Alexandra Homsy
Haute Ecole Arc Ingénierie, HES-SO, La Chaux de Fonds


Microfluidics-based formulation of bacterial-fungal consortia for delivery in soil


In this study, we present a novel type of microfluidics-based formulation for the delivery of microbial control agents (mBCAs) in soil, where bacterial cells and fungal spores are directly combined into micrometer-sized alginate capsules. This process resulted in the reproducible production of 500 µm sized beads in a good throughput for this type of biofluid (up to 48 beads/min). A subsequent chitosan coating (1-2 µm-thick) provided a good storage stability at 3 months, with 100% microcapsules containing viable fungal biomass and 60-80% with viable bacterial cells depending on the species. This novel formulation was tested both in the greenhouse and on-farm with lettuces, and encapsulated microbial biomass had a more prominent effect on crop growth and yield, as compared to their delivery as a liquid suspension.
Optical technologies in particular stand to benefit from concomitant nanomaterial engineering and bioengineering approaches. This presentation highlights specific applications in optical sensing and light-harvesting energy technologies that exploit the synergistic coupling of nanobio-hybrid materials. We discuss the development of bio-conjugated single-walled carbon nanotubes (SWCNTs) for near-infrared fluorescence sensing and the application of these sensors for continuous measurements in living cells and organisms. We further explore the development of living photovoltaics based on bioengineered, photosynthetic organisms with nano-augmented capabilities.


Alexandra Homsy is currently an Associate HES Professor at the HE Arc Ingénierie, Switzerland. She obtained a PhD ès Sciences in 2006 at the University of Neuchâtel, and a Master's degree in Physics in 1999 from the EPFL. She did her post-doc at the Tyndall National Institute in Cork, Ireland where she developed multiphase microfluidics systems. Between 2007 and 2011, she managed the microfluidics team of PhD students in Prof. Nico de Rooij’s laboratory at the EPFL.
Her present research activities at HE-Arc focus on microfluidic systems for real samples handling, like blood, saliva, or biomass. The aim is to develop devices for continuous sample processing towards integrated lab on a chip systems. To achieve such goals, she developed an expertise in membrane integration, lab-on-a-chip optics integration, all-polymer microsystems, and materials and fabrication methods for industrialization of health and food diagnostic systems.