Compared to solid SiNPs, MSNs have higher loading capacity for their larger specific surface area, and better performance in delivery http://www.selleckchem.com/products/ABT-263.html and controlled release due to the tunable hollow and mesoporous structure. In addition, MSNs can be degraded which can then be excreted in the urine [85], [86] and [87]. With these properties, MSNs show potential to become high-efficiency, controlled-release nano-carriers in future vaccine formulations. Calcium phosphate nanoparticles

can be created by mixing calcium chloride, dibasic sodium phosphate and sodium citrate under specific conditions [88] and [89]. They are non-toxic and can be formed into a size of 50–100 nm [90]. These nanoparticles are useful adjuvants for DNA vaccines and mucosal immunity [79], [88], [89] and [90], and show excellent biocompatibility. Liposomes are formed by biodegradable and nontoxic phospholipids. Liposomes can encapsulate antigen within the core MEK inhibitor clinical trial for delivery [91] and incorporate

viral envelope glycoproteins to form virosomes [92] and [93] including for influenza [94]. Combination of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP) modified cationic liposome and a cationic polymer (usually protamine) condensed DNA are called liposome-polycation-DNA nanoparticles (LPD), a commonly used adjuvant delivery system in DNA vaccine studies [95] and [96]. The components of LPD spontaneously rearrange into a nano-structure around 150 nm in size with condensed DNA located inside the liposome [96]. Liposomes modified with maleimide can be synthesized into interbilayer-crosslinked multilamellar vesicles (ICMVs) by cation driven fusion and crosslinking [97] enabling slowed release of entrapped antigen. A number of liposome systems have been established and approved for human use, such as Inflexal® V and Epaxal®, which have been discussed in other reviews [91] and [98]. ISCOMs are cage like particles about 40 nm large in size, made of the saponin adjuvant Quil A, cholesterol, phospholipids, PDK4 and protein antigen [35], [92], [99], [100] and [101]. These spherical particles can trap the antigen

by apolar interactions [35]. ISCOMATRIX comprises ISCOMs without antigen [35], [92], [100] and [102]. ISCOMATRIX can be mixed with antigen, enabling a more flexible application than is possible for ISCOMs, by removing the limitation of hydrophobic antigens [35]. Various antigens have been used to form ISCOMs, including antigens derived from influenza [103] and [104], herpes simplex virus [105], HIV [106], and Newcastle disease [99]. Virus-like particles (VLP) are self-assembling nanoparticles, lacking infectious nucleic acid, formed by self-assembly of biocompatible capsid proteins [107] and [108]. VLPs are the ideal nanovaccine system as they harness the power of evolved viral structure, which is naturally optimized for interaction with the immune system, but avoid the infectious components.