Multifunctional Nanoparticles for biomedical applications
This axis deals with the elaboration, the characterization and the implementation of nanostructures combining several physical, chemical and/or biological properties. The objective is to use these systems as ultra sensitive tools to detect biological targets or as advanced biological imaging techniques. Currently, we are able to manufacture a large library of customized nanoparticles exhibiting specific and well controlled properties. For this purpose, different methods of synthesis and surface functionalization processes are developed and characterized. For example, two projects are described below:
- Hybrid Nanoprobes with plasmon-enhanced fluorescence for cell imaging:
Core@shell nanoparticles including a metal core (Au,Ag) surrounded by a silica layer are synthesized. Fluorescent molecules are grafted on the silica surface or embedded inside the silica layer. The localized surface plasmon resonance of metal induces very high electrical fields which enhance the fluorescent emission. This exaltation effect, depending on both the metal-fluorophore distance and metal core size, has been shown for different types of fluorophores: inorganic (SiC nanoparticles) and organic (Cy3, FITC). The ultimate goal is the use of these fluorescent probes for cell imaging. The enhancement of fluorescence would allow to strongly decreasing the required quantity of these hybrid nanoprobes to be injected for in vitro and/or in vivo studies. Moreover, thanks to an appropriate biofunctionalization of silica surface, these nanoparticles would target efficiently specific cells (tumor cells for example).
Contact: Virginie Monnier
Collaboration: Spectroscopy and Nanomaterials Team INL (France), Geneve University (Switzerland), Kiev University (Ukraine).
- Bio-barcode assay for platelet genotyping through the DNA single nucleotide polymorphism (SNP) detection:
The life-time of blood platelets is below 5 days whereas the current time required for platelet genotyping is more than 24 hours. So, this project aims to develop an analytical system based on bio-barcode and dedicated to platelet genotyping. Challenges are to simplify the analysis, to increase the reliability of assay and to reduce analysis time. For this, we use bio-barcodes combined with a biosensor based on evanescent waves for the platelet genotyping. Our process consists in the formation of sandwiches in which two types of micro-particles are combined to the target to be detected: (i) a magnetic particle bearing probes able to specifically capture the target and (ii) a latex particle bearing a high density of fluorescent bio-barcodes (ensuring a highly sensitive detection) and a low density of probes able to capture the target on its other end side. Thus, for each recognition event, detected signal is amplified (up to 105 times). Our assay allows discriminating 2 alleles from HPA-1 gene which differ from only one nucleotide. Successful detection at a concentration as low as 2 fmol/l of label free targets (corresponding to 6×105 copies of synthesized targets) gives the opportunity to avoid a previous amplification step by PCR (Polymerase Chain Reaction).
Contact: Jean-Pierre Cloarec
Collaboration: French Blood Centre, Davos Diagnostic (Suisse).
