for the development of a tetravalent vaccine against four serotypes of Dengue virus.

Virus-mimetic polymer nanoparticles displaying hemagglutinin as an adjuvant-free influenza vaccine

The generation of virus-mimetic nanoparticles has received much attention in developing a new vaccine for overcoming the limitations of current vaccines. Thus, a method, encompassing most viral features for their size, hydrophobic domain and antigen display, would represent a meaningful direction for the vaccine development. In the present study, a polymer-templated protein nanoball with direction oriented hemagglutinin1 on its surface (H1-NB) was prepared as a new influenza vaccine, exhibiting most of the viral features. Moreover, the concentrations of antigen on the particle surface were controlled, and its effect on immunogenicity was estimated by in vivo studies. Finally, H1-NB efficiently promoted H1-specific immune activation and cross-protective activities, which consequently prevented H1N1 infections in mice.

Advances and Opportunities in Nanoparticle- and Nanomaterial-Based Vaccines against Bacterial Infections

As the dawn of the postantibiotic era we approach, antibacterial vaccines are becoming increasingly important for managing bacterial infection and reducing the need for antibiotics. Despite the success of vaccination, vaccines remain unavailable for many pressing microbial diseases, including tuberculosis, chlamydia, and staphylococcus infections. Amid continuing research efforts in antibacterial vaccine development, the advancement of nanomaterial engineering has brought forth new opportunities in vaccine designs. With increasing knowledge in antibacterial immunity and immunologic adjuvants, innovative nanoparticles are designed to elicit the appropriate immune responses for effective antimicrobial defense. Rationally designed nanoparticles are demonstrated to overcome delivery barriers to shape the adaptive immunity. This article reviews the advances in nanoparticle- and nanomaterial-based antibacterial vaccines and summarizes the development of nanoparticulate adjuvants for immune potentiation against microbial pathogens. In addition, challenges and progress in ongoing antibacterial vaccine development are discussed to highlight the opportunities for future vaccine designs.

Targeting and Enrichment of Viral Pathogen by Cell Membrane Cloaked Magnetic Nanoparticles for Enhanced Detection

Attachment to cellular surfaces is a major attribute among infectious pathogens for initiating disease pathogenesis. In viral infections, viruses exploit receptor-ligand interactions to latch onto cellular exterior prior to subsequent entry and invasion. In light of the selective binding affinity between viral pathogens and cells, nanoparticles cloaked in cellular membranes are herein employed for virus targeting. Using the influenza virus as a model, erythrocyte membrane cloaked nanoparticles are prepared and modified with magnetic functionalities (RBC-mNP) for virus targeting and isolation. To maximize targeting and isolation efficiency, density gradient centrifugation and nanoparticle tracking analysis were applied to minimize the presence of uncoated particles and membrane vesicles. The resulting nanoparticles possess a distinctive membrane corona, a sialylated surface, and form colloidally stable clusters with influenza viruses. Magnetic functionality is bestowed to the nanoparticles through encapsulation of superparamagnetic iron-oxide particles, which enable influenza virus enrichment via magnetic extraction. Viral samples enriched by the RBC-mNPs result in significantly enhanced virus detection by multiple virus quantification methods, including qRT-PCR, immunnochromatographic strip test, and cell-based titering assays. The demonstration of pathogen targeting and isolation by RBC-mNPs highlights a biologically inspired approach toward improved treatment and diagnosis against infectious disease threats. The work also sheds light on the efficient membrane cloaking mechanism that bestows nanoparticles with cell mimicking functionalities.

Nanodiamond enhances immune responses in mice against recombinant HA/H7N9 protein

Background

The continuing spread of the newly emerged H7N9 virus among poultry in China, as well as the possibility of human-to-human transmission, has attracted numerous efforts to develop an effective vaccine against H7N9. The use of nanoparticles in vaccinology is inspired by the fact that most pathogens have a dimension within the nano-size range and therefore can be processed efficiently by the immune system, which leads to a potent immune response. Herein, we report a facile approach to increase antigen size to achieve not only fast but also effective responses against the recombinant HA/H7N9 protein via a simple conjugation of the protein onto the surface of nanodiamond particles.

Results

In this study, trimeric Haemagglutinin (H7) that is transiently expressed in N. benthamiana was purified using affinity chromatography, and its trimeric state was revealed successfully by the cross-linking reaction. The trimeric H7 solution was subsequently mixed with a nanodiamond suspension in different ratios. The successful conjugation of the trimeric H7 onto the surface of nanodiamond particles was demonstrated by the changes in size and Zeta-potential of the particles before and after protein coating, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western-blot analysis. Next, biofunction of the protein-nanodiamond conjugates was screened using a haemagglutination assay. A mixture containing 5 µg of trimeric H7 and 60 µg of nanodiamond corresponds to a ratio of 1:12 (w/w) of agglutinated chicken red blood cells at HA titer of 1024, which is 512-fold higher than the HA titer of free trimeric H7. After the 2nd and 3rd immunization in mice, ELISA and Western blot analyses demonstrated that the physical mixture of trimeric H7 protein and nanodiamond (1:12, w/w) elicited statistically significant stronger H7-specific-IgG response demonstrated by higher amounts of H7N9-specific IgG (over 15.4-fold with P < 0.05 after the second immunization).

Conclusions

These results indicated a potential effect inherent to nanodiamond towards modulating immune systems, which should be further evaluated and broadly applied in nanovaccine development.

Nanoparticle Vaccines Adopting Virus-like Features for Enhanced Immune Potentiation

Synthetic nanoparticles play an increasingly significant role in vaccine design and development as many nanoparticle vaccines show improved safety and efficacy over conventional formulations. These nanoformulations are structurally similar to viruses, which are nanoscale pathogenic organisms that have served as a key selective pressure driving the evolution of our immune system. As a result, mechanisms behind the benefits of nanoparticle vaccines can often find analogue to the interaction dynamics between the immune system and viruses. This review covers the advances in vaccine nanotechnology with a perspective on the advantages of virus mimicry towards immune potentiation. It provides an overview to the different types of nanomaterials utilized for nanoparticle vaccine development, including functionalization strategies that bestow nanoparticles with virus-like features. As understanding of human immunity and vaccine mechanisms continue to evolve, recognizing the fundamental semblance between synthetic nanoparticles and viruses may offer an explanation for the superiority of nanoparticle vaccines over conventional vaccines and may spur new design rationales for future vaccine research. These nanoformulations are poised to provide solutions towards pressing and emerging human diseases.

Applications of Gold Nanoparticles in Nanomedicine: Recent Advances in Vaccines

Nowadays, gold is used in (nano-)medicine, usually in the form of nanoparticles, due to the solid proofs given of its therapeutic effects on several diseases. Gold also plays an important role in the vaccine field as an adjuvant and a carrier, reducing toxicity, enhancing immunogenic activity, and providing stability in storage. An even brighter golden future is expected for gold applications in this area.

Exploiting lymphatic vessels for immunomodulation: Rationale, opportunities, and challenges

Lymphatic vessels are the primary route of communication from peripheral tissues to the immune system; as such, they represent an important component of local immunity. In addition to their transport functions, new immunomodulatory roles for lymphatic vessels and lymphatic endothelial cells have come to light in recent years, demonstrating that lymphatic vessels help shape immune responses in a variety of ways: promoting tolerance to self-antigens, archiving antigen for later presentation, dampening effector immune responses, and resolving inflammation, among others. In addition to these new biological insights, the growing field of immunoengineering has begun to explore therapeutic approaches to utilize or exploit the lymphatic system for immunotherapy.

Immunological properties of gold nanoparticles

In the past decade, gold nanoparticles have attracted strong interest from the nanobiotechnological community owing to the significant progress made in robust and easy-to-make synthesis technologies, in surface functionalization, and in promising biomedical applications. These include bioimaging, gene diagnostics, analytical sensing, photothermal treatment of tumors, and targeted delivery of various biomolecular and chemical cargos. For the last-named application, gold nanoparticles should be properly fabricated to deliver the cargo into the targeted cells through effective endocytosis. In this review, we discuss recent progress in understanding the selective penetration of gold nanoparticles into immune cells. The interaction of gold nanoparticles with immune cell receptors is discussed. As distinct from other published reviews, we present a summary of the immunological properties of gold nanoparticles. This review also summarizes what is known about the application of gold nanoparticles as an antigen carrier and adjuvant in immunization for the preparation of antibodies in vivo. For each of the above topics, the basic principles, recent advances, and current challenges are discussed. Thus, this review presents a detailed analysis of data on interaction of gold nanoparticles with immune cells. Emphasis is placed on the systematization of data over production of antibodies by using gold nanoparticles and adjuvant properties of gold nanoparticles. Specifically, we start our discussion with current data on interaction of various gold nanoparticles with immune cells. The next section describes existing technologies to improve production of antibodies in vivo by using gold nanoparticles conjugated with specific ligands. Finally, we describe what is known about adjuvant properties of bare gold or functionalized nanoparticles. In the Conclusion section, we present a short summary of reported data and some challenges and perspectives.