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.
Magnetics ; Magnetite Nanoparticles

Silver nanoparticles have been widely used in medicinal and biological fields. Their biological evaluation is an important researchful field. In this paper are summarized the status quo of nano-hydroxyapatite biological evaluation at home and abroad. Although silver nanoparticles showed good biological compatibility when they were tested by contrast to ISO 10993 standards, some reports have proved that many medical devices loaded with silver could release silver ions (Ag+) which could translocate in blood circulation and cumulate in some organs such as liver and kidney. It may induce hepatotoxicity or renal toxicity and may lead to death in some situation extremely exposed to a certain dose of Ag+. The dimension of silver nanoparticles is close to silver ions and some reports have proved that they could translocate in body, so it is suggested that silver nanoparticles should induce the same toxicity with silver ions. In addition, silver nanoparticles have shown cytotoxicity in some experiment in vitro. But the mechanisms of its cytotoxity are not clear; it may attribute to the silver ions that release from silver nanoparticles or to the silver nanoparticles that permeate through cell membrane. Hence, there are some potential anxieties for the biological safety of silver nanoparticles.
Metal Nanoparticles ; toxicity ; Silver ; toxicity

Effects of different procedures of magnetic nanoparticles into the liposome structure on the distribution of magnetic particles in the liposome were investigated. Magnetic liposomes with high-encapsulating rate of cisplatin (CDDP) were obtained. Fe3O4 magnetic nanoparticles which was modified by organic functional group on surface was synthesized by an one-step modified hydrothermal method. The CDDP magnetic liposomes were prepared by a film scattering-ultrasonic technique and the concentrations of CDDP in the liposomes were measured by graphite furnace atomic absorbance spectroscopy. Magnetic liposomes with different microstructure were prepared by the two different procedures, where the magnetic particles were combined with phospholipid before the film preparation to form liposome in procedure I, and drug solution and the magnetic particles were mixed before hydrating the lipids film to form liposome in procedure II. The liposome structure was observed by transmission electron microscope (TEM). The CDDP magnetic liposomes were prepared by the optimized method which was selected by orthogonal test. Encapsulation rate of the magnetic particles distributed in the phospholipid bilayer through the procedure I was 34.90%. While liposome, produced by the procedure II technique, contained magnetic particles in the interior aqueous compartment, which encapsulation rate was 28.34%. Encapsulation rates of both I and II were higher than that of conventional liposome. The release profile of all the three different liposomes in vitro fitted with a first-order equation. Because of distribution of magnetic particles in the phospholipid bilayer, the skeleton of phospholipid bilayer was changed. The releasing tl/2 of magnetic liposomes produced by the procedure I technique is 9 h, which is shorter than that of the other two liposomes. Assemble of magnetic nanoparticles into the structure of liposome was succeeded by the procedure I, which showed superiority than by procedure II whatever in CDDP liposome encapsulation efficiency and content of the magnetic particles and would ensure sustained-release character.
Antineoplastic Agents ; administration & dosage ; chemistry ; Cisplatin ; administration & dosage ; chemistry ; Drug Compounding ; methods ; Ferrosoferric Oxide ; chemistry ; Liposomes ; chemistry ; Magnetite Nanoparticles ; chemistry ; Nanoconjugates ; administration & dosage ; chemistry ; Particle Size

The application of nanotechnology significantly benefits clinical practice in cancer diagnosis, treatment, and management. Especially, nanotechnology offers a promise for the targeted delivery of drugs, genes, and proteins to tumor tissues and therefore alleviating the toxicity of anticancer agents in healthy tissues. This article reviews current nanotechnology platforms for anticancer drug delivery, including polymeric nanoparticles, liposomes, dendrimers, nanoshells, carbon nanotubes, superparamagnetic nanoparticles, and nucleic acid-based nanoparticles [DNA, RNA interference (RNAi), and antisense oligonucleotide (ASO)] as well as nanotechnologies for combination therapeutic strategies, for example, nanotechnologies combined with multidrug-resistance modulator, ultrasound, hyperthermia, or photodynamic therapy. This review raises awareness of the advantages and challenges for the application of these therapeutic nanotechnologies, in light of some recent advances in nanotechnologic drug delivery and cancer therapy.
Antineoplastic Agents ; administration & dosage ; therapeutic use ; Dendrimers ; therapeutic use ; Drug Carriers ; Drug Delivery Systems ; Drug Resistance, Multiple ; drug effects ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Liposomes ; therapeutic use ; Magnetite Nanoparticles ; therapeutic use ; Nanoparticles ; therapeutic use ; Nanoshells ; therapeutic use ; Nanotechnology ; trends ; Nanotubes, Carbon ; Neoplasms ; drug therapy ; Polymers ; therapeutic use

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.
Acoustics ; Computer Simulation ; Magnetics ; Magnetite Nanoparticles ; Tomography

In modern medicine the resistance to conventional antibiotics is becoming a serious concern due to high instances of mortality. Several metallic nanoparticles are suggested as promising anti-microbial agents against multidrug-resistant bacteria and some viruses. Among the nanoparticles mentioned, we review the recent finding which demonstrate the impact of silver nanoparticles on antimicrobial activities and recommend them as a potential candidate for restraining infections.
Anti-Bacterial Agents ; Anti-Infective Agents ; Bacteria ; History, Modern 1601- ; Metal Nanoparticles ; Nanoparticles ; Silver

The poor mechanical property and vulnerability to bacterial infections are the main problems in clinic for dental restoration resins. Based on this problem, the purpose of this study is to synthesize silver-titanium dioxide (Ag-TiO₂) nanoparticles with good photocatalytic properties, and add them to the composite resin to improve the mechanical properties and photocatalytic antibacterial capability of the resin. The microstructure and chemical composition of Ag-TiO₂ nanoparticles and composite resins were characterized. The results indicated that Ag existed in both metallic and silver oxide state in the Ag-TiO₂, and Ag-TiO₂ nanoparticles were uniformly dispersed in the resins. The results of mechanical experiments suggested that the mechanical properties of the composite resin were significantly improved due to the incorporation of Ag-TiO₂ nanoparticles. The antibacterial results indicated that the Ag-TiO₂ nanoparticle-filled composite resins exhibited excellent antibacterial activities under 660 nm light irradiation for 10 min due to the photocatalysis, and the Ag-TiO₂ nanoparticle-filled composite resins could also exhibit excellent antibacterial activities after contact with bacteria for 24 h without light irradiation because of the release of Ag ions. In summary, this study provides a new antibacterial idea for the field of dental composite resins.
Anti-Bacterial Agents/pharmacology* ; Composite Resins ; Metal Nanoparticles/chemistry* ; Nanoparticles ; Titanium/pharmacology*

OBJECTIVETo investigate the characteristics of exposure to iron oxide nanoparticles in workplace.

METHODSThe real-time particle number (NC), surface area (SAC), and mass (MC) concentrations of nanoparticles were measured in various locations of a selected workplace manufacturing iron oxide nanoparticles. The collected particles were analyzed for morphology and elemental composition.

RESULTSThe average NCs and SACs in milling site (16,566 pt/cm3, 106.082 µm2/cm3), packaging site (12,386 pt/cm3, 89.861 µm2/cm3), shipping site (13,808 pt/cm3, 102.071 µm2/cm3), and product storage room (17,192 pt/cm, 115.044 µm2/cm3) of the yellow powder (α-Fe2O3 . nH2O) were all significantly higher than the workplace background concentrations (11,420 pt/cm3, 85.026 µm2/cm3) (all P<0.05). The NC was highly correlated with the SAC (r= 0.784), while both NC and SAC were loosely correlated with the MC (r1=0.323, r2=0.331). Scanning electron microscopy revealed a spindle-like shape of the iron oxide nanoparticle; the chemical composition of the collected particles contained 19.33 weight percent iron (Fe).

CONCLUSIONThe milling site and product storage room of the yellow powder are exposed to a higher concentration of nanoparticles, which are mainly composed of iron oxide nanoparticles. The NC is highly correlated with the SAC.

Zinc oxide nanoparticle (nano-ZnO) has a size between 1 and 100 nm. Nano-ZnO has some special effects, such as small size effect, surface effect, quantum size effect, which makes it different from the ordinary ZnO, and is widely used in rubber industry, food processing, cosmetics and pharmaceutical fields. It has been reported that nano-ZnO has toxic effects in vitro and in vivo, but the mechanism of toxicity is still unclear. Therefore, it is important to evaluate the safety nano-ZnO by studying its biological toxic effects and related mechanisms. In this paper, we summarize the characterization, ingestion pathway, metabolism, systematic toxicity of nano-ZnO and its mechanisms, which may provide us with new strategy for the toxic research of nano-ZnO.
Animals ; Humans ; Metal Nanoparticles ; toxicity ; Zinc Oxide ; toxicity

Chitosan has natural abundance, unique bioactivity and attractive physicochemical properties. Recent years, the synthesis of chitosan-based metal nanomaterials has attracted increasing attention. The synthesis of metal nanoparticles utilizing biomolecular or organism offers a mild medium, and thus a greater degree of control over the nanoparticles produced, along with higher reproducibility. In particular, preparation of metal nanoparticles based on biomolecular or organism has its unique facility in integrating "minimum feature sizes" into labile biological components to an excellent synergy and bifunctional effect and consequently a more broad application. Herein, we review the new development of chitosan, chitosan-based synthesis of metal nanomaterials, and their application.
Catalysis ; Chitosan ; chemistry ; Metal Nanoparticles ; chemistry ; Oxidation-Reduction