Given the complexity of biological samples and the trace nature of target materials in forensic trace analysis, a simple and effective method is needed to obtain sufficient target materials from complex substrates. Magnetic nanoparticles (MNPs) have shown a wide range of application value in many research fields, such as biomedicine, drug delivery and separation, due to their unique superparamagnetic properties, stable physical and chemical properties, biocompatibility, small size, high specific surface area and other characteristics. To apply MNPs in the pretreatment of forensic materials, maximize the extraction rate of the target materials, and minimize interference factors to meet the requirements of trace analysis of the target materials, this paper reviews the application of MNPs in the fields of forensic toxicological analysis, environmental forensic science, trace evidence analysis and criminal investigation in recent years, and provides research ideas for the application of MNPs in forensic trace analysis.
Magnetite Nanoparticles/chemistry* ; Forensic Medicine ; Forensic Sciences ; Forensic Toxicology

We established a purification system for glutathione-S-transferase (GST) fusion protein using glutathione coupled magnetic particle. Glutathione was coupled covalently to the surface of magnetic particles with isothiocyanate functional groups. Cell lysate, containing the fusion protein, was then incubated with these glutathione coupled magnetic particles at room temperature. Unbound and non-specifically bound proteins were removed by wash steps. Subsequently, the GST-fusion protein was eluted from the magnetic particles by the addition of reduced glutathione. The resulting fusion protein was tested for purity using SDS-PAGE and demonstrated by Western blotting. The concentration of the fusion protein was measured by Bradford method. Both the conditions for incubation and washing were optimized. The results showed that 150 microg glutathione could be bound on 1 mg of particle surface and 10 mg of the glutatione-coupled magnetic particles was suitable for 100 microL lysate, the optimal incubation time for reaction between particles and lysate was 40 min. The magnetic particles could help purify efficiently GST-fusion protein with a yield of around 516 microg fusion protein per 10 mg particles. Magnetic particles can be successfully used in a simple, rapid and reliable method for the purification of GST-fusion proteins.
Glutathione ; chemistry ; Glutathione Transferase ; chemistry ; isolation & purification ; Magnetite Nanoparticles ; chemistry ; Protein Binding ; Recombinant Fusion Proteins ; chemistry ; isolation & purification

Aqueous dispersion and stability of Fe3O4 nanoparticles remain an issue unresolved since aggregation of naked iron nanoparticles in water. In this study, we successfully synthesized different Fe3O4 super-paramagnetic nanoparticles which were modified by three kinds of materials [DSPE-MPEG2000, TiO2 and poly acrylic acid (PAA)] and further detected their characteristics. Transmission electron microscopy (TEM) clearly showed sizes and morphology of the four kinds of nanoparticles. X-ray diffraction (XRD) proved successfully coating of the three kinds of nanoparticles and their structures were maintained. Vibrating sample magnetometer (VSM) verified that their magnetic properties fitted for the super-paramagnetic function. More importantly, the particle size analysis indicated that Fe3O4@PAA had a better size distribution, biocompatibility, stability and dispersion than the other two kinds of nanoparticles. In addition, using CNE2 cells as a model, we found that all nanoparticles were nontoxic. Taken together, our data suggest that Fe3O4@PAA nanoaparticles are superior in the application of biomedical field among the four kinds of Fe3O4 nanoparticles in the future.
Ferric Compounds ; chemistry ; Magnetite Nanoparticles ; chemistry ; Microscopy, Electron, Transmission ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; Water ; chemistry ; X-Ray Diffraction

We prepared Fe3O4 magnetic nanoparticles (MNPs) with the size of 10 nm by chemical coprecipitation. The effects of six aqueous-organic solvents, including tetrahydrofuran, dioxane, acetone, N, N-Dimethylformamide, methylalcohol, and Dimethyl Sulfoxide, on peroxidase mimetic activity of Fe3O4 MNPs were studied and compared with that of horseradish peroxidase (HRP). The relative activity of Fe3O4 MNPs droped sharply as the elevation of organic solvent concentration increased from 30% to 75% (V/V). In 15% organic solutions, the optimum activity of Fe3O4 MNPs was observed around 50 degrees C, under pH 3.6. After being treated at different temperatures and pH in 15% organic solutions, even under 75% concentration, Fe3O4 MNPs still preserved most of the activity when reacting in aqueous phase. The catalytic performances of Fe3O4 MNPs under given conditions were generally more superior to that of HRP. For it costs lower and it is easy to be prepared and segregated magnetically for recycle, to use the magnetic nanoparticles as a substitution for HRP has potential to be applied into organic catalysis.
Acetone ; chemistry ; Biomimetics ; Catalysis ; Dioxanes ; chemistry ; Ferrosoferric Oxide ; chemistry ; Furans ; chemistry ; Hydrogen-Ion Concentration ; Magnetite Nanoparticles ; chemistry ; Organic Chemicals ; chemistry ; Peroxidase ; metabolism ; Solvents ; Temperature

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

In this study, we investigated the pharmacokinetics parameters of SPIO-shRNA dual functional molecular probe and observed the main organ distribution by MRI in vivo. Eighteen New Zealand white rabbits were randomly divided into three groups and injected intravenously with different doses of SPIO-shRNA molecular probe, respectively. The blood samples were collected to analyze the pharmacokinetic parameters by measuring the iron content at 30 minutes before and after the injection. Twenty-four Kun Ming (KM) mice were randomly divided into 4 groups: the control group was injected intravenously with physiological saline 200 µL per mouse via the tail vein, the other 3 groups were injected intravenously with different doses of SPIO-shRNA molecular probe. MRI observation was performed in 24 hours, and the liver, spleen, kidney, brain and muscle were collected for iron quantification with Prussian blue staining to determine distribution of the SPIO-shRNA molecular probe in the main organ in vivo. Our results suggest that the molecular probe blood half-life is more than 3 hours. The data of MRI suggest the probe was distributed in liver and spleen, and the MRI signal was reduced with the increase in probe's doses (P < 0.05). The results of Prussian blue staining confirmed the results of MRI. Most of the probe could escape the phagocytosis of mononuclear phagocyte system. Our data provide the pharmacokinetic and distribution of SPIO-shRNA molecular probe in organs. Meanwhile, it suggests the choice of the time and dose of probe for MR imaging of tumor in vivo.
Animals ; Half-Life ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; Mice ; Molecular Probes ; pharmacokinetics ; RNA, Small Interfering ; chemistry ; Rabbits

This study aimed to characterize and magnetic resonance imaging (MRI) track the mesenchymal stem cells labeled with polylysine-coated superparamagnetic iron oxide (PLL-SPIO). Rat bone marrow derived mesenchymal stem cells (rMSCs) were labeled with 25, 50 and 100 microg/mL PLL-SPIO for 24 hours. The labeling efficiency was assessed by iron content, Prussian blue staining, electron microscopy and in vitro MR imaging. The labeled cells were also analyzed for cytotoxicity and differentiation potential. Electron microscopic observations and Prussian blue staining revealed that 75% -100% of cells were labeled with iron particles. PLL-SPIO did not show any cytotoxicity up to 100 microg/mL concentration. Both 25 microg/mL and 50 microg/mL PLL-SPIO labeled stem cells did not exhibit any significant alterations in the adipo/osteo/chondrogenic differentiation potential compared to unlabeled control cells. The lower concentration of 25 microg/mL iron labeled cells emitted an obvious dark signal in T1W, T2WI and T2 * WI MR image. The novel PLL-SPIO enables to label and track rMSCs for in vitro MRI without cellular alteration. Therefore PLL-SPIO may potentially become a better MR contrast agent especially in tracking the transplanted stem cells and other cells without compromising cell functional quality.
Animals ; Bone Marrow Cells ; Cell Differentiation ; Dextrans ; chemistry ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; chemistry ; Mesenchymal Stromal Cells ; cytology ; Polylysine ; chemistry ; Rats ; Staining and Labeling

Coprecipitation method was used to prepare triiron tetroxide magnetic nanoparticles enclosed in L-DOPA, and then EDC was used to activate the carboxyl group of L-DOPA after the nanoparticles were synthesized. The carboxyl group of L-DOPA formed amide bond with specific amino on the aptamer by dehydration condensation reaction. The surfaces of magnetic nanoparticles were modified with aptamer and L-DOPA. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), nanoparticle size analysis (SEM), magnetic measurement (VSM) and other testing methods were used to detect the magnetic nanoparticles in different stages. The endothelial progeni-tor cells (EPCs) were cocultured with the surface modified magnetic nanoparticles to evaluate cell compatibility and the combination effect of nanoparticles on EPCs in a short period of time. Directional guide of the surface-modified magnetic nanoparticles to endothelial progenitor cells (EPCs) was evaluated under an applied magnetic field and simulated dynamic blood flow condition. The results showed that the prepared magnetic nanoparticles had good magnetic response, good cell compatibility within a certain range of the nanoparticle concentrations. The surface modified nanoparticles could combine with EPCs effectively in a short time, and those nanoparticles combined EPCs can be directionally guided on to a stent surface under the magnetic field in the dynamic flow environment.
Endothelial Progenitor Cells ; cytology ; drug effects ; Ferrosoferric Oxide ; chemistry ; Humans ; Levodopa ; chemistry ; Magnetite Nanoparticles ; chemistry ; Spectroscopy, Fourier Transform Infrared ; X-Ray Diffraction

OBJECTIVETo investigate the magnetic resonance (MR) signal features of superparamagnetic iron oxide (SPIO) with different particle size and concentration.

METHODSThe superparamagnetic iron oxide with different concentration and particle size was scanned by magnetic resonance; T1, T2 and T2(*) values of each group were recorded to evaluate the features of MR signals.

RESULTSThe T1 value of SPIO with different particle size had negative linear relationship with concentration. In low concentration the T2 and T2(*) values were elevated markedly with the particle size decreased; while in high concentration the T2 and T2(*)values were elevated gently with particle size decreased. lg(T2), particle size and concentration of SPIO had linear relationship.

CONCLUSIONSSPIO affects magnetic resonance signal mainly with effect on T1 and T2. T2 value can be regarded as the major detection index in the magnetic resonance scan of SPIO. There is a linear relationship among particle size, SPIO concentration and lg(T2) value.

Contrast Media ; pharmacology ; Dose-Response Relationship, Drug ; Ferrosoferric Oxide ; chemistry ; pharmacology ; Humans ; Image Enhancement ; Magnetic Resonance Imaging ; methods ; Magnetite Nanoparticles ; chemistry ; Particle Size

Urokinase plasminogen activator receptor (uPAR) is a membrane protein which is attached to the cellular external membrane. The uPAR expression can be observed both in tumor cells and in tumor-associated stromal cells. Thus, in the present study, the human amino-terminal fragment (hATF), as a targeting element to uPAR, is used to conjugate to the surface of superparamagnetic iron nanoparticle (SPIO). Flowcytometry was used to examine the uPAR expression in different tumor cell lines. The specificity of hATF-SPIO was verified by Prussian blue stain and cell phantom test. The imaging properties of hATF-SPIO were confirmed in vivo magnetic resonance imaging (MRI) of uPAR-elevated colon tumor. Finally, the distribution of hATF-SPIO in tumor tissue was confirmed by pathological staining. Results showed that the three cells in which we screened, presented different expression characteristics, i. e., Hela cells strongly expressed uPAR, HT29 cells moderately expressed uPAR, but Lovo cells didn't express uPAR. In vitro, after incubating with Hela cells, hATF-SPIO could specifically combined to and be subsequently internalized by uPAR positive cells, which could be observed via Prussian blue staining. Meanwhile T2WI signal intensity of Hela cells, after incubation with targeted probe, significantly decreased, and otherwise no obvious changes in Lovo cells both by Prussian blue staining and MRI scans. In vivo, hATF-SPIO could be systematically delivered to HT29 xenograft and accumulated in the tumor tissue which was confirmed by Prussian Blue stain compared to Lovo xenografts. Twenty-four hours after injection of targeting probe, the signal intensity of HT29 xenografts was lower than Lovo ones which was statistically significant. This targeting nanoparticles enabled not only in vitro specifically combining to uPAR positive cells but also in vivo imaging of uPAR moderately elevated colon cancer lesions.
Cell Line, Tumor ; Colonic Neoplasms ; diagnosis ; Ferric Compounds ; Humans ; Magnetic Resonance Imaging ; Magnetite Nanoparticles ; chemistry ; Molecular Imaging ; methods ; Receptors, Urokinase Plasminogen Activator ; chemistry ; Staining and Labeling