Diverse applications of nanoparticles (NPs) have revolutionized various sectors in society. In the recent decade, particularly magnetic nanoparticles (MNPs) have gained enormous interest owing to ...their applications in specialized areas such as medicine, cancer theranostics, biosensing, catalysis, agriculture, and the environment. Controlled surface engineering for the design of multi-functional MNPs is vital for achieving desired application. The MNPs have demonstrated great efficacy as thermoelectric materials, imaging agents, drug delivery vehicles, and biosensors. In the present review, first we have briefly discussed main synthetic methods of MNPs, followed by their characterizations and composition. Then we have discussed the potential applications of MNPs in different with representative examples. At the end, we gave an overview on the current challenges and future prospects of MNPs. This comprehensive review not only provides the mechanistic insight into the synthesis, functionalization, and application of MNPs but also outlines the limits and potential prospects.
•Key features of magnetic spinel ferrites (SFs) and their derivative composites were reviewed.•Application of SFs as adsorbents for water treatment was assessed.•Factors affecting the adsorption ...performance of SFs were discussed.•Fabrication, regeneration, stability, and safety of SFs were summarized.
Spinel ferrite (SF) magnetic materials are an important class of composite metal oxides containing ferric ions and having the general structural formula M2+Fe23+O4 (where M=Mg2+, Co2+, Ni2+, Zn2+, Fe2+, Mn2+, etc.). SFs possess unique physicochemical properties including excellent magnetic characteristics, high specific surface area, surface active sites, high chemical stability, tunable shape and size, and the ease with which they can be modified or functionalized. As a result of their multifunctional properties, affordability, and magnetic separation capability, SF adsorbents are a top choice for water purification applications that require high adsorption efficiencies and rapid kinetics. In this review, we discuss adsorption performance and possible applications of SFs and their derivatives for treating a wide range of aqueous pollutants such as metal ions, dyes, and pharmaceuticals. Key parameters influencing the sorption performance such as particle size, shape, annealing temperature, functionalization, and metal ion doping have been comprehensively discussed. In addition, adsorbate–adsorbent interactions, desorption, regeneration, and utilization of spent adsorbent have also been summarized. The review also covered, how SFs are prepared from industrial waste using green synthetic routes and general remarks about toxicological effects.
The use of lanthanum (La)-based materials for phosphate removal from water and wastewater has received increasing attention. However, challenges remain to enhance phosphate sorption capacities and ...recover La-based sorbents. In this study, magnetic La(OH)3/Fe3O4 nanocomposites with varied La-to-Fe mass ratios were synthesized through a precipitation and hydrothermal method. Based upon preliminary screening of synthesized La(OH)3/Fe3O4 nanocomposites in terms of phosphate sorption capacity and La content, La(OH)3/Fe3O4 nanocomposite with a La-to-Fe mass ratio of 4:1 was chosen for further characterization and evaluation. Specifically, for these materials, magnetic separation efficiency, phosphate sorption kinetics and isotherm behavior, and solution matrix effects (e.g., coexisting ions, solution pH, and ionic strength) are reported. The developed La(OH)3/Fe3O4 (4:1) nanocomposite has an excellent magnetic separation efficiency of >98%, fast sorption kinetics of 30 min, high sorption capacity of 83.5 mg P/g, and strong selectivity for phosphate in presence of competing ions. Phosphate uptake by La(OH)3/Fe3O4 (4:1) was pH-dependent with the highest sorption capacities observed over a pH range of 4–6. The ionic strength of the solution had little interference with phosphate sorption. Sorption-desorption cyclic experiments demonstrated the good reusability of the La(OH)3/Fe3O4 (4:1) nanocomposite. In a real treated wastewater effluent with phosphate concentration of 1.1 mg P/L, 0.1 g/L of La(OH)3/Fe3O4 (4:1) efficiently reduced the phosphate concentration to below 0.05 mg P/L. Electrostatic attraction and inner-sphere complexation between La(OH)3 and P via ligand exchange were identified as the sorption mechanisms of phosphate by La(OH)3/Fe3O4 (4:1).
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•La(OH)3/Fe3O4 nanocomposites with high sorption capacity of 83.5 mg P/g are obtained.•La(OH)3/Fe3O4 exhibits 98% separation efficiency and fast sorption kinetics (30 min).•Highly efficient removal of phosphate from real wastewater effluent is achieved.•Electrostatic attraction and ligand exchange contribute to high phosphate sorption.
The poor delivery efficiency remains a major challenge in nanomaterial based tumor targeted imaging and drug delivery. This work demonstrated a strategy to improve nanoparticle delivery and ...intratumoral distribution using a sub-5 nm (3.5 nm core size) ultrafine iron oxide nanoparticles (uIONPs) that can easily extravasate from the tumor vasculature and readily diffuse into the tumor tissue compared to iron oxide nanoparticles (IONP) with larger sizes, followed by self-assembling in the acidic tumor interstitial space to limit their re-entering the circulation. By combining enhanced extravasation and reduced intravasation, improved delivery and tumor retention of nanoparticles are achieved. Multi-photon imaging of mice bearing orthotopic tumors co-injected with fluorescent dye labeled nanoparticles with different sizes showed that uIONPs exhibited more efficient extravasation out of tumor vessels and penetrated deeper into the tumor than larger sized IONP counterparts. Moreover,
in vivo
magnetic resonance imaging (MRI) revealed that uIONPs exhibited “bright” T
1
contrast when dispersed in the tumor vasculature and peripheral area at 1 hour after intravenous administration, followed by emerging “dark” T
2
contrast in the tumor after 24 hours. Observed T
1
–T
2
contrast switch indicated that uIONPs single-dispersed in blood with T
1
contrast may self-assemble into larger clusters with T
2
contrast after entering the tumor interstitial space. Improved passive targeting and intratumoral delivery along with increased tumor retention of uIONP are due to both easy extravasation into the tumor when single-dispersed and restricting intravasation back into circulation after forming clusters, thus, exerting the enhanced permeability and retention (EPR) effect for nanoparticle delivery to tumors.
We report an attomolar sensitive electrochemical genosensor for the detection of cauliflower mosaic virus 35S (CaMV35S) gene. The sandwich-type genosensor uses gold-silver core-shell (Au@Ag)-loaded ...iron oxide (Fe3O4) nanocomposite (Fe3O4-Au@Ag) as label of signal DNA probe (sDNA). Electrochemical sensing is accomplished at interface of electrodeposited AuNPs and carboxylated multiwalled carbon nanotubes-modified glassy carbon electrode through the specific interaction between the capture probe and target CaMV35S (tDNA), and tDNA and the labeled sDNA. The detection sensitivity was improved by the amplified reduction signal of hydrogen peroxide (H2O2), which takes advantage of the enhanced electrocatalytic activity of Fe3O4-Au@Ag. Under the optimal experimental conditions, an ultralow limit of detection was calculated to be 1.26 × 10−17 M (S/N = 3), and the blank value subtracted reduction signal of H2O2 of the sensor increased linearly with the logarithm of CaMV35S concentration over a wide range (1 × 10−16 M to 1 × 10−10 M). This genosensor displayed excellent stability, selectivity and reproducibility, and was successful in detecting the target CaMV35S in genetically modified tomato samples.
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•Au@Ag-loaded magnetic nanoparticles with hydrogen peroxide mimic enzyme properties was used as nanoprobe.•The quantitative genosensor showed high affinity and selectivity to target CaMV35S gene segment.•The genosensor was successfully applied for the accurate detection of GM tomato samples.
Cobalt nanoparticles (Co NPs) embedded in mesoporous graphene (MG) were prepared via a hydrothermal reaction followed by carbothermal reduction in an argon atmosphere. This cobalt ...nanoparticle-embedded mesoporous graphene (CoMG) was systematically investigated for structural, morphological, and magnetic properties before and after 10 successive cycles of adsorption and regeneration, using methylene blue (MB) dye as a model pollutant. The CoMG nanohybrid has a superior specific surface area of 807 m2 g−1, with a significant mesopore volume of 1.63 cm3 g−1 that allows fast and high pollutant removal efficiency of ∼84 % within 30 min as well as the maximum adsorption capacity of 178.6 mg g−1 with MB solution of 100 mg L−1, which is well described with pseudo-second-order adsorption kinetics. The consecutive adsorption−regeneration experiments revealed that the CoMG nanohybrid retained more than half of the initial dye removal efficiency even after being reused 10 times. After the tenth cycle, the regenerated CoMG maintained a high specific area of 688 m2 g−1 and a large mesopore volume of 1.51 cm3 g−1, indicating the long-lasting porous structure of the CoMG nanohybrid. The metallic cobalt phase and ferromagnetic nature of the Co NPs in the nanohybrid are retained because of the host MG, which prevents nanoparticle aggregation and serves as a protective environment for the embedded Co NPs in aqueous media during the adsorption−regeneration cycle tests of the adsorbent. The experimental results demonstrate that the CoMG nanohybrid has superior pollutant removal capacity and maintains more than half of the initial efficiency even after 10 cycles of use, making it a cost-efficient and energy-saving material for the removal of organic pollutants from aqueous media and in other environmental applications.
•A cobalt nanoparticle-embedded mesoporous graphene nanohybrid was synthesized.•The obtained nanohybrid was assessed as a recyclable pollutant adsorbent.•Comparisons between freshly prepared and regenerated nanohybrids were made.•The synthesized nanohybrid retained its characteristics after several sorption tests.•The host mesoporous graphene ensures superior adsorption capacity and recyclability.
Photonic soft materials, especially responsive photonic hydrogels (RPHs) with periodic permittivity on the submicroscale, have been garnering interest as colorimetric indicators and mechanochromic ...sensors. However, the fabrication of RPHs with both bright discoloration, satisfactory mechanical properties, and excellent mechanochromic sensitivity to meet the practical applications is still a great challenge. Herein, we develop a novel photonic crystal material using a Fe3O4 array embedded poly(N-isopropylacrylamide-co-acrylamide)/ laponite-XLS (PNA-XLS) hydrogel, which is dual-cross-linked by chemical and physical cross-linkers. Due to the interaction of sparse chemical links and apposite physical links between the polymeric networks, the PNA-XLS exhibits a significant energy dissipation and high deformation capacity, with an enhanced tensile strength above 819 kPa and elongation above 1015 %. It almost has a full-color tunable range and shows bright discoloration that can be reversibly actuated by bending, stretching, and small pressures (Pa level), with extremely high sensitivities of pressure (161 nm kPa−1) and tension (1.52 nm %−1). Moreover, its self-adhesion (133 kPa) would make it be an appealing candidate to develop portable sensors or wearable devices without auxiliary adhesive tools. Besides, elastic hydrogels with programmable and multicolor patterns can be designed by the mask-assisted UV photopolymerization of regional pregel solution. Therefore, such hydrogel has a great application potential in colorimetric indicators, mechanochromic sensors, anti-counterfeiting and wearable devices.
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•A facile and tunable synthesis of mechanochromic PNA-XLS hydrogels is presented.•It shows highly tensile strength (819 kPa), elongation (1015 %), and self-adhesion (133 kPa).•It exhibits extremely high sensitivities of pressure (161 nm kPa−1) and tension (1.52 nm %−1).•It can be used to monitor human joint motions and construct multicolor PC patterns.
This paper reviews recent developments in the preparation, surface functionalization, and applications of Fe3O4 magnetic nanoparticles. Especially, it includes preparation methods (such as ...electrodeposition, polyol methods, etc.), organic materials (such as polymers, small molecules, surfactants, biomolecules, etc.) or inorganic materials (such as silica, metals, and metal oxidation/sulfide, functionalized coating of carbon surface, graphene, etc.) and its applications (such as magnetic separation, protein fixation, magnetic catalyst, environmental treatment, medical research, etc.). In the end, some existing challenges and possible future trends in the field were discussed.
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•Comprehensive summary of the main aspects of Fe3O4 magnetic nanoparticles related to their preparation and application.•Classification and intrinsic properties of Fe3O4 magnetic nanoparticles were studied.•Perspectives for the future developments of Fe3O4 magnetic nanoparticles were proposed.
Biofilm-producing methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative Staphylococci (MR-CoNS) are a clinical challenge for the treatment of healthcare-associated infections. As ...alternative antimicrobial options are needed, we aimed to determine the effect of curcumin-chitosan magnetic nanoparticles on the biofilm of staphylococcal clinical isolates. MRSA and CoNS clinical isolates were identified by MALDI-TOF mass spectrometry. Antimicrobial susceptibility testing was performed by broth microdilution. Nanoparticles were synthesized by co-precipitation of magnetic nanoparticles (MNP) and encapsulation by ionotropic gelation of curcumin (Cur) and chitosan (Chi). Biofilm inhibition and eradication by nanoparticles with and without the addition of oxacillin was assessed on staphylococcal strains. Cur-Chi-MNP showed antimicrobial activity on planktonic cells of MRSA and MR-CoNS strains and inhibited biofilm of MRSA. The addition of OXA to Cur-Chi-MNP increased biofilm inhibition and eradication activity against all Staphylococci strains (p=0.0007); higher biofilm activity was observed in early biofilm stages. Cur-Chi-MNP showed antimicrobial and biofilm inhibition activity against S. aureus. The addition of OXA increased biofilm inhibition and eradication activity against all Staphylococci strains. A combination treatment of Cur-Chi-MNP and OXA could be potentially used to treat staphylococcal biofilm-associated infections in its early stages before the establishment of biofilm bacterial cells.
Novel strategies utilizing magnetic nanoparticles (MNPs) and magnetic fields are being developed to enhance bone tissue engineering efficacy. This article first reviewed cutting-edge research on the ...osteogenic enhancements via magnetic fields and MNPs. Then the current developments in magnetic strategies to improve the cells, scaffolds and growth factor deliveries were described. The magnetic-cell strategies included cell labeling, targeting, patterning, and gene modifications. MNPs were incorporated to fabricate magnetic composite scaffolds, as well as to construct delivery systems for growth factors, drugs and gene transfections. The novel methods using magnetic nanoparticles and scaffolds with magnetic fields and stem cells increased the osteogenic differentiation, angiogenesis and bone regeneration by 2–3 folds over those of the controls. The mechanisms of magnetic nanoparticles and scaffolds with magnetic fields and stem cells to enhance bone regeneration were identified as involving the activation of signaling pathways including MAPK, integrin, BMP and NF-κB. Potential clinical applications of magnetic nanoparticles and scaffolds with magnetic fields and stem cells include dental, craniofacial and orthopedic treatments with substantially increased bone repair and regeneration efficacy.
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