Contact

Laboratory for General Biochemistry and Physical Pharmacy
Ghent University
Ottergemsesteenweg 460
9000 Gent
Belgium
Tel: 0032 9 264 80 47 (secretary)
Tel: 0032 9 264 80 74 (direct)

E-mail: juan.fraire@ugent.be

Biography

Juan Fraire obtained his degree in Chemical Sciences (equivalent to Ms. Sc.) in 2011 at the University of Cordoba (Argentina) with great distinction. For his master thesis (Design of Hybrid plasmonic nanostructures by Bio-conjugation: Morphological and Optical Characterization) he received the Sabato Institute 2012 Award in the field of Science and Technology (an Argentinean competition to reward best thesis in the field of materials science). After obtaining the degree in chemistry Juan became a doctoral fellow of the National Scientific and Technical Research Council of Argentina (CONICET). He initiated his PhD research at the Nano(Bio)plasmonics Group under the supervision of Prof. Eduardo Coronado. His doctoral research was mainly focused on the design of gold and silver nanostructures based on different functionalization strategies allowing to develop applications as nanosensors and in the nanomedicine field. During his PhD (2015) Juan was honored with a Fulbright fellowship from the Bureau of Educational and Cultural Affairs of the United States Department of State to perform part of his research at the Photonic Center (Boston University, U.S.A.) under the supervision of Prof. Björn M. Reinhard. These studies allowed him to earn the title of Doctor in Chemistry in 2016. Since 2016, Juan Fraire joined the Laboratory for General Biochemistry and Physical Pharmacy at Ghent University as a post-doctoral researcher.

Summary of Research Project(s)

Noble metal nanoparticles (NPs) have long been recognized for their unique optical properties, associated with the localized surface plasmon resonance (LSPR), particularly their capability to couple to each other through near- and far-field interactions. For a given metal (characterized by its dielectric constant), the LSPR frequency can be tuned in the UV-NIR spectral range by changing the NP size, shape and surrounding media. In addition, as a result of the LSPR excitation, a dramatic enhancement of the extinction cross section (absorption + scattering) and of the electromagnetic field (EM-field) around the NP are observed. These features, in combination with the surface properties of metal NPs that allow developing several functionalization strategies, makes them ideal candidates to a number of applications in nanomedicine, especially in diagnosis and treatment. My research is focused on the application of two different optical properties of plasmonic NPs:

1)    Due to their enhanced absorption capabilities, plasmonic NPs are able to produce the conversion of optical energy into heat via non-radiative electron relaxation dynamics, opening up the way to use them as nanosources of heat, and in particular to use them for the formation of water vapor nanobubbles (VNBs). My goal is to use functionalized NPs with cargo molecules that can be used as therapeutic reagents (i.e., siRNA) to directly deliver them inside the cytoplasm by nanobubble-mediated endosomal escape.
2)    If two or more NPs approach each other, the oscillating E-fields surrounding the NPs interfere with each other giving rise to the so called “hot spots” of maximum E-field enhancement. The Raman signals of the molecules located in these regions of maximum enhancement get amplified several orders of magnitude allowing to obtain information about the “fingerprints” of these molecules surrounding the metal surface. This technique, named surface enhanced Raman spectroscopy (SERS), could be used to obtain information about the composition of exosome-like vesicles (ELVs), which are a novel class of biomarkers used for the detection of cancer at an early stage. My goal (in collaboration with Dr. S. Stremersch) is to design nanoparticles and nanostructures that can improve the sensitivity of identification of this type of biomarkers.