Digital Theses Archive


Tesi etd-02182021-110902

Type of thesis
Scientific disciplinary sector
Istituto di Biorobotica - BIOROBOTICS
relatore Prof. CIOFANI, GIANNI
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Exam session start date
Cancers are very different from each other and their heterogeneity is one of the reasons at the base of the difficulties to obtain a single cure, suitable for all types of cancers. Glioblastoma multiforme (GBM) is one of the most aggressive and difficult to treat among all cancers. Currently, there are a few alternatives to treat GBM, and they mostly consist of invasive techniques such as surgical resection and chemotherapy supported by radiotherapy. Moreover, these approaches have heavy side effects. For this reason, there is an urgent need to explore alternative anticancer treatments, to improve efficacy and, also, to ease the burden endured by patients during therapy.<br>Research is increasingly proposing nanotechnological solutions with the aim of delivering a drug or a new treatment directly to the tumor site in order to accumulate the substance just in the tumor, thus avoiding the side effects mentioned above. Nanovectors, if properly designed, can meet these therapeutic needs. Nanovectors suitably functionalized on their surface can selectively target the drug in the tumor. Nanoparticles with particular physicochemical characteristics can also carry out an antitumor action without the use of any drug. On the other hand, conventional 2D in vitro cultures fail at being a reliable and predictable model to describe drug behaviour in vivo, because they suffer from poor representativeness of the tumor microenvironment and lack the complex interactions that occur when a drug has to be targeted inside a tumor. In recent years, in vitro research is being focused on developing biomimetic models capable of imitating some peculiar aspects of cancer tissues and their microenvironment. This thesis takes into consideration the research on glioblastoma multiforme carried out in vitro and aims to propose new biomimetic solutions of the tumor environment to improve the reliability of the experimental results in vitro. Furthermore, in this thesis, two new nanovector systems are presented as possible treatments for GBM.<br>The first part of the thesis reports on the design and construction of “ad hoc” fluidic bioreactors that mimic the dynamic conditions to which the tissue cells in the body are subjected. The cultivation of different cell lines in the bioreactor reveals how the anticancer treatment interfaces with healthy cells and cancer cells at the same time. Another type of fluidic biomimetic bioreactor that is presented in this work attempts to mimic the microenvironment of the blood-brain barrier (BBB) in vitro, in order to test the crossing of anticancer treatments and/or of nanovectors. These bioreactors were extensively used in the validation tests of nanocarriers presented in the second part of in this thesis.<br>The second part of the thesis in fact reports on the design, synthesis and tests carried out on two proposed nanovectors: lipid magnetic nanovectors functionalized with a peptide, angiopep 2, able to favor both the crossing of the BBB and the targeting of the GBM and loaded with a promising anticancer drug, nutlin 3a (Nut-Ang-LMNVs), and boron nitride nanotubes functionalized with plasma membrane coating (CM) extracted directly from a GBM line in order to exploit the ability of the surface proteins of GBM cells that allows homotypic recognition. Besides, CM-coated BNNTs have been loaded with a well-known anticancer drug, doxorubicin, which is not yet used for the treatment of GBM because of its inability to cross the BBB and its important side effects, if not well targeted. Both nanocarriers were characterized in detail and their biological effects were described by numerous in vitro experiments. Both ones resulted highly performing in crossing the BBB, in selectively targeting GBM cells and, finally, in inducing a robust apoptotic response in GBM cells.<br>The third and last part of the thesis shows an innovative GBM spheroid model that is capable of being controlled remotely, with a simple magnet. This spheroid aims to facilitate anti-cancer research with in vitro 3D models that are very representative and predictive of the response of a real solid tumor. Magnetically-driven spheroids (MDS) offer the possibility to easily manipulate cancer cell constructs and control their size to standardize large-scale in vitro studies. These MDS were obtained by designing and realizing a scaffold with a material sensitive to external magnetic fields, and printed using two-photon polymerization, a very refined technique that can generate structures with spatial resolutions up to 10 nanometers. As an example of application, these MDS have been placed in relation to a real scale BBB model, also obtained thorugh two-photon polymerization, to mimic the GBM microenvironment.