COVID-19 Vaccine Knowledge: What is a nanoparticle vaccine?

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COVID-19 Vaccine Knowlege: What is a nanoparticle vaccine?

COVID-19 Vaccine Knowledge: What is a nanoparticle vaccine? Based nanoparticle vaccine showed many excellent physical and chemical properties that can help targeted delivery of new vaccines, while improving its effectiveness.

As of late September 2020, the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused more than 1 million deaths worldwide. In 2016, before the emergence of SARS-CoV-2, the World Health Organization (WHO) reported that respiratory infections directly caused about 3.2 million deaths, of which 1.4 million died only from tuberculosis (TB).

In summary, the millions of deaths caused by old and new infectious diseases have had a major impact on the global socio-economic and healthcare sectors.

Overview of vaccine types

Since many of these infectious diseases are difficult to treat, the ultimate goal in dealing with their spread and deadlines is to develop effective vaccines. For any disease, the ideal vaccine is one that is safe, stable, and can trigger a durable immune response with a minimum dose.

Although many widely distributed vaccines attenuate or kill whole organisms, several other types of vaccines have shown encouraging results in terms of their immunogenicity. Subunit vaccines, also called second-generation vaccines, and third-generation denatured vaccines that can be based on RNA or DNA, are some of the main candidates for new vaccines.

Although many alternative vaccine methods have shown protective immunity against several different diseases, they are accompanied by certain challenges that limit their effectiveness in the clinical setting. For example, DNA and RNA vaccines are cost-effective and have minimal risk of infection, but they are easily degraded due to the challenge of delivery to the target site.

Protein-based vaccines have been successfully used for immunization against a variety of infectious diseases, from acellular pertussis and tetanus to diphtheria and pneumococcus. Adjuvants are usually required to enhance their immunogenicity, and adjuvants may be related to their limitations.

Nano (NP)-based vaccines can enhance vaccine immunity

Various types of NP are related to the inherent physical properties that can activate the immune response. It has been found that gold, carbon, dendrimers, polymers and liposomal NPs can all induce cytokine and antibody responses. Therefore, these unique characteristics extend the potential use of NP from vaccine delivery vehicles to adjuvants that can enhance the immunogenicity of vaccine candidates .

NPs used for this purpose are referred to as nano immune activators or stimulators , and are usually in the size range of 20 to 100 nanometers (nm). Some examples of known nano immunostimulants include inorganic NPs, such as iron and silica; polymeric NPs, including chitosan and poly(lactic-co-glycolic acid) acid (PLGA); cholesterol and liposomes ; And VLP.

After PLGA NP, liposomes are the second most common type of NP used clinically in the form of vaccines and drug delivery vehicles. Liposomes are composed of lipids with a hydrophilic head and a hydrophobic tail. These lipids will self-assemble in water under certain conditions.

Depending on the charge, size and specific lipids that make up a given liposome formulation, such NPs can induce cellular and/or humoral responses. For example, it has been demonstrated that administration of PEGylated liposomes in an in vivo model can elicit immunoglobulin M (IgM) molecular responses.

NP for vaccine delivery

Compared with conventional vaccine methods, nanocarrier-based delivery systems have several advantages, including enhanced protection against premature degradation, good stability and improved adjuvant quality. When used to encapsulate or coat antigen surfaces, nanocarriers can protect immunogens from premature proteolytic degradation, allowing researchers to explore alternative routes of administration.

In addition to its protective effect, nanocarriers can also improve the specificity of antigen delivery to APC, and increase the time for antigen presentation to these cells and other important immune cells required for long-term immunity.

A variety of nanoparticles (NPs) have been evaluated as potential antigen carriers for vaccine applications, some of which include inorganic and polymeric NPs, virus-like particles (VLP), liposomes and self-assembling protein NPs. Gold, carbon and silica NPs are all biocompatible inorganic NPs that have been successfully used to deliver viral antigens.

Due to its ability to induce a strong host immune response, gold NP has shown particular success in the delivery of viral and bacterial antigens. The gold nanoparticles in the vaccine have been used in the body to fight influenza, human immunodeficiency virus (HIV), hand-foot-mouth disease and tuberculosis.

Gold nanoparticles and other inorganic nanoparticles (such as silica) are inexpensive, reproducible, and have good safety, all of which make these nanoparticles have a high advantage in the vaccine development process.

In addition to the potential for immunogenicity alone, liposomes can also deliver vaccines by fusing with the target cell membrane. Liposomes have high versatility, because the water core of these molecules makes it easy for hydrophilic molecules to be incorporated into such NPs, while hydrophobic substances can be reliably encapsulated in their phospholipid bilayers.

Several different types of liposomes have been included in NP-based vaccine research, including unilamellar and multilamellar vesicles composed of biodegradable phospholipids (such as phosphatidylserine, phosphatidylcholine, and cholesterol).

COVID-19 Vaccine Knowlege: What is a nanoparticle vaccine?

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