Superparamagnetic core–shell structured microspheres carrying carboxyl groups as adsorbents for purification of genomic DNA

Preparation, evaluation and application of MRI detectable sunitinib-loaded calcium alginate/poly(acrylic acid) hydrogel microspheres

Transcatheter arterial chemoembolization (TACE) is an effective method for the treatment of unresectable hepatocellular carcinoma. Although many embolic agents have been developed in TACE, there are few ideal embolic agents that combine drug loading, imaging properties and vessel embolization. Here, we developed novel magnetic embolic microspheres that could simultaneously load sunitinib malate (SU), be detected by magnetic resonance imaging (MRI) and block blood vessels. Calcium alginate/poly (acrylic acid) hydrogel microspheres (CA/PAA-MDMs) with superparamagnetic iron oxide nanoparticles (SPIONs) modified by citric acid were prepared by a drip and photopolymerization method. The embolization and imaging properties of CA/PAA-MDMs were evaluated through a series of experiments such as morphology, X-ray diffraction and X-ray photoelectron spectroscopy, magnetic responsiveness analysis, elasticity, cytotoxicity, hemolysis test, in vitro MRI evaluation, rabbit ear embolization and histopathology. In addition, the ability of drug loading and drug release of CA/PAA-MDMs were investigated by using sunitinib (SU) as the model drug. In conclusion, CA/PAA-MDMs showed outstanding drug loading capability, excellent imaging property and embolization effect, which would be expected to be used as a potential biodegradable embolic agent in the clinical interventional therapy.

Simplified Synthesis of the Amine-Functionalized Magnesium Ferrite Magnetic Nanoparticles and Their Application in DNA Purification Method

For pathogens identification, the PCR test is a widely used method, which requires the isolation of nucleic acids from different samples. This extraction can be based on the principle of magnetic separation. In our work, amine-functionalized magnesium ferrite nanoparticles were synthesized for this application by the coprecipitation of ethanolamine in ethylene glycol from Mg(II) and Fe(II) precursors. The conventional synthesis method involves a reaction time of 12 h (MgFe2O4-H&R MNP); however, in our modified method, the reaction time could be significantly reduced to only 4 min by microwave-assisted synthesis (MgFe2O4-MW MNP). A comparison was made between the amine-functionalized MgFe2O4 samples prepared by two methods in terms of the DNA-binding capacity. The experimental results showed that the two types of amine-functionalized magnesium ferrite magnetic nanoparticles (MNPs) were equally effective in terms of their DNA extraction yield. Moreover, by using a few minutes-long microwave synthesis, we obtained the same quality magnesium ferrite particles as those made through the long and energy-intensive 12-h production method. This advancement has the potential to improve and expedite pathogen identification processes, helping to better prevent the spread of epidemics.

Solvent-Responsive Magnetic Beads for Accurate Detection of SARS-CoV-2

Although numerous approaches were proposed for the nucleic acid (NA)-based SARS-CoV-2 detection, the nonideal NA desorption efficiency of conventional magnetic beads (MBs) limits their widespread application. In this study, we developed solvent-responsive MBs (called responsive MBs), which, in the presence of buffers, modulated the absorption and desorption capacities of NA by flipping the surface -COO-. Relative to other commercial MBs, responsive MBs exhibited similar absorption profiles and markedly enhanced desorption profiles. When applied for NA detection of complex samples, responsive MBs exhibited better performance of RNA detection than DNA, with obvious advantages in sensitivity. Specifically, the RNA and DNA desorption rates of commercial MBs were ∼85 and 82.5%, while those of responsive MBs were nearly 94 and 93.5%, respectively. Furthermore, responsive MBs exhibited remarkable extraction ability in a wide range of tissues and better performance of RNA extraction than DNA. When applied for SARS-CoV-2 detection, the responsive MBs along with the simulated digital RT-LAMP (a previously established apparatus) further improved detection efficiency, yielding a precise quantitative detection as low as 25 copies and an ultimate sensibility detection of 5 copies/mL. It was also successfully employed in numerous NA-based technologies such as polymerase chain reaction (PCR), sequencing, and so on.

Pathways to Green Perspectives: Production and Characterization of Polylactide (PLA) Nanocomposites Filled with Superparamagnetic Magnetite Nanoparticles

In the category of biopolymers, polylactide or polylactic acid (PLA) is one of the most promising candidates considered for future developments, as it is not only biodegradable under industrial composting conditions, but it is produced from renewable natural resources. The modification of PLA through the addition of nanofillers is considered as a modern approach to improve its main characteristic features (mechanical, thermal, barrier, etc.) and to obtain specific end-use properties. Iron oxide nanoparticles (NPs) of low dimension (10–20 nm) such as magnetite (Fe₃O₄), exhibit strong magnetization in magnetic field, are biocompatible and show low toxicity, and can be considered in the production of polymer nanocomposites requiring superparamagnetic properties. Accordingly, PLA was mixed by melt-compounding with 4–16 wt.% magnetite NPs. Surface treatment of NPs with a reactive polymethylhydrogensiloxane (MHX) was investigated to render the nanofiller water repellent, less sensitive to moisture and to reduce the catalytic effects at high temperature of iron (from magnetite) on PLA macromolecular chains. The characterization of nanocomposites was focused on the differences of the rheology and morphology, modification, and improvements in the thermal properties using surface treated NPs, while the superparamagnetic behavior was confirmed by VSM (vibrating sample magnetometer) measurements. The PLA−magnetite nanocomposites had strong magnetization properties at low magnetic field (values close to 70% of M_max at H = 0.2 T), while the maximum magnetic signal (M_max) was mainly determined by the loading of the nanofiller, without any significant differences linked to the surface treatment of MNPs. These bionanocomposites showing superparamagnetic properties, close to zero magnetic remanence, and coercivity, can be further produced at a larger scale by melt-compounding and can be designed for special end-use applications, going from biomedical to technical areas.

Adsorption of DNA by using polydopamine modified magnetic nanoparticles based on solid-phase extraction

A polydopamine magnetic composite (PDA@Fe₃O₄) was prepared for the extraction of human genomic DNA and characterized by transmission electron microscopy, X-ray diffraction, FT-IR spectrometer, zeta potential and vibrating sample magnetometry. PDA@Fe₃O₄ based on magnetic solid phase extraction (MSPE) method have highly efficient capture of genomic deoxyribonucleic acid (DNA)and gene fragments ranging from about 100 bp to 200 bp. Compared with commercial beads (Shenggong, China) and spin column nucleic acid extraction kit (Tiangen, China), the PDA coated magnetic nanoparticles display superior genomic DNA extraction capacity (116 mg/g) and yield (90.2%). The isolation protocol used the solutions (composed of PEG and NaCl) with a specific pH for the binding and release of DNA. The procedure can be attributed to the charge switch of amino and hydroxyl groups on surface of the magnetic particle. The extracted DNA with high quality (A260/A280 = 1.82 ± 0.04) can be directly used as template for polymerase chain reaction (PCR) followed by agarose gel electrophoresis. The results showed the new composite to be an ideal adsorbent for separation of DNA which had the advantage of its low cost, high extraction capacity and yield.

One-Step Fabrication of Dual Responsive Lignin Coated Fe₃O₄ Nanoparticles for Efficient Removal of Cationic and Anionic Dyes

A new, simple one-step approach has been developed to synthesize lignin and lignin amine coated Fe₃O₄ nanoparticles. These nanoparticles (lignin magnetic nanoparticles (LMNPs) and lignin amine magnetic nanoparticles (LAMNPs)) are found to possess not only magnetic response but also pH-dependent adsorption behavior. Results show that the combination of lignin with nanoparticles increased the adsorption capacities 2-5 times higher than other traditional single lignin based adsorbents (211.42 mg/g for methylene blue (MB) by LMNPs and 176.49 mg/g for acid scarlet GR (AS-GR) by LAMNPs). Meanwhile, by simply adjusting the pH, the dye-loaded adsorbents can be regenerated to recycle both adsorbents and dyes with a desorption efficiency up to 90%. Mechanistic study shows that dye structure and surface charges of adsorbents play the most important part in adsorption where dyes interact with the adsorbent surface via π-π stacking and electrostatic attraction interactions. The efficient fabrication method, eco-friendly reactant, quick magnetic separation, high adsorption and desorption efficiency suggest this novel type of nano-adsorbents to be promising materials for efficient dye pollutant removal and recovery.

Improved performance of immobilized lipase by interfacial activation on Fe3O4@PVBC nanoparticles

An effective strategy for enhancement of catalytic activity and stability of immobilized lipase by interfacial activation on Fe₃O₄@polyvinylbenzyl chloride nanoparticles is proposed.

Synthesis of Fe3O4/P(St-AA) nanoparticles for enhancement of stability of the immobilized lipases

Core–shell Fe₃O₄/P(St-AA) nanoparticles were synthesized and employed as a magnetic carrier for lipase immobilization, and the properties of the immobilized lipase were studied.