Gold nanoparticle-M2e conjugate coformulated with CpG induces protective immunity against influenza A virus

Generation of Broad Protection against Influenza with Di-Tyrosine-Cross-Linked M2e Nanoclusters

Tyrosine cross-linking has recently been used to produce nanoclusters (NCs) from peptides to enhance their immunogenicity. In this study, NCs were generated using the ectodomain of the ion channel Matrix 2 (M2e) protein, a conserved influenza surface antigen. The NCs were administered via intranasal (IN) or intramuscular (IM) routes in a mouse model in a prime-boost regimen in the presence of the adjuvant CpG. After boost, a significant increase in anti-M2e IgG and its subtypes was observed in the serum and lungs of mice vaccinated through the IM and IN routes; however, significant enhancement in anti-M2e IgA in lungs was observed only in the IN group. Analysis of cytokine concentrations in stimulated splenocyte cultures indicated a Th1/Th17-biased response. Mice were challenged with a lethal dose of A/California/07/2009 (H1N1pdm), A/Puerto Rico/08/1934 (H1N1), or A/Hong Kong/08/1968 (H3N2) strains. Mice that received M2e NCs + CpG were significantly protected against these strains and showed decreased lung viral titers compared with the naive mice and M2e NC-alone groups. The IN-vaccinated group showed superior protection against the H3N2 strain as compared to the IM group. This research extends our earlier efforts involving the tyrosine-based cross-linking method and highlights the potential of this technology in enhancing the immunogenicity of short peptide immunogens.

The Possible Mechanisms of Cu and Zn in the Treatment and Prevention of HIV and COVID-19 Viral Infection

Due to their unique properties and their potential therapeutic and prophylactic applications, heavy metals have attracted the interest of many researchers, especially during the outbreak of COVID-19. Indeed, zinc (Zn) and copper (Cu) have been widely used during viral infections. Zn has been reported to prevent excessive inflammatory response and cytokine storm, improve the response of the virus to Type I interferon (IFN-1), and enhance the production of IFN-a to counteract the antagonistic effect of SARS-CoV-2 virus protein on IFN. Additionally, Zn has been found to promote the proliferation and differentiation of T and B lymphocytes, thereby improving immune function, inhibiting RNA-dependent RNA polymerase (RdRp) in SARS- CoV-2 reducing the viral replication and stabilizing the cell membrane by preventing the proteolytic processing of viral polyprotein and proteases enzymes. Interestingly, Zn deficiency has been correlated with enhanced SARS-CoV-2 viral entry through interaction between the ACE2 receptor and viral spike protein. Along with zinc, Cu possesses strong virucidal capabilities and is known to be effective at neutralizing a variety of infectious viruses, including the poliovirus, influenza virus, HIV type 1, and other enveloped or nonenveloped, single- or double-stranded DNA and RNA viruses. Cu-related antiviral action has been linked to different pathways. First, it may result in permanent damage to the viral membrane, envelopes, and genetic material of viruses. Second, Cu produces reactive oxygen species to take advantage of the redox signaling mechanism to eradicate the virus. The present review focused on Zn and Cu in the treatment and prevention of viral infection. Moreover, the application of metals such as Cu and gold in nanotechnology for the development of antiviral therapies and vaccines has been also discussed.

The use of nanoparticles in the treatment of infectious diseases and cancer, dental applications and tissue regeneration: a review

The emergence of nanotechnology as a field of study can be traced back to the 1980s, at which point the means to artificially produce, control, and observe matter on a nanometer level was made viable. Recent advancements in technology have enabled us to extend our reach to the nanoscale, which has presented an unparalleled opportunity to directly target biomolecular interactions. As a result of these developments, there is a drive to arise intelligent nanostructures capable of overcoming the obstacles that have impeded the progress of conventional pharmacological methodologies. After four decades, the gradual amalgamation of bio- and nanotechnologies is initiating a revolution in the realm of disease detection, treatment, and monitoring, as well as unsolved medical predicaments. Although a significant portion of research in the field is still confined to laboratories, the initial application of nanotechnology as treatments, vaccines, pharmaceuticals, and diagnostic equipment has now obtained endorsement for commercialization and clinical practice. The current issue presents an overview of the latest progress in nanomedical strategies towards alleviating antibiotic resistance, diagnosing and treating cancer, addressing neurodegenerative disorders, and an array of applications, encompassing dentistry and tuberculosis treatment. The current investigation also scrutinizes the deployment of sophisticated smart nanostructured materials in fields of application such as regenerative medicine, as well as the management of targeted and sustained release of pharmaceuticals and therapeutic interventions. The aforementioned concept exhibits the potential for revolutionary advancements within the field of immunotherapy, as it introduces the utilization of implanted vaccine technology to consistently regulate and augment immune functions. Concurrently with the endeavor to attain the advantages of nanomedical intervention, it is essential to enhance the unceasing emphasis on nanotoxicological research and the regulation of nanomedications' safety. This initiative is crucial in achieving the advancement in medicine that currently lies within our reach.

Delivery of gold nanoparticle-conjugated M2e influenza vaccine in mice using coated microneedles

As a prospective influenza vaccination platform, a microneedle patch offers advantages such as self-administration and reduction of needle-phobia-associated vaccination avoidance. In an effort to design a broadly protective influenza vaccine we have previously developed a vaccine formulation containing the highly conserved ectodomain sequence of the M2 influenza protein (M2e) attached to the surface of gold nanoparticles (AuNPs) with CpG as a soluble adjuvant (AuNP-M2e + sCpG). Our previous studies have used the intranasal route for vaccination and demonstrated broad protection from this vaccine. Here we asked the question whether the same formulation can be effective when administered to mice using microneedles. We demonstrate that the microneedles can be coated with AuNP-M2e + sCpG formulation, and the AuNPs from the coating can be readily resuspended without aggregation. The AuNPs were delivered with high efficiency into murine skin, and the AuNPs cleared the skin within 12 h of microneedle treatment. After vaccination, strong M2e-specific humoral and cellular responses were stimulated, and the vaccinated mice were 100% protected following a lethal challenge with influenza A/PR/8/34 (H1N1).

Humoral Response to the Acetalated Dextran M2e Vaccine is Enhanced by Antigen Surface Conjugation

The influenza A virus causes substantial morbidity and mortality worldwide every year and poses a constant threat of an emergent pandemic. Seasonal influenza vaccination strategies fail to provide complete protection against infection due to antigenic drift and shift. A universal vaccine targeting a conserved influenza epitope could substantially improve current vaccination strategies. The ectodomain of the matrix 2 protein (M2e) of influenza is a highly conserved epitope between virus strains but is also poorly immunogenic. Administration of M2e and the immunostimulatory stimulator of interferon genes (STING) agonist 3'3'-cyclic guanosine-adenosine monophosphate (cGAMP) encapsulated in microparticles made of acetalated dextran (Ace-DEX) has previously been shown to be effective for increasing the immunogenicity of M2e, primarily through T-cell-mediated responses. Here, the immunogenicity of Ace-DEX MPs delivering M2e was further improved by conjugating the M2e peptide to the particle surface in an effort to affect B-cell responses more directly. Conjugated or encapsulated M2e co-administered with Ace-DEX MPs containing cGAMP were used to vaccinate mice, and it was shown that two or three vaccinations could fully protect against a lethal influenza challenge, while only the surface-conjugated antigen constructs could provide some protection against lethal challenge with only one vaccination. Additionally, the use of a reducible linker augmented the T-cell response to the antigen. These results show the utility of conjugating M2e to the surface of a particle carrier to increase its immunogenicity for use as the antigen in a universal influenza vaccine.

Recent Advances in Inhaled Nanoformulations of Vaccines and Therapeutics Targeting Respiratory Viral Infections

With the rapid outbreak of respiratory viral infections, various biological (e.g. vaccines, peptides, recombinant proteins, antibodies and genes) and antiviral agents (e.g. ribavirin, palivizumab and valaciclovir) have been successfully developed for the treatment of respiratory virus infections such as influenza, respiratory syncytial virus and SARS-CoV-2 infections. These therapeutics are conventionally delivered via oral, intramuscular or injection route and are associated with several adverse events due to systemic toxicity. The inherent in vivo instability of biological therapeutics may hinder them from being administered without proper formulations. Therefore, we have witnessed a boom in nanotechnology coupled with a needle-free administration approach such as the inhalation route for the delivery of complex therapeutics to treat respiratory infections. This review discussed the recent advances in the inhalation strategies of nanoformulations that target virus respiratory infections.

Preclinical developments in the delivery of protein antigens for vaccination

INTRODUCTION

Vaccine technology has constantly advanced since its origin. One of these advancements is where purified parts of a pathogen are used rather than the whole pathogen. Subunit vaccines have no chance of causing disease; however, alone these antigens are often poorly immunogenic. Therefore, they can be paired with immune stimulating adjuvants. Further, subunits can be combined with delivery strategies such as nano/microparticles to enrich their delivery to organs and cells of interest as well as protect them from in vivo degradation. Here, we seek to highlight some of the more promising delivery strategies for protein antigens.

AREAS COVERED

We present a brief description of the different types of vaccines, clinically relevant examples, and their disadvantages when compared to subunit vaccines. Also, specific preclinical examples of delivery strategies for protein antigens.

EXPERT OPINION

Subunit vaccines provide optimal safety given that they have no risk of causing disease; however, they are often not immunogenic enough on their own to provide protection. Advanced delivery systems are a promising avenue to increase the immunogenicity of subunit vaccines, but scalability and stability can be improved. Further, more research is warranted on systems that promote a mucosal immune response to provide better protection against infection.

Sustained delivery of CpG oligodeoxynucleotide by acetalated dextran microparticles augments effector response to Computationally Optimized Broadly Reactive Antigen (COBRA) influenza hemagglutinin

A subunit or protein-based influenza vaccine can be a safer alternative to live attenuated vaccine (Flumist) and require fewer boosts than an inactivated vaccine (e.g. Fluzone). However, to form an effective subunit vaccine, an adjuvant is often needed. In this work we used electrospray to encapsulate the hydrophilic adjuvant CpG into microparticles made from the hydrophobic biodegradable polymer acetalated dextran. To understand the rate of particle degradation on CpG release, polymer that was slow (21 h at phagosomal pH 5) and fast (0.25 h at pH 5) degrading was used to encapsulate the adjuvant. The slow-degrading particles exhibited the greatest degree of innate immune stimulation of antigen-presenting cells in vitro. In mice, the broadly acting Computationally Optimized Broadly Reactive Antigen (COBRA) Y2 influenza hemagglutinin (HA) antigen was used with CpG particles, soluble CpG, or MF-59 like adjuvant Addavax. Particles and soluble CpG elicited similar induction of anti-HA antibodies and protection against lethal influenza challenge, but the sustained release particles elicited the highest levels antibody effector functions. These results demonstrate a suitable method for encapsulation of CpG oligonucleotide in a hydrophobic particle matrix, and suggest that sustained release of CpG from Ace-DEX microparticles could potentially be used to induce potent antibody effector functions.

Peptide Cross-Linking Using Tyrosine Residues Facilitated by an Exogenous Nickel-Histidine Complex: A Facile Approach for Enhancing Vaccine-Specific Immunogenicity

An improved method for the generation of peptide vaccines using di-tyrosine cross-linking is described. The conserved ion channel peptide, M2e, of influenza A virus was modified with the addition of small tyrosine-rich regions (GYGY-) at both the N- and C-termini and extensively cross-linked via tyrosine-tyrosine linkages to form peptide nanoclusters. The cross-linking was catalyzed using exogenous nickel(II) ions complexed to an exogenous glycine-glycine-histidine peptide in the presence of an oxidizer. Mice that were intranasally or intramuscularly immunized with the M2e-vaccine nanoclusters induced comparable levels of M2e-specific serum antibodies. Vaccination via the intranasal or intramuscular route protected mice from subsequent lethal challenge with an influenza A virus. In comparison to our previous approach, where a histidine-rich tag was added into the peptide structure, the use of exogenous histidine reduced irrelevant off-target immune response. Additionally, the purity of the resulting nanoclusters is an attractive feature, making this approach appealing for vaccine development.

Mucosal delivery of nanovaccine strategy against COVID-19 and its variants

Despite the global administration of approved COVID-19 vaccines (e.g., ChAdOx1 nCoV-19®, mRNA-1273®, BNT162b2®), the number of infections and fatalities continue to rise at an alarming rate because of the new variants such as Omicron and its subvariants. Including COVID-19 vaccines that are licensed for human use, most of the vaccines that are currently in clinical trials are administered via parenteral route. However, it has been proven that the parenteral vaccines do not induce localized immunity in the upper respiratory mucosal surface, and administration of the currently approved vaccines does not necessarily lead to sterilizing immunity. This further supports the necessity of a mucosal vaccine that blocks the main entrance route of COVID-19: nasal and oral mucosal surfaces. Understanding the mechanism of immune regulation of M cells and dendritic cells and targeting them can be another promising approach for the successful stimulation of the mucosal immune system. This paper reviews the basic mechanisms of the mucosal immunity elicited by mucosal vaccines and summarizes the practical aspects and challenges of nanotechnology-based vaccine platform development, as well as ligand hybrid nanoparticles as potentially effective target delivery agents for mucosal vaccines.

Nanoparticle-Based Delivery Systems for Vaccines

Vaccination is still the most cost-effective way to combat infectious illnesses. Conventional vaccinations may have low immunogenicity and, in most situations, only provide partial protection. A new class of nanoparticle-based vaccinations has shown considerable promise in addressing the majority of the shortcomings of traditional and subunit vaccines. This is due to recent breakthroughs in chemical and biological engineering, which allow for the exact regulation of nanoparticle size, shape, functionality, and surface characteristics, resulting in improved antigen presentation and robust immunogenicity. A blend of physicochemical, immunological, and toxicological experiments can be used to accurately characterize nanovaccines. This narrative review will provide an overview of the current scenario of the nanovaccine.

Nano toolbox in immune modulation and nanovaccines

Despite the great success of vaccines over two centuries, the conventional strategy is based on attenuated/altered microorganisms. However, this is not effective for all microbes and often fails to elicit a protective immune response, and sometimes poses unexpected safety risks. The expanding nano toolbox may overcome some of the roadblocks in vaccine development given the plethora of unique nanoparticle (NP)-based platforms that can successfully induce specific immune responses leading to exciting and novel solutions. Nanovaccines necessitate a thorough understanding of the immunostimulatory effect of these nanotools. We present a comprehensive description of strategies in which nanotools have been used to elicit an immune response and provide a perspective on how nanotechnology can lead to future personalized nanovaccines.

Evaluating the immunogenicity of gold nanoparticles conjugated RBD with Freund's adjuvant as a potential vaccine against SARS-CoV-2

Background

and Introduction: SARS-CoV-2 is currently considered as the most challenging issue in the field of health and medicine by causing a global pandemic. Vaccines are counted as a promising candidate to terminate this deadly pandemic. Various structural proteins in SARS-CoV-2 have recently drawn attention to be utilized as candidate vaccines to stimulate immune responses against COVID-19.

Materials and methods

In current study, the RBD protein was cloned and expressed in E. coli host. Then, the expressed RBD protein was purified and its characterizations were evaluated through various methods. Gold nanoparticles, which were utilized as a carrier for candidate Nano-vaccine, were synthesized via oxidation-reduction reaction. While Gold NPs-conjugated RBD was injected into the second treatment group, in the first candidate vaccine, RBD was injected into the first treatment group solely. Complete and Incomplete Freud's Adjuvant were also utilized for both treatment groups to enhance the immune responses against RBD antigen. Immunizations were repeated 2 times in 14-day intervals to boost the immune system of BALB/c mice. The humoral and cell-mediated immune responses were examined through immune and cytokine assays.

Results

Our outcomes demonstrate that strong short-term humoral immunity (IgM) was induced in both the first and second treatment group, while long-term humoral responses (IgG) were only observed in the second treatment group. While stronger short- and long-term humoral (IgM and IgG, respectively) were observed in the second treatment group, particular cytokines production (TNF-ɑ and IFN-γ) as a marker of cell-mediated responses were significantly higher in the first treatment group.

Discussion and conclusion

Our study results show the high potentiality of RBD protein as an appropriate stimulating antigen in vaccine synthesis and testifies RBD-based candidate vaccines to control the COVID-19 pandemic. Our outcomes also recommend that Nano-vaccines can be more suitable candidates when stronger long-term immune responses matter.

Antiviral effects of coinage metal-based nanomaterials to combat COVID-19 and its variants

The world has been suffering from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and millions of people have been infected through human-to-human transmission and lost their lives within months. Although multidisciplinary scientific approaches have been employed to fight against this deadly pandemic, various mutations and diverse environments keep producing constraints in treating SARS-CoV-2. Indeed, the efficacy of the developed vaccines has been limited, and inoculation with the vaccines does not guarantee complete protection even though multiple doses are required, which is a frustrating process. Historically, coinage metals (Cu, Ag, and Au) have been well-known for their effectiveness in antiviral action as well as good biocompatibility, binding receptor inhibition, reactive oxygen species, and phototherapy properties. Thus, this review highlights the diagnostic and therapeutic mechanisms of SARS-CoV-2 using the antivirus ability and mode of action of coinage metals such as viral entry mechanisms into host cells and the NP-inhibition process, which are explained in detail. This article also draws attention to coinage metal nanomaterial-based approaches to treat other contagious viruses. In addition, coinage metal-based biosensors and an overview of some other biocompatible metal-based nanomaterials to fight against SARS-CoV-2 variants are discussed. Finally, the advantages, perspectives and challenges of coinage metal nanoparticles are given to fight against viral infections in the future.

Exploring the Impact of Chitosan Composites as Artificial Organs

Chitosan and its allies have in multiple ways expanded into the medical, food, chemical, and biological industries and is still expanding. With its humble beginnings from marine shell wastes, the deacetylated form of chitin has come a long way in clinical practices. The biomedical applications of chitosan are truly a feather on its cap, with rarer aspects being chitosan’s role in tissue regeneration and artificial organs. Tissue regeneration is a highly advanced and sensitive biomedical application, and the very fact that chitosan is premiering here is an authentication of its ability to deliver. In this review, the various biomedical applications of chitosan are touched on briefly. The synthesis methodologies that are specific for tissue engineering and biomedical applications have been listed. What has been achieved using chitosan and chitosan composites in artificial organ research as well as tissue regeneration has been surveyed and presented. The lack of enthusiasm, as demonstrated by the very few reports online with respect to chitosan composites and artificial organs, is highlighted, and the reasons for this lapse speculated. What more needs be done to expand chitosan and its allies for a better utilization and exploitation to best benefit the construction of artificial organs and building of tissue analogs has been discussed.

Efficacy and Immune Response Elicited by Gold Nanoparticle- Based Nanovaccines against Infectious Diseases

The use of nanoparticles for developing vaccines has become a routine process for researchers and pharmaceutical companies. Gold nanoparticles (GNPs) are chemical inert, have low toxicity, and are easy to modify and functionalize, making them an attractive choice for nanovaccine development. GNPs are modified for diagnostics and detection of many pathogens. The biocompatibility and biodistribution properties of GNPs render them ideal for use in clinical settings. They have excellent immune modulatory and adjuvant properties. They have been used as the antigen carrier for the delivery system to a targeted site. Tagging them with antibodies can direct the drug or antigen-carrying GNPs to specific tissues or cells. The physicochemical properties of the GNP, together with its dynamic immune response based on its size, shape, surface charge, and optical properties, make it a suitable candidate for vaccine development. The clear outcome of modulating dendritic cells, T and B lymphocytes, which trigger cytokine release in the host, indicates GNPs' efficiency in combating pathogens. The high titer of IgG and IgA antibody subtypes and their enhanced capacity to neutralize pathogens are reported in multiple studies on GNP-based vaccine development. The major focus of this review is to illustrate the role of GNPs in developing nanovaccines against multiple infectious agents, ranging from viruses to bacteria and parasites. Although the use of GNPs has its shortcomings and a low but detectable level of toxicity, their benefits warrant investing more thought and energy into the development of novel vaccine strategies.

Nano/microparticle Formulations for Universal Influenza Vaccines

Influenza affects millions of people worldwide and can result in severe sickness and even death. The best method of prevention is vaccination; however, the seasonal influenza vaccine often suffers from low efficacy and requires yearly vaccination due to changes in strain and viral mutations. More conserved universal influenza antigens like M2 ectodomain (M2e) and the stalk region of hemagglutinin (HA stalk) have been used clinically but often suffer from low antigenicity. To increase antigenicity, universal antigens have been formulated using nano/microparticles as vaccine carriers against influenza. Utilizing polymers, liposomes, metal, and protein-based particles, indicators of immunity and protection in mouse, pig, ferrets, and chicken models of influenza have been shown. In this review, seasonal and universal influenza vaccine formulations comprised of these materials including their physiochemical properties, fabrication, characterization, and biologic responses in vivo are highlighted. The review is concluded with future perspectives for nano/microparticles as carrier systems and other considerations within the universal influenza vaccine delivery landscape.

Biomaterial-assisted biotherapy: A brief review of biomaterials used in drug delivery, vaccine development, gene therapy, and stem cell therapy

Biotherapy has recently become a hotspot research topic with encouraging prospects in various fields due to a wide range of treatments applications, as demonstrated in preclinical and clinical studies. However, the broad applications of biotherapy have been limited by critical challenges, including the lack of safe and efficient delivery systems and serious side effects. Due to the unique potentials of biomaterials, such as good biocompatibility and bioactive properties, biomaterial-assisted biotherapy has been demonstrated to be an attractive strategy. The biomaterial-based delivery systems possess sufficient packaging capacity and versatile functions, enabling a sustained and localized release of drugs at the target sites. Furthermore, the biomaterials can provide a niche with specific extracellular conditions for the proliferation, differentiation, attachment, and migration of stem cells, leading to tissue regeneration. In this review, the state-of-the-art studies on the applications of biomaterials in biotherapy, including drug delivery, vaccine development, gene therapy, and stem cell therapy, have been summarized. The challenges and an outlook of biomaterial-assisted biotherapies have also been discussed.

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Biomaterials possess unique advantages to improve the efficacy and safety of biotherapy.

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Various types of biomaterials can be used in a wide range of biotherapy.

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The functions of biomaterials can be tuned by changing their inherent properties or the surrounding environment.

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.

Gold nanoparticle-based platforms for vaccine development

Since their discovery, therapeutic or prophylactic vaccines represent a promising option to prevent or cure infections and other pathologies, such as cancer or autoimmune disorders. More recently, among a number of nanomaterials, gold nanoparticles (AuNPs) have emerged as novel tools for vaccine developments, thanks to their inherent ability to tune and upregulate immune response. Moreover, owing to their features, AuNPs can exert optimal actions both as delivery systems and as adjuvants. Notwithstanding the potential huge impact in vaccinology, some challenges remain before AuNPs in vaccine formulations can be translated into the clinic. The current review provides an updated overview of the most recent and effective application of gold nanoparticles as efficient means to develop a new generation of vaccine.

Gold-Nanostar-Chitosan-Mediated Delivery of SARS-CoV-2 DNA Vaccine for Respiratory Mucosal Immunization: Development and Proof-of-Principle

The COVID-19 pandemic is caused by the coronavirus SARS-CoV-2 (SC2). A variety of anti-SC2 vaccines have been approved for human applications, including those using messenger RNA (mRNA), adenoviruses expressing SC2 spike (S) protein, and inactivated virus. The protective periods of immunization afforded by these intramuscularly administered vaccines are currently unknown. An alternative self-administrable vaccine capable of mounting long-lasting immunity via sterilizing neutralizing antibodies would be hugely advantageous in tackling emerging mutant SC2 variants. This could also diminish the possibility of vaccinated individuals acting as passive carriers of COVID-19. Here, we investigate the potential of an intranasal (IN)-delivered DNA vaccine encoding the S protein of SC2 in BALB/c and C57BL/6J immunocompetent mouse models. The immune response to IN delivery of this SC2-spike DNA vaccine transported on a modified gold-chitosan nanocarrier shows a strong and consistent surge in antibodies (IgG, IgA, and IgM) and effective neutralization of pseudoviruses expressing S proteins of different SC2 variants (Wuhan, beta, and D614G). Immunophenotyping and histological analyses reveal chronological events involved in the recognition of SC2 S antigen by resident dendritic cells and alveolar macrophages, which prime the draining lymph nodes and spleen for peak SC2-specific cellular and humoral immune responses. The attainable high levels of anti-SC2 IgA in lung mucosa and tissue-resident memory T cells can efficiently inhibit SC2 and its variants at the site of entry and also provide long-lasting immunity.

Advanced Nanomaterials for Preparedness Against (Re-)Emerging Viral Diseases

While the coronavirus disease (COVID-19) accounts for the current global pandemic, the emergence of other unknown pathogens, named "Disease X," remains a serious concern in the future. Emerging or re-emerging pathogens continue to pose significant challenges to global public health. In response, the scientific community has been urged to create advanced platform technologies to meet the ever-increasing needs presented by these devastating diseases with pandemic potential. This review aims to bring new insights to allow for the application of advanced nanomaterials in future diagnostics, vaccines, and antiviral therapies, thereby addressing the challenges associated with the current preparedness strategies in clinical settings against viruses. The application of nanomaterials has advanced medicine and provided cutting-edge solutions for unmet needs. Herein, an overview of the currently available nanotechnologies is presented, highlighting the significant features that enable them to control infectious diseases, and identifying the challenges that remain to be addressed for the commercial production of nano-based products is presented. Finally, to conclude, the development of a nanomaterial-based system using a "One Health" approach is suggested. This strategy would require a transdisciplinary collaboration and communication between all stakeholders throughout the entire process spanning across research and development, as well as the preclinical, clinical, and manufacturing phases.

Intranasal Vaccination With Recombinant Antigen-FLIPr Fusion Protein Alone Induces Long-Lasting Systemic Antibody Responses and Broad T Cell Responses

A simple formulation is urgently needed for mucosal vaccine development. We employed formyl peptide receptor-like 1 inhibitory protein (FLIPr), an FcγR antagonist secreted by Staphylococcus aureus, as a vector to target ovalbumin (OVA) to dendritic cells (DCs) via intranasal administration. Our results demonstrate that intranasal administration of recombinant OVA-FLIPr fusion protein (rOVA-FLIPr) alone efficiently delivers OVA to DCs in nasal lymphoid tissue. Subsequently, OVA-specific IgG and IgA antibodies in the circulatory system and IgA antibodies in mucosal tissue were detected. Importantly, activation of OVA-specific CD4+ and CD8+ T cells and induction of a broad-spectrum cytokine secretion profile were detected after intranasal administration of rOVA-FLIPr alone in immunocompetent C57BL/6 mice. Furthermore, we employed immunodeficient AG129 mice as a Zika virus infection model and demonstrated that intranasal administration of recombinant Zika virus envelope protein domain III-FLIPr fusion protein induced protective immune responses against the Zika virus. These results suggest that antigen-FLIPr fusion protein alone via intranasal administration can be applied to mucosal vaccine development.

Tyrosine-Based Cross-Linking of Peptide Antigens to Generate Nanoclusters with Enhanced Immunogenicity: Demonstration Using the Conserved M2e Peptide of Influenza A

A method of creating nanoclusters (NCs) from soluble peptide molecules is described utilizing an approach based on a tyrosine-tyrosine cross-linking reaction. A reactive tag comprising histidine and tyrosine residues was introduced at the termini of the peptide molecules. The cross-linking reaction led to the creation of dityrosine bonds within the tag, which allowed for the generation of peptide NCs. We show that it is essential for the reactive tag to be present at both the "N" and "C" termini of the peptide for cluster formation to occur. Additionally, the cross-linking reaction was systematically characterized to show the importance of reaction conditions on final cluster diameter, allowing us to generate NCs of various sizes. To demonstrate the immunogenic potential of the peptide clusters, we chose to study the conserved influenza peptide, M2e, as the antigen. M2e NCs were formulated using the cross-linking reaction. We show the ability of the clusters to generate protective immunity in a dose, size, and frequency dependent manner against a lethal influenza A challenge in BALB/c mice. Taken together, the data presented suggest this new cluster formation technique can generate highly immunogenic peptide NCs in a simple and controllable manner.

Nanoscience and quantum science-led biocidal and antiviral strategies

The severe acute respiratory syndrome coronavirus (SARS-CoV-2) caused the COVID-19 pandemic. According to the World Health Organization, this pandemic continues to be a serious threat to public health due to the worldwide spread of variants and their higher rate of transmissibility. A range of measures are necessary to slow the pandemic and save lives, which include constant evaluation and the careful adjustment of public-health responses augmented by medical treatments, vaccines and protective gear. It is hypothesized that nanostructured particulates underpinned by nanoscience and quantum science yield high-performing antiviral strategies, which can be applied in preventive, diagnostic, and therapeutic applications such as face masks, respirators, COVID test kits, vaccines, and drugs. This review is aimed at providing comprehensive and cohesive perspectives on various nanostructures that are suited to intensifying and amplifying the effectiveness of antiviral strategies. Growing scientific literature over the past eighteen months indicates that quantum dots, iron oxide, silicon oxide, polymeric and metallic nanoparticles have been employed in COVID-19 diagnostic assays, vaccines, and personal protective equipment (PPE). Quantum dots have displayed their suitability as more sensitive imaging probes in diagnostics and prognostics, and as controlled drug-release carriers that target the virus. Nanoscience and quantum science have assisted the design of advanced vaccine delivery since nanostructured materials are suited for antigen delivery, as mimics of viral structures and as adjuvants. Furthermore, the quantum science- and nanoscience-supported tailored functionalization of nanostructured materials offers insight and pathways to deal with future pandemics. This review seeks to illustrate several examples, and to explain the underpinning quantum science and nanoscience phenomena, which include wave functions, electrostatic interactions, van der Waals forces, thermal and electrodynamic fluctuations, dispersion forces, local field-enhancement effects, and the generation of reactive oxygen species (ROS). This review discusses how nanostructured materials are helpful in the detection, prevention, and treatment of the SARS-CoV-2 infection, other known viral infection diseases, and future pandemics.

M2e conjugated gold nanoparticle influenza vaccine displays thermal stability at elevated temperatures and confers protection to ferrets

Currently approved influenza vaccines are not only limited in breadth of protection but also have a limited shelf-life of 12-18 months when stored under appropriate conditions (2-8 °C). Inadvertent alteration in storage temperatures during manufacturing, transportation, distribution until delivery to patient, can damage the vaccine thus reducing its efficacy. A thermally stable vaccine can decrease the economic burden by reducing reliance on refrigeration system and can also enhance outreach of the vaccination program by allowing transportation to remote areas of the world where refrigerated conditions are scarce. We have previously developed a broadly protective influenza A vaccine by coupling the highly conserved extracellular region of the matrix 2 protein (M2e) of influenza A virus to gold nanoparticles (AuNPs) and upon subsequent addition of toll-like receptor 9 agonist - CpG, as an adjuvant, have shown its breadth of protection in a mouse model. In this study, we show that the vaccine is thermally stable when stored at 4 °C for 3 months, 37 °C for 3 months and 50 °C for 2 weeks in its lyophilized form, and later it was possible to readily reconstitute it in water without aggregation. Intranasal vaccination of mice using reconstituted vaccine induced M2e-specific IgG and IgG subtypes in serum similar to the freshly formulated vaccine, and fully protected mice against lethal influenza A challenge. Immunization of ferrets intranasally or intramuscularly with the vaccine induced M2e-specific IgG and there was reduced virus level in nasal wash of ferrets immunized through intranasal route.

Emerging Advances of Nanotechnology in Drug and Vaccine Delivery against Viral Associated Respiratory Infectious Diseases (VARID)

Viral-associated respiratory infectious diseases are one of the most prominent subsets of respiratory failures, known as viral respiratory infections (VRI). VRIs are proceeded by an infection caused by viruses infecting the respiratory system. For the past 100 years, viral associated respiratory epidemics have been the most common cause of infectious disease worldwide. Due to several drawbacks of the current anti-viral treatments, such as drug resistance generation and non-targeting of viral proteins, the development of novel nanotherapeutic or nano-vaccine strategies can be considered essential. Due to their specific physical and biological properties, nanoparticles hold promising opportunities for both anti-viral treatments and vaccines against viral infections. Besides the specific physiological properties of the respiratory system, there is a significant demand for utilizing nano-designs in the production of vaccines or antiviral agents for airway-localized administration. SARS-CoV-2, as an immediate example of respiratory viruses, is an enveloped, positive-sense, single-stranded RNA virus belonging to the coronaviridae family. COVID-19 can lead to acute respiratory distress syndrome, similarly to other members of the coronaviridae. Hence, reviewing the current and past emerging nanotechnology-based medications on similar respiratory viral diseases can identify pathways towards generating novel SARS-CoV-2 nanotherapeutics and/or nano-vaccines.

Nanostrategies to Develop Current Antiviral Vaccines

Infectious diseases are a worldwide concern. They are responsible for increasing the mortality rate and causing economic and social problems. Viral epidemics and pandemics, such as the COVID-19 pandemic, force the scientific community to consider molecules with antiviral activity. A number of viral infections still do not have a vaccine or efficient treatment and it is imperative to search for vaccines to control these infections. In this context, nanotechnology in association with the design of vaccines has presented an option for virus control. Nanovaccines have displayed an impressive immune response using a low dosage. This review aims to describe the advances and update the data in studies using nanovaccines and their immunomodulatory effect against human viruses.

Virosome-based nanovaccines; a promising bioinspiration and biomimetic approach for preventing viral diseases: A review

Vaccination is the most effective means of controlling infectious disease-related morbidity and mortality. However, due to low immunogenicity of viral antigens, nanomedicine as a new opportunity in new generation of vaccine advancement attracted researcher encouragement. Virosome is a lipidic nanomaterial emerging as FDA approved nanocarriers with promising bioinspiration and biomimetic potency against viral infections. Virosome surface modification with critical viral fusion proteins is the cornerstone of vaccine development. Surface antigens at virosomes innovatively interact with targeted receptors on host cells that evoke humoral or cellular immune responses through antibody-producing B cell and internalization by endocytosis-mediated pathways. To date, several nanovaccine based on virosome formulations have been commercialized against widespread and life-threatening infections. Recently, Great efforts were made to fabricate a virosome-based vaccine platform against a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Thus, this review provides a novel overview of the virosome based nanovaccine production, properties, and application on the viral disease, especially its importance in SARS-CoV-2 vaccine discovery.

Iron nanoparticles as novel vaccine adjuvants

The poor immunogenicity of peptide vaccines compared to conventional ones re usually improved by applying different adjuvants. As chemical or biological substances, adjuvants are added to vaccines to enhance and prolong the immune response. According to considerable investigations over the recent years in the context of finding new adjuvants, a handful of vaccine adjuvants have been licensed for human use. Recently, engineered nanoparticles (NPs) have been introduced as novel alternatives to traditional vaccine adjuvant. Metallic nanoparticles (MeNPs) are among the most promising NPs used for vaccine adjuvant as well as the delivery system that can improve immune responses against pathogens. Iron NPs, as an important class of MeNPs, have gained increasing attention as novel vaccine adjuvants. These particles have shown acceptable results in preclinical studies. Hence, understanding the physicochemical properties of iron NPs, including size, surface properties, charge and route of administration, is of substantial importance. The aim of this review is to provide an overview of the immunomodulatory effects of iron NPs as novel adjuvants. Furthermore, physicochemical properties of these NPs were also discussed.

A meta-analysis of the efficiency of metal nanoparticles in vaccine delivery against infectious disease

Background: Exploration of the efficiency of metal nanoparticles as adjuvants have reported varying results. Objective: The efficacy of metal nanoparticles as adjuvants was investigated Data sources: Database were searched using the terms 'metal nanoparticles' and 'vaccines'. Study eligibility criteria: Studies in animal models utilizing any metal-based vaccines, where the survival rate was described. Study appraisal: The quality of the studies was examined using aspects of the ARRIVE guidelines and assessment of the risk of bias of included studies. Results: Metal nanoparticle-based adjuvants were more effective compared with control (unvaccinated groups) but have not been more successful in competing with common adjuvants or even antigens alone. Limitation: More than 75% of articles have used only gold nanoparticles. Conclusion: Nano-adjuvants do not have a significant effect on reducing mortality.

Nanotechnology against the novel coronavirus (severe acute respiratory syndrome coronavirus 2): diagnosis, treatment, therapy and future perspectives

COVID-19, as an emerging infectious disease, has caused significant mortality and morbidity along with socioeconomic impact. No effective treatment or vaccine has been approved yet for this pandemic disease. Cutting-edge tools, especially nanotechnology, should be strongly considered to tackle this virus. This review aims to propose several strategies to design and fabricate effective diagnostic and therapeutic agents against COVID-19 by the aid of nanotechnology. Polymeric, inorganic self-assembling materials and peptide-based nanoparticles are promising tools for battling COVID-19 as well as its rapid diagnosis. This review summarizes all of the exciting advances nanomaterials are making toward COVID-19 prevention, diagnosis and therapy.

Preparation, Functionalization, Modification, and Applications of Nanostructured Gold: A Critical Review

Gold nanoparticles (Au NPs) play a significant role in science and technology because of their unique size, shape, properties and broad range of potential applications. This review focuses on the various approaches employed for the synthesis, modification and functionalization of nanostructured Au. The potential catalytic applications and their enhancement upon modification of Au nanostructures have also been discussed in detail. The present analysis also offers brief summaries of the major Au nanomaterials synthetic procedures, such as hydrothermal, solvothermal, sol-gel, direct oxidation, chemical vapor deposition, sonochemical deposition, electrochemical deposition, microwave and laser pyrolysis. Among the various strategies used for improving the catalytic performance of nanostructured Au, the modification and functionalization of nanostructured Au produced better results. Therefore, various synthesis, modification and functionalization methods employed for better catalytic outcomes of nanostructured Au have been summarized in this review.

Matrix Protein 2 Extracellular Domain-Specific Monoclonal Antibodies Are an Effective and Potentially Universal Treatment for Influenza A

Influenza virus infection causes significant morbidity and mortality worldwide. Humans fail to make a universally protective memory immune response to influenza A. Hemagglutinin and Neuraminidase undergo antigenic drift and shift, resulting in new influenza A strains to which humans are naive. Seasonal vaccines are often ineffective and escape mutants have been reported to all treatments for influenza A. In the absence of a universal influenza A vaccine or treatment, influenza A will remain a significant threat to human health. The extracellular domain of the M2-ion channel (M2e) is an ideal antigenic target for a universal therapeutic agent, as it is highly conserved across influenza A serotypes, has a low mutation rate, and is essential for viral entry and replication. Previous M2e-specific monoclonal antibodies (M2e-MAbs) show protective potential against influenza A, however, they are either strain specific or have limited efficacy. We generated seven murine M2e-MAbs and utilized in vitro and in vivo assays to validate the specificity of our novel M2e-MAbs and to explore the universality of their protective potential. Our data shows our M2e-MAbs bind to M2e peptide, HEK cells expressing the M2 channel, as well as, influenza virions and MDCK-ATL cells infected with influenza viruses of multiple serotypes. Our antibodies significantly protect highly influenza A virus susceptible BALB/c mice from lethal challenge with H1N1 A/PR/8/34, pH1N1 A/CA/07/2009, H5N1 A/Vietnam/1203/2004, and H7N9 A/Anhui/1/2013 by improving survival rates and weight loss. Based on these results, at least four of our seven M2e-MAbs show strong potential as universal influenza A treatments.IMPORTANCE Despite a seasonal vaccine and multiple therapeutic treatments, Influenza A remains a significant threat to human health. The biggest obstacle is producing a vaccine or treatment for influenza A is their universality or efficacy against not only seasonal variances in the influenza virus, but also against all human, avian, and swine serotypes and, therefore, potential pandemic strains. M2e has huge potential as a target for a vaccine or treatment against influenza A. It is the most conserved external protein on the virus. Antibodies against M2e have made it to clinical trials, but not succeeded. Here, we describe novel M2e antibodies produced in mice that are not only protective at low doses, but that we extensively test to determine their universality and found to be cross protective against all strains tested. Additionally, our work begins to elucidate the critical role of isotype for an influenza A monoclonal antibody therapeutic.

Engineered Nanoparticle Applications for Recombinant Influenza Vaccines

Influenza viruses cause seasonal epidemics and represent a pandemic risk. With current vaccine methods struggling to protect populations against emerging strains, there is a demand for a next-generation flu vaccine capable of providing broad protection. Recombinant biotechnology, combined with nanomedicine techniques, could address this demand by increasing immunogenicity and directing immune responses toward conserved antigenic targets on the virus. Various nanoparticle candidates have been tested for use in vaccines, including virus-like particles, protein and carbohydrate nanoconstructs, antigen-carrying lipid particles, and synthetic and inorganic particles modified for antigen presentation. These methods have yielded some promising results, including protection in animal models against antigenically distinct influenza strains, production of antibodies with broad reactivity, and activation of potent T cell responses. Based on the evidence of current research, it is feasible that the next generation of influenza vaccines will combine recombinant antigens with nanoparticle carriers.

Bi-functional gold nanocages enhance specific immunological responses of foot-and-mouth disease virus-like particles vaccine as a carrier and adjuvant

Virus-like particle (VLP) vaccines have become one of the dominant vaccine candidates for foot-and-mouth disease (FMD). To further enhance the immunogenicity of VLP vaccines, gold nanocages (AuNCs) were selected as an adjuvant for the vaccine. Our experiments demonstrated that AuNCs had little biotoxicity in vivo and in vitro and improved the uptake of VLP in BHK-21 and RAW264.7 cell lines. The VLP-AuNCs activated DCs mainly through toll-like receptor 4 (TLR4) and promoted the secretion of IL-6, IL-1β, and TNF-α. The conjugation of VLP and AuNCs triggered a strong immune response against FMD virus (FMDV) in mice and guinea pigs. The VLP-AuNCs significantly enhanced the proliferation of CD8⁺ T cells (P < 0.05) and the secretion of cellular immune-related cytokines (IFN-γ, P < 0.05; IL-12p70, P < 0.01) compared with VLP. The present study demonstrated that AuNCs, as a great potential adjuvant for FMDV VLP vaccines, significantly enhance the immune response.

Promising Adjuvants and Platforms for Influenza Vaccine Development

Influenza is one of the major threats to public health. Current influenza vaccines cannot provide effective protection against drifted or shifted influenza strains. Researchers have considered two important strategies to develop novel influenza vaccines with improved immunogenicity and broader protective efficacy. One is applying fewer variable viral antigens, such as the haemagglutinin stalk domain. The other is including adjuvants in vaccine formulations. Adjuvants are promising and helpful boosters to promote more rapid and stronger immune responses with a dose-sparing effect. However, few adjuvants are currently licensed for human influenza vaccines, although many potential candidates are in different trials. While many advantages have been observed using adjuvants in influenza vaccine formulations, an improved understanding of the mechanisms underlying viral infection and vaccination-induced immune responses will help to develop new adjuvant candidates. In this review, we summarize the works related to adjuvants in influenza vaccine research that have been used in our studies and other laboratories. The review will provide perspectives for the utilization of adjuvants in developing next-generation and universal influenza vaccines.

A proposed insight into the anti-viral potential of metallic nanoparticles against novel coronavirus disease-19 (COVID-19)

BACKGROUND

Over the last ten months since December 2019, the world has faced infectious emerging novel coronavirus disease-2019 (COVID-19) outbreaks that had a massive global impact affecting over 185 countries.

MAIN BODY

Emerging novel COVID-19 is a global health emergency on a pandemic scale that represents a terror to human health through its ability to escape anti-viral measures. Such viral infections impose a great socioeconomic burden, besides global health challenges. This imposes a pressing need for the development of anti-viral therapeutic agents and diagnostic tools that demonstrate multifunctional, target-specific, and non-toxic properties. Nanotheranostics is regarded as a promising approach for the management of different viral infections. Nanotheranostics facilitates targeted drug-delivery of anti-viral therapeutics as well as contributing to the development of diagnostic systems. Multifunctional metallic nanoparticles (NPs) have emerged as innovative theranostic agents that enable sustainable treatment and effective diagnosis. Here we have reviewed current advances in the use of theranostic metallic NPs to fight against COVID-19, and discussed the application as well as limitations associated with nanotechnology-based theranostic approaches.

CONCLUSION

This review verified the potential use of some metal-based NPs as anti-viral nanotheranostic agents. Metal-based NPs could act as carriers that enable the sustainable and targeted delivery of active anti-viral molecules, or as diagnostic agents that allow rapid and sensitive diagnosis of viral infections.

Anti-Influenza Strategies Based on Nanoparticle Applications

Influenza virus has the potential for being one of the deadliest viruses, as we know from the pandemic's history. The influenza virus, with a constantly mutating genome, is becoming resistant to existing antiviral drugs and vaccines. For that reason, there is an urgent need for developing new therapeutics and therapies. Despite the fact that a new generation of universal vaccines or anti-influenza drugs are being developed, the perfect remedy has still not been found. In this review, various strategies for using nanoparticles (NPs) to defeat influenza virus infections are presented. Several categories of NP applications are highlighted: NPs as immuno-inducing vaccines, NPs used in gene silencing approaches, bare NPs influencing influenza virus life cycle and the use of NPs for drug delivery. This rapidly growing field of anti-influenza methods based on nanotechnology is very promising. Although profound research must be conducted to fully understand and control the potential side effects of the new generation of antivirals, the presented and discussed studies show that nanotechnology methods can effectively induce the immune responses or inhibit influenza virus activity both in vitro and in vivo. Moreover, with its variety of modification possibilities, nanotechnology has great potential for applications and may be helpful not only in anti-influenza but also in the general antiviral approaches.

Biomedical nanomaterials for immunological applications: ongoing research and clinical trials

Research efforts on nanomaterial-based therapies for the treatment of autoimmune diseases and cancer have spiked and have made rapid progress over the past years. Nanomedicine has been shown to contribute significantly to overcome current therapeutic limitations, exhibiting advantages compared to conventional therapeutics, such as sustained drug release, delayed drug degradation and site-specific drug delivery. Multiple nanodrugs have reached the clinic, but translation is often hampered by either low targeting efficiency or undesired side effects. Nanomaterials, and especially inorganic nanoparticles, have gained criticism due to their potential toxic effects, including immunological alterations. However, many strategies have been attempted to improve the therapeutic efficacy of nanoparticles and exploit their unique properties for the treatment of inflammation and associated diseases. In this review, we elaborate on the immunomodulatory effects of nanomaterials, with a strong focus on the underlying mechanisms that lead to these specific immune responses. Nanomaterials to be discussed include inorganic nanoparticles such as gold, silica and silver, as well as organic nanomaterials such as polymer-, dendrimer-, liposomal- and protein-based nanoparticles. Furthermore, various approaches for tuning nanomaterials in order to enhance their efficacy and attenuate their immune stimulation or suppression, with respect to the therapeutic application, are described. Additionally, we illustrate how the acquired insights have been used to design immunotherapeutic strategies for a variety of diseases. The potential of nanomedicine-based therapeutic strategies in immunotherapy is further illustrated by an up to date overview of current clinical trials. Finally, recent efforts into enhancing immunogenic cell death through the use of nanoparticles are discussed.

Nanomaterials for oncotherapies targeting the hallmarks of cancer

An increasing amount of evidence has demonstrated the diverse functionalities of nanomaterials in oncotherapies such as drug delivery, imaging, and killing cancer cells. This review aims to offer an authoritative guide for the development of nanomaterial-based oncotherapies and shed light on emerging yet understudied hallmarks of cancer where nanoparticles can help improve cancer control. With this aim, three nanomaterials, i.e. those based on gold, graphene, and liposome, were selected to represent and encompass metal inorganic, nonmetal inorganic, and organic nanomaterials, and four oncotherapies, i.e. phototherapies, immunotherapies, cancer stem cell therapies, and metabolic therapies, were characterized based on the differential hallmarks of cancer that they target. We also view physical plasma as a cocktail of reactive species and carrier of nanomaterials and focus on its roles in targeting the hallmarks of cancer provided with its unique traits and ability to selectively induce epigenetic and genetic modulations in cancer cells that halt tumor initiation and progression. This review provides a clear understanding of how the physico-chemical features of particles at the nanoscale contribute alone or create synergistic effects with current treatment modalities in combating each of the hallmarks of cancer that ultimately leads to desired therapeutic outcomes and shapes the toolbox for cancer control.

Nanoparticles and Vaccine Development

In spite of the progress of conventional vaccines, improvements are required due to concerns about the low immunogenicity of the toxicity, instability, and the need for multiple administrations of the vaccines. To overcome the mentioned problems, nanotechnology has recently been incorporated into vaccine development. Nanotechnology increasingly plays an important role in vaccine development nanocarrier-based delivery systems that offer an opportunity to increase the cellular and humoral immune responses. The use of nanoparticles in vaccine formulations allows not only enhanced immunogenicity and stability of antigen, but also targeted delivery and slow release. Over the past decade, nanoscale size materials such as virus-like particles, liposomes, ISCOMs, polymeric, inorganic nanoparticles and emulsions have gained attention as potential delivery vehicles for vaccine antigens, which can both stabilize vaccine antigens and act as adjuvants. This advantage is attributable to the nanoscale particle size, which facilitates uptake by Antigen- Presenting Cells (APCs), then leading to efficient antigen recognition and presentation. Modifying the surfaces of nanoparticles with different targeting moieties permits the delivery of antigens to specific receptors on the cell surface, thereby stimulating selective and specific immune responses. This review provides an overview of recent advances in nanovaccinology.

Immunogenicity of Antigen Adjuvanted with AS04 and Its Deposition in the Upper Respiratory Tract after Intranasal Administration

Adjuvant system 04 (AS04) is in injectable human vaccines. AS04 contains two known adjuvants, 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and insoluble aluminum salts. Data from previous studies showed that both MPL and insoluble aluminum salts have nasal mucosal vaccine adjuvant activity. The present study was designed to test the feasibility of using AS04 as an adjuvant to help nasally administered antigens to induce specific mucosal and systemic immunity as well as to evaluate the deposition of antigens in the upper respiratory tract when adjuvanted with AS04. Alhydrogel, an aluminum (oxy)hydroxide suspension, was mixed with MPL to form AS04, which was then mixed with ovalbumin (OVA) or 3× M2e-HA2, a synthetic influenza virus hemagglutinin fusion protein, as an antigen to prepare OVA/AS04 and 3× M2e-HA2/AS04 vaccines, respectively. In mice, AS04 enabled antigens, when given intranasally, to induce specific IgA response in nasal and lung mucosal secretions as well as specific IgG response in the serum samples of the immunized mice, whereas subcutaneous injection of the same vaccine induced specific antibody responses only in the serum samples but not in the mucosal secretions. Splenocytes isolated from mice intranasally immunized with the OVA/AS04 also proliferated and released cytokines (i.e., IL-4 and IFN-γ) after in vitro stimulation with the antigen. In the immunogenicity test, intranasal OVA/AS04 was not more effective than intranasal OVA/MPL at the dosing regimens tested. However, when compared to OVA/MPL, OVA/AS04 showed a different atomized droplet size distribution and more importantly a more favorable OVA deposition profile when atomized into a nasal cast that was 3-D printed based on the computer tomography scan of the nose of a child. It is concluded that AS04 has mucosal adjuvant activity when given intranasally. In addition, there is a reason to be optimistic about using AS04 as an adjuvant to target an antigen of interest to the right region of the nasal cavity in humans for immune response induction.

Gold nanoparticles for preparation of antibodies and vaccines against infectious diseases

INTRODUCTION

Vaccination remains very effective in stimulating protective immune responses against infections. An important task in antibody and vaccine preparation is to choose an optimal carrier that will ensure a high immune response. Particularly promising in this regard are nanoscale particle carriers. An antigen that is adsorbed or encapsulated by nanoparticles can be used as an adjuvant to optimize the immune response during vaccination. a very popular antigen carrier used for immunization and vaccination is gold nanoparticles, with are being used to make new vaccines against viral, bacterial, and parasitic infections.

AREAS COVERED

This review summarizes what is currently known about the use of gold nanoparticles as an antigen carrier and adjuvant to prepare antibodies in vivo and design vaccines against viral, bacterial, and parasitic infections. The basic principles, recent advances, and current problems in the use of gold nanoparticles are discussed.

EXPERT OPINION

Gold nanoparticles can be used as adjuvants to increase the effectiveness of vaccines by stimulating antigen-presenting cells and ensuring controlled antigen release. Studying the characteristics of the immune response obtained from the use of gold nanoparticles as a carrier and an adjuvant will permit the particles' potential for vaccine design to be increased.

Advancements in prophylactic and therapeutic nanovaccines

Vaccines activate suitable immune responses to fight against diseases but can possess limitations such as compromised efficacy and immunogenic responses, poor stability, and requirement of adherence to multiple doses. ‘Nanovaccines’ have been explored to elicit a strong immune response with the advantages of nano-sized range, high antigen loading, enhanced immunogenicity, controlled antigen presentation, more retention in lymph nodes and promote patient compliance by a lower frequency of dosing. Various types of nanoparticles with diverse pathogenic or foreign antigens can help to overcome immunotolerance and alleviate the need of booster doses as required with conventional vaccines. Nanovaccines have the potential to induce both cell-mediated and antibody-mediated immunity and can render long-lasting immunogenic memory. With such properties, nanovaccines have shown high potential for the prevention of infectious diseases such as acquired immunodeficiency syndrome (AIDS), malaria, tuberculosis, influenza, and cancer. Their therapeutic potential has also been explored in the treatment of cancer. The various kinds of nanomaterials used for vaccine development and their effects on immune system activation have been discussed with special relevance to their implications in various pathological conditions.

Statement of Significance

Interaction of nanoparticles with the immune system has opened multiple avenues to combat a variety of infectious and non-infectious pathological conditions. Limitations of conventional vaccines have paved the path for nanomedicine associated benefits with a hope of producing effective nanovaccines. This review highlights the role of different types of nanovaccines and the role of nanoparticles in modulating the immune response of vaccines. The applications of nanovaccines in infectious and non-infectious diseases like malaria, tuberculosis, AIDS, influenza, and cancers have been discussed. It will help the readers develop an understanding of mechanisms of immune activation by nanovaccines and design appropriate strategies for novel nanovaccines.

Gold nanoparticles enhance immune responses in mice against recombinant classical swine fever virus E2 protein

OBJECTIVE

To create a novel subunit vaccine that used AuNPs as carriers to enhance immune responses in mice against recombinant classical swine fever virus E2 protein (CSFV E2).

RESULTS

Gold nanoparticles (AuNPs) were successfully coupled to the E2 protein and formed stable particle complexes called E2 conjugated AuNPs (E2-AuNPs). In vitro studies have shown that the E2-AuNPs complex has the same immunogenicity as the E2 protein, and AuNPs can promote the phagocytosis of the E2 protein by antigen-presenting cells (APCs). In vivo results of BALB/c mice showed that the antibody levels, lymphocyte proliferation index, IFN-γ and IL-10 cytokines induced by E2-AuNPs were relatively higher than those of E2 or AuNPs group.

CONCLUSIONS

This finding demonstrated the potential of using AuNPs as a carrier to enhance the body's immune response for developing CSFV subunit vaccines. This model also contributes to the development of other flavivirus subunit vaccines, such as hepatitis C virus (HCV) and bovine viral diarrhea virus (BVDV).

Surface chemistry of gold nanoparticles for health-related applications

Functionalization of gold nanoparticles is crucial for the effective utilization of these materials in health-related applications. Health-related applications of gold nanoparticles rely on the physical and chemical reactions between molecules and gold nanoparticles. Surface chemistry can precisely control and tailor the surface properties of gold nanoparticles to meet the needs of applications. Gold nanoparticles have unique physical and chemical properties, and have been used in a broad range of applications from prophylaxis to diagnosis and treatment. The surface chemistry of gold nanoparticles plays a crucial role in all of these applications. This minireview summarizes these applications from the perspective of surface chemistry and explores how surface chemistry improves and imparts new properties to gold nanoparticles for these applications.

Nanoparticles in influenza subunit vaccine development: Immunogenicity enhancement

The threat of novel influenza infections has sparked research efforts to develop subunit vaccines that can induce a more broadly protective immunity by targeting selected regions of the virus. In general, subunit vaccines are safer but may be less immunogenic than whole cell inactivated or live attenuated vaccines. Hence, novel adjuvants that boost immunogenicity are increasingly needed as we move toward the era of modern vaccines. In addition, targeting, delivery, and display of the selected antigens on the surface of professional antigen-presenting cells are also important in vaccine design and development. The use of nanosized particles can be one of the strategies to enhance immunogenicity as they can be efficiently recognized by antigen-presenting cells. They can act as both immunopotentiators and delivery system for the selected antigens. This review will discuss on the applications, advantages, limitations, and types of nanoparticles (NPs) used in the preparation of influenza subunit vaccine candidates to enhance humoral and cellular immune responses.

One-pot synthesis and characterization of ovalbumin-conjugated gold nanoparticles: A comparative study of adjuvanticity against the physical mixture of ovalbumin and gold nanoparticles

Only few adjuvants are licensed for use in humans and there is a need to develop safe and improved vaccine adjuvants. In this study, we report the one-pot synthesis of antigen ovalbumin (OVA)-conjugated gold nanoparticles (OVA@GNPs). A systematical study was performed by comparing OVA@GNPs with the simple mixture of OVA and gold nanoparticles (OVA+GNPs), including their physiochemical properties through spectrometric and electrophoretic analysis, in vitro stability, cytotoxicity and cellular uptake, and in vivo humoral immune responses following subcutaneous and transcutaneous immunization in mice. The results demonstrate a much stronger interaction between protein and GNPs in OVA@GNPs than OVA+GNPs, which makes OVA@GNPs more stable under in vitro conditions than OVA+GNPs with the ability to induce 4 times higher OVA-specific serum IgG titers following subcutaneous immunization. We also show the dose sparing of OVA@GNPs, as the dosage for aluminum adjuvant required to reach to an equivalent OVA-specific antibody titer was almost five times higher than OVA@GNPs. However, we found that the co-administration of small-sized GNPs had a limited ability for the transcutaneous delivery of OVA. These results demonstrate the potential application of one-pot synthesis approach for producing antigen protein-conjugated gold nanoparticles for vaccine delivery.