Surface modification of multifunctional ferrite magnetic nanoparticles and progress in biomedicine / 生物医学工程学杂志

Magnetic ferrite nanoparticles (MFNPs) have great application potential in biomedical fields such as magnetic resonance imaging, targeted drugs, magnetothermal therapy and gene delivery. MFNPs can migrate under the action of a magnetic field and target specific cells or tissues. However, to apply MFNPs to organisms, further modifications on the surface of MFNPs are required. In this paper, the common modification methods of MFNPs are reviewed, their applications in medical fields such as bioimaging, medical detection, and biotherapy are summarized, and the future application directions of MFNPs are further prospected.

Study on the thermal field distribution of cholangiocarcinoma model by magnetic fluid hyperthermia / 生物医学工程学杂志

Cholangiocarcinoma is a highly malignant tumor. It is not sensitive to radiotherapy and chemotherapy and has a poor prognosis. At present, there is no effective treatment. As a new method for treating cancer, magnetic fluid hyperthermia has been clinically applied to a variety of cancers in recent years. This article introduces it to the cholangiocarcinoma model and systematically studies the effect of magnetic fluid hyperthermia on cholangiocarcinoma. Starting from the theory of magnetic fluid heating, the electromagnetic and heat transfer models were constructed in the finite element simulation software COMSOL using the Pennes biological heat transfer equation. The Helmholtz coil was used as an alternating magnetic field generating device. The relationship between the magnetic fluid-related properties and the heating power was analyzed according to Rosensweig's theory. After the multiphysics coupling simulation was performed, the electromagnetic field and thermal field distribution in the hyperthermia region were obtained. The results showed that the magnetic field distribution in the treatment area was uniform, and the thermal field distribution met the requirements of hyperthermia. After the magnetic fluid injection, the cholangiocarcinoma tissue warmed up rapidly, and the temperature of tumor tissues could reach above 42 °C, but the surrounding healthy tissues did not heat up significantly. At the same time, it was verified that the large blood vessels around the bile duct, the overflow of the magnetic fluid, and the eddy current heat had little effect on thermotherapy. The results of this article can provide a reference for the clinical application of magnetic fluid hyperthermia for cholangiocarcinoma.

Design of Magnamosis System for Endoscopic Tissue Clamping / 中国医疗器械杂志

Based on the principle of magnetic anastomosis technique, the design of magnetic anastomosis system for endoscopic tissue clamping is proposed. The system includes a semi-ring magnet, a special structure transparent cap and a detachable push rod. With the help of the existing digestive endoscopy and endoscopic tissue gripper, the endoscopic close clamping and anastomosis of the bleeding or perforated tissue can be completed. After the anastomosis, the magnet falls off and is discharged through the digestive tract. Animal experiments showed that the system was easy to use, the fistula was clamped firmly, the magnet was discharged for 7~21 days, and there was no magnet retention and digestive tract obstruction. Further safety verification, optimization of endoscopic operation, the system can be used in clinical trial.

Application of magnetotactic bacteria and magnetosomes in cancer therapy: a review / 生物工程学报

The targeting of anti-tumor drugs is an important means of tumor treatment and reducing drug side effects. Oxygen-depleted hypoxic regions in the tumour, which oxygen consumption by rapidly proliferative tumour cells, are generally resistant to therapies. Magnetotactic bacteria (MTB) are disparate array of microorganism united by the ability to biomineralize membrane-encased, single-magnetic-domain magnetic crystals (magnetosomes) of minerals magnetite or greigite. MTB by means of flagella, migrate along geomagnetic field lines and towards low oxygen concentrations. MTB have advantage of non-cytotoxicity and excellent biocompatibility, moreover magnetosomes (BMs) is more powerful than artificial magnetic nanoparticles(MNPs). This review has generally described the biological and physical properties of MTB and magnetosomes, More work deals with MTB which can be used to transport drug into tumor based on aerotactic sensing system as well as the competition of iron which is a key factor to proliferation of tumor. In addition, we summarized the research of magnetosomes, which be used as natural nanocarriers for chemotherapeutics, antibodies, vaccine DNA. Finally, We analyzed the problems faced in the tumor treatment using of MTB and bacterial magnetosomes and prospect development trends of this kind of therapy.

Design of Detection Module in Coagulometers Based on Dual-magnetic Circuit Beads Method / 中国医疗器械杂志

Coagulometer, known as blood coagulation analyzer, is a product that can provide accurate test results for medical diagnosis and treatment analysis by detecting a series of items closely related to thrombosis and hemostasis in coagulation reaction. On the basis of previous traditional methods, and with our deep understanding about the principles of hemagglutination detection, we propose a hemagglutination detection method by using the dual-magnetic circuit beads method. Then, the corresponding hemagglutination detection module is designed. The coagulation time of plasma can be measured by detecting the movement of the magnetic beads when the magnetic field intensity is appropriate. The activated partial thromboplastin time(APTT) of plasma is tested when the most suitable magnetic field intensity is found. The results preliminarily show that this blood coagulation test method is valid and the corresponding test module has a potential value in business.

Detection method of nonlinear magnetized harmonic signal of medical magnetic nanoparticles / 生物医学工程学杂志

Medical magnetic nanoparticles are nano-medical materials with superparamagnetism, which can be collected in the tumor tissue through blood circulation, and magnetic particle imaging technology can be used to visualize the concentration of magnetic nanoparticles in the living body to achieve the purpose of tumor imaging. Based on the nonlinear magnetization characteristics of magnetic particles and the frequency characteristics of their magnetization, a differential detection method for the third harmonic of magnetic particle detection signals is proposed. It was modeled and analyzed, to study the nonlinear magnetization response characteristics of magnetic particles under alternating field, and the spectral characteristics of magnetic particle signals. At the same time, the relationship between each harmonic and the amount of medical magnetic nanoparticle samples was studied. On this basis, a signal detection experimental system was built to analyze the spectral characteristics and power spectral density of the detected signal, and to study the relationship between the signal and the excitation frequency. The signal detection experiment was carried out by the above method. The experimental results showed that under the alternating excitation field, the medical magnetic nanoparticles would generate a spike signal higher than the background sensing signal, and the magnetic particle signal existed in the odd harmonics of the detected signal spectrum. And the spectral energy was concentrated at the third harmonic, that is, the third harmonic magnetic particle signal detection that meets the medical detection requirement could be realized. In addition, the relationship between each harmonic and the particle sample volume had a positive growth relationship, and the detected medical magnetic nanoparticle sample volume could be determined according to the relationship. At the same time, the selection of the excitation frequency was limited by the sensitivity of the system, and the detection peak of the third harmonic of the detection signal was reached at the excitation frequency of 1 kHz. It provides theoretical and technical support for the detection of medical magnetic nanoparticle imaging signals in magnetic particle imaging research.

Targeting of temozolomide using magnetic nanobeads: an in vitro study

Temozolomide, a chemotherapeutic drug that is often administered for the treatment of brain cancer has severe side effects and a poor aqueous solubility. In order to decrease the detrimental effect of the drug over healthy cells, a novel drug delivery vehicle was developed where the therapeutic drug was encapsulated within the hydrophobic cavities of b-CD modified magnetite nanoparticles, which are embedded in chitosan nanobeads prepared by salt addition. In-vitro studies have shown that the magnetic properties of the novel delivery vehicle are adequate for targeted drug delivery applications under an external magnetic field. Additionally, an increase in the amount of chitosan was shown to exhibit a strong shielding effect over the magnetic properties of the delivery vehicle, which lead to deterioration of the amount of captured drug at the targeted area, suggesting a delicate balance between the amounts of constituents composing the drug delivery vehicle.

Simulation research on magnetoacoustic B-scan imaging of magnetic nanoparticles / 生物医学工程学杂志

As drug carriers, magnetic nanoparticles can specifically bind to tumors and have the potential for targeted therapy. It is of great significance to explore non-invasive imaging methods that can detect the distribution of magnetic nanoparticles. Based on the mechanism that magnetic nanoparticles can generate ultrasonic waves through the pulsed magnetic field excitation, the sound pressure wave equation containing the concentration information of magnetic nanoparticles was derived. Using the finite element method and the analytical solution, the consistent transient pulsed magnetic field was obtained. A three-dimensional simulation model was constructed for the coupling calculation of electromagnetic field and sound field. The simulation results verified that the sound pressure waveform at the detection point reflected the position of magnetic nanoparticles in biological tissue. Using the sound pressure data detected by the ultrasonic transducer, the B-scan imaging of the magnetic nanoparticles was achieved. The maximum error of the target area position was 1.56%, and the magnetic nanoparticles regions with different concentrations were distinguished by comparing the amplitude of the boundary signals in the image. Studies in this paper indicate that B-scan imaging can quickly and accurately obtain the dimensional and positional information of the target region and is expected to be used for the detection of magnetic nanoparticles in targeted therapy.

Method for active ingredients' in vivo target identification of traditional Chinese medicine using magnetic nanoparticles / 中国中药杂志

Target identification is an important prerequisite for the study of medicine action mechanism. Currently,drug target identification is mostly based on various cell models in vitro. However,the growth microenvironment,nutrition metabolism,biological properties as well as functions are quite different between in vitro cell culture and physiological environment in vivo; wherefore,it is a challenging scientific issue to establish an effective method for identifying drug targets in vivo condition. In this study,we successfully prepared a kind of magnetic nanoparticles( MNPs) which can be chemically modified by the hydroxyl structure of natural bioactive compound echinacoside( ECH) via the epoxy group label on the surface of MNPs. Therefore,organ-selective and recoverable nanoscale target-recognizing particles were prepared. We then intravenously injected the ECH-binding MNPs into rats and distributed them to specific organs in vivo. After cell endocytosis,ECH-binding MNPs captured target proteins in situ for further analysis. Based on this method,we discovered several potential target proteins in the spleen lysates for ECH,and preliminarily clarified the immuno-regulation mechanism of ECH. Collectively,our strategy developed a proof-of-concept technology using nanoparticles for in vivo target identification,and also provided a feasible approach for drug target prediction and pharmacological mechanism exploration.

A modified protocol of mouse hippocampal primary microglia culture by using manual dissociation, magnetic activated cell sorting and TIC medium / 生理学报

In this study, we improved the culture method of mouse hippocampal primary microglia to obtain hippocampal ramified microglia with high activity and purity, which were resemble to the resting status of normal microglia in healthy brain in vivo. Hippocampal tissue was excised from 2-4-week-old SPF C57BL/6J mice and cut into pieces after PBS perfusion, and then manually dissociated into the single-cell suspension by using Miltenyi Biotec's Adult Brain Dissociation Kit. The tissue fragments such as myelin in the supernatant were removed by debris removal solution in the kit. The cell suspension was incubated with CD11b immunomagnetic beads for 15 min at 4 °C. To obtain high-purity microglia, we used two consecutive cell-sorting steps by magnetic activated cell sorting (MACS). After centrifugation, the cells were resuspended and seeded in a 24-well culture plate. The primary microglia were cultured with complete medium (CM) or TIC medium (a serum-free medium with TGF-β, IL-34 and cholesterol as the main nutritional components) for 4 days, and then were used for further experiments. The results showed that: (1) The cell viability was (56.03 ± 2.10)% by manual dissociation of hippocampus; (2) Compared with immunopanning, two-step MACS sorting allowed for efficient enrichment of microglia with higher purity of (86.20 ± 0.68)%; (3) After being incubated in TIC medium for 4 d, microglia exhibited branching, quiescent morphology; (4) The results from qRT-PCR assay showed that the levels of TNF-α, IL-1β and CCL2 mRNA in TIC cultured-microglia were similar to freshly isolated microglia, while those were much higher in CM cultured-microglia after incubation for 4 d and 7 d (P < 0.05). Taken together, compared to the conventional approaches, this modified protocol of mouse hippocampal primary microglia culture by using MACS and TIC medium enables the increased yield and purity of microglia in the quiescent state, which is similar to normal ramified microglia in healthy brain in vivo.

Simulation of the relationship between magnetic medium parameters and heating temperature in magnetic fluid hyperthermia / 生物医学工程学杂志

In this paper, we established magnetic fluid hyperthermia (MFH) model for rat tumor using the finite element software COMSOL based on the linear response theory. By analyzing four kinds of magnetic medium within relaxation mechanism, such as Fe O 、FeCo、fccFePt and L1 FePt, we studied the influence of the change of magnetic medium radius on dissipation power and temperature field, respectively. At the same time, the optimization method for the parameters of several magnetic medium is proposed, and the applications of four kinds of magnetic medium are given as well. By increasing the dissipation power of the magnetic medium as much as possible, the dose of magnetic medium used in the treatment can be reduced, meanwhile, the adverse effects on health tissue surrounding the tumor will be minimized. The conclusions of this paper can provide reference for magnetic medium preparation applied to MFH.

Effects of magnetic thermotherapy mediated by magnetic nanocomposite PEG-APTESMNP on proliferation of liver cancer cells / 南方医科大学学报

OBJECTIVE@#To observe the inhibitory effects of PEG-APTES-MNP magnetic heating on liver cancer cells.@*METHODS@#The magnetic nanoparticle complex PEG-APTES-MNP was synthesized and its physiochemical properties and biocompatibility were characterized. HepG2 cells were incubated with the PEG-APTES-MNP nanoparticles for magnetic heating or nanoparticle therapy. Prussian blue staining was used to detect the uptake efficiency of the magnetic nanoparticles by HepG2 cells. MTT assay and flow cytometry were used to evaluate the inhibitory effect of the nanoparticles on HepG2 cells, and laser scanning confocal microscopy was used to detect the production of reactive oxygen species (ROS) in the cells. Fifteen nude mice bearing HepG2 cell xenografts were randomized equally into PEG-APTES-MNP injection group (with nanocomposite injection only), PEG-APTES-MNP magnetic heating group and control group (with PBS injection), and the tumor growth were observed in the mice after the treatments.@*RESULTS@#The synthesized PEG-APTES-MNP nanoparticles showed good physicochemical properties and biocompatibility. Incubation of HepG2 with the nanoparticles resulted in significantly increased ROS production, obvious inhibition of the cell growth through the synergetic effects of magnetic heating ( < 0.05), and significantly enhanced cell apoptosis. In the tumor-bearing nude mice, the nanoparticles strongly inhibited the tumor growth by magnetic heating ( < 0.05).@*CONCLUSIONS@#The magnetic nanocomposite PEG-APTES-MNP has good physicochemical properties and bioavailability and can strongly inhibit the growth of liver cancer cells both and in nude mice through magnetic heating, demonstrating its potential as a candidate nanomedicine for liver cancer treatment.

Design of Internal Grasper Based on Magnetic Anchoring Technique in Trocar-Less Laparoscopic Surgery / 中国医疗器械杂志

Laparoscopic surgery based on magnetic anchor technique has great potential for further minimally invasive surgery and good surgical field exposure, in which the internal grasper is the key factor. In this paper, an internal grasper based on magnetic anchor laparoscopic surgery is designed, which consists of three parts:target magnet, connection module and tissue forceps. The magnetic shield shell is used to wrap the magnetic core in the target magnet, which not only can increase the magnetic force in the working area, but also reduce the magnetic interference between the instruments, and the connecting module can flexibly adjust the length of the internal grasper. The special structure of tissue gripper can effectively reduce deputy injury and facilitate the replacement of clamp position. It has many advantages, such as ingenious design, easy processing, simple operation and wide range of application, which greatly increased its clinical application value.

Development and Application of Permanent Magnet Motor and Its Control in the Field of Artificial Blood Pump / 中国医疗器械杂志

Permanent magnet motor has been widely used in the field of artificial heart pump due to its high power density, high stability and easy control. In this paper, the development history and research progress of permanent magnet motor for blood pump were described. Firstly, the motors were classified according to their structures and application scenarios. And then, the measures taken by different types of motors to meet the corresponding performance requirements were introduced, and the specific application cases were given. After that, commonly used control algorithms of these motors were enumerated. What's more, the advantages and disadvantages of the control algorithms and their application emphasis were carefully explained. Finally, the paper was summarized in short.

Yersinia pestis detection by loop-mediated isothermal amplification combined with magnetic bead capture of DNA

ABSTRACT We developed a loop-mediated isothermal amplification (LAMP) assay for the detection of Y. pestis by targeting the 3a sequence on chromosome. All 11 species of the genus Yersinia were used to evaluate the specificity of LAMP and PCR, demonstrating that the primers had a high level of specificity. The sensitivity of LAMP or PCR was 2.3 or 23 CFU for pure culture, whereas 2.3 × 104 or 2.3 × 106 CFU for simulated spleen and lung samples. For simulated liver samples, the sensitivity of LAMP was 2.3 × 106 CFU, but PCR was negative at the level of 2.3 × 107 CFU. After simulated spleen and lung samples were treated with magnetic beads, the sensitivity of LAMP or PCR was 2.3 × 103 or 2.3 × 106 CFU, whereas 2.3 × 105 or 2.3 × 107 CFU for magnetic bead-treated liver samples. These results indicated that some components in the tissues could inhibit LAMP and PCR, and liver tissue samples had a stronger inhibition to LAMP and PCR than spleen and lung tissue samples. LAMP has a higher sensitivity than PCR, and magnetic bead capture of DNAs could remarkably increase the sensitivity of LAMP. LAMP is a simple, rapid and sensitive assay suitable for application in the field or poverty areas.

Clinical observation on auricular magnetotherapy for convalescent stroke patients with depression / 中国针灸

OBJECTIVE@#To observe the effect of auricular magnetotherapy on depression and quality of life in stroke patients with depression after recovery.@*METHODS@#Ninety-three stroke patients with depression were randomly divided into a conventional group(a control group), a conventional combined with magnetotherapy group (an observation 1 group), a conventional combined with vaccaria seed group (an observation 2 group), 31 cases in each group. Conventional treatments were applied in the three groups. On the basis of conventional treatments, auricular magnetotherapy was added in the observation 1 group, and in the observation 2 group, vaccaria seed was applied at gan (CO), xin (CO), pi (CO), shen (CO), shenmen (TF), pizhixia (AT), press 3 times a day, replace once every 3 days, alternate ears and treating for 4 weeks. The scores of 17 Hamilton Depression Scales (HAMD-17) and stroke-specific quality of life scales (SS-QOL) were observed before and after treatment in each group. Depression was assessed at follow-up 4 weeks after treatment, and the clinical efficacy of each group was compared.@*RESULTS@#A total of 83 cases completed the test. After treatment and follow-up, the scores of HAMD decreased in the observation 1 group and observation 2 group compared with that before treatment (all 0.05). After treatment, the total score of SS-QOL in the observation 1 group and observation 2 group were higher than that in the control group (0.05). The scores of energy, family characters, and emotional dimensions in the observation 1 group were higher than those in the observation 2 group and control group (<0.05, <0.01). The score of personality and upper limb function were higher than those in the control group (<0.05, <0.01); the score of the family role dimension of the observation 2 group was significantly higher than that in the control group (<0.01). The total effective rate in the observation 1 group was 72.4% (21/29), which was higher than 44.4% (12/27) in the observation 2 group (<0.05) and 11.1% (3/27) in the control group (<0.01).@*CONCLUSION@#Auricular magnetotherapy can improve the depressive symptoms of convalescent stroke patients with depression and improve their quality of life.

Design of Magnetic Clutch System for Electromagnetic Control Laparoscopic Surgery Based on Magnetic Anchoring System / 中国医疗器械杂志

Magnetic anchor technique can reduce the number of trocar in laparoscopic surgery. The laparoscopic magnetic anchor system consists of an external anchor magnet and the magnetic clutch system. Electromagnetic control laparoscopic surgery clutch system includes the internal grasper and the operating forceps. In this design, a permanent magnet is set at the tail of the internal grasper, and an electromagnetic device is installed at the head of the operating forceps. The magnetic field direction of the electromagnetic device can be changed by switching the positive pole and the negative pole of the electromagnetic device, so as to control the separation and combination of the operating forceps and the internal grasper. The design of this system is ingenious, easy to manufacture and the operation is simple.

Cultura científica, magnetismo y espiritismo durante fines del siglo XIX en Buenos Aires: un análisis desde Ovidio Rebaudi / Scientific culture, magnetism and spiritualism during the end of the 19th century in Buenos Aires: an analysis from Ovidio Rebaudi

El objetivo de este artículo es analizar a un personaje remarcable del escenario cultural y científico de Buenos Aires de fines de siglo, el director de la Revista Magnetológica: Ovidio Rebaudi (1860-1931), renombrado químico así como adherente al espiritismo y el magnetismo. La vida y obra del mismo, oriundo de Paraguay y radicado en Argentina, resulta de utilidad para comprender cómo actores de filiación científica practicaban y defendían, al mismo tiempo, la hipnosis y el magnetismo. De hecho, Rebaudi dedicó gran parte de su vida a estudiar y conceptualizar acerca de los fenómenos sobrenaturales, llevando a cabo también curaciones magnéticas y diversas experiencias espiritistas, siempre dotando sus prácticas de cientificidad. El presente artículo analiza a este personaje de fin de siglo que abogaba, al mismo tiempo, por las prácticas científicas y por el estudio de lo sobrenatural. Entendemos que dicho análisis servirá para iluminar las zonas de mixtura y entrelazamiento entre terrenos tan disímiles como el científico y el de las energías y fluidos magnéticos.

The aim of this paper is to analyze a remarkable character of Buenos Aires cultural and scientific scenario during the end of the century, the producer of the Revista Magnetológica (Magazine of magnetism) Ovidio Rebaudi (1860-1931), a well-known chemist and follower of magnetism and spiritualism. The life and work of this chemist, native of Paraguay and resident of Argentina, seem useful to understand how scientific actors held and protect hypnotic and magnetic practices. In fact, Rebaudi dedicated a great part of his life to the study and conceptualization of supernatural phenomena, performing magnetic healings and diverse spiritualist experiments, enduing their practices with scientific attributes. This paper intends to analyze this end-of-the-century character, who pleaded for scientific practices on the one hand, and for supernatural studies on the other. We understand that this analysis could enlighten some mixture zones and interweaved soils between the scientific and the magnetic grounds.

Nitrate removal from aqueous solutions by magnetic nanoparticle

Introduction: Due to causing methemoglobinemia, different cancers, and teratogen effects in human nitrate contamination of water resources has become a critical environmental problem Therefore, the aim of this work was to determine the optimum condition of nitrate sorption onto magnetic nanoparticle

Materials and Methods: The removal of nitrate from aqueous solutions by magnetic nanoparticles has been studied through using batch adsorption method. X-ray diffraction [XRD], Transmission Electron Microscopy [TEM], and Scanning Electron Microscopy [SEM] was applied to characterize the synthesized Fe[3]O[4]. The effect of pH, nano-magnetic, adsorbent dose, initial concentration of nitrate, and contact time were investigated

Results: According to SEM and TEM images, the adsorbent particles were nanosized and spheroidal; the sizes were about 20-30 nm. The experiments' results indicated that the optimum adsorbent dose was 750 mg in 1000 ml of solution, with a contact time of 90 min, while the optimum pH was 9. The kinetic models for nitrate adsorption showed rapid sorption dynamics by both first-order kinetic [R2 = 0.97] and second-order kinetic [R2 = 0.96] models. Nitrate adsorption equilibrium data were fitted well to the Freundlich isotherm than Langmuir isotherm

Conclusion: The results showed that, magnetic nanoparticles can be used as a low cost and efficient adsorbent for removal of nitrate from aqueous solutions

Recent advances in biomagnetism and its applications

No abstract available.