Synthesis and characterization of magnetic chitosan microspheres as low-density and low-biotoxicity adsorbents for lake restoration

We propose a novel magnetic adsorbent for optimal Phosphorus (P) removal from the upper sediment layers. For this aim, magnetic chitosan microparticles were prepared using a reverse-phase suspension cross-linking technique. The resulting particles and suspensions were characterized using scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, magnetometry, thermogravimetric analysis, electrophoretic mobility and turbidity measurements. The hybrids are multicore particles consisting of well dispersed magnetite nanoparticles (approx. 10% w/w) homogeneously distributed within the biopolymer matrix. These microparticles can be easily separated from the water column and sediment using magnetic field gradients. Their P adsorption capacity is evaluated in batch conditions resulting in a maximum P adsorption capacity of ML ¼ 4.84 mg g 1 at pH ¼ 7. We demonstrate that these particles are excellent candidates to remove P from water column and also P mobile from the upper sediment layers due to two main reasons: they sediment slower and present lower potential toxicity (due to a their larger size) than conventional iron/iron oxide microparticles previously proposed for lake restoration.The authors would like to thank F. Galisteo-Gonz alez for providing the Bool2k software used for the generation of particlesize distributions from SEM micrographs and F. Vereda for his help in the Chemistry Laboratory. This workwas supported by Junta de Andalucía projects of excellence P10-RNM-6630 and P11-FQM- 7074 (Spain); MINECO CTM 2013-46951-R, MAT 2013-44429-R and PCIN 2015-051, MAT 2016-78778-R projects (Spain); and by the European Regional Development Fund

An enclosure experiment for testing the consequences of using magnetic microparticles on water quality and sediment phosphorus pools

By using microcosm enclosures containing brackish water (6000 µS cm-1) and natural surface sediment from an hypertrophic aquatic ecosystem, this study assessed the effects of adding iron (Fe) magnetic microparticles (MPs) on water quality, with special focus on P concentrations in water column and in the sediment. Two different treatments were considered for a constant 85:1 MPs:PMobile molar ratio: T-W, where MPs were applied above the surface layer of water, and T-S, where MPs were added directly above the sediment. Our study demonstrated the convenience of adding MPs for reducing both P concentrations in lake water and lake sediment. Both, T-W and T-S exhibited a reduction of 68 ± 6% in dissolved inorganic P concentration (DIP) on average for a 70-days oxic period and a reduction of 80 ± 8% (T-W) and 80 ± 4% (T-S) for a 5-days anoxic period. MPs also decreased reactive silicate (Si) concentration approx. by 50% on average for both periods whereas dissolved organic carbon (DOC) was only reduced by 15% after 24 h of MPs addition. Despite the drastic reduction in DIP concentration due to MPs addition, chlorophyll a (Chl a) was not reduced because total P (TP) concentration after treatments (> 200 µg L-1; before treatments: > 700 µg L-1) was still higher than that required (0.05–0.1 mg L-1) to see changes in biological community. P bound to Al oxides, clay minerals and humic substances (P→NaOH) and easily degradable organic P (Org-PLabile) showed a reduction of 15% and 12%, respectively in T-S compared to control. P bound to humic substances (P→NaOH, Humic) was reduced by 11-22% in both treatments. Finally, considering the efficiency in P and MPs removal in both treatments (T-W and T-S), we recommend T-W treatment for a future whole-lake application to ensure the effectiveness of P export (in water and sediment) and the recovery of MPs.This work was supported by Junta de Andalucía projects P10-RNM-6630 and P11-FQM-7074 (Proyectos de Excelencia, Spain), MINECO CTM 2013-46951-R, MAT 2013-44429-R and PCIN 2015-051 projects (Spain) and by the European Regional De-velopment Fund (ERDF)

Magnetic microparticles as a new tool for lake restoration: A microcosm experiment for evaluating the impact on phosphorus fluxes and sedimentary phosphorus pools

In the last decades, magnetic particles (MPs) as adsorbents have gained special attention due to their high adsorption capacity and the possibility of recovering them by applying a magnetic separation gradient. For the first time MPs have been tested as P adsorbents in a microcosm experiment in a context of lake restoration. MPs were added to sediment cores from a hypertrophic lake, at Fe:PMobile molar ratio of 285:1 and 560:1 under both, oxic and anoxic conditions. We have found that, under anoxic conditions (anoxic), MPs are able to reduce P release rate from the sediment to the overlying water and to reduce sedimentary PMobile concentration (a 22e25% reduction within 0e4 cm depth compared to controls). Under oxic conditions, the addition of MPs do not affect P fluxes across the sediment and water interface since the lake sediment is naturally rich in iron oxides. However a measured reduction in sedimentary PMobile concentration (12e16% reduction in 0e10 cm depth) contributes to a potential reduction in longterm P efflux.This work was supported by Junta de Andalucía projects P10- RNM-6630 and P11-FQM-7074 (Proyectos de Excelencia, Spain), and MINECO CTM 2013-46951-R and MAT 2013-44429-R and projects (Spain)

Determining major factors controlling phosphorus removal by promising adsorbents used for lake restoration: a linear mixed model approach

Phosphorus (P) removal from lake/drainage waters by novel adsorbents may be affected by competitive substances naturally present in the aqueous media. Up to date, the effect of interfering substances has been studied basically on simple matrices (single-factor effects) or by applying unsuitable statistical approaches when using natural lake water. In this study, we determined major factors controlling P removal efficiency in 20 aquatic ecosystems in the southeast Spain by using linear mixed models. Two non-magnetic -CFH-12® and Phoslock®- and two magnetic materials -hydrous lanthanum oxide loaded silica-coated magnetite (Fe-Si-La) and commercial zero-valent iron particles (FeHQ)- were tested to remove P at two adsorbent dosages. Results showed that the type of adsorbent, the adsorbent dosage and color of water (indicative of humic substances) are major factors controlling P removal efficiency. Differences in physico-chemical properties (i.e. surface charge or specific surface), composition and structure explain differences in maximum P adsorption capacity and performance of the adsorbents when competitive ions are present. The highest P removal efficiency, independently on whether the adsorbent dosage was low or high, were 85-100% for Phoslock and CFH-12®, 70-100% for Fe-Si-La and 0-15% for FeHQ. The low dosage of FeHQ, compared to previous studies, explained its low P removal efficiency. Although non-magnetic materials were the most efficient, magnetic adsorbents (especially Fe-Si-La) could be proposed for P removal as they can be recovered along with P and be reused, potentially making them more profitable in a long-term period.This work was supported by Junta de Andalucía project P10-RNM-6630 [Proyectos de Excelencia, Spain]; MINECO CTM 2013-46951-R project; and MAT 2016-78778-R project [Spain]. Authors would also like to thank Fernando Ortega for helping in the sampling procedure

Magnetorheology: a review

Magnetic Soft Matter is a rapidly evolving discipline with fundamental and practical interest. This is due to the fact that its physical properties can be easily controlled through external magnetic fields. In this review paper, we revisit the most recent progress in the field (since 2010) emphasizing the rheological properties of these fascinating materials. New formulations and flow kinematics are discussed. Also, new members are integrated into the long-lived magnetorheology family and suggestions are provided for future development.Spanish Government PID2019-104883GB-I00Junta de Andalucia P18-FR-2465European Union (EU) FPU14/0157

Divergent approach to nanoscale glycomicelles and photo-responsive supramolecular glycogels. Implications for drug delivery and photoswitching lectin affinity

The field of stimuli-responsive supramolecular biomaterials has rapidly advanced in recent years, with potential applications in diverse areas such as cancer theranostics, tissue engineering, and catalysis. However, designing molecular materials that exhibit predetermined hierarchical self-assembly to control the size, morphology, surface chemistry, and responsiveness of the final nanostructures remains a significant challenge. In this study, we present a divergent synthetic approach for the fabrication of spherical micelles and functional 1D-glyconanotube-based photoresponsive gels from structurally related diazobenzene/diacetylene glycolipids. The resulting nanostructures were characterized using NMR, TEM, and SEM, confirming the formation of spherical and tubular nanostructures in both the gel and solution states. Upon UV irradiation, a reversible gel-sol transition was observed, resulting from the photoswitching of the azobenzene unit from the stretched trans form to the compact, metastable cis form. Our gels were shown to enable spatio-temporal control of the adhesion and release of the lectin Concanavalin A, demonstrating potential use as regenerable biomaterials to fight against infections with toxins and pathogens. Additionally, our micelles and gels were evaluated as nanocontainers for loading and controlled release of hydrophobic dyes and antitumoural agents, suggesting their possible use as smart theranostic drug delivery systems. Divergent synthesis of stimuli-responsive biomaterials with varied sizes and topologies for potential applications in cancer theranostics, tissue engineering, and catalysisFinancial support was provided by the Spanish Ministry of Science and Innovation (Ref: PID2020-119949RB-I00/AEI/10.13039/501100011033), the Andalusian Ministry of Economy, Science and Innovation cofinanced by the European Regional Development Fund (ERDF) f PID2020-119949RB-I00/AEI/10.13039/501100011033Spanish GovernmentAndalusian Ministry of Economy, Science and InnovationEuropean Union (EU) Marie Curie Actions PY20_00882European Social Fund (ESF) CSIC-COV19-047CSIC FQM-313 CA-18132PAIDI Program from the Andalusian Government FPU15/04267German Research Foundation (DFG) National Health and Medical Research Council (NHMRC) of AustraliaSpanish GovernmentCentre of Research Technology and Innovation of the University of Sevill

Fabrication of strong magnetic micron-sized supraparticles with anisotropic magnetic properties for magnetorheology

Dr Tavacoli is acknowledged for useful discussions. This work was supported by MICINN PID2019-104883GB-I00 project (Spain), Junta de Andalucı´a P18-FR-2465 project and European Regional Development Fund (ERDF). J. R. M. acknowledges FPU14/01576 fellowship. E. C.-G. acknowledges financial support by CONACYT (Ref. #232347).We propose three different techniques to synthesize anisotropic magnetic supraparticles for their incorporation in the formulation of magnetorheological fluids with novel potential applications. The techniques include microtransfer molding, electrodeposition and microfluidic flow-focusing devices. Although the yield of these methods is not large, with their use, it is possible to synthesize supraparticles with anisotropy in both their magnetic content and shape. The magnetorheological characteristics (yield stress) of the resulting field-induced structures were computed using finite element method simulations and demonstrated to be strongly dependent on the microstructural anisotropy of the supraparticles. In anisotropic particles, the simulated yield stress is always larger than that of the isotropic ones consisting of magnetically homogeneous spherical particles.MICINN PID2019-104883GB-I00 project (Spain)Junta de Andalucía P18-FR-2465 projectEuropean Regional Development Fund (ERDF)FPU14/01576CONACYT (Ref. #232347

Enhancing magnetorheological effect using bimodal suspensions in the singlemultidomain limit

We demonstrate a new route to enhance the magnetorheological effect using bimodal suspensions in the single-multidomain limit. Experimental results are satisfactorily compared to 3D finite element method simulations. The physical reason behind this enhancement is the coating of the larger particles by the smaller ones due to the remnant magnetization of the latter.This work was supported by MAT 2016-78778-R and PCIN 2015-051 projects (FEDER FUNDS and MINECO, Spain). A J F Bombard is grateful to FAPEMIG grants: APQ-01824-17, PEE-00081-16, RED-00144-16, ETC-00043-15, PEP-00231- 15, APQ-00463-11 and RDP-00164-10. J R Morillas acknowledges FPU14/01576 fellowship

Clinical Trials of Thermosensitive Nanomaterials: An Overview

Currently, we are facing increasing demand to develop efficient systems for the detection and treatment of diseases that can realistically improve distinct aspects of healthcare in our society. Sensitive nanomaterials that respond to environmental stimuli can play an important role in this task. In this manuscript, we review the clinical trials carried out to date on thermosensitive nanomaterials, including all those clinical trials in hybrid nanomaterials that respond to other stimuli (e.g., magnetic, infrared radiation, and ultrasound). Specifically, we discuss their use in diagnosis and treatment of different diseases. At present, none of the existing trials focused on diagnosis take advantage of the thermosensitive characteristics of these nanoparticles. Indeed, almost all clinical trials consulted explore the use of Ferumoxytol as a current imaging test enhancer. However, the thermal property is being further exploited in the field of disease treatment, especially for the delivery of antitumor drugs. In this regard, ThermoDox®, based on lysolipid thermally sensitive liposome technology to encapsulate doxorubicin (DOX), is the flagship drug. In this review, we have evidenced the discrepancy existing between the number of published papers in thermosensitive nanomaterials and their clinical use, which could be due to the relative novelty of this area of research; more time is needed to validate it through clinical trials. We have no doubt that in the coming years there will be an explosion of clinical trials related to thermosensitive nanomaterials that will surely help to improve current treatments and, above all, will impact on patients’ quality of life and life expectancy.This research was supported by the Fundación Mutua Madrileña by the project FMM-AP16683-2017, Consejería de Salud Junta de Andalucía (PI-0089-2017), MINECO MAT 2016-78778-R, PCIN-2015-051 projects (Spain), European Regional Development Fund (ERDF) and from the Chair “Doctors Galera-Requena in cancer stem cell research”

Thermo-Sensitive Nanomaterials: Recent Advance in Synthesis and Biomedical Applications

Progress in nanotechnology has enabled us to open many new fronts in biomedical research by exploiting the peculiar properties of materials at the nanoscale. The thermal sensitivity of certain materials is a highly valuable property because it can be exploited in many promising applications, such as thermo-sensitive drug or gene delivery systems, thermotherapy, thermal biosensors, imaging, and diagnosis. This review focuses on recent advances in thermo-sensitive nanomaterials of interest in biomedical applications. We provide an overview of the different kinds of thermoresponsive nanomaterials, discussing their potential and the physical mechanisms behind their thermal response. We thoroughly review their applications in biomedicine and finally discuss the current challenges and future perspectives of thermal therapies.This research was supported by the Fundación Mutua Madrileña (project FMM-AP16683-2017), Consejería de Salud Junta de Andalucía (PI-0089-2017), Instituto de Salud Carlos III (FEDER funds PIE16/00045), MINECO MAT2015-63644-C2-R, MAT 2016-78778-R, PCIN-2015-051 projects (Spain), European Regional Development Fund (ERDF) and from the Chair “Doctors Galera-Requena in cancer stem cell research”