UCL

Advanced materials are at the heart of many scientific fields, particularly in the biomedical and biotechnological areas. Many devices (e.g., biosensors, implants, catheters, and systems for drug delivery) would benefit from an effective control over molecular and cellular interactions at material surfaces. Main challenges in this field include the control of biomolecules (e.g., proteins, DNA) adsorption on different surfaces. Designing surfaces that allow proteins to be adsorbed in a controlled manner is particularly important and challenging. Many strategies were recently developed to spatially or temporally control protein adsorption. In this project, a novel strategy for selective protein adsorption from a mixture of proteins will be developed. This strategy will be based on the use of mixed polymer brushes sensitive to ionic strength and pH of the surrounding medium. The project rests on the following steps: i. The design of mixed polymer brushes whose properties will be tuned by adjusting pH and ionic strength of the medium. The influence of polymer properties (molecular weight, and degree of dissociation and conformation through pH and ionic strength variations) on protein adsorption will be studied. ii. The development of a procedure, based on time-of-flight secondary ion mass spectrometry (ToF-SIMS), to distinguish different proteins adsorbed together on model interfaces. iii. The use of this ToF-SIMS-based procedure to investigate the potential of the created mixed brushes to selectively adsorb one protein, at first from a mixture of two or three proteins, and then from a more complex medium. The results obtained in this work will be significant for material science and biomedical applications through the development of a robust procedure to prepare “smart” surfaces with novel properties to control protein adsorption.

Major scientific challenges nowadays are to preserve the environment, reduce global warming and grow more food to meet the global demand. Mass-producing the right soil microbiota essential to plant health and yield has the potential to be a key part of the next big revolution in the development of sustainable agriculture and food security. Arbuscular mycorrhizal fungi (AMF) are among the most ancient, widespread and functionally important symbioses on Earth that help feed the world. Yet, mass-production of clean (i.e. in vitro produced), safe and robust inoculum at affordable costs remains a critical challenge. MycUpscaling addresses the challenging question of what are the genes responsible for increasing triacylglycerides (TAGs) accumulation in the symbiotic interface and increasing spore numbers to create a novel generation of high-quality and cost-effective AMF inoculants for application in agroecosystems. The project will include combinatorial lipid metabolic engineering, selection of mycorrhized TAG-accumulating hosts, in vitro and in vivo lipid flux analysis, and in vitro spore domestication. We hypothesize that engineering lipid metabolism in mycorrhized plants will (i) increase TAG-based carbon sources in AMF, with spores accumulating more lipids for a higher root-colonization potential (bio-fortification=best quality), ii) stimulate the asexual reproduction machinery to produce more spores in plates and bioreactors (biomass production=high quantity), decreasing cost-fees of in vitro spore production systems (cost-efficiency=industry profitable). MycUpscaling will employ an inter-disciplinary approach combining expertise of the researcher in cell engineering and his supervisors in plant lipid flux monitoring (WSU, USA) and large-scale AMF production (UCLouvain, Belgium). This project will enable the researcher to interact with key leading experts, re-inforce skills and competences, and forge a mature and outstanding international research carrer.

Heat engines are an integral part of our daily lives. They power cars or produce electricity by converting heat into work. Increasing their efficiency is very difficult and only marginal improvements have been achieved over the last decades. Thus, to reach the ambitious climate goals, it is necessary to go beyond conventional technologies. Atom-sized systems where quantum mechanical effects come into play could enable this: theory predicts that their efficiency can be boosted beyond the classical limits imposed by thermodynamics. However, so far, this has not been tested in practice due to a lack of suitable model systems. I propose to build a molecular heat engine of only a few atoms in size, with such high control over its structure and properties that these predictions can finally be tested. The engine's quantum properties will be robust at experimentally accessible temperatures, its coupling to the environment will be controllable, and electrical transport through it will be quantum coherent. I seek to exploit the full gamut of their physical properties to boost efficiency, including spin entropy and vibrational coupling. Practically, I will 1) implement a scanning probe setup into a dilution refrigerator, 2) fabricate single-molecule junctions with micro-heaters and ultra-sensitive superconducting thermometers, and 3) perform and interpret caloric experiments on single molecules at unprecedented precision. The results will teach us about the fundamental properties of atom-scale quantum systems and heat flowing through single molecules. It will inspire new ways to increase the performance of thermoelectric applications such as waste heat harvesters, nanoscale spot-cooling devices, or even thermal rectifiers and transistors. I am one of the forerunners in molecular thermoelectrics, with extensive hands-on experience in material sciences, nanotechnology, and mesoscopic physics. This multidisciplinary background is needed to make this ambitious project a success.