Biomedical Engineering Reference
In-Depth Information
agents. The high incidence of recurrence and poor prognosis of malignant
gliomas compel the development of more powerful anti-cancer treatments.
The compromise of the quality of remaining life as well as the limited suc-
cess of current treatment options in shrinking tumors, raise increasing
concerns about the adverse effects of cancer treatment on brain function.
Deterioration in neurological function is accompanied by significant deteri-
oration in the global quality of life in patients affected by malignant gliomas.
The advent of molecular studies allows evaluation of the possibility of re-
examination of the biology of gliomas with, a level of precision that prom-
ises interesting advances toward the development of specific and effective
therapies. It is now generally understood that tumor genesis occurs either,
by over-expression of oncogenes, or inactivation of tumor suppressor genes.
The modulation of gene expression at more levels, such as DNA, mRNA,
proteins and transduction signal pathways, may be the most effective mo-
dality to down-regulate or silence some specific gene functions.
Cerebral gliomas represent an important challenge in modern oncology,
and only in the last years has the development of new multimodal thera-
peutic strategies given the beginning to a new research field of neuroon-
cology: nanotechnology and nanomedicine. With the advancement in BBB
structure and pathophysiology knowledge, brain delivery and targeting
skills, and brain tumor biology, these new interesting possibilities could
lead to new perspectives in brain tumor treatment. Nanotechnology is an
emerging field that deals with interactions between molecules, cells and
engineered substances such as molecular fragments, atoms and molecules.
The impact of nanotechnology in medicine can mainly be seen in diagnostic
methods, drug-release techniques and regenerative medicine. In the recent
past, nanotechnology has garnered much attention due to its potential ap-
plication in cancer, and the National Cancer Institute has constituted an
Alliance of Nanotechnology in Cancer with focus on the development of
novel nanoplatform-based diagnostics, therapeutics and preventive agents.
Nanomedicine could lead to new possibilities to overcome important prob-
lems in malignant brain tumors, such as the non specificity of cancer cells
drug-delivering and targeting, as well as the non complete passage of drugs
through the BBB and into cancer cells avoiding side effects in normal brain
tissue. Nanoparticles are colloidal particles typically synthesized in either
aqueous or organic phases. Due to their small size, nanoparticles can easily
flow through blood capillaries and enter the target cancer cells. Reduction
of toxicity to peripheral organs can also be achieved with these systems
[4]. Nanoparticle-based drug-delivery systems, an antisense approach to
modify gene expression in cancer cell genome, and molecular-based cancer
cell targeting all represent important possibilities in cerebral gliomas treat-
ment. Nanosystems with different compositions and biological properties
have been extensively investigated for drug and gene delivery applications
[4-5]. The type and the number of linkers within and on the surface of
