APTES monolayer coverage on self-assembled magnetic nanospheres for controlled release of anticancer drug Nintedanib

The use of an appropriate delivery system capable of protecting, translocating, and selectively releasing therapeutic moieties to desired sites can promote the efficacy of an active compound. In this work, we have developed a nanoformulation which preserves its magnetization to load a model anticancerous drug and to explore the controlled release of the drug in a cancerous environment. For the preparation of the nanoformulation, self-assembled magnetic nanospheres (MNS) made of superparamagnetic iron oxide nanoparticles were grafted with a monolayer of (3-aminopropyl)triethoxysilane (APTES). A direct functionalization strategy was used to avoid the loss of the MNS magnetization. The successful preparation of the nanoformulation was validated by structural, microstructural, and magnetic investigations. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to establish the presence of APTES on the MNS surface. The amine content quantified by a ninhydrin assay revealed the monolayer coverage of APTES over MNS. The monolayer coverage of APTES reduced only negligibly the saturation magnetization from 77 emu/g (for MNS) to 74 emu/g (for MNS-APTES). Detailed investigations of the thermoremanent magnetization were carried out to assess the superparamagnetism in the MNS. To make the nanoformulation pH-responsive, the anticancerous drug Nintedanib (NTD) was conjugated with MNS-APTES through the acid liable imine bond. At pH 5.5, which mimics a cancerous environment, a controlled release of 85% in 48 h was observed. On the other hand, prolonged release of NTD was found at physiological conditions (i.e., pH 7.4). In vitro cytotoxicity study showed dose-dependent activity of MNS-APTES-NTD for human lung cancer cells L-132. About 75% reduction in cellular viability for a 100 μg/mL concentration of nanoformulation was observed. The nanoformulation designed using MNS and monolayer coverage of APTES has potential in cancer therapy as well as in other nanobiological applications.

A Novel Nonenzymatic Hydrogen Peroxide Sensor Based on Magnetic Core-Shell Fe3O4@C/Au Nanoparticle Nanocomposite

Fe3O4@C/Au nanoparticle (AuNP) nanocomposites were prepared through electrostatic adsorption of AuNPs onto PDDA-functionalized core/shell Fe3O4@C magnetic nanospheres, which had been synthesized by a facile solvothermal method. The morphology and composition of the nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), etc. Moreover, highly electrocatalytic activity to the reduction of hydrogen peroxide (H2O2) was also exhibited on the Fe3O4@C/AuNP-modified indium tin oxide (ITO) electrode. The effect of solution pH and the modification amount of Fe3O4@C/AuNPs on the performance of electrocatalytic H2O2 reduction was investigated. Under the optimal conditions, the catalytic current showed a linear relationship with the increase of H2O2 concentration in the range of 0.007–15 mM and a detection limit of 5 μM. The H2O2 sensor showed high selectivity for H2O2 detection, which could effectively resist the interference of ascorbic acid (AA), uric acid (UA), and citric acid (CA). Finally, the H2O2 sensor was used in the real fetal bovine serum to detect H2O2 and obtained satisfactory results with the recovery values ranging from 95.14 to 103.6%.

Hierarchical micro- and mesoporous metal–organic framework-based magnetic nanospheres for the nontargeted analysis of chemical hazards in vegetables

H-MOF6@Fe3O4 nanospheres for complete removal of phytochromes through size selectivity to realize nontargeted analysis of chemical hazards in vegetables.

Effect of Varying Expression of EpCAM on the Efficiency of CTCs Detection by SERS-Based Immunomagnetic Optofluidic Device

The circulating tumor cells (CTCs) isolation and characterization has a great potential for non-invasive biopsy. In the present research, the surface–enhanced Raman spectroscopy (SERS)-based assay utilizing magnetic nanoparticles and solid SERS-active support integrated in the external field assisted microfluidic device was designed for efficient isolation of CTCs from blood samples. Magnetic nanospheres (Fe2O3) were coated with SERS-active metal and then modified with p-mercaptobenzoic acid (p-MBA) which works simultaneously as a Raman reporter and linker to an antiepithelial-cell-adhesion-molecule (anti-EpCAM) antibodies. The newly developed laser-induced SERS-active silicon substrate with a very strong enhancement factor (up to 108) and high stability and reproducibility provide the additional extra-enhancement in the sandwich plasmonic configuration of immune assay which finally leads to increase the efficiency of detection. The sensitive immune recognition of cancer cells is assisted by the introducing of the controllable external magnetic field into the microfluidic chip. Moreover, the integration of the SERS-active platform and p-MBA-labeled immuno-Ag@Fe2O3 nanostructures with microfluidic device offers less sample and analytes demand, precise operation, increase reproducibly of spectral responses, and enables miniaturization and portability of the presented approach. In this work, we have also investigated the effect of varying expression of the EpCAM established by the Western Blot method supported by immunochemistry on the efficiency of CTCs’ detection with the developed SERS method. We used four target cancer cell lines with relatively high (human metastatic prostate adenocarcinoma cells (LNCaP)), medium (human metastatic prostate adenocarcinoma cells (LNCaP)), weak (human metastatic prostate adenocarcinoma cells (LNCaP)), and no EpCAM expressions (cervical cancer cells (HeLa)) to estimate the limits of detection based on constructed calibration curves. Finally, blood samples from lung cancer patients were used to validate the efficiency of the developed method in clinical trials.

Synthesis and application of magnetic@layered double hydroxide as an anti-inflammatory drugs nanocarrier

Background Magnetic nanocomposites with a core–shell nanostructure have huge applications in different sciences especially in the release of the drugs, because of their exclusive physical and chemical properties. In this research, magnetic@layered double hydroxide multicore@shell nanostructure was synthesized by the facile experiment and is used as novel drug nanocarrier. Methods Magnetic nanospheres were synthesized by a facile one-step solvothermal route, and then, layered double hydroxide nanoflakes were prepared on the magnetic nanospheres by coprecipitation experiment. The synthesized nanostructures were characterized by FTIR, XRD, SEM, VSM, and TEM, respectively. After intercalation with Ibuprofen and Diclofenac as anti-inflammatory drugs and using exchange anion experiment, the basal spacing of synthesized layered double hydroxides was compared with brucite nanosheets from 0.48 nm to 2.62 nm and 2.22 nm, respectively. Results The results indicated that Ibuprofen and Diclofenac were successfully intercalated into the interlay space of LDHs via bridging bidentate interaction. In addition, in-vitro drug release experiments in pH 7.4, phosphate-buffered saline (PBS) showed constant release profiles with Ibuprofen and Diclofenac as model drugs with different lipophilicity, water solubility, size, and steric effect. Conclusion The Fe3O4@LDH-ibuprofen and Fe3O4@LDH-diclofenac had the advantage of the strong interaction between the carboxyl groups with higher trivalent cations by bridging bidentate, clarity, and high thermal stability. It is confirmed that Fe3O4@LDH multicore-shell nanostructure may have potential application for constant drug delivery.