Fully Biodegradable Magnetic Micro-Nanoparticles: A New Platform for Tissue Regeneration and Theranostic

2013 ◽  
Author(s):  
Monica Sandri ◽  
Michele Iafisco ◽  
Silvia Panseri ◽  
Elisa Savini ◽  
Anna Tampieri
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Magnetic Materials ◽  
Tissue Regeneration ◽  
Biomedical Applications ◽  
The Body ◽  
Nano Particles ◽  
Delivery Vehicles

Nowadays, magnetic materials are receiving special attention due to their potential applications in different fields and in particular in medicine. Magnetic micro-nano-particles have been progressively employed as support materials for enzyme immobilization, and have been used as drug-delivery vehicles, contrast agents for magnetic resonance imaging as well as heat mediators for hyperthermia-based anti-cancer treatments and many other exciting biomedical applications. Magnetic materials have also attracted a big interest in the field of bone tissue regeneration because it has been demonstrated that magnetic nanoparticles have effect of osteoinduction even without external magnetic force. Therefore, one of the most big challenge in this field is the production of magnetic materials with good biocompatibility and biodegradability. In fact, the long-term effects in the human body of iron oxide (maghemite or magnetite), the most popular magnetic phase used in medicine and biotechnology, are not yet completely assessed. To this aim, in this work we developed an innovative biocompatible and bioresorbable superparamagnetic-like phase by doping nano-hydroxyapatite with Fe2+/Fe3+ ions (FeHA). Moreover the same magnetic nanoparticles were used as nano-particulate emulsifier for the preparation of hollow hybrid Fe-HA-poly(L-lactic) acid (PLLA) micro-nano-spheres. PLLA has been used because poly(α-hydroxy-esters) are the most frequently used synthetic polymers for biomedical applications owing to their biocompatibility, hydrolytic degradation process and proper mechanical properties. These micro-nanospheres could be used as new type of scaffold for hard tissue regeneration. In fact, spherical scaffold display several advantages respect to the monolithic counterpart e.g., (i) improving control over sustained delivery of therapeutic agents, signalling biomolecules and even pluripotent stem cells, (ii) serving as stimulus-sensitive delivery vehicles for triggered release, (iii) introducing porosity and/or improve the mechanical properties of bulk scaffolds by acting as porogen or reinforcement phase, (iv) supplying compartmentalized micro-reactors for dedicated biochemical processes, (v) functioning as cell delivery vehicle, and, finally, (vi) giving possibility of preparing injectable and/or mouldable formulations to be applied by using minimally invasive surgery. Moreover, the same magnetic materials could find applications in nanomedicine as a multifunctional carrier. Their magnetic functionality could be utilized to move them into the body towards target organs by an external magnetic field. Furthermore, the superparamagnetic feature of the nanoparticles could allow to tailor the release of the therapeutic agent by switching (on-off) the external magnetic field and/or to treat cancer cells by hyperthermia.

scholarly journals Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew N. Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

scholarly journals Magnetoviscosity of a Magnetic Fluid Based on Barium Hexaferrite Nanoplates

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1870
Author(s):  
Dmitry Borin ◽  
Robert Müller ◽  
Stefan Odenbach
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Shear Flow ◽  
Magnetic Fluid ◽  
Barium Hexaferrite ◽  
Dipole Interaction ◽  
Field Dependent ◽  
Fluid Behaviour

This paper presents the results of an experimental study of the influence of an external magnetic field on the shear flow behaviour of a magnetic fluid based on barium hexaferrite nanoplates. With the use of rheometry, the magnetoviscosity and field-dependent yield-stress in the fluid are evaluated. The observed fluid behaviour is compared to that of ferrofluids with magnetic nanoparticles having high dipole interaction. The results obtained supplement the so-far poorly studied topic of the influence of magnetic nanoparticles’ shape on magnetoviscous effects. It is concluded that the parameter determining the observed magnetoviscous effects in the fluid under study is the ratio V2/l3, where V is the volume of the nanoparticle and l is the size of the nanoparticle in the direction corresponding to its orientation in the externally applied magnetic field.

scholarly journals Modulation of Crystallinity through Radiofrequency Electromagnetic Fields in PLLA/Magnetic Nanoparticles Composites: A Proof of Concept

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4300
Author(s):  
Marta Multigner ◽  
Irene Morales ◽  
Marta Muñoz ◽  
Victoria Bonache ◽  
Fernando Giacomone ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Nanoparticles ◽  
Electromagnetic Fields ◽  
Biomedical Applications ◽  
Infrared Camera ◽  
Proof Of Concept ◽  
Scanning Calorimetry ◽  
Radiofrequency Electromagnetic Fields ◽  
Degradation Properties ◽  
Heat Released

To modulate the properties of degradable implants from outside of the human body represents a major challenge in the field of biomaterials. Polylactic acid is one of the most used polymers in biomedical applications, but it tends to lose its mechanical properties too quickly during degradation. In the present study, a way to reinforce poly-L lactic acid (PLLA) with magnetic nanoparticles (MNPs) that have the capacity to heat under radiofrequency electromagnetic fields (EMF) is proposed. As mechanical and degradation properties are related to the crystallinity of PLLA, the aim of the work was to explore the possibility of modifying the structure of the polymer through the heating of the reinforcing MNPs by EMF within the biological limit range f·H < 5·× 109 Am−1·s−1. Composites were prepared by dispersing MNPs under sonication in a solution of PLLA. The heat released by the MNPs was monitored by an infrared camera and changes in the polymer were analyzed with differential scanning calorimetry and nanoindentation techniques. The crystallinity, hardness, and elastic modulus of nanocomposites increase with EMF treatment.

Mittag–Leffler Function as an Approximant to the Concentrated Ferrofluid’s Magnetization Curve

2021 ◽  
Vol 5 (4) ◽  
pp. 147
Author(s):  
Petr A. Ryapolov ◽  
Eugene B. Postnikov
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
External Magnetic Field ◽  
Magnetization Curve ◽  
Force Fields ◽  
Physical Characteristics ◽  
Concentrated Solutions ◽  
Static Magnetization ◽  
Simple Tool ◽  
Technical Systems

In this work, we show that the static magnetization curve of high-concentrated ferrofluids can be accurately approximated by the Mittag–Leffler function of the inverse external magnetic field. The dependence of the Mittag–Leffler function’s fractional index on physical characteristics of samples is analysed and its growth with the growing degree of system’s dilution is revealed. These results provide a certain background for revealing mechanisms of hindered fluctuations in concentrated solutions of strongly interacting of the magnetic nanoparticles as well as a simple tool for an explicit specification of macroscopic force fields in ferrofluid-based technical systems.

Study of the Performance of Practical Magneto-Rheological Elastomers

2012 ◽  
Vol 430-432 ◽  
pp. 1979-1983
Author(s):  
Wei Bang Feng ◽  
Xue Yang ◽  
Zhi Qiang Lv
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Mechanical Property ◽  
Magnetic Properties ◽  
External Magnetic Field ◽  
Magnetic Particles ◽  
Poor Performance ◽  
Electrical And Magnetic Properties ◽  
Intelligent Material ◽  
Magneto Rheological

Magneto-rheological elastomer( MR elastomer) is an emerging intelligent material made up of macromolecule polymer and magnetic particles. While a promising wide application it has in the fields of warships vibration controlling for its controllable mechanical, electrical and magnetic properties by external magnetic field, design and application of devices based on it are facing great limitations imposed by its poor performance in mechanical properties and magneto effect. Aiming at developing a practical MR elastomer, a new confecting method was proposed in this paper. Then, following this new method and using a specificly designed solidifying matrix, an amido- polyester MR elastomer was developed with its mechanical property systemically explored.

scholarly journals Magnetic behaviour of supraconducting tin spheres

1935 ◽  
Vol 151 (873) ◽  
pp. 316-333 ◽  
Author(s):  
K. Mendelssohn ◽  
J. D. Babbitt ◽  
Frederick Alexander Lindemann
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Force ◽  
Magnetic Behaviour ◽  
The Body ◽  
Whole Body ◽  
Measured Field ◽  
Lines Of Force ◽  
As If ◽  
Field Strengths

Until a year ago it was generally accepted that if a body is made supraconducting while in a magnetic field the lines of magnetic force were "frozen in," i. e ., whatever lines of force passed through the body at the time when it became supraconducting remained there afterwards, unaffected by any change in the external field, so long as the body was supraconducting. Meissner and Ochsenfeld, however, showed that this supposition was not true. They measured field strengths in the immediate neighbourhood of cylinders which had been cooled to supraconductivity in an external magnetic field, and found that the field of force was then of the same nature as that to be expected in the neighbourhood of perfectly diamagnetic bodies. Thus it appeared that when a body becomes supraconducting in a magnetic field the lines of force are all pressed out of the body, and the induction inside the body falls to zero. At the same time, however, these authors report on another experiment, the result of which appears to us not entirely in accordance with the assumption that the induction in the whole body became zero. They measured the field strengths inside and outside a hollow cylinder, after it had become supraconducting in a field perpendicular to its axis, and found again that the field strength outside was as if the cylinder were almost perfectly diamagnetic, but the field inside was appreciably the same as if the cylinder were non-supraconducting. We therefore made a number of experiments, hoping to find out more exactly the nature of the phenomenon.

scholarly journals Remote manipulation of magnetic nanoparticles using magnetic field gradient to promote cancer cell death

2018 ◽  
Author(s):  
Mahendran Subramanian ◽  
Arkadiusz Miaskowski ◽  
Stuart Iain Jenkins ◽  
Jenson Lim ◽  
Jon Dobson
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Field Gradient ◽  
Biomedical Applications ◽  
Magnetic Field Gradient ◽  
Field Source ◽  
Remote Manipulation ◽  
Cancer Cell Death ◽  
The Magnetic Field

AbstractThe manipulation of magnetic nanoparticles (MNPs) using an external magnetic field, has been demonstrated to be useful in various biomedical applications. Some techniques have evolved utilizing this non-invasive external stimulus but the scientific community widely adopts few, and there is an excellent potential for more novel methods. The primary focus of this study is on understanding the manipulation of MNPs by a time-varying static magnetic field and how this can be used, at different frequencies and displacement, to manipulate cellular function. Here we explore, using numerical modeling, the physical mechanism which underlies this kind of manipulation, and we discuss potential improvements which would enhance such manipulation with its use in biomedical applications, i.e., increasing the MNP response by improving the field parameters. From our observations and other related studies, we infer that such manipulation depends mostly on the magnetic field gradient, the magnetic susceptibility and size of the MNPs, the magnet array oscillating frequency, the viscosity of the medium surrounding MNPs, and the distance between the magnetic field source and the MNPs. Additionally, we demonstrate cytotoxicity in neuroblastoma (SH-SY5Y) and hepatocellular carcinoma (HepG2) cells in vitro. This was induced by incubation with MNPs, followed by exposure to a magnetic field gradient, physically oscillating at various frequencies and displacement amplitudes. Even though this technique reliably produces MNP endocytosis and/or cytotoxicity, a better biophysical understanding is required to develop the mechanism used for this precision manipulation of MNPs, in vitro.

scholarly journals Magnetosensibility and Magnetic Properties of Ectatomma brunneun Smith, F. 1858 Ants

Sociobiology ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 5188
Author(s):  
Márlon César Pereira ◽  
Maria da Graça Cardoso Pereira-Bomfim ◽  
Ingrid De Carvaho Guimarães ◽  
Candida Anitta Pereira Rodrigues ◽  
Jilder Peña Serna ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Nanoparticles ◽  
Geomagnetic Field ◽  
Nestmate Recognition ◽  
The Body ◽  
Superparamagnetic Nanoparticles ◽  
Behavioral Repertoire ◽  
Behavior Study ◽  
The Social ◽  
First Time

The aim of the present paper is to study magnetosensibility and to seek for magnetic nanoparticles in ants. The social insects, by living in colonies, developed very efficient methods of nestmate recognition, being less tolerant towards individuals from other colonies. Therefore, any kind of strange behavior between nestmates and/or conspecifics, besides those present in their own behavioral repertoire, is not expected. The behavior study in the present paper analyze whether changes in the intensity of applied magnetic fields on Ectatomma brunneun (Smith) ants can cause changes in the normal pattern of interaction between conspecifics. A pair of coils generating a magnetic field was used to change the whole local geomagnetic field. Magnetometry studies were done on abdomens and head + antennae using a SQUID magnetometer. The results show that changes in the geomagnetic field affect the usual pattern of interactions between workers from different colonies. The magnetometry results show that abdomens present superparamagnetic nanoparticles and heads present magnetic single domain nanoparticles. Behavior experiments show for the first time that Ectatomma brunneun ants are magnetosensible. The change in nestmate recognition of Ectatomma ants observed while a magnetic field is applied can be associated to some kind of disturbance in a magnetosensor presented in the body based on magnetic nanoparticles.

scholarly journals Injectable Non-leaching Tissue-mimetic Bottlebrush Elastomers: A New Platform for Advancing Reconstructive Surgery

2020 ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

Abstract Current materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

Isotropic polyconvex electromagnetoelastic bodies

2018 ◽  
Vol 24 (3) ◽  
pp. 738-747
Author(s):  
M Šilhavý
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Electromagnetic Field ◽  
Smart Materials ◽  
Equilibrium Solution ◽  
Deformation Gradient ◽  
Electric Displacement ◽  
The Body ◽  
Sufficient Condition ◽  
Energy Functions

The recent renewal of interest in nonlinear electromagnetoelastic interactions comes from the technological importance of electro- or magnetosensitive elastomers, smart materials whose mechanical properties change instantly on the application of an electric or magnetic field. We consider materials with free energy functions of the form [Formula: see text], where F is the deformation gradient, d is the electric displacement, and b is the magnetic induction. It was recently shown by the author that such an energy function is polyconvex if and only if it is of the form [Formula: see text] where [Formula: see text] is a convex function (of 31 scalar variables). Moreover, an existence theorem was proved for the equilibrium solution for a system consisting of a polyconvex electromagnetoelastic solid plus the vacuum electromagnetic field outside the body. The condition (8), is not just the combination of Ball’s polyconvexity of elastomers [Formula: see text] with the convexity in the electromagnetic variables. The differential constraints div [Formula: see text], div [Formula: see text] allow for the cross mechanical–electric and mechanical–magnetic terms Fd and Fb which substantially enlarge the class of energies covered by the theory. The result (*), applies to a material of any symmetry; this paper analyzes the condition in the case of isotropic materials. A broad sufficient condition for the polyconvexity is given in that case. Further, it is shown that the commonly used isotropic electroelastic or magnetoelastic invariants are polyconvex except for the biquadratic ones; the paper explicitly determines their quasiconvex envelopes and shows that they are polyconvex.

Sign in / Sign up

Export Citation Format

Share Document