Nanomaterials have emerged as promising tools to amplify or suppress host's immune response. By acting as adjuvants added to vaccines for COVID-19, engineered nanomaterials can aid subjects with impaired immune system, such as the elderly, and reduce the amount of vaccine protein production and injection.

Intranasal delivery of polymer-encapsulated antigen triggers a strong immune response, and the success of vaccination depends on the appropriate type of polymer in combination with the antigen. Similarly, researchers have developed lipid and lipid-based NPs as delivery platforms for mRNAs or siRNAs to enable the synthesis of key viral proteins for vaccination (for example, Moderna’s mRNA-1273/NCT04283461 vaccine) or to inactivate critical viral target genes, respectively.

Considering the possibility of random viral mutations that may alter the antigen shape, functionalizing nanomaterials with a wide number of molecules at the same time to target the virus, or motifs that are specific for pathogens, will increase the efficiency of vaccines and their ability to prevent viral infection.

There are ongoing screenings and classifications of various nanomaterials based on their immunomodulatory properties and cytotoxicity levels. Developing an adjuvant for clinical use requires Phase III randomized trials, which could take several years.