BIOMAGNETISM OF DRUG-SENSITIVE AND DRUG-RESISTANT MALIGNANT TUMORS AFTER INJECTION OF FERROMAGNETIC NANOCOMPOSITE.

Magnetic signals emitted by living organisms, regardless of a biological species, are important biophysical indicators. The study of these indicators is very relevant and promising for the visualization of the tumor process and the development of technologies using artificial intelligence when it comes to malignant neoplasms, particularly resistant to chemotherapy. AIM: To measure magnetic signals from transplantable rat tumors and their counterparts resistant to cytostatics for evaluating the features of the accumulation of iron-containing nanocomposite Ferroplat. MATERIALS AND METHODS: Doxorubicin (Dox)-sensitive and Dox-resistant Walker-256 carcinosarcoma and cisplatin-sensitive and cisplatin-resistant Guerin's carcinoma transplanted in female Wistar rats were studied. The magnetism of tumors, liver and heart was determined using Superconductive Quantum Interference Device (SQUID) - magnetometry in a non-contact (13 mm over the tumor) way using specially designed computer programs. In a group of the experimental animals, a ferromagnetic nanocomposite (Ferroplat) was administered as a single intravenous injection and biomagnetism was assessed in 1 h. RESULTS: The magnetic signals coming from Dox-resistant Walker-256 carcinosarcoma in the exponential growth phase were significantly higher in comparison with sensitive tumor. Intravenous administration of Ferroplat increased biomagnetism by at least an order of magnitude, especially in resistant tumors. At the same time, the magnetic signals of the liver and heart were within the magnetic noise. CONCLUSION: The use of SQUID-magnetometry with ferromagnetic nanoparticles as a contrast agent is a promising approach for visualization of malignant neoplasms with varying sensitivity to chemotherapy.

Biomagnetism of tumor in rats with Guerin's carcinoma after injection of ferromagnetic nanocomposite (Ferroplat): contactless measurement.

AIM: In order to develop fundamentally new technologies for non-invasive and safer diagnosis of cancer, we aimed to detect non-contact magnetic signals from a malignant tumor in animals treated or not-treated with the ferromagnetic nanocomposite Ferroplat. MATERIALS AND METHODS: Guerin's carcinoma was used as a model of tumor growth. The biomagnetism of the tumor was evaluated in the dynamics of its growth. Ten days after tumor transplantation, Ferroplat was administered intravenously to half of the animals with the tumor and to half of the control animals. The magnitude of the magnetic signals was determined 1 h and every two days after administration of the nanocomposite using a Superconducting Quantum Interference Device magnetometer of the original design. RESULTS: We have found that the magnetic signals coming from the tumor are significantly higher compared to control tumor-free animals. Intravenous administration of a ferromagnetic nanocomposite (Ferroplat: Fe3O4 + cisplatinum) led to a significant increase of the magnetic signal, especially in the tumor tissue, and inhibition of Guerin's carcinoma growth. Ferromagnetic nanoparticles (32.7 nm) are retained in malignant cells for a longer time than in normal ones. CONCLUSION: Tumor cells accumulate iron nanoparticles more intensively than normal ones. Nanocomposite Ferroplat can be used for a targeted delivery of cisplatin to malignant cells.

Low-cost 7-channel magnetocardiographic system for unshielded environment.

The purpose of this work was to develop a low-cost magnetocardiography (MCG) system for use at cardiology clinics, without any magnetic shielding. The device consists of seven channels: four signal and three reference channels. The signal channels are based on relaxation-oscillation SQUIDs. The reference channels are assembled into an orthogonal reference vector magnetometer (RVM). The 11-litre magnetotransparent helium cryostat allows operation for 5 days without refilling. With the 4-channel device, it is possible to perform measurements of magnetic maps in a standard 36-point grid so that only 9 spatial positions of the multichannel magnetometer are used; acquiring 30 s of data for each observation point takes about 10-15 minutes. Software was developed for the device adjustment, data acquisition, and data processing, including preliminary processing, MCG-mapping, and medical analysis. Digital filtering, adaptive noise compensation, and averaging are used to suppress magnetic noises. Cardiac sources were modelled with effective magnetic dipoles, and with estimated 2D current density distributions at a frontal plane.