Final Report Summary - MAGBIOMAT (Study of magnetic responsive biopolymer based materials)
The aim of the Marie Curie Action MAGBIOMAT was to elaborate and to characterise new nanostructured magneto-responsive biopolymer-based materials by the introduction of functionalised magnetic nanoparticles in biopolymer networks to gain a deeper understanding of two fundamental aspects:-The understanding of the formation mechanisms of such structures: magneto-responsive networks.-The correlation between the behaviour of the nanostructured composite biopolymer-based materials under the change of external conditions, such as magnetic field, shear, ionic strength, pH and composition of polymer and magnetic nanoparticles or the chemical structure of the constituents.
The combination of synthesis, characterisation and analysis has provided a synergy for the elaboration and optimisation of novel magnetic-responsive biopolymer based materials with fine tuned properties and for their future applications in industries (vehicle for drug delivery, smart materials for medical and structural applications).
In a first step, the magnetic particles have been synthesized by a co-precipitation method and then stabilised by adsorption of sodium citrate ions. After that the complete characterisation of the obtained ferrofluids has been carried out. In the same way, the preparation and characterisation of alginate solutions at different concentrations has been performed.
In order to analyse and optimise the preparation of alginate and ferrofluids solutions, we have prepared several samples with different alginate concentrations and ferrofluid volume fractions. The stability of these samples has been examined by means of macroscopic and microscopic observations. The rheological behaviour has been also studied using flow and oscillatory shear measurements. In order to analyse the effect of the magnetic field in the mechanical properties of the materials, the development and adjustment of a magnetic cell that allows the application of an external continuous magnetic field over the sample during the rheological measurements have been performed.
To prepare the alginate gel and the alginate and ferrofluid ferrogels the internal gelling method has been chosen. Gels and ferrogels with different concentrations of alginate, volume fractions of ferrofluid and ratios between calcium and sodium ions concentrations have been obtained. The gelation time and the mechanical properties of gel and ferrogel in the absence of magnetic field and when an external magnetic field is applied have been studied.
The development and adjustment of the magnetorheological cell allows us to carry out controlled temperature flow shear measurements and oscillatory measurements under continuous magnetic fields, with maximum field strength of about 40 mT. These measurements show that there is magneto-viscous effect in the alginate and ferrofluid suspensions, as it proved by means of an increase in the viscosity at low shear rate and the elastic and viscous modulus when the magnetic field is applied. The microscopic observation of the solutions in the absence of magnetic field and when a magnetic field is applied provides information about the behaviour of the particles under the effect of the field and allows us to explain the results obtained in the rheological measurements and the observed magneto-viscous effect. The characterisation of alginate, ferrofluid, and alginate-ferrofluids suspensions was performed to obtain the optimal conditions to formulate biogels and ferrogels. The internal gelling method provides quite homogeneous alginate gels and alginate and ferrofluid ferrogels. We have studied the gelation time, depending on ion concentration and we have prepared biogel and ferrogel, with different alginate concentrations and ferrofluid volume fractions.
The introduction of magnetic nanoparticles in the biopolymer network as well as the application of a magnetic field over the ferrogels modulates the gelation time and the gel stiffness. Especially, we have observed an enhancement of viscoelastic properties by the application of external magnetic field.
In conclusion, MAGBIOMAT has shown the possibility to form self-assembly supramolecular morphologies by means of biopolymers and magnetic nanoparticles, which can be controlled using external magnetic fields. Especially, the control of the mechanical properties by continuous magnetic fields that we have observed and studied in this work will enable the use of these materials in micro fluidics, pharmaceutical or medical applications.
One of the most important applications could be the controlled delivery of biological molecules where the nanocomposites play the role of biocompatible dynamic vectors. The magnetic nanoparticles embedded in biopolymer networks enable the encapsulation of therapeutic and imaging agents for targeted delivery systems. The polymeric matrixes allow the dispersion of the particles, enhance their stability (sedimentation, shielding), chemical functionality, compatibility (hydrophobicity or hydrophilicity, toxicity, stealth), and biocompatibility. The behaviour shown in this project for this kind of materials opens the possibility to their use as delivery systems capable of protecting, transporting, and selectively depositing therapeutic agents to desired sites. The use of superparamagnetic composites with polymeric networks for the delivery of biocompounds allows the system to be easily localised using an external magnetic field and controlled release may be achieved. On the other hand, the development and adjustment of the magnetic cell has allowed the opportunity of applying magnetic fields during the rheological measurements, without interfering in the normal operation of the rheometer.
An attached file with figures presents the main results from the project and includes the project logo.
More information on the project can be also found on the website: http://www.physique. univ-paris-diderot. fr/magbiomat/
The combination of synthesis, characterisation and analysis has provided a synergy for the elaboration and optimisation of novel magnetic-responsive biopolymer based materials with fine tuned properties and for their future applications in industries (vehicle for drug delivery, smart materials for medical and structural applications).
In a first step, the magnetic particles have been synthesized by a co-precipitation method and then stabilised by adsorption of sodium citrate ions. After that the complete characterisation of the obtained ferrofluids has been carried out. In the same way, the preparation and characterisation of alginate solutions at different concentrations has been performed.
In order to analyse and optimise the preparation of alginate and ferrofluids solutions, we have prepared several samples with different alginate concentrations and ferrofluid volume fractions. The stability of these samples has been examined by means of macroscopic and microscopic observations. The rheological behaviour has been also studied using flow and oscillatory shear measurements. In order to analyse the effect of the magnetic field in the mechanical properties of the materials, the development and adjustment of a magnetic cell that allows the application of an external continuous magnetic field over the sample during the rheological measurements have been performed.
To prepare the alginate gel and the alginate and ferrofluid ferrogels the internal gelling method has been chosen. Gels and ferrogels with different concentrations of alginate, volume fractions of ferrofluid and ratios between calcium and sodium ions concentrations have been obtained. The gelation time and the mechanical properties of gel and ferrogel in the absence of magnetic field and when an external magnetic field is applied have been studied.
The development and adjustment of the magnetorheological cell allows us to carry out controlled temperature flow shear measurements and oscillatory measurements under continuous magnetic fields, with maximum field strength of about 40 mT. These measurements show that there is magneto-viscous effect in the alginate and ferrofluid suspensions, as it proved by means of an increase in the viscosity at low shear rate and the elastic and viscous modulus when the magnetic field is applied. The microscopic observation of the solutions in the absence of magnetic field and when a magnetic field is applied provides information about the behaviour of the particles under the effect of the field and allows us to explain the results obtained in the rheological measurements and the observed magneto-viscous effect. The characterisation of alginate, ferrofluid, and alginate-ferrofluids suspensions was performed to obtain the optimal conditions to formulate biogels and ferrogels. The internal gelling method provides quite homogeneous alginate gels and alginate and ferrofluid ferrogels. We have studied the gelation time, depending on ion concentration and we have prepared biogel and ferrogel, with different alginate concentrations and ferrofluid volume fractions.
The introduction of magnetic nanoparticles in the biopolymer network as well as the application of a magnetic field over the ferrogels modulates the gelation time and the gel stiffness. Especially, we have observed an enhancement of viscoelastic properties by the application of external magnetic field.
In conclusion, MAGBIOMAT has shown the possibility to form self-assembly supramolecular morphologies by means of biopolymers and magnetic nanoparticles, which can be controlled using external magnetic fields. Especially, the control of the mechanical properties by continuous magnetic fields that we have observed and studied in this work will enable the use of these materials in micro fluidics, pharmaceutical or medical applications.
One of the most important applications could be the controlled delivery of biological molecules where the nanocomposites play the role of biocompatible dynamic vectors. The magnetic nanoparticles embedded in biopolymer networks enable the encapsulation of therapeutic and imaging agents for targeted delivery systems. The polymeric matrixes allow the dispersion of the particles, enhance their stability (sedimentation, shielding), chemical functionality, compatibility (hydrophobicity or hydrophilicity, toxicity, stealth), and biocompatibility. The behaviour shown in this project for this kind of materials opens the possibility to their use as delivery systems capable of protecting, transporting, and selectively depositing therapeutic agents to desired sites. The use of superparamagnetic composites with polymeric networks for the delivery of biocompounds allows the system to be easily localised using an external magnetic field and controlled release may be achieved. On the other hand, the development and adjustment of the magnetic cell has allowed the opportunity of applying magnetic fields during the rheological measurements, without interfering in the normal operation of the rheometer.
An attached file with figures presents the main results from the project and includes the project logo.
More information on the project can be also found on the website: http://www.physique. univ-paris-diderot. fr/magbiomat/
