Peter Babinec

AC-magnetic field controlled drug release from magnetoliposomes: design of a method for site-specific chemotherapy

Large unilamellar magnetoliposomes (MLs) with encapsulated doxorubicin (DOX) (anticancer drug) were prepared by reverse-phase evaporation. They were exposed to an alternating magnetic field with a frequency of 3.5 MHz and an induction of 1.5 mT produced in three-turn pancake coil. The results showed that magnetoliposomes could be specifically heated to 42 degrees C (phase transition temperature of a used lipid) in a few minutes and during this, the encapsulated doxorubicin is massively released.

SUPERPARAMAGNETIC GEL AS A NOVEL MATERIAL FOR ELECTROMAGNETICALLY INDUCED HYPERTHERMIA

Heating properties of a magnetically responsive gel in an alternating magnetic field at 217 kHz were evaluated. Superparamagnetic ferrite nanocrystals of approximately 10 nm were formed within the gel network by bridging anionic bis(ethylhexyl) sodium sulfosuccinate reverse micelles. Specific absorption rates up to 150 W/g for ferrite concentrations up to 50 mg/ml were observed. Temperature measurements of the gel without ferrite particles showed no heating effect. Magnetic gels therefore represent a novel promising hyperthermic material.

In Vitro Analysis of Cisplatin Functionalized Magnetic Nanoparticles in Combined Cancer Chemotherapy and Electromagnetic Hyperthermia

A novel platform has been developed for combined cancer chemotherapy and hyperthermia based on iron oxide magnetic nanoparticles functionalized with cis-diamminedichloroplatinum(II) (cisplatin). The capabilities of this system for heating and controlled drug release were investigated, and the system was tested in vitro by the treatment of BP6 rat sarcoma cells, where we demonstrated a synergism between the effects of cisplatin-targetMAG nanoparticles and the application of electromagnetic field.

In vivo heating of magnetic nanoparticles in alternating magnetic field.

We have evaluated heating capabilities of new magnetic nanoparticles. In in vitro experiments they were exposed to an alternating magnetic field with frequency 3.5 MHz and induction 1.5 mT produced in three turn pancake coil. In in vivo experiments rats with injected magnetic nanoparticles were also exposed to an ac field. An optimal increase of temperature of the tumor to 44 degrees C was achieved after 10 minutes of exposure. Obtained results showed that magnetic nanoparticles may be easily heated in vitro as well as in vivo, and may be therefore useful for hyperthermic therapy of cancer.

Site-specific in vivo targeting of magnetoliposomes using externally applied magnetic field.

Abstract Human serum albumin labeled with technetium-99m was encapsulated together with magnetite particles into phosphatidylcholine/cholesterol liposomes. In order to investigate the stability of this complex and its ability to be used for magnetic drug targeting, the in-vivo distribution after intravenous administration in rats was estimated. For in-vivo targeting an SmCo permanent magnet with intensity ~ 0.3 5 T was attached near the right kidney. Difference between the relative radioactivity in the magnetically targeted right kidney (25.92±5.84%) and non-targeted left kidney (0.93±0.05%) is sufficiently high for relevant clinical applications.

High-gradient magnetic capture of ferrofluids: implications for drug targeting and tumor embolization.

Abstract One of the perspective methods of cancer chemotherapy is magnetic targeting of drugs to tumors. This task is usually accomplished using small permanent magnets attached near the desired sites. In this study a new much more effective approach is proposed which is based on a strong magnetic gradient using a ferromagnetic wire placed in a strong magnetic field. Feasibility of this approach has been evaluated by the formation of ferrofluid seals and measurement of maximum pressure the formed seal can resists. Using this method it is possible to capture even superparamagnetic particles with nanosize dimensions, therefore the method may have an interesting applications in biomedical sciences.

STOCHASTIC RESONANCE IN THE WEIDLICH MODEL OF PUBLIC OPINION FORMATION

Abstract As a prototypical nonlinear sociological system we study the Weidlich model of public opinion formation. At an optimal value of the collective climate parameter (which plays the role of noise for this system) we have found a maximal value of signal-to-noise ratio and a largest amplification of a periodic external preference factor which are the characteristics of stochastic resonance.

Stochastic resonance in an interacting-agent model of stock market

Abstract On the specific example of an interacting-agent model of speculative activity we have demonstrated that stochastic resonance (SR), where an increase in the noise (market volatility) increases the signal-to-noise ratio (SNR) describing the response to global periodic investment bias, can occur in the stock market. This phenomenon may be in principle utilized by market traders.

INFLUENCE OF ALTERNATING MAGNETIC FIELDS ON TWO-DIMENSIONAL TUMOR GROWTH

We have studied the effect of an alternating magnetic field on the growth rate of the two-dimensional C6 rat glioma tumor. Tumors growing on a plate surface were subjected to a 10-mT magnetic field at frequencies from 10 to 50 Hz. The rate of tumor growth at each frequency studied was measured and compared with a control group growing in the absence of the field. Tumor growth rate at each frequency was increased compared with a control group. The highest growth rate was observed with a magnetic field at a frequency of 20 Hz.

Lysis of photosensitized erythrocytes in an alternating magnetic field

Exposure of human erythrocytes photosensitized with hematoporphyrin dihydrochloride to a magnetic field (180 kHz, 4.6 kA/m) resulted in time- and hematoporphyrin-concentration-dependent lysis. The singlet oxygen scavenger histidine inhibited lysis, indicating the direct involvement of radicals in erythrocyte lysis. Exposure not only to light but also to an AC magnetic field may thus enhance the efficiency of photodynamic tumor therapy.