1. MAGNETIC NANOCOMPOSITE PARTICLES FOR BIO-APPLICATIONS
Ana Luísa Daniel da Silva

2. Nanoparticles vs Nanobiosystems1 10
100 nm
hemoglobina
ribossoma
The relative particle size between nanoparticles and nanobiosystems

3. Bio-applications of magnetic nanoparticles
Magnetite Fe3O4
Maghemite g-Fe2O3
Magnetic Separation
Protein purification
Cell isolation
Biocatalysis
....
Endorem®, Resovist®
Diagnosis
MRI (contrast enhancement agents)
Biosensors
....
Chem Comm 12 (2008) 1203
Drug Delivery
Magnetic drug targeting
Controlled drug release (magnetic heating)
....
Therapeutics
Magnetic Hyperthermia
Cancer therapy
....
Adv. Mater. (2003) 15, 1729

4. Multifunctional Magnetic Nanoparticles
Combine various components
Multiple bio-applications
Sun et al., Adv Drug Delivery Rev 60 (2008) 1252
Gao et al., Acc Chem Res 42 (2009) 1097

5. Superparamagnetism H=0 : negligible remanent magnetization
superparamagnetic Iron Oxide NPs: Ø< 15 nm
H=0 : negligible remanent magnetization
minimal NPs agglomeration
Biomedical applications
Hysteresis loop (M vs H):
ferrimagnetic
superparamagnetic

6. Research activities
- Inorganic functional nanomaterials and organic-inorganic hybrids (Research Group 1)
- Nanostructured Materials
Magnetic NPs (Iron oxides,…)
Metallic NPs
Semiconducting NPs
Nanocomposites
biopolymers
synthetic polymers ….
Bio-applications
Heterogeneous catalysis
Paints and coatings ….
Synthesis
Materials characterization
Surface modification
Interface phenomena ….

7. Aim of the work
Magnetic Nanocomposites based on Thermosensitive Hydrogels
(Drug delivery applications)
Why to use thermoreversible gels? T
Controlled drug release upon local heating induced by external stimuli
Biofunctionalization, magnetic driving, MRI..

8. Aim of the work
Magnetic Nanocomposites based on Thermosensitive Hydrogels
(Drug delivery applications)
- Synthesis of magnetic bio-nanocomposites
Magnetic properties
Stability to oxidation
Rheological properties
- Synthesis of composite nanoparticles
- Biofunctionalization
- In vitro release studies

9. In-situ synthesis of magnetic bio-nanocomposites
Co-precipitation within carrageenan biopolymer
Fe Fe OH Fe3O4 + 4H2O
Prevention of the agglomeration
Control of the particle size ~ nm (superparamagnetism)
> Gel strength
A.L. Daniel-da-Silva et al., Biomacromolecules 8 (2007) 2350

10. Particle size & Gel strength
In-situ synthesis of magnetic bio-nanocomposites
Chemical stability to oxidation ?
k- 0.5%
k- 2.0%
i- 2.0%
l- 2.0%
k- 2.0%*
Fe3O g-Fe2O3
Magnetite oxidation
Diffusion based mechanism
Chemical Stability
Balance between
Particle size & Gel strength
A.L. Daniel-da-Silva et al., Biomacromolecules 8 (2007) 2350

11. Rheological studies in bio-nanocomposites
k-carrageenan /Fe3O4
Sol
Gel
k-1.0wt%
Sol
Gel
Tgel
In-situ & Ex-situ synthesis
G’ (k-car+Fe3O4+ K+) > G’ (k-car + K+)
Ex-situ synthesis
G’ (k-car + Fe3O4) < G’ (k-car)
Reinforcement of gel
Combined effect
Fe3O4 & K+ ions
A.L. Daniel-da-Silva et al., J. Colloid Interf Sci 324 (2008) 205

12. increases [K+] within “polymer cages” electrostatic repulsions
Rheological studies in bio-nanocomposites
Reinforcement of gel
Combined effect
Fe3O4 & K+ ions
KOH
Stronger gels
Fe3O4 K+
increases [K+] within “polymer cages”
z (Fe3O4) < 0
electrostatic repulsions
magnetite / -OSO3-
Weaker gels
(as for Carr/SiO2 NPs)
- Model system k-carrageenan /SiO2 NPs
A.L. Daniel-da-Silva et al., J. Colloid Interf Sci 320 (2008) 571
A.L. Daniel-da-Silva et al., J. Colloid Interf Sci 324 (2008) 205

13. Biofunctionalized magnetic hydrogel nanospheres
(k-carrageenan/Fe3O4)
NP size control
W=[H2O]/[surfactant]
A.L. Daniel-da-Silva et al., Nanotechnology 20 (2009)

14. Biofunctionalized magnetic hydrogel nanospheresNP
Surface carboxymethylation followed by bovine IgG antibody conjugation
(Carbodiimide-mediated reaction) T
37-45ºC
DSC
Superparamagnetic properties (MRI, magnetic targeting)
Biofunctionalization (local targeting)
Thermosensitive (Thermally controlled drug release)
A.L. Daniel-da-Silva et al., Nanotechnology 20 (2009)

15. In vitro release profiles
ONGOING WORK
k-carrageenan discs
k-carrageenan discs (bulk)
Methylene Blue
Parameters of AzM encapsulation in nanospheres
k-carrageenan nanospheres
EE(%)
LC(%)
k-car1
19±8. 5
0.18±0.0 7
k-car4
42±2. 8
0.36±0.0 4

16. In vitro release profiles
ONGOING WORK
k-carrageenan/Fe3O4 nanocomposite discs
37ºC

17. Main Conclusions
- Magnetic nanocomposites were prepared via in situ co-precipitation of Fe3O4 NPs. Carrageenan plays a relevant role in the control of size and chemical stability of NPs. The resulting bio-nanocomposites are thermoreversible hydrogels with superparamagnetic properties.
Successful preparation of k-carrageenan/Fe3O4 bio-nanocomposite particles showing NP size <100 nm Superparamagnetic properties Thermosensitivity in T range acceptable for living cells Ability for coupling to active biomolecules Envisaged applications include local targeted and thermally controlled drug delivery.
In vitro release tests regarding their behavior as carrier for controlled drug release are in progress. Evidences of possible reaction to external stimuli (radiation).

18. Perspectives of Future Work
- In vitro release tests upon magnetic stimuli
- Evaluation of toxicity
- Extension of this work to other systems (in progress) -magnetic bionanocomposites with other nanofillers (e.g. MWCNTs) -other thermosensitive hydrogels

19. Acknowledgements Ana Estrada (UA) Ana M. Gil (UA)
António J. Guiomar (UC)
Benilde F.O. Costa (UC)
Brian Goodfellow (UA)
Ernest Mendoza (ICN-Barcelona)
Joana Moreira (UA)
José A. Lopes-da-Silva (UA)
Luciana Ferreira (UA)
Nuno João Silva (UA)
Sara Fateixa (UA)
Tito Trindade (UA)
SFRH/BPD/39105/2007
FEDER (PTDC/QUI/67712/2006)
NANO/NMed-SD/0140/2007

20. Nanocomposite Particles for Bio-Applications Materials and Bio-Interfaces edited by Tito Trindade & Ana Luísa Daniel-da-Silva
(University of Aveiro, Portugal)
One of the first books on bio-applications of nanocomposite particles.
Includes contributions from specialists with international published research in their field of expertise.
Illustrated with excellent figures and containing a very good survey of references to accompany each chapter.
For more information, please or visit
Sep 2010, 400 pages (approx.)
(Hardback)