Synthesis and functionalization of magnetic and metallic nanoparticles for biological and environmental applications Adriana P. Herrera, PhD University of Cartagena, Colombia Department of Chemical Engineering. Piedra de Bolivar, Avenida del Consulado #34-100 aherrerab2@unicartagena.edu.co Abstract
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Normalized absorption
Normalized absorption
Magnetic and metallic nanoparticles are the subject of intense research focusing on their synthesis, characterization, and functionalization. These nanomaterials are attractive in various novel applications including: nano-/bio-sensors, catalyst recovery, antimicrobial, and separation of pollutants, among other. These applications require suitable nanoparticle surface modification, which provides colloidal stability in aqueous or biological fluids and improves the nanoparticle's transport and retention in specific areas.
Optical properties of gold nanoparticles:
Using reverse micelles for nanostructure synthesis takes advantage of the small size of the micellar water pools, which essentially act as nanoreactors that collide and exchange contents.
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a) Gold colloids absorption in aqueous medium
Synthesis of Nanoparticles
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b) Gold colloids absorption in w10 system
Potential Applications of Nanoparticles
Co-precipitation: The most common method to synthesize magnetic nanoparticles is the co-precipitation of aqueous iron salts in presence of strong bases such as ammonium hydroxide or sodium hydroxide. This chemical precipitation allows a large scale synthesis of magnetic nanoparticles easily and economically.
Representation of the micellar exchange process for the synthesis of gold nanoparticles in the water/AOT/Isooctane system
Surface modification of magnetite-APS nanoparticles with CMDx or PEG
Biocompatible magnetic nanoparticles inside cancer cells. Application of an AC magnetic field. Temperature rise to ~46 °C Destruction cancer cell
37 °C
~ 46 °C
of
Local generation of heat in cancerous cells with AC magnetic field.
Synthesis of silver
Typically the co-precipitation route yields magnetic nanoparticles with a polydisperse size distribution and results in formation of cluster-like aggregates.
nanoparticles by using leaves extracts of cilantro (Coriandrum sativum)
Thermal-decomposition:
Surface modification
To control particle size and distribution the thermaldecomposition technique is used employing high boiling solvents such as 1-octadecene to separate the nucleation and growth stages during particle synthesis.
with cellulose
Evaluation of the
Characterization Fourier Transform Infrared spectroscopy: Antimicrobial application of silver nanoparticles modified with cellulose for the production of active food packs
antimicrobial action of silver nanoparticles modified with cellulose after contact with E. coli bacteria
TEM measurement of magnetite nanoparticles with a Dpgv of 13 nm and g of 0.19 synthesized in 1-octadecene using oleic acid (OA) as a surfactant
Reverse Micelles:
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3+
Sample
pI
Mag-APS
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MagAPS/CMDX
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MagAPS/PEG
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40 20 0 -20 COO
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Dh 6.61 0.298w Reverse micelle structure and relationship Dh vs w
Modified nanoparticles
Zeta potential measurements:
Zeta Potential (mV)
Reverse micelles consist of aqueous droplets that are separated from the bulk organic phase by a surfactant layer. The diameter (Dh) of these droplets greatly influences the size of the resulting nanoparticles; we found by Dynamic Light Scattering (DLS) measurements, that this value is dependent on the water-surfactant molar ratio (w) selected for the system water/AOT/Isooctane :
FTIR spectra of a) magnetite nanoparticles coated with APS molecules, b) magnetite-APS/CMDx and c) magnetite-APS/PEG.
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Zeta potential measurements of magnetiteFe3O APS/CMDx - APS/CMDx nanoparticles with NaCl at pH 7.0
Fe3O4 - APS 4
Fe3O4 - APS/PEG
Synthesis of magnetic nanoparticles modified with TiO2 for photodegradation of phenol in aqueous solutions
References Herrera,
A. et al., Journal of Materials Chemistry, vol. 18, pp. 36503654, 2008. Barrera, C. et al., Journal of Colloid and Interface Science, vol. 329, pp. 107-113, 2009. Herrera, A. et al., Nanotechnology vol. 16, p.p S618–S625, 2005. Bao, L. et al., Chemistry of Materials, vol. 21, pp. 3458-3468, 2009. Polking, M. et al., Journal of the American Chemical Society, vol. 133, pp. 2044-2047, 2011.