Projects 2023

Ever since their discovery, multi-walled carbon nanotubes (MWCNTs) have found numerous applications in different fields due to their extraordinary property pool. In most investigations, a MWCNT-based drug-eluting coating for metallic cardiovascular implants has been developed to improve the hemocompatibility of implant surfaces. MWCNTs can be grown on 316L stainless steel mesh substrates by chemical vapour deposition. Pristine MWCNTs are chemically inert and hydrophobic. For biomedical applications, it is crucial for the MWCNTs to be chemically modified in order to reduce their cytotoxicity and to increase their chemical affinity for pharmaceutical drug molecules. A popular functionalization technique for MWCNTs, which introduces polar chemical groups, such as amines, onto the sidewalls of individual tubes, is non-thermal low-pressure plasma treatment. In this project, plasma diagnostics using techniques such as optical emission spectroscopy are performed to understand the reaction mechanisms involved during ammonia plasma functionalization. Due to the nanoscopic size of MWCNTs, the plasma treatment effects are examined by Raman spectroscopy, chemical derivatization, and x-ray photoelectron spectroscopy. Preference will be given to upper-year chemical engineering undergraduate students who took CHEE 543 – Plasma Engineering in a previous semester.

The student will be in charge of synthesizing MWCNTs, testing different plasma functionalization protocols on MWCNTs, performing material characterization and plasma diagnostics, as well as interpreting the results. After a thorough literature review, the efforts of the student will mainly take place in laboratory spaces under the supervision of a PhD student.

Plasma processing is mainly applied to the materials processing and functionalization sectors such as semiconductor and automotive manufacturing. Recent developments in the studies of non-thermal and warm plasmas have enabled significant progress in expanding plasma processing to include chemical synthesis. Synthesizing chemicals and alternative fuels with plasma processes can allow green and renewable chemical processes that can help reduce the emissions of the current carbon intensive chemical industry. Developing an effective plasma chemical synthesis process requires the integration of optimized reactor design, catalyst design and efficient power delivery. By attempting to ‘power’ chemical processes with electricity, the choice of method of delivering power is critical to create ideal plasma chemical conditions for a given synthesis reaction. Ideally a process would be exposed to many different forms of power delivery such as 60Hz AC, high voltage DC, high frequency AC (kHz region) and radiofrequency. However, constraints relating to cost of power supplies and incompatibilities between electrical systems and plasma systems begin to arise. Designing and building in-house power supplies allows the testing of different power delivery mechanisms as each one can be scaled down and modified to suit the plasma process being studied. Preforming this effectively requires electrical design knowledge that spans the engineering process from circuit schematics and simulations to manufacturing and diagnostics.

The student will be responsible for the design and manufacturing of power supplies and microelectronic circuits for the control of certain power supplies. Regarding the design process, the student must have a basic power electronics understanding and be familiar with circuit simulation and PCB design software. As for manufacturing and diagnostics, the student must have experience with soldering and electrical diagnostic equipment.

M13 bacteriophage is used in multiple biomaterials because of its scalability and ease of production in Escherichia coli bacteria, high tolerance to mutation, and ability to assemble non-covalently into ordered structures and wires due to its high aspect ratio of around 200:1. To improve their mechanical robustness and processability into different materials (hydrogel, fibers, dry films), the phage can be blended with other polymers, such as natural protein biopolymers with excellent processability but poor genetic tunability. This project aims at optimizing a phage-biopolymer composite for material processing, and characterizing the processed fibers and films by their mechanical properties, as well as other properties endowed by genetic engineering of the phage (fluorescence, conductivity, etc.). Finding processable materials with tunable functions from purely biological sources helps advance the field of green plastic alternatives.

The student will be involved in all steps of the fabrication process of the composites: from the production and purification of the phage, to the composite fabrication and characterization.

Cold reactive plasmas (ionized gases produced by an electrical discharge) have been used in several applications, including lighting and thin film deposition. A currently innovative field of research is plasma interactions with liquids for decomposition, synthesis, or generation of active species. A particularly novel direction is the use of plasmas in interaction with organic liquids to perform the synthesis of useful small organic molecules. The project will involve the investigations of a methodology for the preparation of plasma treated organic liquids and the characterization of the species produced. The candidate should demonstrate scientific curiosity as well as maturity and autonomy.

- Contribution the design and assembly of a plasma liquid treatment system. - Characterization of the species produced. - Literature search.

Synthetic Polymers are used in several technological applications due to their many desirable properties: low cost, good mechanical properties, resistance to corrosion and durability. However, their surfaces are typically hydrophobic which limits their wettability and biocompatibility. This issue can be addressed using surface engineering: selectively tailoring the surface properties of materials without affecting the desirable bulk properties. Cold reactive plasmas (ionized gases produced by an electrical discharge) have been used to alter a surface by the addition of functional groups or a functional layer. The project will involve the preparation of plasma deposited organic coatings with compositional gradients and their surface chemical characterization. This method has been demonstrated as promising to improve the performance of thin films for biomedical applications. The project will involve the use of a new X-Ray Photoelectron Spectrometer to understand the chemical composition of these coatings.

- Deposition of thin organic coatings using plasma technology. - Surface analysis and characterization of the deposits - Literature search

Transmission of pathogens through contaminated surfaces is one of the many important contributors to the spread of some microorganisms as they are able to survive on surfaces for relatively long time. There is therefore an established need for materials that can inhibit the transmission of infections via surfaces. In this project, you will contribute to the development of a porous microcapsule virucidal agent based on calcium hydroxide, which serves as a component to obtain highly durable multifunctional coatings which are able to target different pathogenic microorganisms via multiple active synergistic mechanism. The coatings will be evaluated for efficacy and durability. The virucidal, antibacterial and accelerated aging properties will be tested. A special focus will be put on the in-depth surface analysis of the coatings using a novel X-Ray Photoelectron Spectrometer.

- Preparation of thin coatings. - Surface analysis and characterization of the coatings - Literature search.

Cavities spanning the nanometer to micron scales have been suggested to significantly enhance the conductivity of hydrogels: an important characteristic for biological and technological applications of hydrogels, including materials for batteries, energy storage devices, sensors, implants, brain tissue. The mechanism for this enhancement is unknown, but some hypotheses have been proposed, drawing on electrokinetic transport. This project seeks to experimentally test the theory, by conducting a systematic experimental study on polyelectrolyte hydrogels that are doped with uncharged microgel inclusions.

The student will conduct an experimental design and execute it to synthesize a series of micro-gel doped polyelectrolyte hydrogels, systematically varying the charge density of the continuous phase and the concentration of the uncharged dispersed phase. These soft nanocomposites will be characterized by measuring how their ionic conductivity varies with the micro-gel loading and polyelectrolyte charge density.

Despite their contribution to the advancement of modern medicine, cell therapies to treat cancer or cardiovascular diseases remain limited by the complexity of their biomanufacturing process and the high associated costs. In recent years, tools such as microscopic beads and microcarriers have been developed and used in cell therapy manufacture for the isolation, activation and expansion of cells without fully addressing the current challenges. Our team has developed a technology that allows the specific selection of cells from a mixture and the activation of those cells through contact with specific biomolecules. This bifunctionalization method combines two steps of conventional cell culture processes reducing manipulations and complexity, with the potential of greater yields for scale-up. The overall goal of this project is to assist the development of a commercial prototype using our technology for the capture and expansion of endothelial colony forming cells (ECFCs), a highly proliferative cell subtype with vascular healing potential. The specific aims of this project are to (1) determine optimal conditions for ECFC culture on bifunctionalized microcarrier and (2) establish standard operating procedures for the characterization of the cell responses to bifunctionalized microcarrier surfaces such as cell viability, cell proliferation and changes in cell phenotype. Commercialization of this technology has the potential to make cellular therapies more affordable and accessible for the treatment of a wide range of degenerative diseases. Note: This project will be conducted in collaboration with Capcyte Biotherapeutics Inc., a McGill spin-off that is commercializing this technology. Please submit your application in a single pdf (cover letter, CV, transcript) directly on our website (www.hoeslilab.com/join-the-lab). Under “title of position” please indicate SURE 2023: Cell responses to bifunctionalized microcarrier surface.

The trainee will be involved in experiment design, data acquisition, and data analysis. Wet lab techniques could include mammalian cell culture, fluorescence microscopy, flow cytometry, qPCR, Western blotting, immunocytochemistry, and more. The trainee will also be expected to present updates at group meetings. The trainee will also have the opportunity to participate in the business development activities related to the project.

The potential of endothelial colony forming cells (ECFCs) for tissue engineering and cell therapy is increasingly evident. These highly proliferative cells can be applied to sites of ischemia and vascular damage to aid in the healing process. Upon maturation, the endothelial cells (ECs) contribute significantly to the maintenance of vessel homeostasis by producing factors such as nitric oxide, formed through the activity of endothelial nitric oxide synthase (eNOS). Nitric oxide regulates smooth muscle proliferation, vessel tone, and has anti-inflammatory properties. The maturation of proliferative ECFCs into eNOS-producing ECs is critical in vascular homeostasis but not well understood. These two cell types are nearly indistinguishable based on surface marker expression and proliferation and clonogenicity assays are laborious and time-consuming. Current eNOS reporters are either in mouse models (which lack circulating ECFCs) or they contain a promoter/reporter design, which reportedly lacks endothelial specificity due to the complex DNA methylation patterns of the native eNOS promoter. We propose to create a human pluripotent stem cell (hPSC) eNOS reporter cell line by targeted insertion of green fluorescent protein (GFP) downstream of the native eNOS coding sequence, including a cleavage peptide sequence. This will transcriptionally link the expression of GFP to native eNOS, while minimally affecting the protein functionality. We hypothesize that this reporter can be used to study the differentiation of ECFCs to EC non-invasively in real-time and will be invaluable for engineering new treatments for cardiovascular disease .

The trainee will be involved in experiment design, data acquisition, and data analysis. Wet lab techniques could include mammalian cell culture, fluorescence microscopy, flow cytometry, qPCR, Western blotting, immunocytochemistry, and more. The trainee will also be expected to present updates at group meetings.

Pump-probe spectroscopy has become a popular technique for studying energy transport at small length and timescales. Accurate numerical modelling of these experiments remains a challenge due to the large number of input parameters required and the complicated interactions between different degrees of freedom. In this project, we will build upon our in-house software to numerically solve a set coupled heat and carrier diffusion equations for different experimental geometries. By systematically varying the different input parameters to the solver, the relative sensitivities to the quantities of interests (i.e., thermal conductivity and/or recombination time) will obtained. The predictions from these simulations will then be used to interpret recent frequency domain thermoreflectance experiments on germanium.

-Learn the basics of thermal and electronic transport -Read the source code of the in-house numerical solver (Matlab/Python) -Use the solver to simulate an experimental geometry (i.e., frequency domain thermoreflectance) -Predict the sensitivity of the experiment to different model parameters -Use the solver to fit to real experimental data

Rain drops freezing onto engineering infrastructure like wind turbines, airplanes, power transmission lines, wind shields, etc. poses a safety hazard, which has triggered considerable research activity. Traditionally, icing has been addressed by unsustainable and energy extensive heating and chemical freezing point depressants. The ultimate goal of our research program is to develop passively water and ice-shedding surfaces. This project aims at the integration of two existing experimental setups to holistically study the impact dynamics of supercooled water droplets or small ice particles onto fast moving surfaces in cold environments.

The physical integration of the Cold Drop Impact Apparatus (c-DIA) and the droplet levitator will require redesigning fixtures and holds. Furthermore, the student will analyze, rewrite and adapt existing Arduino codes with clear documentation to synchronize drop dispense, sample motion and filming of impact events. Finally, calibration experiments will be executed at ambient and subzero temperatures. The interested student should have experience, skills and interest in Arduino coding and debugging and very good manual skills.

Catalytic and Plasma Process Engineering (CPPE) laboratory is engaged in the development and understanding of catalyzed processes and reactor engineering concepts dedicated to sustainable energy conversion technologies. Within this project, the student in collaboration with a PhD student will focus on the synthesis of novel catalysts for (1) CO2 capture and subsequent hydrogenation to renewable natural gas and (2) the direct non-oxidative methanol conversion to value-added chemicals (olefine). The UG student will work closely together with PhD student and develop, synthesize, characterize new catalysts as well as to test them in our catalytic reactors.

1. Literature review 2. Catalyst preparation (impregnation, solvothem method, ...) 3. Catalyst characterization (BET, chemisorption, TPR, TPD,...) 4. Catalyst activity measurements (Fixed bed reactor, TGA, Plate Reactor connected to mass spectrometer or gas chromatograph) 5. Data analysis and kinetic modeling (material balance calculation in Excel and potentially modeling with Athena Visual Studio)

Itaconic acid (IA) has been cited as one of the top 12 platform chemicals for future bio refineries. IA has been converted to various esters and polymerized via conventional and reversible deactivation radical polymerization (RDRP), the latter providing greater control of the molecular weight distribution and the ability to access controlled microstructures. However, the molecular weights attained have been limited and we have functionalized the IA with a single methacrylic group, which should make polymerization easier, allowing higher molecular weights to be attainable and improved mechanical properties for many applications. Our group has successfully designed a diheptylitaconyl methacrylate (DHIAMA) through multi-step esterification and borylation chemistries and demonstrated its RDRP, yielding a completely new, low glass transition temperature (Tg) polymer (poly(DHIAMA)). To further examine the possibilities with this new monomer, the undergraduate student will further expand the design space by blending or by copolymerization with more rigid monomers that are largely bio-based, such as poly(isobornyl methacrylate) (poly(IBOMA)), which is a high Tg polymer. The student will learn how to apply polymer blending of the poly(DHIAMA) with other bio-based or biodegradable polymers or to copolymerize DHIAMA with other monomers to evaluate its utility in bio-based copolymer compositions.

The undergraduate student will be contributing towards developing a novel bio-based rubbery methacrylic functional monomer derived from itaconic acid (IA), cited as one of the top 12 platform chemicals for future biorefineries. Miscibility studies by blending the two polymers will be conducted to examine the properties of desirable blends with bio-based and or biodegradable polymers, and compatibilization schemes will be developed if necessary. The student will initially learn and apply group contribution theory to estimate miscibility a priori. Further, simple binary copolymerization of IBOMA with DHIAMA to yield statistical copolymers will also be performed by the student and copolymerization models will be tested to determine reactivity ratios and predict final copolymer microstructure and recommend compositions for targeted mechanical properties. Tensile and impact strength will be also performed near the conclusion of the project. The student will learn synthetic techniques, apply characterization tools and report the mechanical properties of various compositions.

Engineering microscale versions of tissues allows us to create designer replacement organs, understand the principles that underlie biological development, and create new sustainable approaches to healthcare and material synthesis. Here, we will investigate the use of laser machining, designer biomaterials, and microfluidic systems, to construct next-generation "organ-on-a-chip" models. Projects will primarily target pancreatic tissue engineering, breast cancer biology and brain tissue engineering; and will require the student to become familiar with cell culture, microscopy, and cleanroom fabrication. These projects broadly require an interdisciplinary mindset, a willingness to figure out how things work, and an interest in collaborating between engineers, scientists, and clinicians.

Hands-on training and experiments for cleanroom microfabrication, materials characterization, cell culture, and microscopy. Literature reading and scientific writing is essential. Room to explore computational modelling if that is of interest.

In this project students will learn how to run DFT computations on simple molecular system and find their optimized structures. Then, they will utilize these skills and knowledge to understand the reaction mechanism on catalytic systems, specifically for CO2 conversion and biomass upgrading.

Students should participate in weekly group meetings. Follow the training instruction week by week, and report their progress during the meetings. Their specific tasks include: working on Compute Canada clusters working with editors such as Vim working with CP2K code working with ASE code working with visualization softwares such as VESTA

Humanity's increasing energy requirements, and instability in countries where most of our global oil resides, forces us to explore new/alternative methods to sustain our current quality of life. An ice-like material called gas hydrates are a possible solution to this crisis. Gas hydrates are non-stoichiometric crystalline compounds that belong to the inclusion group known as clathrates. When water molecules form a network through hydrogen bonding, they leave cavities that can be occupied by a single gas or volatile liquid. The presence of a gas or volatile liquid inside the water network thermodynamically stabilizes the structure through physical bonding via weak van der Waals forces. At present, hydrate research is recognized as an important field due to the hazards and possibilities that gas hydrates pose. Naturally occurring hydrates, containing mostly methane, exist in vast quantities within and below the permafrost zone and in sub-sea sediments. At present the amount of organic carbon entrapped in hydrate exceeds all other reserves (fossil fuels, soil, peat, and living organisms). In 2008, a panel of experts was assembled to assess the potential of gas hydrates as a future energy source in Canada. They concluded that Canada has some of the world’s most favourable conditions for the occurrence of gas hydrate, and is well positioned to be a global leader in exploration, research and development and ultimately, the exploitation of gas hydrates. Moreover, the demand for natural gas has been continuously increasing due to its relatively low emission of CO2 during combustion as well as its use as a feedstock for catalytic processes such as steam-methane reforming for the production of hydrogen. The proposed research program will employ density functional theory modeling methods on clathrates to predict crystal properties and behavior. This is essential in order to design safe, economical, and environmentally acceptable processes and facilities to exploit in-situ methane hydrate as a future energy resource. The work will focus on 3 main hydrate crystal structures (SI, SII & SH) and will also investigate the effect of several inclusion compounds (methane, carbon dioxide, propane, hydrogen, etc.) as well as their mixtures.

The student should have a strong background in multi-phase thermodynamics and crystallization processes. He/she should be fluent in programming and will learn how to use SIESTA. He/she will work closely with a graduate student on this project but must also be able to work independently and diligently.

Primary nucleation in supercooled water droplets is classified as either homogeneous or heterogeneous. Homogeneous nucleation occurs when nuclei of the solid ice phase develop uniformly within the liquid parent phase. Heterogeneous nucleation occurs when nuclei preferentially form at structural inhomogeneities, in other words surfaces and interfaces. At the same temperature, heterogeneous nucleation occurs more favourably, which makes homogeneous nucleation and crystallization difficult to characterize. However, the study of homogeneous nucleation is critical to understanding atmospheric chemistry and crystallization phenomena. Therefore, several droplet levitation methods have been developed to eliminate the effects caused by the presence of solid surfaces and container walls. Recently, an acoustic levitation device called the TinyLev was developed. It uses two arrays of small acoustic transducers to keep several droplets stably suspended in the air simultaneously, and, therefore, eliminates the presence of solid surface effects. There has already been significant study of levitated pure water samples. However, to further our understanding of crystallization in other useful and distinctive solutions, studies of levitated nanofluids and hydrate-forming mixtures must now be conducted.

The student should have a strong background in multi-phase thermodynamics and crystallization processes. They will design and carry out experiments related to nucleation and freezing in acoustically-levitated solutions. Thermal and digital imaging will be used to determine both temperature and morphological characteristics. The effect of various factors, such as position, nanoparticle addition, and promoter concentration, that influence nucleation time of a sample will be investigated. They will work closely with a graduate student on this project but must also be able to work independently and diligently.

The growing presence of micro/nanoplastics in the environment has garnered significant attention from the media and the scientific community due to concerns over their potential environmental and health impacts. Upon their release to the environment, plastics degrade into smaller particles that can bioaccumulate. Detecting and visualizing these plastic particles remain a challenge due to their small size and the complex nature of environmental samples (e.g., natural waters, soils). However, the improvements in technology serve as a springboard to advance our ability to image and identify these plastic pollutants. The primary objective of this project is to develop methods to visualize and characterize different types of plastics as well as their uptake in small aquatic organisms.

The student will be trained in a range of nanotechnology and laboratory techniques that will include, for example: generation of micro/nanoplastics through simulated weathering conditions, particle size determination by dynamic light scattering, particle labelling techniques, fluorescence spectroscopy and advanced microscopy techniques. After receiving the required training in the lab (first month), the student will start working more independently. The student will be introduced to a range of new areas including microscopy, spectroscopy, chemistry, and environmental nanotechnology.

Wastewaters are important stressors for aquatic ecosystems. Some (emerging) contaminants such as microplastics are refractory to conventional treatment such as coagulation, settling and filtration. New low-cost, sustainable, and functionalized materials are promising alternatives to conventional chemicals (coagulant and flocculant) used in the water treatment industry.

Two students will work on distinct but complementary projects. They will be trained in a range of analytical/laboratory techniques related to the water treatment industry that will include, for example: jar test procedures, raw and treated water characterization, floc size measurement, fiber enumeration, microplastics detection, etc. After receiving the required training in the lab, the students will start working more independently. The students will be introduced to a range of new areas including colloid chemistry, water chemistry, materials science, and environmental nanotechnology.

During the last century, plastic drastically accumulated in the environment. Once in the environment, although plastic is a durable material, its weathering produces plastics fragments down to nanometric scale called nanoplastic. Nanoplastics are a great concern as their small size and surface properties enhance their mobility, and their interaction with organisms and pollutants. While nanoplastics are considered as ubiquitous in the environment, little is known concerning their fate and toxicity. This is principally due to the difficulties in detecting, isolating and studying nanoplastics. Due to methodological limitation, fluorescent labeled polymerized nanospheres are commonly used as model nanoplastics for fate and behavior studies. However, these particles are not representative of environmental nanoplastic. The main objective of this study is to produce a relevant traceable model nanoplastic.

The student will be involved in the synthesis of model traceable nanoplastics as well as the physico-chemical characterization of the produced nanoparticles (e.g., microscopy, surface charge). During the training, the student will also be introduced to new scientific areas such as environmental and colloid science; achieving a better understanding of how plastic pollution is studied. After the training completed (first month), the student will conduct the research under the supervision of a postdoctoral fellow.

The use of pesticides is accompanied by significant risk. Unlike many other chemical pollutants, pesticides are developed with inherent biological toxicity and are intentionally released into the environment. While agrochemicals would ideally only impact the target species, pesticide from cultivated lands are transported into surrounding water systems. Consequently, the omnipresence of pesticide residues in the environment has been recognized to threaten freshwater ecosystems globally. This project aims to address these risks with the testing of a new sampling methodologies that was developed in our lab in 2022. Field samples will be collected using this new sampling strategy and will be analyzed for various contaminants including pesticides.

The student will first get familiarized with the background information as well as the context of the project, then will be trained on the various sample collection, preparation and analysis methods relevant to the project, which will later be applied to the samples collected. The student will work in close collaboration with the team members to develop and execute the fieldwork. The student will also participate in weekly research meetings and on a regular basis exchange with members of the other research groups involved in the project.