Breast Cancer Tissue Marked Selectively by Magnetic Nanoparticles in an Experimental Animal Model.

The use of magnetic nanoparticles have been proposed as alternative techniques to assist breast cancer diagnosis and treatment. Peritumoral and intratumoral biodistribution of magnetic nanoparticles have been the main practical approaches, and the evaluation of breast tumor tissue marked selectively by magnetic nanoparticles has been not widely studied so far. The aim of this study was to evaluate the c-erbB-2 antigen in tissue of a breast cancer animal model as specific target for the use of magnetic nanoparticles coupled to specific Monoclonal Antibody (Mab). A breast cancer animal model was adapted and standardized in female rats. Tumor tissue was characterized histopathological and inmunohistochemical for cancer type and c-erbB-2 expression respectively. A bioconjugate was developed by the covalent union of fluorescent magnetic nanoparticles and anti c-erbB-2 Mab, and was used for incubation in two consecutive slides of breast cancer tissue acoordingly following conditions: (a) the c-erbB-2 receptor previously blocked by a primary antibody, and (b) the c-erbB-2 receptor non-blocked. Microscopy fluorescence was used to determine the selective marked of tumor tissue by the bioconjugate. Healthy breast tissue was used as negative control of selective labeling of the bioconjugate. The results show a well-differentiated fluorescent mark by magnetic nanoparticles in the non-blocked c-erbB-2 receptor breast cancer tissue condition, the observation suggests the use of the c-erbB-2 antigen as specific target to mark selectively breast tumor tissue by magnetic nanoparticles.

Impedance spectroscopy assisted by magnetic nanoparticles as a potential biosensor principle for breast cancer cells in suspension.

Breast cancer (BC) is the leading cause of cancer death in women worldwide, with a higher mortality reported in undeveloped countries. Ideal adjuvant therapeutic strategies require the continuous monitoring of patients by regular blood tests to detect circulating cancer cells, in order to determine whether additional treatment is necessary to prevent cancer dissemination. This circumstance requires a non-complex design of tumor cell biosensor in whole blood with feasibility for use in poor regions. In this work we have evaluated an inexpensive and simple technique of relative bioimpedance measurement, assisted by magnetic nanoparticles, as a potential biosensor of BC cells in suspension. Measurements represent the relative impedance changes caused by the magnetic holding of an interphase of tumor cells versus a homogenous condition in the frequency range of 10-100 kHz. The results indicate that use of a magnet to separate tumor cells in suspension, coupled to magnetic nanoparticles, is a feasible technique to fix an interphase of tumor cells in close proximity to gold electrodes. Relative impedance changes were shown to have potential value as a biosensor method for BC cells in whole blood, at frequencies around 20 kHz. Additional studies are warranted with respect to electrode design and sensitivity at micro-scale levels, according to the proposed technique.

Expression of c-erbB-2 in breast cancer cell lines as experimental receptor of magnetic nanoparticles.

High mortality in breast cancer is associated to a late diagnosis and therapy of the disease. Our research group is working on the development of an innovative technology to promote selective ablation of breast cancer in early stages by the use of high frequency magnetic fields assisted by magnetic nanoparticles. The concept behind the technical proposal is to increase the electrical conductivity of tumoral tissue by the use of bioconjugated "magnetic nanoparticle-monoclonal antibody". Is expected that bioconjugated recognizes specific genes on the surface of cancer cells. The aim of this study was to evaluate the expression of the c-erbB-2 gene and c-erbB-2 antigen in breast cancer cells type BT-474, MCF-7 and MDA-MB-231, as previous step to propose the c-erbB-2 protein as receptor of magnetic nanoparticles. The results suggest that the elected breast cancer cell lines show well-differentiated relative expression of the elected gen and antigen, and sems suitable for experimental evaluation of selective targeting by magnetic nanoparticles.