Nanoparticles For Purification Research Articles

Preparation and characterization of polymyxin B- and histidine-coupled magnetic nanoparticles for purification of biologics from acquired endotoxin contamination

BackgroundEndotoxin is a major process-related impurity that can act as a strong immunostimulant leading to fever and hypotensive shock. Thus, the US FDA and international quality standards strictly direct the biologics manufacturers to control the endotoxin contamination during the purification process. In this work, a developed method for biologics purification from acquired endotoxin contamination is introduced. This is accomplished by the preparation of dextran-coated magnetic nanoparticles using a facile rapid co-precipitation method.ResultsThe resulting magnetic nanoparticles (MNPs) are characterized by dynamic light scattering, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometry. The dextran-coated magnetic nanoparticles are further coupled to either polymyxin B or histidine to provide a positively charged ligand which enhances the affinity to the negatively charged endotoxin. Both ligands-coupled MNPs are tested for purification efficiency using the chromogenic kinetic assay. The method conditions are optimized using a two-level factorial design to achieve best purification conditions of the contaminated biologics and indicated endotoxin removal percentage 85.12% and maximum adsorption capacity of 38.5 mg/g, for histidine-coupled MNPs.ConclusionsThis developed method is introduced to serve biologics manufacturers to improve their manufacturing processes through providing a simple purifying tool for biologics from acquired endotoxin contamination.Graphical

Green synthesis of silver nanoparticles, characterization and evaluation of their photocatalytic dye degradation activity

In the present study, silver nanoparticles were synthesized by Citrus reticulata Blanco (Kinnow mandarin hybrid) peel extract. The formation of silver nanoparticles was observed by color change from pale yellow to brown and then confirmed by UV spectral analysis, which showed a peak at 423 ​nm. The silver nanoparticles were found to be spherical and appeared to form nanoclusters as confirmed by TEM and FE-SEM respectively. FTIR analysis was conducted to identify the functional groups present in nanoparticles. Several peaks were observed in the range 525–3251 ​cm⁻1. The major peak observed at 1641.8 ​cm⁻1 exhibit C–N and C–C stretching. The band at 3251.0 ​cm−1 was observed due to stretching vibrations of O–H groups in water, alcohol and phenols. The biosynthesized silver nanoparticles were used for the degradation of malachite green dye, which is harmful for both aquatic and human life. Complete degradation of MG dye was observed after 120 ​h (5 days) of incubation in the presence of sunlight. The results of photo catalytic degradation of malachite green by using nanoparticles demonstrated the feasibility of nanoparticles in purification of water.

Application of Fe2O3/CeO2 nanocomposites for the purification of aqueous media

The paper presents the results of a study of the applicability of Fe2O3/CeO2 nanoparticles for purification of aqueous media from manganese ions, by its absorption on the surface of nanoparticles, with further removal from the aqueous medium by magnetic separation. According to the data obtained, the structures under study are a mixture of two phases: the rhombohedral phase Fe2O3, which is characteristic of the hematite structure, and the hexagonal phase CeO2 with a phase ratio of 1:2. During corrosion tests, it was found that acid solutions with pH = 1 and 0.1% HCl, which varies from 0.0004 to 0.0007 nm/day, have the highest degradation rate and a decrease in the degree of ordering of the crystal structure of nanoparticles. Moreover, in the case of corrosion tests in PBS solutions, the degradation rate was 0.0002 nm/day. According to the data obtained, it was found that the absorption of manganese ions on the surface of nanoparticles leads to the formation of highly disordered or amorphous-like inclusions. In this case, an increase in the residence time in the medium leads to partial degradation of the nanoparticles, which leads to a decrease in the degree of purification.

Enhanced catalytic reduction of 4-nitrophenol and congo red dye By silver nanoparticles prepared from Azadirachta indica leaf extract under direct sunlight exposure

ABSTRACTThe manuscript reports an efficient approach for the synthesis of biogenic silver (Ag) nanoparticles from Azadirachta indica leaf extract-mediated reduction of silver nitrate under solar radiation at mild temperature conditions for nanoparticles (NPs) preparation. Spectroscopic and electron microscopic characterization studies revealed the formation of stable and monodisperse Ag NPs with sharp absorption band at 438 nm and average diameter of 10–15 nm. Catalytic potential of the NPs was descriptively investigated for the reduction of 4-nitrophenol to 4-aminophenol in alkaline medium. Apparent rate constant () values were determined to be 0.014, 0.0238, 0.0338, 0.063, and 0.0794 at 5, 10, 15, 20, 40, and 50 µL Ag NPs volume, respectively, thereby depicting linear relationship between the variables under study. Catalytic reduction of Congo red dye was achieved within 2 h, thus validating the efficacy of Ag NPs as a photocatalyst. The NPs also exhibited linear increment in antibacterial activity on cultured Escherichia coli plates with increasing volumes. These catalytic capabilities firmly advocate the applications of Ag NPs in purification of polluted water by the removal of toxic and contaminant materials and harmful/pathogenic bacteria.

Synthesis of Cholesterol-Conjugated Magnetic Nanoparticles for Purification of Human Paraoxonase 1

Human serum paraoxonase 1 (PON1) is known as an antioxidant and is also involved in the detoxification of many compounds. In this study, a novel purification strategy was employed to purify the PON1 by using cholesterol-conjugated magnetic nanoparticles. Magnetic nanoparticles were synthesized and conjugated with cholesterol through diazotized p-aminohippuric acid. In Fourier transform infrared spectrum of cholesterol-p-aminohippuric acid-Fe(3)O(4) nanoparticles, the appearance of peaks at 3,358.3, 1,645 cm(-1), and at 2,334.9 cm(-1) confirmed the conjugation. The molecular weight of purified PON1 was nearly 45 kDa on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), and isoelectric point was 5.3. The specific activity was 438 U mg(-1) protein, and the purification fold was 515 with 73% yield. The K (m) values were 1.3 and 0.74 mM with paraoxon and phenyl acetate, respectively. Western blot of 2D-PAGE confirmed the homogeneity and stability of the enzyme. Mg(+2), Mn(+2), glycerol, (NH(4))(2)SO(4), PEG 6000, Triton X-100, and phenylmethylsulfonyl fluoride did not show any effect on activity. Pb(+2), Co(+2), Zn(2+), ethanol, beta-mercaptoethanol, and acetone reduced the activity while Ni(2+), Cd(2+), Cu(2+), iodoacetic acid, SDS, dimethylformamide, DMSO inhibited the activity. In vitro enzyme activity was slightly reduced by acetyl salicylic and acetaminophen and reduced 50% with amino glycosides and ampicillin antibiotics at concentrations of 0.6 and 30 mg ml(-1), respectively. This is the first report for the synthesis of cholesterol-conjugated magnetic nanoparticles for simple purification of PON1 enzyme.

Application of superparamagnetic nanoparticles in purification of plasmid DNA from bacterial cells

The aim of this study was to develop a simple and rapid method for purification of ultrapure supercoiled plasmid DNA with high yields from bacterial cultures. Nanosized superparamagnetic nanoparticles (Fe 3O 4) were prepared by chemical precipitation method using Fe 2+, Fe 3+ salt, and ammonium hydroxide under a nitrogen atmosphere. The surface of Fe 3O 4 nanoparticles was modified by coating with the multivalent cationic agent, polyethylenimine (PEI). The nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier transformation infrared spectroscopy and superconducting quantum interference device magnetometer. The PEI-modified magnetic nanobeads were employed to simplify the purification of plasmid DNA from bacterial cells. We demonstrated a useful plasmid, pRSETB-EGFP, encoding the green fluorescent protein with T7 promoter, was amplified in DE3 strain of Escherichia coli. The loaded nanobeads are recovered by magnetically driven separation and regenerated by exposure to the elution buffer with optimal ionic strength (1.25 M) and pH (9.0). Up to approximately 35 μg of high-purity (A 260/A 280 ratio = 1.87) plasmid DNA was isolated from 3 ml of overnight bacterial culture. EGFP expression was detected by fluorescent microscopy in the transformed E. coli cells, indicating the biological activities of DNA fragments were retained after purified from magnetic nanobeads. The protocol, starting from the preparation of bacterial lysate and ending with purified plasmids takes less than 10 min. Thus, the separation and purification qualities of PEI-modified magnetic nanobeads as well as its ease of use surpass those of conventional anion-exchange resins.