Synthesis and characterization of a magnetic bacterial cellulose-chitosan nanocomposite and evaluation of its applicability for osteogenesis.

Introduction: Natural biopolymers are used for various purposes in healthcare, such as tissue engineering, drug delivery, and wound healing. Bacterial cellulose and chitosan were preferred in this study due to their non-cytotoxic, biodegradable, biocompatible, and non-inflammatory properties. The study reports the development of a magnetic bacterial cellulose-chitosan (BC-CS-Fe3O4) nanocomposite that can be used as a biocompatible scaffold for tissue engineering. Iron oxide nanoparticles were included in the composite to provide superparamagnetic properties that are useful in a variety of applications, including osteogenic differentiation, magnetic imaging, drug delivery, and thermal induction for cancer treatment. Methods: The magnetic nanocomposite was prepared by immersing Fe3O4 in a mixture of bacterial cellulose-chitosan scaffold and then freeze-drying it. The resulting nanocomposite was characterized using FE-SEM and FTIR techniques. The swelling ratio and mechanical strength of the scaffolds were evaluated experimentally. The biodegradability of the scaffolds was assessed using PBS for 8 weeks at 37°C. The cytotoxicity and osteogenic differentiation of the nanocomposite were studied using human adipose-derived mesenchymal stem cells (ADSCs) and alizarin red staining. One-way ANOVA with Tukey's multiple comparisons test was used for statistical analysis. Results: The FTIR spectra demonstrated the formation of bonds between functional groups of nanoparticles. FE-SEM images showed the integrity of the fibrillar network. The magnetic nanocomposite has the highest swelling ratio (2445% ± 23.34) and tensile strength (5.08 MPa). After 8 weeks, the biodegradation ratios of BC, BC-CS, and BC-CS-Fe3O4 scaffolds were 0.75% ± 0.35, 2.5% ± 0.1, and 9.5% ± 0.7, respectively. Magnetic nanocomposites have low toxicity (P < 0.0001) and higher osteogenic potential compared to other scaffolds. Conclusion: Based on its high tensile strength, low water absorption, suitable degradability, low cytotoxicity, and high ability to induce an increase in calcium deposits by stem cells, the magnetic BC-CS-Fe3O4 nanocomposite scaffold can be a suitable candidate as a biomaterial for osteogenic differentiation.

Electrospinning Aligned SF/Magnetic Nanoparticles-Blend Nanofiber Scaffolds for Inducing Skeletal Myoblast Alignment and Differentiation.

In the realm of skeletal muscle tissue engineering, anisotropic materials that emulate natural tissues show substantial promise. Electrospun scaffolds, mimicking the fibrillar structure of the extracellular matrix, are commonly employed but often fall short in achieving optimal alignment and mechanical strength. Silk fibroin has emerged as a versatile material in tissue engineering, valued for its biocompatibility, mechanical robustness, and biodegradability. However, conventional electrospinning methods of SF result in randomly oriented fibers, limiting their efficacy. In this work, we developed a straightforward method to fabricate directional tissue scaffolds using silk fibroin. By integrating a magnetic field collecting device and incorporating Fe3O4 nanoparticles into the spinning solution, we successfully produced well-aligned silk nanofiber scaffolds. These aligned fibers not only improved scaffold orientation and mechanical properties but also exhibited magnetic responsiveness. The aligned SF scaffolds effectively guided the adhesion, proliferation, and differentiation of mesenchymal stem cells along the fiber direction. Cultured on these scaffolds, myoblast C2C12 cells demonstrated oriented growth, highlighting the potential of aligned SF fibers in advancing skeletal muscle engineering for biomedical applications.

4D Printing of Multifunctional and Biodegradable PLA-PBAT-Fe3O4 Nanocomposites with Supreme Mechanical and Shape Memory Properties.

4D printing magneto-responsive shape memory polymers (SMPs) using biodegradable nanocomposites can overcome their low toughness and thermal resistance, and produce smart materials that can be controlled remotely without contact. This study presented the development of 3D/4D printable nanocomposites based on poly (lactic acid) (PLA)-poly (butylene adipate-co-terephthalate) (PBAT) blends and magnetite (Fe3O4) nanoparticles. The nanocomposites are prepared by melt mixing PLA-PBAT blends with different Fe3O4 contents (10, 15, and 20 wt%) and extruded into granules for material extrusion 3D printing. The morphology, dynamic mechanical thermal analysis (DMTA), mechanical properties, and shape memory behavior of the nanocomposites are investigated. The results indicated that the Fe3O4 nanoparticles are preferentially distributed in the PBAT phases, enhancing the storage modulus, thermal stability, strength, elongation, toughness, shape fixity, and recovery of the nanocomposites. The optimal Fe3O4 loading is found to be 10 wt%, as higher loadings led to nanoparticle agglomeration and reduced performance. The nanocomposites also exhibited fast shape memory response under thermal and magnetic activation due to the presence of Fe3O4 nanoparticles. The 3D/4D printable nanocomposites demonstrated multifunctional multi-trigger shape-memory capabilities and potential applications in contactless and safe actuation.

An overlooked nanofluids effect from Fe3O4 nanoparticles enhances mass transfer in anammox granular sludge.

Magnetite (Fe3O4) particles have been widely reported to enhance the anammox's activity in anammox granular sludge (AnGS), yet the underlying mechanisms remain unclear. This study demonstrates that both Fe3O4 microparticles (MPs) and nanoparticles (NPs) at a dosage of 200 mg Fe3O4/L significantly increased the specific anammox activity (SAA) of AnGS. Additionally, the transcriptional activities of the hzs and hdh genes involved in the anammox process, as well as the heme c content in AnGS, were also notably enhanced. Notably, Fe3O4 NPs were more effective than MPs in boosting anammox activity within AnGS. Mechanistically, Fe3O4 MPs released free iron, which anammox bacteria utilized to promote the synthesis of key enzymes, thereby enhancing their activity. Compared to MPs, Fe3O4 NPs not only elevated the synthesis of these key enzymes to a higher level but also induced a nanofluids effect on the surface of AnGS, improving substrate permeability and accessibility to intragranular anammox bacteria. Moreover, the nanofluids effect was identified as the primary mechanism through which Fe3O4 NPs enhanced anammox activity within AnGS. These findings provide new insights into the effects of nanoparticles on granular sludge systems, extending beyond AnGS.

Ultrasound-responsive nanocarriers with siRNA and Fe3O4 regulate macrophage polarization and phagocytosis for augmented non-small cell lung cancer immunotherapy.

The immunosuppressive tumor microenvironment (TME) significantly inhibits the effective anti-tumor immune response, greatly affecting the efficacy of immunotherapy. Most tumor-associated macrophages (TAMs) belong to the M2 phenotype, which contributes significantly to the immunosuppressive effects in non-small cell lung cancer (NSCLC) TME. The interaction between signal regulatory protein α (SIRPα) expressed on macrophages and CD47, a transmembrane protein overexpressed on cancer cells, activates the "eat-me-not" signaling pathway, inhibiting phagocytosis. In this study, a folic acid (FA)-modified ultrasound responsive gene/drugs delivery system, named FA@ PFP @ Fe3O4 @LNB-SIRPα siRNA (FA-PFNB-SIRPα siRNA), was developed using 1,2-dioleoacyl-3-trimethylammonium-propane (DOTAP), FA-1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N- [amino (polyethylene glycol)2000] (DSPE-PEG2000-FA), cholesterol, and perfluoropentane (PFP), for the delivery of siRNA encoding SIRPα mRNA and immune adjuvant Fe3O4 nanoparticles. Under ultrasound conditions, the nanobubbles effectively transfected macrophages, inhibiting SIRPα mRNA and protein expression, promoting the phagocytosis of TAMs, and synergistically reversing M2 polarization. This system promotes the infiltration of T cells, enhances the proliferation and activation of cytotoxic T cells, and inhibits the infiltration of immunosuppressive cells in tumor tissues. Administration of FA-PFNB-SIRPα siRNA combined with ultrasound significantly inhibits NSCLC progression. The study highlights the potential of ultrasound nanotechnology-enabled delivery of SIRPα siRNA and Fe3O4 as an effective strategy for macrophage-based immunotherapy to reshape the immunosuppressive TME for cancer therapy.

Enhanced anaerobic co-digestion of food waste and sewage sludge by co-application of biochar and nano-Fe3O4.

Conductive materials have been utilized to facilitate direct interspecies electron transfer (DIET) in anaerobic digestion (AD) to enhance methane production. However, the impact and efficacy of the co-application of biochar and nano-Fe3O4 have not been adequately elucidated, particularly their interaction on electron transfer efficiency. In this investigation, we examined the influence of simultaneously or independently adding biochar and nano-Fe3O4 to food waste (FW) and sewage sludge (SS) anaerobic co-digestion. A synergistic effect was observed under the co-application condition. Methane production reached 300.3 ± 19.8 mL/gCOD with the co-application of biochar and nano-Fe3O4, representing a 43.3%, 35.4%, and 5.4% increase compared to the sole Fe3O4, biochar, and nano-Fe3O4, respectively. Mechanistic analysis revealed that, in comparison to sole biochar and nano-Fe3O4, their co-occurrence significantly accelerated hydrolysis and acidogenesis, thereby enhancing the release of soluble organic components. Furthermore, the application of nano-Fe3O4 improved system stability and significantly promoted propionate degradation, maintaining a favorable condition for methane production. Additionally, the noteworthy increase in INT-ETS activity and cytochrome c concentration indicated that the co-application of biochar and nano-Fe3O4 stimulated electron transfer. Correspondingly, the activity of coenzyme F420, which indicates the performance of methanogenesis, exhibited a 2.44-fold increase compared to the control. This indicated that nano-Fe3O4 and biochar co-amendment can serve as a robust platform to strengthen DIET. This study provided a new insight regarding the application of biochar and nano-Fe3O4 in the AD system for strengthening electron transfer to promote methane production.

Targeted delivery of quercetin using gelatin/starch/Fe3O4 nanocarrier to suppress the growth of liver cancer HepG2 cells.

To suppress HepG2 liver cancer cells, a nanocarrier (NC) consisting of Fe3O4, Gelatin (G), and Starch (S) was synthesized and characterized for targeted delivery of Quercetin (QC) drug. The spectra obtained from X-ray diffraction (XRD) and Fourier transform infrared (FTIR) demonstrated that the nanoparticles (NP) in the NC are well-interconnected to each other and have formed a regular structure. Also, field emission scanning electron microscopy (FE-SEM) indicates a smooth and homogeneous surface of the synthesized NC. The results of the vibrating sample magnetometer (VSM) also corroborated the correctness of the synthesis of Fe3O4 NPs and Gelatin/Starch/Fe3O4@Quercetin NC (G/S/Fe3O4@QC) because the magnetic properties of Fe3O4 decreased with the addition of G/S@QC. Stability and particle size were determined by zeta potential and Dynamic light scattering (DLS). The percentage of drug loading and encapsulation efficiency of QC in the NC was 46.25 % and 87 %, respectively. QC profile release in acidic and natural environments showed controlled release and pH sensitivity of the NC. Cytotoxicity of L929 and HepG2 treated cells with the G/S/Fe3O4@QC was investigated by MTT staining, which agreed with the flow cytometry result. The results of Flowcytometry and MTT showed 43.5 % apoptosis and 42 % cytotoxicity in treated HepG2 cells by G/S/Fe3O4@QC, while it was not toxic to L929 normal cells. According to the results, G/S/Fe3O4@QC is a suitable NC for the targeted delivery of QC as a drug against HepG2 cancer cells.

Ultrasound-Responsive Nanocarriers Delivering siRNA and Fe3O4 Nanoparticles Reprogram Macrophages and Inhibit M2 Polarization for Enhanced NSCLC Immunotherapy.

Lung cancer has emerged as the second most common type of malignant tumor worldwide, and it has the highest mortality rate. The overall 5-year survival rate stands at less than 20%, which is primarily related to the limited therapeutic options and the complexity of the tumor immune microenvironment. In the tumor microenvironment, M1 macrophages are known for their tumor-killing capabilities. Although they are less numerous, they play an important role in tumor immunity. Therefore, increasing M1 macrophages' presence is considered a strategy to enhance targeted phagocytosis and antitumor efficacy in nonsmall cell lung cancer (NSCLC). This study introduces the development of folic acid (FA)-conjugated liposomal nanobubbles for precise delivery of PFH, STAT3 siRNA, and Fe3O4 to the tumor microenvironment. These encapsulated PFH liposomal nanobubbles exhibit significant visualization potential and underwent phase transition when exposed to low-intensity focused ultrasound (LIFU). The release of Fe3O4 activates the IRF5 signaling pathway, converting M2-like macrophages to M1. In addition, STAT3 siRNA effectively interrupts the JAK-STAT3 pathway, inhibiting the polarization of M2-like macrophages in tumor-associated macrophages (TAMs). This dual-action therapy facilitates T-cell activation and proliferation, thereby enhancing the immune response against NSCLC.

Key Magnetized Exosomes for Effective Targeted Delivery of Doxorubicin Against Breast Cancer Cell Types in Mice Model.

Introduction: Exosomes (Exos) are promising drug delivery systems due to their low immunogenicity, minimal toxicity, high biocompatibility, and effective delivery capabilities. However, addressing the cardiotoxicity and other toxic side effects associated with anthracyclines has proven challenging. Methods: In this study, we loaded doxorubicin (Dox) into Exos derived from human placental mesenchymal stem cells (MSCs) and modified them with carboxylated Fe3O4 nanoparticles (NPs) to create an Exo-Dox-NP delivery system. Using an external magnetic force (MF), we regulated the distribution of Exos for targeted Dox delivery in breast cancer treatment. We characterized and determined the drug-loading efficiency of Exo-Dox-NPs, their uptake by tumor cells, and the modulation of drug release. The therapeutic efficacy of Exo-Dox-NPs was evaluated through both in vitro and in vivo anti-tumor experiments. Results: Our results indicated that Exo-Dox-NPs remain stable in the bloodstream while releasing the drug in the acidic environment of tumor cells and their lysosomes. As a drug delivery system, Exo-Dox-NPs enhanced Dox absorption by tumor cells, demonstrating high targeting specificity. Moreover, Exo-Dox-NPs inhibited the migration of breast cancer cells, as confirmed by scratch migration and Transwell Matrigel invasion assays. In vivo experiments confirmed the effective targeting and delivery of Dox to malignant tumors using Exo-Dox-NPs/MFs, with the Exo-Dox-NP/MF formulation exhibiting the most potent anti-tumor activity. Conclusion: The utilization of Exos as carriers for Dox showed promising efficacy in breast cancer management. Carboxylated Fe3O4 NPs demonstrated to be suitable targeting agents, potentially advancing the development of natural nanocarriers for combination cancer therapy.

Optimizing green waste composting with iron-based Fenton-like process.

The presence of refractory lignocellulose presents a significant challenge in green waste (GW) composting. This research applied both a conventional iron-based Fenton-like process (with a Fenton-like reagent composed of 1.0 % Fe3O4 nanoparticles and 1.0 % H2O2) and three modified iron-based Fenton-like processes (with a Fenton-like reagent composed of 1.0 % Fe3O4 nanoparticles and 1.0 % oxalic acid/1.0 % sodium percarbonate/0.5 % Phanerochaete chrysosporium) in GW composting to systematically assess their impacts on lignocellulose degradation during GW composting. The results revealed that iron-based Fenton-like process modified sodium percarbonate exhibited the most significant effects on lignocellulose degradation. Compared with control, degradation rates for lignin, cellulose, and hemicellulose increased by 49.8 %, 39.3 %, and 26.2 % (p < 0.05), respectively. Furthermore, this process enhanced the relative abundance of bacterial communities linked to lignocellulose degradation, particularly Firmicutes and Bacteroidota. These findings offer valuable insights into optimizing GW composting, understanding reactive oxygen species dynamics, and the application of iron-based Fenton-like process.

A novel LL-37@NH2@Fe3O4 inhibits the proliferation of the leukemia K562 cells: in-vitro study.

LL-37 can inhibit the growth of K562 cancer cells when it is conjugated with iron oxide nanoparticles. In this study, Fe3O4 nanoparticles were synthesized using the co-precipitation method and then modified with the LL-37 peptide through an NH2 bridge. The accuracy of the synthesis process was confirmed through various analytical tests, including FTIR, XRD, FESEM, and EDX. To assess the treatment's effectiveness, a viability test was carried out on K562 leukemia cells and normal peripheral blood mononuclear cells. In addition, flow cytometry and Hoechst staining were used to investigate the mechanism of action of the drug. The expression levels of the Bcl-2, Bax, and TP53 genes in the treated cells and the control group were measured using qRT-PCR. The results indicated that the size of the nanoparticles ranged between 34 and 40 nm. The NH2@LL-37@Fe3O4 nanoparticles more effectively inhibited the growth of cancer cells in a concentration-dependent manner, as compared to Fe3O4 alone. Further analysis revealed that apoptosis occurred through increased expression of TP53 and Bax genes compared to the Bcl-2 gene. Therefore, induction of apoptosis and inhibition of growth in K562 cells was attributed to the impact of iron oxide magnetic nanoparticles conjugated with the LL-37 peptide through the TP53/Bax/Bcl-2 pathway.

Development of Fe3O4/DEX/PDA@Au(Raman reporters)@Au-MPBA nanocomposites based multi-hotspot SERS probe for ultrasensitive, reliable, and quantitative detection of glucose in sweat.

Glucose is a key biomarker of diabetes, and effective glucose monitoring methods are crucial to the prevention and management of diabetes. Therefore, in this paper, Fe3O4/DEX/PDA@Au (Raman reporters) @Au nanocomposites were synthetized that with DTNB (5,5'-dithiobis(2-nitrobenzoic)), MMTA (2-mercapto-4-methyl-5-thiazole acetic acid), MBA (4-mercaptobenzoic acid) and 4-Mpy(4-Mercaptopyridine) were used separately as Raman reporters. Fe3O4 and PDA (Polymerized dopamine) could supply more high surface area of active sites and high SERS (Surface-Enhanced Raman Scattering) substrate, which has high stability and reproducibility. Dextran coating is an effective way to prepare biocompatible materials TEM, XRD, TG and VSM were used to analyze the size, morphology and magnetic properties of the nanocomposites. Fe3O4/DEX/PDA@Au(Raman reporters)@Au that integrates a multi-hotspot structure and magnetic separation techniques were studied the enhancement effect of Raman spectra, and glucose solutions with different concentrations were tested. Furthermore, the optimal Fe3O4/DEX/PDA@Au(Raman reporters)@Au nanocomposites were supplied as SERS substrates for detection of glucose accurately and quickly in sweat. SERS signal intensity is linearly correlated with glucose concentration within the measurement range of 5 × 10-3 to 10 mM, and the minimum detectable concentration is 5 µM. The Fe3O4/DEX/PDA@Au(Raman reporters)@Au nanocomposites exhibit high reliability, specificity and repeatability of the strategy were then verified by practical detection of sweat.

Optimizing Mechanical and Electrical Performance of SWCNTs/Fe3O4 Epoxy Nanocomposites: The Role of Filler Concentration and Alignment.

The demand for polymer composites with improved mechanical and electrical properties is crucial for advanced aerospace, electronics, and energy storage applications. Single-walled carbon nanotubes (SWCNTs) and iron oxide (Fe3O4) nanoparticles are key fillers that enhance these properties, yet challenges like orientation, uniform dispersion, and agglomeration must be addressed to realize their full potential. This study focuses on developing SWCNTs/Fe3O4 epoxy composites by keeping the SWCNT concentration constant at 0.03 Vol.% and varying with Fe3O4 concentrations at 0.1, 0.5, and 1 Vol.% for two different configurations: randomly orientated (R-) and magnetic field-assisted horizontally aligned (A-) SWCNTs/Fe3O4 epoxy composites, and investigates the effects of filler concentration, dispersion, and magnetic alignment on the mechanical and electrical properties. The research reveals that both composite configurations achieve an optimal mechanical performance at 0.5 Vol.% Fe3O4, while A- SWCNTs/Fe3O4 epoxy composites outperformed at all concentrations. However, at 1 Vol.% Fe3O4, mechanical properties decline due to nanoparticle agglomeration, which disrupts stress distribution. In contrast, electrical conductivity peaks at 1 Vol.% Fe3O4, indicating that the higher density of Fe3O4 nanoparticles enhances the conductive network despite the mechanical losses. This study highlights the need for precise control over filler content and alignment to optimize mechanical strength and electrical conductivity in SWCNTs/Fe3O4 epoxy nanocomposites.

Magnetic Tunability via Control of Crystallinity and Size in Polycrystalline Iron Oxide Nanoparticles.

Iron oxide nanoparticles (IONPs) are widely used for biomedical applications due to their unique magnetic properties and biocompatibility. However, the controlled synthesis of IONPs with tunable particle sizes and crystallite/grain sizes to achieve desired magnetic functionalities across single-domain and multi-domain size ranges remains an important challenge. Here, a facile synthetic method is used to produce iron oxide nanospheres (IONSs) with controllable size and crystallinity for magnetic tunability. First, highly crystalline Fe3O4 IONSs (crystallite sizes above 24 nm) having an average diameter of 50 to 400 nm are synthesized with enhanced ferrimagnetic properties. The magnetic properties of these highly crystalline IONSs are comparable to those of their nanocube counterparts, which typically possess superior magnetic properties. Second, the crystallite size can be widely tuned from 37 to 10 nm while maintaining the overall particle diameter, thereby allowing precise manipulation from the ferrimagnetic to the superparamagnetic state. In addition, demonstrations of reaction scale-up and the proposed growth mechanism of the IONSs are presented. This study highlights the pivotal role of crystal size in controlling the magnetic properties of IONSs and offers a viable means to produce IONSs with magnetic properties desirable for wider applications in sensors, electronics, energy, environmental remediation, and biomedicine.

Alignment of lyotropic liquid crystals using magnetic nanoparticles improves ionic transport through built-in peptide ion channels.

HYPOTHESIS: We hypothesize that simultaneous incorporation of ion channel peptides (in this case, potassium channel as a model) and hydrophobic magnetite Fe3O4 nanoparticles (hFe3O4NPs) within lipidic hexagonal mesophases, and aligning them using an external magnetic field can significantly enhance ion transport through lipid membranes. EXPERIMENTS: In this study, we successfully characterized the incorporation of gramicidin membrane ion channels and hFe3O4NPs in the lipidic hexagonal structure using SAXS and cryo-TEM methods. Additionally, we thoroughly investigated the conductive characteristics of freestanding films of lipidic hexagonal mesophases, both with and without gramicidin potassium channels, utilizing a range of electrochemical techniques, including impedance spectroscopy, normal pulse voltammetry, and chronoamperometry. FINDINGS: Our research reveals a state-of-the-art breakthrough in enhancing ion transport in lyotropic liquid crystals as matrices for integral proteins and peptides. We demonstrate the remarkable efficacy of membranes composed of hexagonal lipid mesophases embedded with K+ transporting peptides. This enhancement is achieved through doping with hFe3O4NPs and exposure to a magnetic field. We investigate the intricate interplay between the conductive properties of the lipidic hexagonal structure, hFe3O4NPs, gramicidin incorporation, and the influence of Ca2+ on K+ channels. Furthermore, our study unveils a new direction in ion channel studies and biomimetic membrane investigations, presenting a versatile model for biomimetic membranes with unprecedented ion transport capabilities under an appropriately oriented magnetic field. These findings hold promise for advancing membrane technology and various biotechnological and biomedical applications of membrane proteins.

Nano-immuno-conjugates inspired by hydrophilic perovskite fluorescent spheres and magnetic assisted for detection of hepatitis B surface antigen.

The rampant hepatitis B virus (HBV) seriously endangers human health, and hepatitis B surface antigen (HBsAg) is its early diagnostic marker. Therefore, it is crucial to construct a fast and highly sensitive HBsAg detection method. Based on high-efficiency magnetic separation technology and fluorescent composite material labelling technology, an accurate, fast and sensitive fluorescent immunosensing system for HBsAg detection was developed. Immunomagnetic beads constructed from carboxyl-functionalized Fe3O4 nanoparticles (Fe3O4-COOH) with excellent magnetic response performance were used as efficient capture carriers for HBsAg. Immunofluorescence composite microspheres constructed based on ultra-stable polystyrene-coated CsPbBr3 perovskite nanocrystals (CPB@PSAA) with high hydrophilic properties, were excellent fluorescent markers for HBsAg. Using this sensitive sandwich fluorescence sensing system a good linear relationship within the range of 0.2-15 ng/mL was established between HBsAg concentration and fluorescence intensity with a limit of detection (LOD) of  0.05 ng/mL. The system obtained satisfactory results when tested on real human serum samples. The magnetic-assisted fluorescence immune-sandwich sensor system has broad application prospects in biomedicine such as rapid and early diagnosis and effective prevention of infectious diseases.

Using Hybrid PDI-Fe3O4 Nanoparticles for Capturing Aliphatic Alcohols: Halogen Bonding vs. Lone Pair-π Interactions.

In this study, Fe3O4 nanoparticles (FeNPs) decorated with halogenated perylene diimides (PDIs) have been used for capturing VOCs (volatile organic compounds) through noncovalent binding. Concretely, we have used tetrachlorinated/brominated PDIs as well as a nonhalogenated PDI as a reference system. On the other hand, methanol, ethanol, propanol, and butanol were used as VOCs. Experimental studies along with theoretical calculations (the BP86-D3/def2-TZVPP level of theory) pointed to two possible and likely competitive binding modes (lone pair-π through the π-acidic surface of the PDI and a halogen bond via the σ-holes at the Cl/Br atoms). More in detail, thermal desorption (TD) experiments showed an increase in the VOC retention capacity upon increasing the length of the alkyl chain, suggesting a preference for the interaction with the PDI aromatic surface. In addition, the tetrachlorinated derivative showed larger VOC retention times compared to the tetrabrominated analog. These results were complemented by several state-of-the-art computational tools, such as the electrostatic surface potential analysis, the Quantum Theory of Atoms in Molecules (QTAIM), as well as the noncovalent interaction plot (NCIplot) visual index, which were helpful to rationalize the role of each interaction in the VOC···PDI recognition phenomena.

Radiation-Induced Synthesis and Superparamagnetic Properties of Ferrite Fe3O4 Nanoparticles.

Ultra-small magnetic Fe3O4 nanoparticles are successfully synthesized in basic solutions by using the radiolytic method of the partial reduction in FeIII in the presence of poly-acrylate (PA), or by using the coprecipitation method of FeIII and FeII salts in the presence of PA. The optical, structural, and magnetic properties of the nanoparticles were examined using UV-Vis absorption spectroscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and SQUID magnetization measurements. The HRTEM and XRD analysis confirmed the formation of ultra-small magnetite nanoparticles in a spinel structure, with a smaller size for radiation-induced particles coated by PA (5.2 nm) than for coprecipitated PA-coated nanoparticles (11 nm). From magnetization measurements, it is shown that the nanoparticles are superparamagnetic at room temperature. The magnetization saturation value Ms = 50.1 A m2 kg-1 of radiation-induced nanoparticles at 60 kGy is higher than Ms = 18.2 A m2 kg-1 for coprecipitated nanoparticles. Both values are compared with nanoparticles coated with other stabilizers in the literature.

Antibiotic-Fe3O4 nanoparticles with highly efficient catalytic activity for enhanced chemiluminescence detection of tetracyclines residues in foods.

Tetracyclines (TCs) are the most commonly antimicrobial agents that used in livestock production worldwide. It is important to supervise tetracyclines residues in food for environmental monitoring and food safety. In this study, a novel, label-free chemiluminescence (CL) assay without antibody was established. Fe3O4 NPs could facilitate the CL interaction between luminol and H2O2. Interestingly, TCs could enhance the catalytic ability of Fe3O4 NPs and result in a further amplification of the CL intensity. The CL intensity varied linearly with the concentration of tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC), and ranging from 10-2400, 10-2800, and 5-2100 nmol/L, respectively; The limits of detection were 4 nmol/L for TC, 6 nmol/L for OTC, and 2 nmol/L for CTC. This CL strategy was applied successfully in testing three TCs residues in milk, eggs and honey samples with more sensitive results, which provided an alternative strategy for monitoring the correct use of TCs.

Efficient delivery of anticancer drugs using functionalized-Ag-decorated Fe3O4@SiO2 nanocarrier with folic acid and ß-cyclodextrin.

Nanocarrier surface functionalization has been widely regarded as a promising approach for achieving precise and targeted drug delivery systems. In this work, the fabrication of functionalized-Ag-decorated Fe3O4@SiO2 (Fe3O4@SiO2-Ag) nanocarriers with folic acid (FA) and ß-cyclodextrin (BCD) exhibit a remarkable capacity for delivering two types of anticancer drugs, i.e., doxorubicin (DOX) and epirubicin (EPI), into cancer cells. The effective functionalization of Fe3O4@SiO2-Ag nanoparticles has been achieved through the use of cysteine (Cys) as an anchor for attaching FA and BCD via EDC-NHS coupling and Steglich esterification methods, respectively. The findings indicate that surface functionalization had no significant impact on the physicochemical characteristics of the nanoparticles. However, it notably affected DOX and EPI loading and release efficiency. The electrostatic conjugation of DOX/EPI onto the surface of Fe3O4@SiO2-Ag/Cys/FA and Fe3O4@SiO2-Ag/Cys/BCD exhibited maximum loading efficiency of 50-60% at concentration ratio of DOX/EPI to nanoparticles of 1:14. These nanocarriers also achieved an 40-47% DOX/EPI release over 36 days. Furthermore, the drug-loaded functionalized-nanocarrier showed cytotoxic effects on SK-MEL-2 cells, as demonstrated by an in vitro MTT assay. This suggests that the as-prepared functionalized-nanoparticles have promise as a carrier for the efficient anticancer drugs.