Biomedical Engineering Reference
In-Depth Information
(20)
Wash the IOMNP~dDNA three times with sodium citrate buffer (1XSSC).
(21)
Reconstitute with 1× SSC.
(22)
Observe under UV light.
In the presence of dsDNA, intercalated acridine orange (AO) gives a yellow
coloration to the otherwise black IOMNPs (
Figure 7.2
). This is exhibited by
the tube 1 at the bottom of the picture that is labeled IO+DNA. After 4 times of
washing, the supernatant did not exhibit the presence of AO anymore while the
IOMNPs exposed to the lysed SK-BR3 still gave a yellow color. The IO that
was not exposed to the lysed SK-BR3, and therefore, did not capture dsDNA
remained black as shown in tube 1 on top labeled IO only.
7.4 NANOIMMUNOTHERAPY
The part of the human system which deals with antigens (foreign substances
that stimulate antibody generation) is the immune system (IS). The IS consist
of a dynamic network of cells that undergoes a process whereby it must rec-
ognize and deal with antigens or highly conserved structural motifs expressed
by microbial pathogens, called pathogen-associated microbial patterns.
95
These processes involve adaptive (acquired or humoral) events on the surface
of antigen-presenting cells (APCs) which perform the function of displaying
antigens coupled with the major histocompatibility complex (MHC)
95
that are
recognized by T-cells using their T-cell receptor (TCR) complexes. Recogni-
tion by APCs (macrophages, dendritic cells (DCs), and B cells) elicit an early
innate immune response by cytokine communication. This steers the differen-
tiation of T-helper (Th) cells into Th1 or Th2 subsets
96
that activate other cells
of the immune system such as cytotoxic T cells and macrophages.
97
The DCs
are responsible for connecting innate and adaptive immune responses and have
particular functions at different stages of maturation.
95
Before activation, DCs
are found in peripheral tissues as immature cells that capture self-antigens.
98
After the antigen is processed forming an antigen-loaded mature DC it moves
to the secondary lymphoid organs where it induces antigen-specific immunity
by presenting the antigen to T cells. This initiates T cell-mediated immunity
through intracellular signaling that is mediated by the MHC and co-stimulatory
molecules.
95
NMs can modulate cellular and humoral immune responses and would be
potentially useful as effective vaccine adjuvants for the therapy of infectious
diseases and cancer.
99
NMs can be engineered with specific physical properties
and chemical composition to be used as vehicles for specific DC targeting. Dif-
ferent strategies and approaches are available to use NMs as effective vehicles,
including conjugation to antigens that are recognized by specific receptors;
encapsulating antigens within NMs that potentially protect the antigen from
degradation; and labeling NMs to be recognized by specific receptors and allow
tracking of their journey in the host system.
95
These various approaches can
be leveraged for various medical applications such as cancer immunotherapy,
