Magnetic Mesoporous Nanoparticles Research Articles

Drug delivery and anticancer activity of biosynthesised mesoporous Fe2 O3 nanoparticles.

Mesoporous magnetic nanoparticles of haematite were synthesised using plant extracts according to bioethics principles. The structural, physical and chemical properties of mesoporous Fe2O3 nanoparticles synthesised with the green chemistry approach were evaluated by XRD, SEM, EDAX, BET, VSM and HRTEM analysis. Then, their toxicity against normal HUVECs and MCF7 cancer cells was evaluated by MTT assay for 48 h. These biogenic mesoporous magnetic nanoparticles have over 71% of doxorubicin loading efficiency, resulting in a 50% reduction of cancer cells at a 0.5 μg.ml−1 concentration. Therefore, it is suggested that mesoporous magnetic nanoparticles be used as a multifunctional agent in medicine (therapeutic‐diagnostic). The produced mesoporous magnetic nanoparticles with its inherent structural properties such as polygonal structure (increasing surface area to particle volume) and porosity with large pore volume became a suitable substrate for loading the anti‐cancer drug doxorubicin.

Core-shells of magnetite nanoparticles decorated by SBA-3-SO3H mesoporous silica for magnetic solid phase adsorption of paraquat herbicide from aqueous solutions

Paraquat, the most well-known herbicides of toxicological class I, is widely used as an effective herbicide despite its high toxicity for humans and animals. In the current research, a simple synthesis approach was utilized to prepare Fe3O4 @SiO2 @SBA-3-SO3H core-shell mesoporous magnetic nanoparticles (MMNPs) as effective adsorbent for paraquat removal from the aqueous solutions. The characterization of nanoparticles was examined by XRD, BET, FT-IR, FESEM, VSM, mapping and TEM. To optimize the various experimental variables affecting the removal efficiency of paraquat, the effects of four experimental parameters at four levels including solution pH, adsorbent amount, contact time and ionic strength were evaluated by Taguchi fractional factorial design method (OA16). Based on the ANOVA results, ionic strength (80.69%) was recognized as the most significant factor contributing to the paraquat removal efficiency followed by the adsorbent mass (12.67%), pH of the solution (3.52%), and stirring time (0.141%). At the optimum conditions (sample volume = 50 mL, adsorbent dose = 2.4 g L−1, solution pH = 7 and ionic strength = without salt addition), the four kinetic models for the paraquat adsorption on the Fe3O4 @SiO2 @SBA-3-SO3H MMNPs were studied at two concentrations of 25 and 75 mg L−1 in the time range of 0.5–120 min. According to the results, the pseudo-second order kinetic model is the best model (R2 > 0.99, qe, cal =80.0 mg g−1), confirming diffusion plays a key role in determining the rate of adsorption process. Adsorption equilibrium data were investigated by four known isotherm models and the results demonstrated the best fitting with the Langmuir model. From the thermodynamic studies, ΔH°, ΔS°, ΔG°, and Ea of adsorption process were obtained as − 4697.08 J mol−1, − 3.938 J mol−1 K−1, − 3523.45 J mol−1 and − 4246.46 J mol−1, respectively. The negative ΔH° and ΔG° values indicated the exothermic and spontaneous nature of paraquat sorption on the surface of nanoparticles, respectively. Moreover, the obtained values of ΔH°, ΔG° and Ea confirmed the physisorption nature of interaction. The negative ΔS° and Ea shows a decrease in the randomness at the interface of solution-adsorbent with the progress of the sorption process and exothermic nature of adsorption, respectively. The calculated sticking probability (S*) showed the high probability of sticking to the surface. The proposed adsorbent showed very good adsorption behavior and showed reusability more than six cycles without significant reduction in its performance that makes it as a proper adsorbent for paraquat removal.

S‐Benzylisothiourea Complex of Palladium Supported on Modified Mesoporous Magnetic Nanoparticles (Pd-SBTU@Fe3O4@SBA-3) as Sustainable Environmental Catalyst for Suzuki and Stille Reactions

S‐Benzylisothiourea Complex of Palladium Supported on Modified Mesoporous Magnetic Nanoparticles (Pd-SBTU@Fe3O4@SBA-3) as Sustainable Environmental Catalyst for Suzuki and Stille Reactions

Introducing a green nanocatalytic process toward the synthesis of benzo[a]pyrano-[2,3-c]phenazines utilizing copper oxide quantum dot-modified core-shell magnetic mesoporous silica nanoparticles as high throughput and reusable nanocatalysts.

In this contribution, a green, simple, efficient, and straightforward nanocatalytic process was developed for the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives under mild thermal conditions. In this regard, the copper oxide quantum dot-modified magnetic silica mesoporous nanoparticles (M-MSNs/CuO(QDs)) were synthesized by surface modification of M-MSNs with CuO QDs to prepare a highly powerful magnetic core–shell nanocatalyst. The prepared nanocatalyst was then characterized for its functionality, size, morphology, elemental composition, surface area, crystallinity, and magnetic properties. Afterwards, it was applied for the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives under green reaction conditions. The factors affecting the reaction yield were optimized by the one-factor-at-a-time optimization method. Under obtained optimal conditions, the developed method showed a reaction yield range as high as 86–95% for different derivatives. The reusability studies were performed for indexing the cycling stability of the prepared magnetic nanocatalyst. The results exhibited that the catalytic efficiency of the nanocatalyst was saved for at least 5 operational times, showing high cycling stability of M-MSNs/CuO(QDs). Finally, the catalytic performances of the nanocatalyst was compared with the reported ones, revealing that the M-MSNs/CuO(QDs) presents very better performances toward the synthesis of benzo[a]pyrano[2,3-c]phenazine derivatives than the reported ones.

Sonochemical route for mesoporous silica-coated magnetic nanoparticles towards pH-triggered drug delivery system

This work reports a pH-triggered release system based on core@shell mesoporous magnetic nanoparticles (MNP@mSiO 2 ) obtained using a simple and rapid ultrasound-assisted method. Performed characterization reveals magnetic cores of Fe 2.9 Mn 0.1 O 4 (38 ± 6 nm) and specific loss power values adequate for hyperthermia (463 W/g), surrounded by a mesoporous silica shell (10 ± 2 nm) with large surface area (269 m 2 g -1 ) functionalized with hydroxyl groups (-OH). MNP@mSiO 2 were loaded with DOX and amino-silane grops, providing pH-triggered DOX release at acidic environments, driving by dipolar intermolecular interactions. The experimental DOX release kinetics at pH 5.5, 6.6 and 7.4 were determined and adjusted to Gompertz dissolution model (Nash–Sutcliffe efficiency coefficient (NSE>0.9)), where the only strongly pH-dependent variable is the percentage of DOX released. The pH-triggered response observed in the system was ~20% of the DOX loaded into the MNP@mSiO 2 is released at pH 6.6 or 7.4, whereas up to 80 wt% is released at pH 5.5. Time to 50% of release and dissociation rate of the system remaining constant, suggesting no-pH influence on these parameters. The biological assays highlight negligible hemolytic effect and cytocompatibility of the hybrid material, pointing out the potential use of MNP@mSiO 2 as a magnetic driven drug delivery system with pH-triggered drug release kinetics at acidic environments. These results probe the feasibility of sonochemical methods in the elaboration of biocompatible and controlled properties nanomaterials for drug release applications, with the advantage of accurately responses predictions by mathematical model and using minimal processing steps or laboratory equipment.

Facile N‐Formylation of Amines on Magnetic Fe3O4−CuO Nanocomposites

AbstractA facile, eco‐friendly, efficient, and recyclable heterogeneous catalyst is synthesized by immobilizing copper impregnated on mesoporous magnetic nanoparticles. The surface chemistry analysis of Fe3O4−CuO nanocomposites (NCs) by XRD and XPS demonstrates the synergistic effect between Fe3O4 and CuO nanoparticles, providing mass‐transfer channels for the catalytic reaction. TEM images clearly indicate the impregnation of CuO onto mesoporous Fe3O4. This hydrothermally synthesized eco‐friendly and highly efficient Fe3O4−CuO NCs are applied as a magnetically retrievable heterogeneous catalyst for the N‐formylation of wide range of aliphatic, aromatic, polyaromatic and heteroaromatic amines using formic acid as a formylating agent at room temperature. The catalytic activity of the NCs for N‐formylation is attributable to the synergistic effect between Fe3O4 and CuO nanoparticles. The N‐formylated product is further employed for the synthesis of biologically active quinolone moieties.

Expression of Bacillus amyloliquefaciens γ-Glutamyltransferase in Lactococcus lactis and Immobilization on Magnetic Nanoparticles

γ-Glutamyltransferase (GGT) can catalyze the transfer of a γ-glutamyl group to amino acids or peptides. Bacterial GGTs have a wide substrate specificity, which means that a variety of γ-glutamyl amino acid derivatives or peptides can be synthesized under GGT catalysis. In this work, in order to enhance the expression and stability of GGT, a recombinant plasmid harboring Bacillus amyloliquefaciens ggt gene with a Usp45 signal peptide gene fused upstream was constructed and transferred into Lactococcus lactis NZ9000 to express BaGGT. After on-column hydrolysis and purification by immobilized metal affinity chromatography, 90.2 ± 0.7 mg/L of BaGGT-6His with an enzymatic activity of 57.3 ± 0.9 U/mg was purified. Subsequently, BaGGT-6His was immobilized onto magnetic mesoporous nanoparticles (Fe3O4NPs) by covalent binding. The immobilized BaGGT-6His largely retained the activity and, importantly, could be recovered and reused. After optimization of the production and immobilization conditions, the biotechnologically relevant product l-theanine was synthesized with free and immobilized BaGGT-6His.

Facile Preparation of ZIF-8 MOF Coated Mesoporous Magnetic Nanoarticles to Provide a Magnetic Solid Phase Extraction Platform

In this work, zeolitic imidazolate framework (ZIF-8) coated mesoporous magnetic nanoparticles (Fe3O4@PDA@mSiO2@ZIF-8) were prepared through a facile and efficient strategy and used as a magnetic solid phase extraction platform for phthalates detection. Polydopamine (PDA) not only provides a hydrophilic layer, but also possesses π electrons for aromatic compounds recognition; mSiO2 endows the nanoparticles with large surface area and regular channels, which facilitates the rapid transport of phthalates. The prepared Fe3O4@PDA@mSiO2@ZIF-8 with imposed properties showed ultrahigh efficiency and reusability for phthalates determination in human plasma samples. The linearity range was 50–8000 ng/mL, limits of detection were between 50–80 ng/mL, the intra-day RSDs were lower than 4.8%, inter-day RSDs were lower than 6.7%, the recoveries ranged from 90 to 107%. The new prepared nanoparticles displayed potential performance for aromatic compounds detection.

PEI grafted Fe3O4@SiO2@SBA-15 labeled FA as a pH-sensitive mesoporous magnetic and biocompatible nanocarrier for targeted delivery of doxorubicin to MCF-7 cell line

In this study, the synthesis and surface modification of mesoporous magnetite nanoparticles (Fe3O4@SiO2@SBA-15) using a cationic biodegradable and biocompatible copolymer have been reported. For this purpose firstly, the mesoporous magnetic nanoparticles (MMNPs) were synthesized by sol-gel methods on Fe3O4 nanoparticles. Then they were modified with TMVS and amino acid L-cysteine for preparing VMMNPs- L-cysteine. In another reaction, the PEI was modified with CM-β-CD and FA which was embedded into the CD cavity via host-guest interaction for preparing PEI/CM-β-CD/FA. Finally, the PEI/CM-β-CD/FA was successfully grafted onto VMMNPs- L-cysteine for the synthesis of a novel hollow mesoporous sphere as a nanocarrier. The structure and magnetic properties of the targeted MMNPs nanocarrier were confirmed by FT-IR, TGA, XRD, VSM, zeta potential analysis, SEM, and EDX analysis. The in-vitro drug release and drug loading capacity were measured using UV spectroscopy. Finally, to investigate the effect of this drug-nanocarrier on breast cancer cells, the MCF7 cells were cultured and the cell death rate was determined by MTT assay and drug IC50 after treatment with these drug nanocarriers (The concentration of each drug derivative that reduces cell growth by 50 % compared to control culture). Fluorescence microscopy was used to observe the morphology changes of the cancer cell nuclei.

Folic Acid-Terminated Poly(2-Diethyl Amino Ethyl Methacrylate) Brush-Gated Magnetic Mesoporous Nanoparticles as a Smart Drug Delivery System.

Currently, chemotherapy is an important method for the treatment of various cancers. Nevertheless, it has many limitations, such as poor tumour selectivity and multi-drug resistance. It is necessary to improve this treatment method by incorporating a targeted drug delivery system aimed to reduce side effects and drug resistance. The present work aims to develop pH-sensitive nanocarriers containing magnetic mesoporous silica nanoparticles (MMSNs) coated with pH-responsive polymers for tumour-targeted drug delivery via the folate receptor. 2-Diethyl amino ethyl methacrylate (DEAEMA) was successfully grafted on MMSNs via surface initiated ARGET atom transfer radical polymerization (ATRP), with an average particle size of 180 nm. The end groups of poly (2-(diethylamino)ethyl methacrylate) (PDEAEMA) brushes were converted to amines, followed by a covalent bond with folic acid (FA) as a targeting agent. FA conjugated to the nanoparticle surface was confirmed by X-ray photoelectron spectroscopy (XPS). pH-Responsive behavior of PDEAEMA brushes was investigated by Dynamic Light Scattering (DLS). The nanoparticles average diameters ranged from ca. 350 nm in basic media to ca. 650 in acidic solution. Multifunctional pH-sensitive magnetic mesoporous nanoparticles were loaded with an anti-cancer drug (Doxorubicin) to investigate their capacity and long-circulation time. In a cumulative release pattern, doxorubicin (DOX) release from nano-systems was ca. 20% when the particle exposed to acidic media, compared to ca. 5% in basic media. The nano-systems have excellent biocompatibility and are minimally toxic when exposed to MCF-7, and -MCF-7 ADR cells.

Enhanced Antimalarial Efficacy Obtained by Targeted Delivery of Artemisinin in Heparin-Coated Magnetic Hollow Mesoporous Nanoparticles.

Malaria is one of the deadliest infectious diseases threatening half of the world population. With the deterioration of the parasiticidal effect of the current antimalarials, novel approaches such as screening of more specific inhibitors and targeted delivery of drugs have been under intensive research. Herein, we prepare hollow mesoporous ferrite nanoparticles (HMFNs) of 200 nm with ferromagnetic properties using a one-pot hydrothermal reaction. A magnetically targeted drug-delivery system coloaded with artemisinin in the inner magnetite shell and heparin on the outer mesoporous shell (HMFN@ART@HEP) is developed. Specific targeting of the magnetic nanoparticles to the parasite-infected erythrocytes is achieved by the attraction between the HMFNs and hemozoin (paramagnetic), a vital metabolite of plasmodium in the erythrocytic stage. With the hemozoin production reaching the maximum during the schizont period of the parasite, HMFN@ART@HEPs are adsorbed to the infected red blood cells (iRBCs), which not only interferes with the release of merozoites but also significantly enhances the inhibitory efficacy due to the increased local concentration of artemisinin. Subsequently, the heparin coated on the surface of the nanoparticles can efficiently interfere with the invasion of freshly released merozoites to new RBCs through the specific interaction between the parasite-derived ligands and heparin, which further increases the inhibitory effect on malaria. As a cluster of heparin, heparin-coated nanoparticles provide stronger blocking capability than free heparin, resulting from multivalent interactions with surface receptors on merozoite. Thus, we have developed a HMFN-based delivery system with considerable antimalarial efficacy, which is a promising platform for treatment against malaria.

Spirulina platensis‐capped mesoporous magnetic nanoparticles for the adsorptive removal of chromium

AbstractThe magnetic nanoparticles prepared through the co‐precipitation method were surface modified using Spirulina platensis. The mesoporous and superparamagnetic nature of the adsorbent was confirmed by Brunauer‐Emmett‐Teller (BET) and vibrating sample magnetometer (VSM) analyses, respectively. Further, an increased specific surface area of 75.3 m2/g was reported in the BET studies. Parameters such as pH, contact time, concentration, and temperature were studied to optimize the operating conditions influencing adsorption. Thermodynamic studies justified the spontaneity and endothermic nature of adsorption. The adsorbent exhibited a better performance at 1.5 pH and 120 minutes of contact time. The monolayer adsorption capacity of the material was found to be 29.23 mg/g from the evaluation of Langmuir adsorption isotherm. The second‐ order kinetic studies suggest the predominance of chemisorption. Further, the X‐ray photoelectron spectroscopy (XPS) studies confirmed that the adsorption mechanism is electrostatic attraction accompanied by reduction. Notably, a regeneration efficiency of 75.26% was achieved with NaOH as the desorbing agent.

Desirability function approach for optimization of enzymatic transesterification catalyzed by lipase immobilized on mesoporous magnetic nanoparticles

Abstract Lipase-catalyzed transesterification for biodiesel production is clean, effective and water tolerance compare with conventional chemical or physical biodiesel synthesis methods. Therefore, in the present research, Burkholderia cepacia lipase was immobilized onto mesoporous silica/iron oxide magnetic core-shell nanoparticles for canola waste cooking oil (WCO) conversion to biodiesel. Response Surface Methodology (RSM) with Central Composite Design (CCD) was used to optimize the transesterification parameters. A quadratic polynomial equation was obtained for biodiesel yield by multiple regression analysis. Desirability function approach gave the optimal transesterification condition as: immobilized lipase concentration of 36%, reaction time of 25 h, methanol to WCO molar ratio of 6.2 and reaction temperature of 34 °C. The predicted biodiesel yield was 92% at the optimal condition. Transesterification catalyzed by the immobilized lipase carried out three times repeatedly, by losing just 11% of lipase activity in the third cycle of the transesterification.

Platelet Membrane-Camouflaged Magnetic Nanoparticles for Ferroptosis-Enhanced Cancer Immunotherapy.

Although cancer immunotherapy has emerged as a tremendously promising cancer therapy method, it remains effective only for several cancers. Photoimmunotherapy (e.g., photodynamic/photothermal therapy) could synergistically enhance the immune response of immunotherapy. However, excessively generated immunogenicity will cause serious inflammatory response syndrome. Herein, biomimetic magnetic nanoparticles, Fe3 O4 -SAS @ PLT, are reported as a novel approach to sensitize effective ferroptosis and generate mild immunogenicity, enhancing the response rate of non-inflamed tumors for cancer immunotherapy. Fe3 O4 -SAS@PLT are built from sulfasalazine (SAS)-loaded mesoporous magnetic nanoparticles (Fe3 O4 ) and platelet (PLT) membrane camouflage and triggered a ferroptotic cell death via inhibiting the glutamate-cystine antiporter system Xc- pathway. Fe3 O4 -SAS @ PLT-mediated ferroptosis significantly improves the efficacy of programmed cell death 1 immune checkpoint blockade therapy and achieves a continuous tumor elimination in a mouse model of 4T1 metastatic tumors. Proteomics studies reveal that Fe3 O4 -SAS @ PLT-mediated ferroptosis could not only induce tumor-specific immune response but also efficiently repolarize macrophages from immunosuppressive M2 phenotype to antitumor M1 phenotype. Therefore, the concomitant of Fe3 O4 -SAS @ PLT-mediated ferroptosis with immunotherapy are expected to provide great potential in the clinical treatment of tumor metastasis.

Copper/Schiff‐base complex immobilized on amine functionalized silica mesoporous magnetic nanoparticles under solvent‐free condition: A facile and new avenue for the synthesis of thiazolidin‐4‐ones

A copper/Schiff‐base complex supported on amine‐functionalized silica mesoporous magnetic nanoparticles was prepared as novel magnetically interphase nanoparticles and its morphology and structure were evaluated using Fourier transform infrared spectroscopy, X‐ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X‐ray spectroscopy, thermogravimetric analysis, zeta potential, and a vibrating sample magnetometer. The catalytic activity of the synthesized nanoparticles was evaluated for the synthesis of thiazolidine‐4‐ones.

Co-precipitation synthesis of mesoporous maghemite for catalysis application

Mesoporous magnetic nanoparticles (MNPs) were synthesized using the chemical co-precipitation method. The structure, morphology and magnetic properties of the MNPs were examined by X-ray diffraction (XRD), Mossbauer spectroscopy (MS), Brunauer–Emmett–Teller (BET) method, Transmission Electron Microscopy (TEM) and Vibrating Sample Magnetometer (VSM). The results of XRD and MS indicated that the MNPs were composed of γ-Fe2O3. TEM microphotography showed that the magnetic material was an aggregate of small spherical particles with a size of 6–12 nm. According to the BET data, the agglomeration of individual maghemite nanoparticles lead to formation of a complex mesoporous structure with the specific surface area of 88.3 m2 g−1. The average pore diameter was 5–7 nm, which correlates with the γ-Fe2O3 particles size. The VSM measurement (MS = 40.54 emu g−1, Mr = 5.27 emu g−1, HC = 88 Oe) indicated that the γ-Fe2O3 exhibited weak ferromagnetic and soft magnetic properties confirming the agglomeration of the small γ-Fe2O3 nanoparticles. The synthesized mesoporous maghemite showed excellent ability to absorb polymer protected colloidal palladium particles (Pd-PAM). The magnetic properties of MNPs were not significantly changed after modification with Pd-PAM. The resulting catalyst of Pd-PAM/MNPs showed activity (WC≡C = 3.3 × 10–6 mol s−1) and selectivity (93%) in the hydrogenation of phenylacetylene under mild conditions of 40 °C and 0.1 MPa. The Pd-PAM/MNPs catalyst can be easily recovered with an external magnet and reused for at least seven runs without significant degradation in the catalytic activity and selectivity.

One-pot synthesis of propargylamines using magnetic mesoporous polymelamine formaldehyde/zinc oxide nanocomposite as highly efficient, eco-friendly and durable nanocatalyst: optimization by DOE approach.

Magnetic mesoporous polymelamine formaldehyde nanocomposite-incorporating ZnO nanoparticles were successfully synthesized using solvothermal and sol-gel methods. Fourier-transform infrared spectrometry (FT-IR), X-ray diffraction, Brunauer-Emmett-Teller, vibrating sample magnetometer, thermogravimetric analysis, elemental analysis, transmission electron microscopy and field emission scanning electron microscopy techniques were then utilized for evaluation of nanocomposites. The as-prepared nanocomposite can be used as heterogeneous nanocatalyst with remarkable performance for A3 coupling reaction toward one-pot synthesis of propargylamine and its derivatives under solvent-less condition. In order to maximize the product yield, the variables, i.e., reaction time, temperature and catalyst amount, were optimized by using a statistical approach. The synthesized nanocomposite can be easily separated from the reaction medium and reused over and over, without significant changes in its catalytic activity.

Citric acid functionalized silane coupling versus post-grafting strategy for dual pH and saline responsive delivery of cisplatin by Fe3O4/carboxyl functionalized mesoporous SiO2 hybrid nanoparticles: A-synthesis, physicochemical and biological characterization

Synthesis of monodisperse carboxylic acid-functionalized magnetic mesoporous silica nanoparticles is performed by either two-step sol-gel process or post-grafting using citric acid modified isocyanate silane coupling agent (MMSN-NCO-CA) or succinic anhydride modified magnetic mesoporous silica (MMSN-NH-SA). Morphology, structure and magnetic properties of bare and mesoporous silica coated Fe3O4 core were studied using various techniques such as FTIR, VSM, TEM, FESEM, XRD and N2 adsorption-desorption isotherms (BET). Cisplatin (cis-Pt) adsorption isotherms and its release profile in various media were investigated by ICP-OES. MMSN-NCO-CA with mean particle size 107 nm had lower surface area (87.5 m2/g) and larger pore size (6.9 nm) in comparison with MMSN-NH-SA (respective values of 151.2 m2/g and 3.5 nm). cis-Pt loading into particles followed a saturable adsorption with respect to the drug to particle mass ratios. More sustained release of cis-Pt was observed for MMSN-NCO-CA, though both nanoparticles exhibited a pH- and saline concentration-dependent drug release. In addition, general and cis-Pt specific cytotoxicity were examined by MTT assay in MDA-MB-231 breast cancer cell line, and to further detect apoptosis, acridine orange/ethidium bromide dual cell staining was investigated by fluorescence microscopy. In-vitro anti-tumor efficiency of cis-Pt loaded MMSN-NCO-CA and MMSN-NH-SA were similarly enhanced in comparison to free cis-Pt; however, more specific apoptotic death occurred for cis-Pt loaded MMSN-NCO-CA. Therefore, the as-synthesized citric acid functionalized core-shell magnetic mesoporous hybrid nanoparticles could be used as a promising drug carriers for cancer therapy in-vivo.

VHPKQHR peptide modified magnetic mesoporous nanoparticles for MRI detection of atherosclerosis lesions

Mortality attributable to atherosclerosis can be reduced significantly with timely diagnosis and treatment. It is meaningful to find a proper way to diagnose and prevent the progression of atherosclerosis. Vascular cell adhesion molecule-1 (VCAM-1) expressed by endothelial cells is a prominent marker of atherosclerotic plaques. There are a number of researches on VCAM-1 based probes for targeted imaging, but rarely on a system with both targeting and drug delivery. Here, we report a novel magnetic mesoporous silicon nanoparticle that is capable of drug delivery and targeting at atherosclerosis plaque. The nanoparticles were constructed using incorporated FITC (fluorescein isothiocyanate) and VHPKQHR peptide into Fe3O4@SiO2 (FITC-VHP-Fe3O4@SiO2). The FITC-VHP-Fe3O4@SiO2 nanoparticles showed great morphological characteristics, superior targeting ability, low toxicity and good biocompatibility in vitro and in vivo. The in vivo experiments showed that FITC-VHP-Fe3O4@SiO2 is a superior contrast agent of magnetic resonance imaging (MRI) for diagnosis of atherosclerosis plaques.

Magnetic mesoporous nanoparticles modified with poly(ionic liquids) with multi-functional groups for enrichment and determination of pyrethroid residues in apples.

Considering that the determination of pyrethroid residues is of value for the safety of food, a new poly(ionic liquid)-functionalized magnetic mesoporous nanoparticle was designed and used as an adsorbent in magnetic solid-phase extraction for the enrichment of eight pyrethroids. The porous structure and large surface area of the mesoporous silica shell endow the adsorbent with abundant binding sites. In contrast to the reported poly(ionic liquids) with only one kind of functional group in the cationic part, the new poly(ionic liquids) with mixed cyano and phenyl groups in cationic part matched the chemical structure of the analytes to improve extraction efficiency. Under the optimum conditions, an effective method was established for the determination of eight pyrethroids in apples. Adsorption equilibrium can be quickly reached in 1min, greatly decreasing the extraction time. The linearity range was found to be 10-200ng/g, and the detection limits ranged from 0.24 to 1.99ng/g. Recoveries of analytes in apple samples ranged from 87.3 to 119.0%, with relative standard deviations varying in the range of 3-21.2% (intraday) and 0.3-15.2% (interday). The results indicate that the proposed method is a good candidate for pyrethroid residues in apple samples.