Biomedical Engineering Reference
In-Depth Information
Fig. 1 Induction of immune responses by vaccination
proteins, or synthetic peptides. These new generation of vaccines are generally very
safe, with well-defined components. However, these antigens are often poorly
immunogenic, and thus require the use of adjuvants and delivery systems to induce
optimal immune responses [
3
-
5
]. Immunological adjuvants were originally
described by Ramon as “substances used in combination with a specific antigen
that produced a more robust immune response than the antigen alone” [
6
]. Until
recently, the hydroxide and phosphate salts of aluminum and calcium were the only
adjuvants licensed for human use. However, the use of alum-type adjuvants for
vaccination has some disadvantages [
7
,
8
]. They are not effective for all antigens,
induce local reactions, induce IgE antibody responses, and generally fail to induce
cell-mediated immunity, particular CTL responses. Therefore, the development of
more efficient and safe adjuvants and vaccine delivery systems to obtain high and
long-lasting immune responses is of primary importance.
Polymeric nanoparticles formulated from biodegradable polymers are being
widely explored as carriers for controlled delivery of different agents including
proteins, peptides, plasmid DNA (pDNA), and low molecular weight compounds
[
9
-
11
]. Self-assembling polymer or block/graft copolymers that can form
nanostructures have been extensively investigated in the field of biotechnology
and pharmaceuticals. In general, hydrophobic interactions, electrostatic forces,
hydrogen bonds, van der Waal forces, or combinations of these interactions are
available as the driving forces for the formation of the polymer complexes [
12
-
16
].
Numerous investigators have shown that the biological distribution of drugs,
