Chitosan-coated Fe3O4 Nanoparticles Research Articles

Surface Modification Strategies for Chrysin-Loaded Iron Oxide Nanoparticles to Boost Their Anti-Tumor Efficacy in Human Colon Carcinoma Cells.

Enhancing nanoparticles' anti-cancer capabilities as drug carriers requires the careful adjustment of formulation parameters, including loading efficiency, drug/carrier ratio, and synthesis method. Small adjustments to these parameters can significantly influence the drug-loading efficiency of nanoparticles. Our study explored how chitosan and polyethylene glycol (PEG) coatings affect the structural properties, drug-loading efficiency, and anti-cancer efficacy of Fe3O4 nanoparticles (NPs). The loading efficiency of the NPs was determined using FTIR spectrometry and XRD. The quantity of chrysin incorporated into the coated NPs was examined using UV-Vis spectrometry. The effect of the NPs on cell viability and apoptosis was determined by employing the HCT 116 human colon carcinoma cell line. We showed that a two-fold increase in drug concentration did not impact the loading efficiency of Fe3O4 NPs coated with PEG. However, there was a 33 Å difference in the crystallite sizes obtained from chitosan-coated Fe3O4 NPs and drug concentrations of 1:0.5 and 1:2, resulting in decreased system stability. In conclusion, PEG coating exhibited a higher loading efficiency of Fe3O4 NPs compared to chitosan, resulting in enhanced anti-tumor effects. Furthermore, variations in the loaded amount of chrysin did not impact the crystallinity of PEG-coated NPs, emphasizing the stability and regularity of the system.

A nudge over the relaxation plateau: effect of pH, particle concentration, and medium viscosity on the AC induction heating efficiency of biocompatible chitosan-coated Fe3O4 nanoparticles

The effects of pH, MNP concentration, and medium viscosity on the magnetic fluid hyperthermia (MFH) properties of chitosan-coated superparamagnetic Fe3O4 nanoparticles (MNPs) are probed here. Due to the protonation of the amide groups, the MNPs are colloidally stable at lower pH (∼2), but form aggregates at higher pH (∼8). The increased aggregate size at higher pH causes the Brownian relaxation time (τ B) to increase, leading to a decrease in specific absorption rate (SAR). For colloidal conditions ensuring Brownian-dominated relaxation dynamics, an increase in MNP concentrations or medium viscosity is found to increase the τ B. SAR decreases with increasing MNP concentration, whereas it exhibits a non-monotonic variation with increasing medium viscosity. Dynamic hysteresis loop-based calculations are found to be in agreement with the experimental results. The findings provide a greater understanding of the variation of SAR with the colloidal properties and show the importance of relaxation dynamics on MFH efficiency, where variations in the frequency-relaxation time product across the relaxation plateau cause significant variations in SAR. Further, the in vitro cytotoxicity studies show good bio-compatibility of the chitosan-coated Fe3O4 MNPs. Higher SAR at acidic pH for bio-medically acceptable field parameters makes the bio-compatible chitosan-coated Fe3O4 MNPs suitable for MFH applications.

An Alternating Magnetic Field-Controlled Drug Delivery System Based on 4,4′-Azobis (4-cyanovaleric Acid)-Functioned Fe3O4@Chitosan Nanoparticles

Herein, we designed chitosan-coated Fe3O4 nanocomposites for the control release of drugs by an alternating magnetic field (AMF). The chitosan-coated Fe3O4 nanoparticles (Fe3O4@CS) were prepared by a alkaline co-precipitation method, and then, the model drug toluidine blue (TB) was covalently grafted onto the surface of the nanocomposite by a two-step amide reaction with the thermosensitive molecule 4,4'-azobis (4-cyanovaleric acid) (ACVA) as the linker group. The prepared nanocomposites were superparamagnetic and showed high magnetization saturation (about 54.0 emu g-1). In vitro hydrothermal release studies showed that most parts of the TB would be effectively enclosed within the nanocarriers at lower ambient temperatures (23 or 37 °C) due to the molecular bonding of ACVA. The results of kinetic fitting of hydrothermal release data showed that TB released from nanoparticles followed first-order kinetics (R2 > 0.99) and the Korsemeyer-Peppas model (R2 > 0.99, n < 0.5). Most importantly, a single magnetron release experiment demonstrated an approximately linear relationship between the cumulative release of the drug and the duration of action of AMF (R2 = 0.9712). Moreover, the increase in the cumulative release of the drug can be controlled by controlling the switch of the AMF generation device. Therefore, the ACVA-modified Fe3O4@CS nanocarrier designed in this study is a promising model for drug delivery that enables the control of drug release dose by AMF.

The human immune cell simulated anti-breast cancer nanorobot: the efficient, traceable, and dirigible anticancer bio-bot

BackgroundVarious types of cancer therapy strategies have been investigated and successfully applied so far. There are a few modern strategies for improving drug selectivity and biocompatibility, such as nanoparticle-based drug delivery systems. Herein, we designed the traceable enzyme-conjugated magnetic nanoparticles to target human breast cancer cells by simulating the innate immune cell’s respiratory explosion response.MethodsThe human immune cell simulated anti-breast cancer-nanorobot (hisABC-NB) was produced by conjugating the mouse-derived iNOS and human-originated MPO enzymes on the folate-linked chitosan-coated Fe3O4 nanoparticles. The synthesized nanoparticles were functionalized with folic acid as the breast cancer cell detector. Then, the hisABC-NB’s stability and structural properties were characterized by studying Zeta-potential, XRD, FTIR, VSM, FESEM, and DLS analysis. Next, the selectivity and anti-tumor activity of the hisABC-NB were comparatively analyzed on both normal (MCF-10) and cancerous (MCF-7) human breast cells by analyzing the cells’ survival, apoptotic gene expression profile (P53, BAX, BCL2), and flow cytometry data. Finally, the hisABC-NB’s traceability was detected by T2-weighted MRI imaging on the balb-c breast tumor models.ResultsThe hisABC-NB significantly reduced the MCF-7 human breast cancer cells by inducing apoptosis response and arresting the cell cycle at the G2/M phase compared with the normal cell type (MCF-10). Moreover, the hisABC-NB exhibited a proper MRI contrast at the tumor region of treated mice compared with the non-treated type, which approved their appropriate MRI-mediated traceability.ConclusionThe hisABC-NB’s traceability, dirigibility, and selective cytotoxicity were approved, which are the three main required factors for an efficient anticancer compound. Therefore, it has the potential to be used as an intelligent safe anticancer agent for human breast cancer treatment. However, several in vitro and in vivo studies are required to clarify its selectivity, stability, and safety.

Cytocompatibility of pH-sensitive, chitosan-coated Fe3O4 nanoparticles in gynecological cells.

Nanoparticles that contact human cells without damaging basic human tissues are becoming more widely used in medicine. Efficient delivery to the intracellular target cell or compartment through the cell membrane must be achieved with minimal cytotoxicity to healthy cells. Fe3O4 nanoparticles have been widely used in biomedical research for their magnetic, non-toxic, and biocompatible properties. However, the effects of Fe3O4 nanoparticles coated with chitosan (CS) on gynecological cells are unclear. In this study, the Fe3O4 nanoparticles were coated with CS to enhance their cytocompatibility and dispersion in water. These CS-Fe3O4 nanoparticles were taken up by gynecological cells and did not affect cell viability in vitro. They have greater cytocompatibility in acidic environments than normal Fe3O4 nanoparticles and have the potential for drug delivery into gynecological cells.

Synthesis and Characterization Studies of Mesostructured Chitosan Coated Fe3O4 Nanoparticles with Folic Acid

In this present work, Fe3O4 nanoparticles were obtained by a one-part Co-precipitation method. Secondly, a simple solvothermal method was employed to synthesize Chitosan (CS) coated Fe3O4 nanoparticles. Chitosan was used as a surface modification agent. The surface of Chitosan-coated Fe3O4 nanoparticles was conjugated with Folic Acid (FA). Various properties of the resultant products were performed by characterization studies. The structure and surface morphology of as-prepared nanoparticles were characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The physical parameter such as strain and the crystallite size was evaluated for all the reflection peaks of the samples by using Williamson–Hall (W-H plot) method. Determination of the chemical component was marked by Fourier transform infrared spectroscopy (FTIR) and Energy-dispersive X-ray spectroscopy (EDAX) analyses. UV- Vis experiment was carried out to record optical absorbance and the bandgap energy of the nanoparticles was determined by Tauc’s plot. Thermogravimetric analysis (TGA) was conducted to recognize the thermal stability of the magnetic nanoparticles and endothermic peaks were observed from the first derivative of the TGA curve (DTG curve).

Post-hydrolysis of cellulose oligomers by cellulase immobilized on chitosan-grafted magnetic nanoparticles: A key stage of butanol production from waste textile

The recently developed technologies for immobilization of cellulase may address the challenges in costly hydrolysis of cellulose for cellulosic butanol production. In this study, a “hybrid” hydrolysis was developed based on chemical hydrolysis of cellulose to its oligomers followed by enzymatic post-hydrolysis of the resulting “soluble oligomers” by cellulase immobilized on chitosan-coated Fe3O4 nanoparticles. This hybrid hydrolysis stage was utilized in the process of biobutanol production from a waste textile, jeans waste, leading to selective formation of glucose and high yield of butanol production by Clostridium acetobutylicum. After validating the immobilization process, the optimum immobilization parameters including enzyme concentration and time were achieved on 8 h and 15.0 mg/mL, respectively. The reusability of immobilized enzyme showed that immobilized cellulase could retain 51.5% of its initial activity after three times reuses. Dilute acid hydrolysis of regenerated cellulose at 120–180 °C for 60 min 0.5–1.0% phosphoric acid led to less than 10 g/L glucose production, and enzymatic post-hydrolysis of the oligomers resulted in up to 51.5 g/L glucose. Fermentation of the hydrolysate was accompanied by 5.3 g/L acetone-butanol-ethanol (ABE) production. The simultaneous co-saccharification and fermentation (SCSF) of soluble and insoluble oligomers of cellulose led to 17.4 g/L ABE production.

Comparative Study of Specific Loss Power and Transverse Relaxivity of Spinel Ferrite Nanoensembles Coated With Chitosan and Polyethylene Glycol

We synthesized spinel ferrite nanoensembles (MnFe2O4, CoFe2O4, and Fe3O4) using the chemical co-precipitation method and characterized their physical, chemical, and magnetic properties by X-ray diffraction (XRD), transmission electron microscopy (TEM), physical properties measurement system (PPMS), Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS) and Raman spectroscopy. Their relaxation properties and potential for hyperthermia therapy were determined using nuclear magnetic resonance (NMR) and cell viability assay, respectively. XRD and TEM data confirmed that the particle core sizes were 6–9 nm before coating while their sizes increased to 10–14 nm and 14–20 nm after coating with chitosan and polyethylene glycol (PEG), respectively. Mössbauer spectroscopy showed superparamagnetic behavior for MnFe2O4 nanoparticles and ferrimagnetic behavior for the CoFe2O4 and Fe3O4 nanoparticles. A detailed studies of MH loops of all three ferrites before and after coating showed surface functionalization by a large reduction of coercivity and anisotropy. The successful coating was further confirmed by the peak shifts in the FTIR spectra of the particles whereas Raman spectra of coated ferrites also displayed the characteristic absorption patterns and suppression of the ferrite peaks suggesting successful coating. The induced heating profile of the nanoparticles in stable suspension was tested with a radio frequency magnetic field of 76 mT and a frequency of 400 kHz. High mortality (&amp;gt;98%) of 9 L gliosarcoma cancer cells by hyperthermia suggested that these nanoparticles could be used for cancer therapy. Transverse relaxivities (r2) determined by NMR for chitosan-coated MnFe2O4, CoFe2O4, and Fe3O4 nanoparticles were 297 (±22), 353 (±26), and 345 (±13), mM−1S−1, while for PEG-coated nanoparticles are 165 (±22), 146 (±14), and 159 (±07) mM−1S−1, respectively. Overall these spinel ferrite nanoensembles show great promise for cancer theranostics research applications.

Effect of Aminated Chitosan-Coated Fe3O4 Nanoparticles with Applicational Potential in Nanomedicine on DPPG, DSPC, and POPC Langmuir Monolayers as Cell Membrane Models.

An adsorption process of magnetite nanoparticles functionalized with aminated chitosan (Fe3O4-AChit) showing application potential in nanomedicine into cell membrane models was studied. The cell membrane models were formed using a Langmuir technique from three selected phospholipids with different polar head-groups as well as length and carbon saturation of alkyl chains. The research presented in this work reveals the existence of membrane model composition-dependent regulation of phospholipid-nanoparticle interactions. The influence of the positively charged Fe3O4-AChit nanoparticles on a Langmuir film stability, phase state, and textures is much greater in the case of these formed by negatively charged 1,2-dipalmitoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DPPG) than those created by zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC). The adsorption kinetics recorded during penetration experiments show that this effect is caused by the strongest adsorption of the investigated nanoparticles into the DPPG monolayer driven very likely by the electrostatic attraction. The differences in the adsorption strength of the Fe3O4-AChit nanoparticles into the Langmuir films formed by the phosphatidylcholines were also observed. The nanoparticles adsorbed more easily into more loosely packed POPC monolayer.

Effects of shell-thickness on the powder morphology, magnetic behavior and stability of the chitosan-coated Fe3O4 nanoparticles

Chitosan-coated Fe3O4 nanoparticles were prepared by coprecipitation followed by reaction with chitosan and different volumes of glutaraldehyde. Coating was modified by varying the volume of glutaraldehyde and reaction time. XRD pattern shows maxima compatible Fe3O4 structure. FTIR spectroscopía confirms the presence of chitosan, more evident in samples with higher chitosan content, as denoted by TGA. TEM images of samples with low glutaraldehyde content reveal particles coated with a homogeneous chitosan shell. Meanwhile, those prepared with high glutaraldehyde volume show nanoparticles dispersed in an organic matrix. Samples present almost superparamagnetic behavior with magnetization saturation values that are reduced as the content of organic matter increases. Regarding the stability of these samples in solution, the presence of a homogeneous coating improves the initial suspension, although it does not prevent its subsequent aggregation over time. However, this aggregation process is reduced for sample synthesized with 1mL of glutaraldehyde after 6h of reaction.

Rapid tumor inhibition via magnetic hyperthermia regulated by caspase 3 with time-dependent clearance of iron oxide nanoparticles.

Among conventional cancer therapies, radio-frequency magnetic hyperthermia (MHT) has widely been investigated for use with magnetic nanoparticles (MNPs). However, the majority of in vivo biodistribution studies have tested very low MNP dosages (equivalent to magnetic resonance imaging (MRI) applications) to check for clearance rate; which is far below the clinical dose of MHT. Due to this poor validation in preclinical scenarios, quite a few MNPs already in clinical use were later discontinued, on grounds of unexpected clinical outcomes in terms of inflammation, and prolonged clearance in vivo. By exploiting an economical method of synthesis, we have developed chitosan-coated Fe3O4 nanoparticles with high heating efficiency performance. Their anti-tumor response was evaluated in an ectopic tumor model of C6 glioblastoma by MHT. The intratumoral injection of MNPs on days 1 and 7 resulted in rapid tumor inhibition rate of 69.4% within 8 days, with complete inhibition within 32 days, and no recurrence recorded over a 5-month follow-up. Notably, the MNP-mediated MHT therapy achieved the highest degree of therapeutic efficacy required for complete tumor ablation by combining controlled temperature range (<44 °C), reduced MNP dosage; much lower than in most reported studies, and AMF parameters (time of exposure and frequency) within the clinical safety limit. Periodic body weight measurements confirmed negligible adverse side effects in rats. The anti-tumor activity was validated by severe apoptosis (TUNEL, cleaved Caspase-3), reduced proliferation (Ki 67) and disrupted vasculature (CD 31) in the Fe3O4-MHT-treated group. Real-time gene expression of pro-inflammatory cytokines (IL-6, TNF-α, IL-1α, IL-1β) confirmed the intratumoral activation of IL-6, suggesting the role of immunomodulation in triggering the adaptive immune response for faster tumor regression in the treated group. In addition, the biodistribution and clearance rate of MNPs monitored using ICP-OES confirmed their time-dependent biodegradation via excretion (urine, feces), phagocytosis (liver) and circulatory system (blood), with negligible deposition in other major organs (kidney, heart, lungs). Although we could not show complete clearance of our MNPs within the time frame tested, future studies should focus on combining MHT with immunotherapy, and target tumors at a much-reduced iron dose, consequently improving in vivo clearance rate, and hence overcoming the limitations of MHT in clinical therapy.

Laccase immobilized on chitosan-coated Fe3O4 nanoparticles as reusable biocatalyst for degradation of chlorophenol

The enzyme immobilization technology could enhance the overall stability and recover-ability of enzyme, which will promote the enzyme’s further application in more fields. Compared to most complex and cumbersome process of enzyme immobilization, we present a simple, mild and effective strategy to immobilize laccase on magnetic carrier and further applied in degradation chlorophenol. The Fe3O4@CS (Fe3O4@Chitosan) composite nanoparticles as enzyme carrier were prepared by self-assembly method. Laccase was successfully immobilized on Fe3O4@CS composite nanoparticles through covalent bonding and effectively remove chlorophenol from water. The specific activity of IM-laccase (immobilized laccase) reaches 112.4 U and the activity recovery is 51.8%. The storage stability, operational stability, pH stability and thermostability were all improved compare free laccase. The 2,4-DCP (2,4-Dichloro-Phenol) and 4-CP (Chloro-Phenol) were degraded by IM-laccase to test the degradation efficiency and the results showed that the degradation rate to 2,4-DCP and 4-CP reached 91.4% and 75.5% after 12 h. In test of reusability, IM-laccase showed excellent performance that the degradation rate retained 75.8% and 57.4% after 10 cycles of degradation.

Synthesis, characterization and cytotoxicity of chitosan-coated Fe3O4 nanoparticles functionalized with ascorbic acid for biomedical applications

Iron oxide magnetic nanoparticles (Fe3O4 NPs) are used to drive and to promote sustained release of drugs in target sites. Biocompatibility and superparamagnetic behaviour are important features to the successful biomedical applications of Fe3O4 NPs. In this study, Fe3O4 NPs were synthesized by the co-precipitation method and coated with chitosan (CS) containing ascorbic acid (AA), allowing formation of Fe3O4@CS-AA NPs. The antioxidant AA was used as a drug model. The synthesized NPs were characterized by different techniques. The results showed the formation of spherical nanoparticles with average diameter of 67.22 ± 0.82 nm, at solid state, as analysed by atomic force microscopy (AFM). The NPs were found to have a superparamagnetic behaviour at room temperature, and the presence of CS-AA on the surface of Fe3O4 NPs did not affect the superparamagnetic behaviour of the nanoparticles. The in vitro AA release assay showed a sustained release of the model drug from Fe3O4@CS-AA NPs for at least 48 h. In addition, cytotoxicity assays for Fe3O4 NPs and Fe3O4@CS-AA NPs did not show significant toxicity towards mammary epithelium (MCF-10A) cell line after 24 h of incubation. This present study demonstrated the successful synthesis of superparamagnetic and biocompatible Fe3O4@CS-AA NPs, which are able to release the model drug in a sustained manner. Thus, this nanomaterial might act as a nanocarrier in target drug release.

Graphene/chitosan-functionalized iron oxide nanoparticles for biomedical applications

Abstract

Continuous Flow Removal of Anionic Dyes in Water by Chitosan-Functionalized Iron Oxide Nanoparticles Incorporated in a Dextran Gel Column.

This paper describes a novel chromatographic method for efficient removal of anionic dyes from aqueous solutions. Chitosan-coated Fe3O4 nanoparticles can easily be immobilized on a dextran gel column. Single elution of Evans Blue (EB) solution to the nanoadsorbent-incorporated columns provides high removal efficiency with a maximum adsorption capacity of 243.9 mg/g. We also investigated the influence of initial concentration and solution pH on the removal efficiency of EB. The electrostatic interaction between the adsorbent surface and negatively charged sulfate groups on EB molecules promotes the efficient adsorption of dyes. The equilibrium data matched well with the Langmuir isotherm model, which indicated monolayer dye adsorption onto the adsorbent surface. To extend the application of the current method, we performed further adsorption experiments using other anionic dyes of different colors (Cy5.5, Acid Yellow 25, Acid Green 25, and Acid Red 1). All of these molecules can efficiently be captured under continuous flow conditions, with higher removal efficiency obtained with more negatively charged dyes. These findings clearly demonstrate that the present approach is a useful method for the removal of anionic dye contaminants in aqueous media by adsorption.

Catalytic application of new manganese Schiff-base complex immobilized on chitosan-coated magnetic nanoparticles for one-pot synthesis of 3-iminoaryl-imidazo[1,2-a]pyridines

In this paper, new chitosan (CS) coated magnetic iron oxide nanoparticles (MNPs) supported manganese Schiff-base complex was designed, synthesized and screened as an efficient, reusable nanocatalyst by the three-component reaction of various aldehyde derivatives with trimethylsilyl cyanide and 2-aminopyridine for the synthesis of 3-iminoaryl-imidazo[1,2-a]pyridine (IAIP) derivatives. Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) have been used to characterize the nanocatalyst before reaction. For the first time, earlier than immobilizing of manganese complex, the chitosan-coated Fe3O4 nanoparticles prepared through covalent bond formation between CS and chlorosilane-modified MNPs which were treated with triethylamine. It is a promising nanocatalyst providing high yield, short reaction times, and excellent turnover number. The recycle studies show a significant loss of activity after recycling six times.

Fabrication of Fe3O4 nanoparticles coated by extracted shrimp peels chitosan as sustainable adsorbents for removal of chromium contaminates from wastewater: The design of experiment

Water is the most critical substance on Earth; any contamination of water may cause harmful consequences for the entire living creatures. Today, removal of various pollutants from the water is one of the most critical concerns; in this regard, application of the minimum amount of chemicals or use of the natural structures and bio-synthetic methods for pollutant elimination are of critical importance. In this paper, Fe3O4 nanoparticles were biosynthesized by co-precipitation method at the presence of the shrimp-extracted chitosan and tripolyphosphate. The pure and chitosan-coated nanoparticles were characterized by scanning electron microscope SEM, TEM, EDX, FTIR, XRD, XPS, VSM and TGA methods. The application of the chitosan-coated Fe3O4 nanoparticles was then evaluated in the extraction and green removal of chromium (VI) from water samples. The effective parameters such as pH, contact time, adsorbent dosage, and agitation speed were optimized by design of experiment method and investigated by response surface methodology (RSM). Based on the results, 75–88% of Cr(VI) could be removed from the actual samples indicating the high chromate removal efficiency of the synthetic adsorbents.

In vitro biological evaluations of Fe3O4 compared with core–shell structures of chitosan-coated Fe3O4 and polyacrylic acid-coated Fe3O4 nanoparticles

Today the use of magnetic nanoparticles (MNPs) is widely investigated because of their biocompatibility and nontoxicity. The objective of this study was to synthesis a uniform superparamagnetic Fe3O4, the core–shell structures of chitosan-coated Fe3O4 (cc/Fe3O4) and polyacrylic acid-coated Fe3O4 (pc/Fe3O4) nanoparticles using an in situ co-precipitation process for evaluation of biomedical applications. To structurally characterize the synthesized nanoparticles, morphological and magnetic properties, Fourier transform infrared, X-ray diffraction, transmission electron microscopy, dynamic light scattering and vibrating sample magnetometry studies were employed. Our results showed that Fe3O4, cc/Fe3O4 and pc/Fe3O4 nanoparticles possess an average mean diameter of 10, 15 and 11 nm (dry samples) per Scherrer's equation in a dry state with saturation magnetization (MS) values of 70.64, 38.65 and 23.53 emu/g, respectively. The cytotoxicity of nanoparticles was evaluated by MTT assay using breast cancer (MCF7) and human normal skin (fibroblast) cell lines. Both of the two core–shell structures did not show toxicity on the fibroblast cell line even after 24 and 48 h. The viability rate of the bare Fe3O4 MNPs on the MCF7 cell line was significantly less than two the coated nanoparticles. MTT assays demonstrated that core–shell nanoparticles have less cytotoxicity than bare Fe3O4 MNPs (in 100 μg/ml during 24 h, the viability of bare Fe3O4 MNPs, cc/Fe3O4 and pc/Fe3O4 nanoparticles was 68.01%, 85.91%, and 88.13%, respectively). Moreover, hemolysis assay was performed to measure cytotoxicity of the nanoparticles on red blood cells (RBCs). The cc/Fe3O4 structure at all concentrations had less hemolysis percentage than the pc/Fe3O4 structure. The chitosan-coated Fe3O4 nanoparticle showed the highest biocompatibility.

Sulfonated chitosan encapsulated magnetically Fe3O4 nanoparticles as effective and reusable catalyst for ultrasound-promoted rapid, three-component synthesis of spiro-4H-pyrans

A facile one-pot protocol for synthesis of spiro-4H-pyrans using sulfonated chitosan-coated Fe3O4 nanoparticles (Fe3O4@CS-SO3H NPs) as an efficient catalyst under ultrasonic condition has been developed. First, the Fe3O4@CS NPs were prepared from the reaction of chitosan with Fe3O4 NPs. Then, the treatment of Fe3O4@CS NPs with chlorosulfonic acid leads to the formation of Fe3O4@CS-SO3H NPs which exerts excellent catalytic activity toward one-pot, three-component synthesis of spiro-4H-pyran derivatives. The core–shell structure and the composition of produced magnetic nanocatalyst were characterized by FT-IR, XRD, VSM, SEM and EDX techniques.

Biocompatible nanoclusters of O-carboxymethyl chitosan-coated Fe3O4 nanoparticles: synthesis, characterization and magnetic heating efficiency

In this work, we developed a polymer encapsulation of Fe3O4 nanoparticles as a core–shell nanocluster with different sizes to investigate the cluster structure effect on their magnetic properties and magnetic heating behavior. Well-dispersed nanoclusters of O-carboxymethyl chitosan-coated Fe3O4 nanoparticles were synthesized by microwave-assisted co-precipitation. The cluster sizes were tunable by varying the concentration of polymers used during synthesis. Nanoclusters present superparamagnetic behavior at room temperature with a reduction in saturation magnetization as a consequence of coating layer. The shift of blocking temperature to the higher value with increasing clusters size shows the stronger magnetic interaction in larger magnetic clusters. In a low alternating magnetic field with frequency of 178 Hz and amplitude of 103 Oe, nanoclusters offer a high heating efficiency. A maximum specific absorption rate of 204 W/g is observed in the sample with hydrodynamic size of 53 nm. In vitro cytotoxicity analysis performed on HeLa cells verified that nanoclusters show a good biocompatibility and can be an excellent candidate for applications in hyperthermia cancer treatment.