Antibody-labeled magnetic nanoparticles were redispersed in PBS (1 mL) and stored at 4C for use. == Immunomagnetic Assay == The above store suspension (100 L) was added to a tube and rinsed three times with washing Miriplatin hydrate buffer (PBST) in a magnetic field. total elimination toxicity to the environment and human health in green chemistry [1,14]. The nontoxic, renewable raw materials and environmentally benign solvents Miriplatin hydrate are generally considered in a green synthetic strategy Miriplatin hydrate [1]. As society and environment can benefit from the products, green chemistry can convey a responsible attitude to public toward the development of nanoscience and nanotechnology [14]. Magnetite (Fe3O4) nanoparticles have attracted intensive interests for a wide range of fields, including magnetic fluids, immobilization of proteins, peptides and enzymes, immunoassays, drug or gene delivery magnetic resonance imaging, data storage, environmental remediation [15-25]. The Fe3O4nanoparticles perform best in most of biomedicinal applications when the size of the nanoparticles is around 1020 nm. In this range, an individual nanoparticle becomes a single magnetic domain and shows superparamagnetic behavior above blocking temperature [26,27]. Large numbers of methods have been developed for the synthesis of high-quality Fe3O4nanoparticles of various surface modifier based DCHS2 on the thermal decomposition of iron organometallic compounds in a high-boiling point organic solvent [28-37]. When those magnetite nanoparticles are applied in biomedical fields, surface post-treatments are usually needed. In the present work, we described a facile and green approach toward synthesis and stabilization of Fe3O4nanoparticles. Water and glycerol were used as environmentally benign solvents in the synthesis. Inartificial amino acidl-arginine was chosen as the nontoxic, renewable stabilizing agent. == Experimental Section == == Materials == Chloramphenicol (CAP) and 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) were purchased from SigmaAldrich. o-Phenylenediamine (OPD) was purchased from Xinjingke Biotechnology. Hydrogen peroxide (30%) was supplied by Guangmang Chemical Co. The anti-CAP monoclonal antibody and HRP-CAP conjugates were produced by our lab. Other analytical grade chemicals were purchased from Shanghai Chemical Reagents Company. All of the chemicals were used as received without further purification. Buffers and solutions used were listed below: a. Phosphate-buffered saline (PBS): 138 mM NaCl, 1.5 mM KH2PO4, 8 mM Na2HPO4H2O and 2.7 mM KCl, pH = 7.4. b. Washing buffer (PBST): PBS containing 0.05 (v/v) Tween 20. c. Citrate buffer: 19 mM citric acid, 33.5 mM Na2HPO4H2O, Miriplatin hydrate pH = 5.0 d. Substrate solution: 5 mg OPD, 12.5 mL citrate buffer, 2.5 L H2O2(30%). e. Stopping solution: 2 N HCl. == Synthesis ofl-Arginine-Capped Fe3O4Nanoparticles == l-Arginine (3.0 g) and FeCl3(0.5 g) were added to a component solvent containing glycerol (10 mL) and water (10 mL). A transparent solution formed through sonication of this mixture. This solution was transferred into a Teflon-lined stainless steel autoclave with a capacity of 50 mL and maintained at 200C for 6 h. Then, the autoclave was cooled to room temperature naturally. The product was washed with distilled water to remove residue of solvent and unboundl-arginine, finally dried by vacuum freeze-desiccation technology before characterization. During each step, the product was separated from the suspension by magnetic force. == Preparation of Magnetic Nanoparticles Conjugates == A solution was formed by mixing 250 L Fe3O4nanoparticles suspension and 1 mL phosphate-buffered saline (PBS). Then, 10 L of anti-CAP monoclonal antibody and 1 mg of 1-ethyl-3-(dimethylaminopropyl) carbodiimide hydrochloride (EDC) were added. Afterward, the mixture was incubated overnight with light shaking at room temperature. Excess EDC and the supernatant were removed by Miriplatin hydrate magnetic separation, and the precipitate was washed three times with PBS. Antibody-labeled magnetic nanoparticles were redispersed in PBS (1 mL) and stored at 4C for use. == Immunomagnetic Assay == The above store suspension (100 L) was added to a tube and rinsed three times with washing buffer (PBST) in a magnetic field. Then, 100 L.
