My Latest Projects

Welcome to my portfolio. From experimental passionate projects to commissioned research work, I’ve had the opportunity to create a variety of projects in this dynamic engineering field. I thrive on creative challenges and enjoy building strong relationships along the way. I hope you’ll enjoy viewing my projects as much as I enjoyed working on them. Explore my work below, and contact me directly to learn more.

Characterization of a co-electrospun nanofibrous gelatin polyurethane composite scaffold for cardiac tissue engineering

Researcher: Willa Yue Ying Wei; Principal Supervisor: J. Paul Santerre; Co-supervisor: Yizhou Chen; May 2021 - September 2021

My fourth-year summer research project in Dr. Paul Santerre's laboratory focused on developing a biocompatible, hydrogel-based polyurethane scaffold as a vehicle for delivering human pluripotent stem cell-derived cardiomyocytes into the infarct heart tissue to regenerate viable cardiac tissue. Electrospinning was used to produce nano-scaled fibers by ejecting a polymer solution charged with a high voltage onto a grounded collector. Electrospun nanofibrous scaffolds are suitable for tissue engineering as their fibrous structure resembles the native extracellular matrix. A 50:50 degradable polar/hydrophobic/ionic polyurethane (D-PHI) and polycarbonate polyurethane (PCNU) composite scaffold was generated previously, which showed good compatibility with various cell types. However, this scaffold remained too stiff (~55MPa) and took longer than 90 days to degrade for cardiac applications of interest. When blended with synthetic polymers, gelatin improves the scaffolds' hydrophilicity and cell attachments. Hence, we generated a 55:20:25 crosslinked gelatin/D-PHI/PCNU co-electrospun scaffold.

I characterized the in vitro degradation rate and pattern of the gelatin/D-PHI/PCNU co-electrospun scaffolds, measured the mechanical properties of this composite scaffold, including elastic modulus, tensile strength, and percentage elongation using a custom-built device. The gelatin D-PHI/PCNU co-electrospun scaffolds were placed in 10 units/mL collagenase and cholesterol esterase PBS solution at 37 °C. Weight loss of the scaffold with respect to time was recorded. Degraded samples were imaged using scanning electron microscopy to gain insight into the pattern of scaffold structure changes as they degrade.

I assessed the in vitro cardiomyocyte biocompatibility of this scaffold. Briefly, hPSC-CMs were seeded onto the gelatin/D-PHI/PCNU co-electrospun scaffold. Live/dead staining was performed after 2 days of culture to assess the viability of the seeded cells. SEM imaging was performed to investigate cell adhesion, alignment, and morphology. I studied scaffolds’ structural changes in degradations via Scanning Electron Microscopy, Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and biaxial mechanical tests.

I presented my findings at The Undergraduate Engineering Research Conference and co-authored the conference paper "A Gelatin Polyurethane Composite Electrospun Scaffold with Cardiac Tissue-Compliant Character" for The 2022 Society of Biomaterials Annual Exposition. I was proud to receive The Ted Rogers Center for heart research Translational Biology and Engineering Program USRP Scholarship and The J. Edgar McAllister Foundation Undergraduate Research Award for my research.

The SickKids Project - Design and Development of the Fontan Jacket

The Biphasic Vest Ventilator Fontan Jacket

Researcher: Willa Wei; Jasmine Xiong; Safwan Hossain; Ada Yang

Principal Supervisor: Dr. Osami Honjo;

Co-supervisor: Prof. Kamran Behdinan;

September 2021 - April 2022

My Multidisciplinary Capstone Design project - The Fontan Jacket device project is developed and carried out by the Capstone Design Team in collaboration with Dr. Osami Honjo from The Hospital for Sick Children. The project is supervised by Professor Kamran Behdinan. I am the research lead of my team.

The central objective is to develop a portable non-invasive external ventilation (NIEV) with a controller and pressurization device for synchronization of biphasic ventilation to respiration as to increase cardiac outputs of patients with Fontan surgeries. On a team of four, we would be studying NIEV's effectiveness on various mechanisms of failing Fontan circulation via CFD simulation, rapid prototyping and development of a high-fidelity test rig.

The Fontan Jacket is composed of several subsystems which work together to transform the device input (natural pressure inside the chest cavity) into the desired output (device output pressure which creates increased venous return and subsequent cardiac output). These subsystems include the power module, micro-controllers, actuators, and pressure sensors.

A vest made of elastic fabric material can be used to house the pressure system, and to secure the pressure chamber tightly to the body. A storage compartment implemented at the back of the vest can be used to hold the electronic control systems of the device.

Pressure systems and electronic control systems work together to carry out a suitable biphasic ventilation process that helps achieve the objective of a desirable pressure and cardiac output. The pressure system uses a micro air pump coupled with a solenoid valve to regulate airflow while the control systems use pressure sensors, transducers and microcontrollers that send instructions to the pressure system on how to precisely execute the ventilation process. The process flow chart is outlined in the figure above.

Investigation of the effect from secretions of human monocyte-derived macrophages, post-exposure to gelatin incorporated polyurethane co-electrospun scaffold, on cardiac fibroblast fibrotic character

Researcher: Willa Yue Ying Wei; Principal Supervisor: J. Paul Santerre; Co-supervisor: Yizhou Chen; September 2021 - April 2022

My undergraduate Thesis project aims to investigate the structures and compositions of gelatin incorporated polyurethane co-electrospun scaffolds as they degrade, and to evaluate further the interactions of scaffolds with autologous monocytes/monocyte-derived macrophages (MDM)s and Human cardiac fibroblasts (HCFs). MDMs can provide a viable path for repairing and regenerating damaged cardiac tissue as an endogenous source of stimulatory biomolecules. HCFs play an essential role in the synthesis and degradation of collagen in the heart, and the regulation of collagen degradation enabled by a matrix metalloproteinase. Excess production of extracellular matrix (ECM) structural proteins increases the stiffness of the myocardium and subsequently contributes to impaired heart functions. Currently, I am investigating the effects from secretions of MDMs after being exposed to scaffolds on their cardiac fibroblast fibrotic character via seeding MDMs on scaffolds, a proteome analysis of MDMs’ secretions, and conducting RT-PCRs on fibrosis-related genes in HCFs-cultured MDMs’ supernatant.

Previously, a 50:50 degradable polar/hydrophobic/ionic polyurethane (D-PHI) and polycarbonate polyurethane (PCNU) composite (D-PHI/PCNU) scaffold was generated, which showed good biocompatibility with multiple cell types. Furthermore, a faster-degraded and softer 55:20:25 Gel/D-PHI/PCNU composite co-electrospun scaffold was developed and characterized in the Santerre lab. However, there was no study on the potential adaptation of heart tissue to the scaffolds mentioned above. The human pro-inflammatory cytokines TNF-α, IL-6, IL-1β, and IL-10 in the MDM secretions post-exposure to the scaffold are identified in this work. The proliferation of the HCFs post-exposure to the MDM secretions will be examined. It was hypothesized that there would be similar levels of cytokines TNF-α, IL-6, IL-1β, and IL-10 in MDM secretions collected from Gel/D-PHI/PCNU and D-PHI/PCNU scaffolds, higher levels of IL-10 and lower levels of IL-6, IL-1β, and TNF-α compared to the MDM secretions collected from TCPS. The HCF’s proliferation in the MDM secretions collected from Gel/D-PHI/PCNU scaffold or D-PHI/PCNU scaffold is anticipated to be higher than those in the MDM secretions from TCPS. Differential scanning calorimetry (DSC) was performed on both as-made and degraded scaffolds in order to characterize the differential microstructure of the scaffolds as the gelatin has been shown to lower the material modulus in other work. Changes in modulus affect the biomechanical stimulus of cells.

Mechanical properties of soft contact lenses during handling and cleaning processes

Researcher: Willa (Yue Ying) Wei; Principal Supervisor: Dr. Ahmed Abass;

June 2021 - September 2021

This project aims to report the mechanical properties of commonly used soft contact lenses during handling and cleaning off the human, including the Taco test, compression test, tensile test, and shear test. The Young’s modulus, tensile strength, and the material’s elongation to break for different types of soft contact lens materials were summarized in a report based on literature findings. Based on this information, a three-dimensional(3-D) digital human hand model when handling the soft contact lenses was built using the MATLAB coding and Abaqus software.

Current mechanical test methods and factors that may impact the lens’ mechanical properties and performances including the temperature, shape, composition, and water content of the lens materials are summarized and reported. In addition to that, the average dimensions of human hands of males and females were found from the literature. The average dimensions of human hands of males and females were determined based on several comprehensive studies of the proportions of the human hands. The Abaqus simulations for the soft contact lens materials showed that all commercially available lenses listed in the report can stand the applied loading and compression without significant modifications to their structure during the handling and cleaning processes.

I first-authored a manuscript on the journal Heliyon and later presented it at The University of Liverpool Research Programme Conference.

Microencapsulation of Active Ingredients Into Salts

Researcher: Willa (Yue Ying) Wei; Principal Supervisor: Dr. Levente Diosady; May 2020 - September 2020

The central objective of my third-year research project is to explore the possibility of adding vitamin A/D to salt through a solid premix.

I conducted literature reviews on topics of:

1. Plant-based edible polymers that are water-insoluble.

2. The microencapsulation of active ingredients, such as vitamins.

3. The characteristics of calcium alginates, specifically its solubility in water at higher temperatures.

Active ingredients are substances that can bring beneficial health effects on consumers, such as vitamins. Microencapsulation is a process in which particles are surrounded by a coating or film to give small capsules. This technique is widely applied in ingredients and drug delivery. There are four main methods of microencapsulation: spray-drying, phase separation, spray-cooling, and inclusion complexation. By comparing the advantages and disadvantages of all four methods, the spray-drying method is determined to be the most preferred microencapsulation for thermally-sensitive materials such as active ingredients. This is because spray drying can provide easy control of the material’s properties by changing the operational parameters such as temperature and pressure in the process. The spray drying method produces a dry powder from a liquid by rapidly drying with a hot gas. The ingredients would be dispersed with an encapsulating agent in a solution, the solution is then sent to the drying chamber. The hot drying gas will be blown through the chamber, it will evaporate the moisture and allow the powder to be produced.

I mentored and guided a second-year student, Erin Ng with her prospective summer project in April 2021.

At the end of the summer, I submitted a Summer Thesis report in summarizing my research findings. I presented my findings before the University of Toronto Cafe Food Engineering Research Panel.

Production, Characterization, and Applications of Biochar Carbon

Researcher: Willa (Yue Ying) Wei; Principal Supervisor: Dr. Charles Jia; July 2019 - February 2020

The central objective of my first-year summer and second-year research project is to study the production, characterization and application of Monolithic Biocarbon for Water Desalination and the environmental effects of biochar carbon.

Biomass and biofuels made from biomass are alternative energy sources to fossil fuels—coal, petroleum, and natural gas. Burning either fossil fuels or biomass releases carbon dioxide (CO2), a greenhouse gas. However, the plants that are the source of biomass capture a nearly equivalent amount of CO2 through photosynthesis, which can make biomass a carbon-neutral energy source. Using wood and charcoal for heating and cooking can replace fossil fuels and may result in lower CO2 emissions overall.

I produced biochar carbon materials, cut them into equal cubes, conducted a literature review, and performed characterization experiments on the biocarbon. Furthermore, I assisted the graduate student Mina with interpreting her data with Excel and generating graphs. I presented my findings at the Weekly Update Presentations at Research Group Meetings. I enjoy conducting independent research and designing my own experiments. Before starting my experiments, I ask myself a series of questions, conduct a thorough literature review, or consult my colleagues who have experience in similar work. I work with great focus and maintain a high level of attention to experiment details.