Page 605 - Book Hosokawa Nanoparticle Technology Handbook

37 PINPOINT DRUG AND GENE DELIVERY APPLICATIONS

Bio-nanocapsule

Liver

Displacement of living body
recognition molecule

Retargeting

Figure 37.3
Retargeting of BNC to other cells than liver cell.

(2) Treatment by BNC including anticancer drug considerable research before practical application.
In many cases of cancer treatment, an anticancer drug The latter techniques show adequate bioactivity in
is used simultaneously. However, whole body adminis- spite of the extremely low stability in the body, and
tration of an anticancer drug often causes a serious side practical application may be realized sooner as there
effect. The anticancer drug itself cannot distinguish is less possibility of damaging chromosomes of the
cancer cells from healthy cells, but delivery of the anti- patients.
cancer drug to only the diseased part would minimize Consequently, BNC is attracting attention for raising
the side effects and maximize the medicinal effects. the stability of siRNA in blood and achieving tissue
Certain sugar chains and antigens specific to cancer are specific siRNA delivery in a living body. Although the
usually present on the surface of the cancer tissue. By major pharmaceutical companies are focusing atten-
making altered BNC that presents the relevant mole- tion on RNA interference as a new medical means, it
cule (antibody, etc.) that recognizes the sugar chain and cannot be systemically administered. Therefore, a
antigen, pinpoint drug delivery may be realized. combination of an in vivo pinpoint delivery system
and RNA interference is sought.
(3) Gene therapy by BNC With the spread of tailor-made health care based on
There are a number of genetic illnesses and most of increases in gene information availability, BNC will
them are caused by lack of expression of a single be applied in gene therapy personalized for each
protein, such as hemophilia and phenylketonuria. patient, selecting target organs, target molecules and
BNC is a method of gene replacement therapy by genes for the treatment.
introducing the lacking protein gene into the human
liver. RNA interference is a new living body level 3. Assignment
gene regulatory technique that can be classified
broadly into two categories, one technique using a In practical application of BNC, the main target is
plasmid vector and the other technique using small realizing administration by lowering immunogenicity
interfering RNA (siRNA). In the former, as there is and antigenicity. In particular there is a possibility
a risk of gene integration with the chromosomes of that BNC would not be effective in patients with
the patients, this complete gene therapy will require Hepatitis B virus antibody by vaccine inoculation,

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