Table 2.

Pros and cons of oral nano/microparticle-based carriers

Categories	Liposomes	Emulsion	ISCOMs	Natural polymers	Synthetic polymers
Application	DNA, peptides, proteins	Whole-cell killed, proteins, peptides	Proteins, peptides	Proteins, peptides, conjugates	Proteins, peptides, conjugates
Pros	-Intrinsic adjuvant characteristics -Can accommodate both hydrophilic and lipophilic antigens -Modified liposomes have optimal stability across the intestine -Controlled release	-Tailored immunomodulation, for example, Th1 (water-in-oil) and Th 2 (oil-in-water) -High loading efficiency of both hydrophilic (water in oil) and hydrophobic (oil-in-water) -Slow or controlled release	-Easy modification -High antigen loading efficiency -Potent built-in adjuvant (Quil A)	-Controlled release -Easy modification -Highly stable and adaptable	-Controlled release -Controlled size -Engineered surface chemistry
Cons	-Weak loading efficiency of hydrophilic antigens -Nonspecific interactions -Cationic liposomes could be toxic	-Poor stability under the harsh environment in the GI system	-Poor loading of hydrophilic antigens -Rapid clearance	-Low antigen loading -Poor aqueous solubility	-May have poor solubility -Insufficient antigen protection -Exposed to proteolysis in mucus