Description
The study, based on a top-down approach, aims at developing a new type of functionalized artificial micro/ nanoswimmers with magnetic flagella, for biotechnological applications.

Partners
SPINTEC : Nanomagnetism integrated in microtechnology
INAC/SPrAM/CREA : Functionalization, biotechnological applications
LTM (CNRS) : Microfluidics
Contact/Discussion François Alouges mathématicien/physicien, CMAP, Ecole Polytechnique.

Financing
Région Rhône-Alpes Projet CIBLE 2012
Allocation doctorale CFR (CEA)

Objectives
The proposed study, pertaining to basic research, aims at developing a new type of nanostructured and functionalized magnetic particles : artificial micro/nanoswimmers with magnetic flagella. These particles, composed of a head and a magnetic flexible flagellum are perfectly controlled in composition, shape, and size, of micronic or nanometric dimensions. Likewise they can be functionalized for different biotechnological applications. Dispersed in solution, these particles can be moved thanks to their flapping or waving magnetic flagella, controlled and actuated by a variable externally applied magnetic field. The swimming at low Reynolds number will be optimized, varying the temporal variation of the magnetic field, the flagellum elasticity, the composition and shape of the magnetic material.

Latest results
The technological realization is studied and tested, based on a “top-down” construction, comprising the following main steps :
1) manufacturing of a mold with the desired shape, nanostructured by lithography or nanoimprint
2) deposition of an underlayer of low Young’s modulus to increase the elasticity of the flagella
3) deposition of new magnetic material developed in the field of strong expertise of SPINTEC, particularly magnetic multilayers named “synthetic antiferromagnetic”, imitating the magnetic properties of conventional superparamagnetic materials, but with much higher magnetizations and magnetic susceptibilities.
4) deposition of biocompatible coatings (Au, SiO2)
5) upper surface functionalization (SPrAM)
6) release of the nanoswimmers from the substrate by lift-off.

Staff
Hélène JOISTEN (Characterization, modeling), Bernard DIENY (Scientific Direction), Philippe SABON (Technological research)
PhD students (2011-2014) : Selma LEULMI, Thomas DIETSCH , Cécile ISS
Internship 2012 : Ezgi DOGMUS
PhD students (2012-2015) : Mélissa MORCRETTE
Instrumentation research : Isabelle JOUMARD, Eric BILLIET
PTA Plateforme Technologique Amont (Clean room platform)
PhD Thesis defended in May 2011 : Paul BALINT
Internship 2010 : Thierry COURCIER

Related content
[1] “Self-polarization phenomenon and control of dispersion of synthetic antiferromagnetic nanoparticules for biological applications”, H. Joisten, T. Courcier, P. Balint, P. Sabon, S. Auffret, J. Faure-Vincent, and B. Dieny, Appl. Phys. Lett. 97, 253112 , (2010).

[2]”Tumbling motion yielding fast displacements of synthetic antiferromagnetic nanoparticles for biological applications” ,T. Courcier, H. Joisten, P. Sabon, S. Leulmi, T. Dietsch, J. Faure-Vincent, S. Auffret, B. Dieny, Appl. Phys. Lett. 99, 093107 (2011).

[3] “Swimming at low Reynolds number at optimal strokes : An example”, F. Alouges, A. Lefebvre et A. DeSimone, J. of Nonlinear Sci. 18, no. 3, 277-302, (2008).

Patents
“MICROSCALE OR NANOSCALE MAGNETIC TWEEZERS AND PROCESS FOR FABRICATING SUCH TWEEZERS”, B. Dieny, P. Sabon, H. Joisten, WO201217024 ; FR2963615 ; (2010).

“MAGNETIC MICROPARTICLE AND METHOD FOR MAKING SUCH A MICROPARTICLE”, B. Dieny, H. Joisten, P. Sabon, WO2011033080, FR2950042, (2009)

“METHOD FOR MANUFACTURING PARTICLES SUCH AS MAGNETIC MICRO- OR NANOPARTICLES”, B. Dieny, P. Sabon, J. Faure-Vincent

Figure 1

Experimental Set-up : Optical video microscope, objective inserted in a triaxial coil pairs for applying magnetic field and magnetic field gradient on 3 axis

Figure 2

Micro-swimmers : Heads fixed to the substrate, flagella released First technological realizations

Figure 3

Micro-swimmers : schematic principle and first technological realizations