Magnetic labeling of natural lipid encapsulations wit ron-based nanoparticles

With superior biocompatibility and unique magnetic properties, iron-based nanoparticles （IBNP） are commonly encapsulated in cells and extracellular vesicles （EV） to allow for magnetic force controlled drug delivery and non-invasive tracking. Based on their natural source and similar morphologs; we classify both cells and EVs as being natural lipid encapsulations （NLEs）, distinguishing them from synthetic liposomes. Both their imaging contrast and drug effects are dominated by the amount of iron encapsulated in each NLE, demonstrating the importance of magnetic labeling efficiency. It is known that the membranes function as barriers to ensure that substances pass in and out in an orderly manner. The most important issue in increasing the cellular uptake of IBNPs is the interaction between the NLE membrane and IBNPs, which has been found to be affected by properties of the IBNPs as well as NLE heterogeneity. Two aspects are important for effective magnetic labelling： First, how to effectively drive membrane wrapping of the nanoparticles into the NLEs, and second, how to balance biosafety and nanoparticle uptake. In this review, we will provide a systematic overview of the magnetic labeling of NLEs with IBNPs. This article provides a summary of the applications of magnetically labeled NLEs and the labeling methods used for IBNPs. The review also analyzes the role of IBNPs physicochemical properties, especially their magnetic properties, and the of NLEs in the internalization pathway. At the same time, the future of magnetically labeled NLEs is also discussed. development

Highly Efficient Labeling of Human Lung Cancer Cells Using Cationic Poly-L-lysine-Assisted Magnetic Iron Oxide Nanoparticles

Cell labeling with magnetic iron oxide nanoparticles(IONPs)is increasingly a routine approach in the cellbased cancer treatment.However,cell labeling with magnetic IONPs and their leading effects on the biological properties of human lung carcinoma cells remain scarcely reported.Therefore,in the present study the magnetic c-Fe2O3nanoparticles(MNPs)were firstly synthesized and surface-modified with cationic poly-L-lysine(PLL)to construct the PLL-MNPs,which were then used to magnetically label human A549 lung cancer cells.Cell viability and proliferation were evaluated with propidium iodide/fluorescein diacetate double staining and standard 3-(4,5-dimethylthiazol-2-diphenyl-tetrazolium)bromide assay,and the cytoskeleton was immunocytochemically stained.The cell cycle of the PLL-MNPlabeled A549 lung cancer cells was analyzed using flow cytometry.Apoptotic cells were fluorescently analyzed with nuclear-specific staining after the PLL-MNP labeling.The results showed that the constructed PLL-MNPs efficiently magnetically labeled A549 lung cancer cells and that,at low concentrations,labeling did not affect cellular viability,proliferation capability,cell cycle,and apoptosis.Furthermore,the cytoskeleton in the treated cells was detected intact in comparison with the untreated counterparts.However,the results also showed that at high concentration(400 lg m L-1),the PLL-MNPs would slightly impair cell viability,proliferation,cell cycle,and apoptosis and disrupt the cytoskeleton in the treated A549 lung cancer cells.Therefore,the present results indicated that the PLL-MNPs at adequate concentrations can be efficiently used for labeling A549 lung cancer cells and could be considered as a feasible approach for magnetic targeted anti-cancer drug/gene delivery,targeted diagnosis,and therapy in lung cancer treatment.

Ultralow detection limit of giant magnetoresistance biosensor using Fe3O4–graphene composite nanoparticle label

A special Fe3O4nanoparticles–graphene（Fe3O4–GN） composite as a magnetic label was employed for biodetection using giant magnetoresistance（GMR） sensors with a Wheatstone bridge. The Fe3O4–GN composite exhibits a strong ferromagnetic behavior with the saturation magnetization MS of approximately 48 emu/g, coercivity HC of 200 Oe, and remanence Mr of 8.3 emu/g, leading to a large magnetic fringing field. However, the Fe3O4 nanoparticles do not aggregate together, which can be attributed to the pinning and separating effects of graphene sheet to the magnetic particles. The Fe3O4–GN composite is especially suitable for biodetection as a promising magnetic label since it combines two advantages of large fringing field and no aggregation. As a result, the concentration x dependence of voltage difference ｜？V｜ between detecting and reference sensors undergoes the relationship of ｜？V｜ = 240.5 lgx ＋ 515.2 with an ultralow detection limit of 10 ng/mL（very close to the calculated limit of 7 ng/mL） and a wide detection range of 4 orders.

Biocompatibility of iron carbide and detection of metals ions signaling proteomic analysis via HPLC/ESl-Orbitrap

Recently, magnetic nanopartides （NPs） have been extensively used in food industry and biomedical treatments. However, the biocompatibility mechanism on expression proteomics, before consideration of magnetic NPs for clinical application, has not yet been fully elucidated. Therefore, this study was undertaken to identify potential biomarkers of metal ion signaling proteins in human cervical cancer cell line （HeLa） cells. Here, we report the in vitro investigations of the cell cycle response and significant changes in protein abundance of HeLa cells when exposed to self-tailored hydrophilic Fe2C NPs. The comparative proteomic approach based on 180 labeling coupled with high performance liquid chromatography/ electrospray ionization with ion trap mass analyzer （HPLC/ESI-Orbitrap） was applied, and 394 proteins were identified. There were 46 significantly differentiated proteins based on the specific metal ion signaling response. Among them, 60S ribosomal protein L37a, serine/arginine-rich splicing factor 7, calmodulin, and calumenin were downregulated, whereas transketolase was overexpressed. Functional interaction network of Fe2C-regulated proteins was successfully created by the STRING algorithm to show the strong interactions between proteins. This work will not only help to understand the molecular mechanism of metal ion signaling proteins that can potentially be used to develop therapeutic protocols for diagnosis of diseases but also give direction for tailoring biocompatible magnetic NPs.