AGENDA | SPEAKER | PRIZES | POSTERS | REGISTER
Join us for a celebration of research and innovation in Biomedical Engineering and Health Technology at our upcoming event: Biomedical Engineering and Technology Research Day. Co-hosted by the NSERC CREATE Training in Global Biomedical Technology Research and Innovation, the Centre for Bioengineering and Biotechnology (CBB), The Office of Research Health Initiatives, and the Biomedical Engineering Graduate Program (BME), this event wants to celebrate your discoveries!
Biomedical Engineering and Technology Research Day is dedicated to showcasing the remarkable research endeavors of our Master's and PhD students in Biomedical and Health Technology. The event will feature a dynamic poster symposium, a thought-provoking keynote address, and ample opportunities for networking and collaboration.
Don't miss your chance to be part of this exciting event. Register your posters now to secure your spot and a chance to win up to $1000!
*Please note that you can re-use posters from previous conferences, events, etc.
We invite graduate students who wish to present a poster to register here.
If you are a faculty or staff member who would like to attend, please register here.
Agenda
Time: 12:00 p.m. - 4:30 p.m. EDT
Location: E7 Event Space
|
Time |
Location |
Session |
|---|---|---|
| 11:00 a.m. - 12:00 p.m. | E7 Event Space | Poster Setup |
| 12:00 p.m. - 1:00 p.m. | E7 Event Space | Lunch and Discussion |
| 1:00 p.m. - 2:30 p.m. | E7 Event Space |
Posters Showcase |
| 3:00 - 4:00 p.m. | DC 1302 |
Keynote Presentation Title: Advanced microscopies for the development and characterization of biomaterials and biomineralized tissue Speaker: Kathryn Grandfield *If you would only like to attend this talk, please visit here. |
| 4:00 p.m. - 4:30 p.m. | DC 1302 | Prizes Announcement |
For any questions regarding this event, please contact Kenrick Vassall.
Keynote Speaker
Associate Professor, Department of Materials Science & Engineering, Associate Dean of Graduate Studies | McMaster University, Canada
Kathryn Grandfield is an Associate Professor in the Department of Materials Science & Engineering and the Associate Dean Graduate Studies for the Faculty of Engineering at McMaster University, Canada. She holds the Canada Research Chair in Microscopy of Biomaterials and Biointerfaces and is the Past-President of the Microscopy Society of Canada. Dr. Grandfield studied Materials Science and Engineering at McMaster University before attaining a Ph.D. in Engineering Sciences at Uppsala University, Sweden and then completed a postdoctoral fellowship at the University of California, San Francisco. She is the recipient of several early career awards including the Early Researcher Award from the Ministry of Science, Research, and Innovation. Her research within the Canadian Centre for Electron Microscopy focuses on the development of multiscale, multidimensional and in situ correlative microscopies including focused ion beam, electron tomography, atom probe tomography, and liquid phase TEM for advancing the study of biomaterials and biomineralized tissues for applications in bone.
Prizes
Posters
Negin Bouzari, PhD | Chemical Engineering
Title: MiRoCell: Micro robots for cell transport
Abstract: The integration of robotics into medicine is promising due to its potential for improving the quality, speed, and precision of biomedical procedures. However, traditional rigid and bulky robots pose challenges in safely navigating soft and confined tracts of the human body. A robotics paradigm shift towards small-scale soft medical robotics aims to overcome these limitations, enabling untethered and minimally invasive procedures such as biopsy, single-cell manipulation, and drug delivery. This research project proposes the development of a microrobotic system for non-invasive and targeted cell transportation. Key objectives include developing a soft, stimuli-responsive, and biocompatible material that is visible through current imaging modalities; fabricating millimeter-scale robots using additive manufacturing techniques; fabricating micrometer-scale robots using advanced lithography methods; and applying the microrobot for untethered biomedical applications, specifically in transferring single cells or clusters for therapeutic purposes. The suggested functional materials represent an innovative solution offering opportunities for affordable and accessible health improvements.
Irina Bukhteeva, PhD | Physics and Astronomy
Title: Effects of lithium isotopes on sodium/lithium co-transport and calcium efflux through the sodium/calcium/lithium exchanger in mitochondria
Abstract:
The effects of lithium (Li) isotopes and their impact on biological processes have recently gained increased attention due to the significance of Li as a pharmacological agent and the potential that Li isotopic effects in neuroscience contexts may constitute a new example of quantum effects in biology. Previous studies have shown that the two Li isotopes, which differ in mass and nuclear spin, have unusual different effects in vivo and in vitro and, although some molecular targets for Li isotope fractionation have been proposed, it is not known whether those result in observable downstream neurophysiological effects.
In this work, we studied fluxes of Li+, sodium (Na+) and calcium (Ca2+) ions in the mitochondrial sodium/calcium/lithium exchanger (NCLX), the only transporter known with recognized specificity for Li+. We studied the effect of Li+ isotopes on Ca2+ efflux from heart mitochondria in comparison to natural Li+ and Na+ using Ca2+-induced fluorescence and investigated a possible Li isotope fractionation in mitochondria using inductively coupled plasma mass spectrometry (ICP-MS). Our fluorescence data indicate that Ca2+ efflux increases with higher concentrations of either Li+ or Na+. We found that the simultaneous presence of Li+ and Na+ increases Ca2+ efflux compared to Ca2+ efflux caused by the same concentration of Li+ alone. However, no differentiation in the Ca2+ efflux between the two Li+ isotopes was observed, either for Li+ alone or in mixtures of Li+ and Na+. Our ICP-MS data demonstrate that there is selectivity between Na+ and Li+ (greater Na+ than Li+ uptake) and, most interestingly, between the Li+ isotopes (greater 6Li+ than 7Li+ uptake) by the inner mitochondrial membrane.
In summary, we observed no Li+ isotope differentiation for Ca2+ efflux in mitochondria via NCLX but found a Li+ isotope fractionation during Li+ uptake by mitochondria with NCLX active or blocked. Our results suggest that the transport of Li+ via NCLX is not the main pathway for Li+ isotope fractionation and that this differentiation does not affect Ca2+ efflux in mitochondria. Therefore, explaining the puzzling effects of Li+ isotopes observed in other contexts will require further investigation to identify the molecular targets for Li+ isotope differentiation.
Jonathan Chu, Mater's | Mechanical and Mechatronics Engineering
Title: Vertebral detection and labelling using deep learning for spine MRI registration
Abstract: Medical image registration is an important but often challenging aspect for clinical image analysis. It has applications in treatment planning requiring image fusion, inter-subject atlas-based analyses, as well as longitudinal analyses. Spine registration presents extra challenges because of the variability in the field of view (FoV) of the spinal column between different image series. In addition, many vertebrae have a similar appearance leading to many local registration minima. To help improve spine registration robustness, we generate a labelled dataset of cervical spine magnetic resonance imaging (MRI) and successfully apply a Mask R-CNN model with a graph post-processing step to localize and label vertebra. This automated method to generate labelled bounding boxes and masks can then be used to seed initial alignment or crop to appropriate FoV for subsequent affine and deformable cervical spine registration
Chris Czarnecki, Master's | Systems Design Engineering
Title: μArr-Synth – a synthetic dataset generator for DNA-microarray-image-denoising AI models
Abstract: Many microarray images are captured with a considerable amount of noise due to imperfections in slide preparation. The most recent application of a denoising autoencoder has shown promise in removing such noise from the captured images. However, the autoencoder has been trained on experimentally-obtained images, which inherently contain environmental noise. In this paper we present uArr-Synth, a synthetic dataset generator for idealized microarray images. We prove that using a larger set of training images from our generated dataset significantly improves on the baseline flipped peak-signal-to-noise ratio (f-PSNR) metric enabling the training of state-of-the-art AI models for microarray image denoising.
Dency David, PhD | Chemical Engineering
Title: Modulation of vascular smooth muscle cell behaviour by micro and nanotopographical patterning
Abstract: Micro- and nanoscale surface topography has been proven to affect cell fate and has attracted researchers to evaluate the topographic influence on different cell behaviours. Vascular smooth muscle cells (VSMCs) play an active role in the pathogenesis of cardiovascular diseases. Proliferation and migration of VSMCs result in atherosclerosis and intimal hyperplasia formation and have been identified as one of the main contributors to stent and bypass graft re-stenosis. The modulation behaviours of topographies on the VSMC responses have been previously demonstrated, but many focused on limited types and dimensions of topographies. In this study, we hypothesized that by changing the geometry, isotropy and size of topographies, VSMC fate, especially proliferation, migration and contractile-synthetic phenotype changes, could be directed.
Elizabeth Diederichs, PhD | Systems Design Engineering
Title: The effects of physiologically relevant environmental conditions on the mechanical properties of 3D-printed biopolymer nanocomposites
Abstract: Synthetic biomaterials have shown increasing promise for bone replacement materials in recent years. These biomaterials are crucial to replace natural bone grafts and metal prostheses, which historically have had significant practical and clinical issues. To meet the material requirements for these applications, novel nanocomposite biomaterials capable of masked stereolithography printing have been developed from functionalized plant-based monomers and hydroxyapatite (HA) with mechanical properties exceeding those of commercial bone cements. However, these biomaterials have previously not been evaluated under relevant physiological conditions. The effects of temperature, water absorption, and oxidative degradation on the physical, surface, and mechanical properties of HA-containing biopolymer nanocomposites were investigated. Exposure to relevant conditions led to substantial impacts on material performance, such as significantly reduced mechanical strength and stiffness, and surface defects. This project demonstrates the importance of evaluating biomaterials under appropriate physiological conditions throughout their development, and provides direction for further material development of HA-containing biopolymer nanocomposites.
Rachel DiMaio, Master's | Systems Design Engineering
Title: KAUWbot: A language model for pediatric occupational therapy documentation
Abstract: While documentation plays an important role in pediatric rehabilitation, the current amount of time that clinicians spend on the process reduces the amount of direct treatment time with clients and therefore the overall capacity of rehabilitation centres. Reducing the documentation time by 50% at KidsAbility is projected to provide 30,000 more visits to the community. To achieve this reduction in documentation time, the KidsAbility Innovation team has collaborated with University of Waterloo engineering researchers to create KAUWbot, a generative AI documentation assistant for pediatric rehabilitation. KAUWbot uses a custom large language model that has been trained to transform point-form notes from pediatric occupational therapy appointments into draft SOAP notes. The team developed a dataset of point-form notes derived from anonymized clinical notes from KidsAbility to fine-tune a Llama 3 8B model on the task. A secure web application for therapists to use the AI model was developed with clinician input to streamline the challenges of the documentation process. KAUWbot is currently being tested by clinicians at KidsAbility, and preliminary results from the pilot study show that the model can significantly reduce the time that clinicians spend on documentation once clinicians have been properly trained to use the system. Future studies will focus on the quality of the generated notes and quantifying the impact of the time savings.
Abdelrahman Elbadrawy, Master's | Electrical and Computer Engineering
Title: Revolutionizing geriatric care: Radar and digital twin technology for fall severity detection
Abstract: In this study, we present a novel approach for fall detection, leveraging radar-based sensing systems and advanced digital twin simulations. The choice of radar technology is rooted in its capability for high-resolution detection of micro-movements and its inherent respect for individual privacy, as it does not require visual imaging. The integration of digital twins, replicating a diverse array of human physiology and fall dynamics, allows for extensive, varied, and ethical training of sophisticated machine learning algorithms without the constraints and ethical concerns of using human subjects. Our proposed methodology has led to significant advancements in the accuracy and sensitivity of detecting and assessing fall severity, especially in diverse populations and scenarios. We observed notable improvements in the system’s ability to discern subtle variations in falls, a critical factor in elderly care where such incidents can have serious health implications. Our approach not only sets a new benchmark in fall detection technology, but also demonstrates the vast potential of combining radar technology with digital simulations in medical research. This research paves the way for innovative patient monitoring solutions, offering a beacon of hope in improving seniors care and proactive health management. In this study, diverse fall scenarios were simulated under varied conditions. The correlation between the simulation and measurement results is presented. Employing convolution neural networks, we obtained an accuracy of 99.45% using simulated data and 81.25% using measured data, in detecting severity of falls. The analysis addressed various parameters distinguishing different scenarios, including fall speed and the participant’s body size.
Piyush Garg, PhD | School of Optometry and Vision Science, Centre for Ocular Research and Education (CORE)
Title: 3D printed contact lenses for the delivery of polyvinyl alcohol as a wetting agent
Abstract: Ocular drug delivery using contact lenses (CLs) can result in higher drug residence time and drug penetration into the eye, compared to traditional eye drop formulations. Although there are different strategies to fabricate them, to some extent, they are limited by degree of design freedom and complex geometries. To this end, 3D printing may offer a viable solution, enabling on-demand fabrication of CLs. To fabricate a proof-of-concept 3D printed contact lens to release polyvinyl alcohol (PVA). PVA, a commonly used viscosity enhancing agent in eye drops, can stabilize the tear film and protect the human corneal epithelial cells against desiccation stress. PVA, at concentrations around 2%, showed significantly higher cell viability (p<0.05) compared to the control. Similar results were observed with the Refresh Classic eye drop (p<0.05). Moreover, the CLs were printed in about an hour and the minimum thickness for the lenses that was reliably printed each time using the current 3D printing setup was 400 µm. Overall, the results from this study suggest that 3D printing of a delicate structure such as contact lens is possible by tuning the material/ink properties and 3D printing parameters.
Ali Gharamohammadi, PhD | Mechanical and Mechatronics Engineering
Title: A radar-based in-cabin health monitoring system
Abstract: In-cabin health care monitoring is increasingly important for tracking vital signs and detecting occupancy in vehicles. This study employs frequency-modulated continuous wave (FMCW) radar technology to provide a privacy-preserving and contactless monitoring solution.
A dual radar system is developed to observe both chest and abdominal movements, detecting breathing abnormalities such as Tachypnea, Bradypnea, Biot, Cheyne–Stokes, and Apnea. The system achieves a maximum breathing rate (BR) error of 1.9 breaths per minute and accurately identifies breath-hold periods with minimal false detections.
For multi-person monitoring, a multi-input-multi-output (MIMO) FMCW radar system is used. It effectively tracks the vital signs of multiple subjects in the same row and uses variance in detected points for occupancy detection, achieving 96.7% accuracy and a 1.3% miss-detection rate for babies.
Additionally, a 60 GHz FMCW radar positioned behind a seat monitors heart waveforms. Using variational mode decomposition (VMD), the system attains a median interbeat interval (IBI) estimation error of 30 ms and an average heart rate (HR) estimation error of 4.8%. To address vehicle-induced vibrations, an ARIMA model is used for signal reconstruction, resulting in an IBI estimation error of 37 ms and an HR estimation error of 5.9%.
These findings demonstrate the potential of radar technology to enhance in-cabin health monitoring, offering a reliable, non-invasive, and cost-effective solution.
Bhavya Giri Goswami, Master's | Systems Design Engineering
Title: Evaluation of novel model-based exoskeleton controllers in executing assisted compensatory stepping-based balance recovery
Abstract: Compensatory stepping is a balancing strategy humans take as an automatic response to high-magnitude perturbations. It involves changing the base of support by taking single or multiple steps in the direction along/opposite to that of perturbation depending on its type. Assuming our central nervous system (CNS) is trying to control our motion optimally, it's still not clear what specific cost function it's minimizing. Knowing this cost function will allow us to create an approximate intent model of humans that can be integrated with lower-limb exoskeletons. This can be accomplished by modeling the human compensating stepping action with optimal control algorithms, which include calculating foot placement position and comparing the motion to experimental kinematic and kinetic data.
Exoskeletons are wearable robotics suits that can be used for assisting or augmenting human motion. Using state-of-the-art model-based control strategies like Model-predictive Controls (MPC) combined with machine learning on these exoskeletons can help us explore their effects in improving balancing with compensatory stepping behavior. Broadly, this study will bring us one step closer to the understanding human control system and the benefits an exoskeleton can provide to the balance-impaired population and healthy factory workers, in the near future.
Lauren Hoare, Master's | Optometry and Vision Science
Title: Gait and oculomotor function during walking in children with amblyopia
Abstract: Introduction: Amblyopia interferes with typical visual development, leading to deficits in visual acuity, binocularity, and ocular motor function. Previous studies show impaired balance and walking when binocular vision is disrupted by amblyopia. However, the role of ocular motor dysfunction in the development of walking in amblyopia is unclear. Here, I will describe methods designed to assess eye movements during walking in children with amblyopia.
Methods: Children aged 8−12 years old diagnosed with amblyopia and age-similar controls will be recruited. Eye movements will be recorded (Tobii Glasses 2) as well as gait parameters (GAITRite pressure sensitive walkway) during walking. Three walking conditions will be completed: 1) Straight Walk: walk the length of the walkway, 2) Isolated Target Walk: walk the length of the walkway and step on two-dimensional targets, and 3) Distractor Target Walk: walk the length of the walkway and step on two-dimensional target while avoiding distractors. Group differences in gait and ocular motor function during will be analyzed. Relationships of performance to clinical and sensory factors will also be evaluated.
Results: No results reported yet. Preliminary data will be discussed.
Discussion: I predict that compared to controls, children with amblyopia will have impaired gait parameters and ocular motor dysfunction during walking. Exploring these measures will reveal the role of normal binocular vision during the development of visuomotor ability and highlight the contribution of ocular motor dysfunction to poor eye-body coordination in amblyopia. Findings may help guide development of interventions to help prevent or ameliorate visuomotor impairments in amblyopic children.
Afarin Khabbazian, Master's | Mechanical and Mechatronics Engineering
Title: Magnetically actuated soft robots for applications in the urinary tract
Abstract: Kidney stones, affecting about 10% of the global population, are a significant health concern due to their high prevalence and recurrence. Traditional treatments vary from pain management to invasive procedures, but these often have high recurrence rates and complications. This research explores an innovative solution using a small-scale soft magnetic robot to facilitate the dissolution of kidney stones and prevent recurrence. The robot, made of Gelatin-methacrylate, utilizes magnetic actuation for minimal tissue interaction and reliable control. Experiments conducted in 3D-printed urinary tract models demonstrate the robot's maneuverability and effectiveness in delivering drugs to dissolve uric acid stones. In this study, the efficacy of the filaments and the magnet placement and orientation in the robots for actuation are discussed.
Peter Q. Lee, PhD | Systems Design Engineering
Title: Collaborative robot aligning swabs towards freestanding patients
Abstract: This preliminary work examines the usage of a visual servo system to align a nasopharyngeal swab next to a patient's face with a robotic arm. Such systems that have been examined in other works rely on scenarios where patient's heads are held in head fixtures and the target orientation and position is constrained. We consider the scenario where a freestanding patient would approach the arm and receive the test. This presents some challenges, because of the natural motion of a freestanding patient requires the state estimation system to determine the appropriate 6-DOF pose of the face and be robust to natural motion. In addition, consideration is needed to move the end-effector through the workspace while avoiding joint limits, self-collisions, and singular configurations. This work uses a general collaborative arm (Franka Emika Research 1) to serve the role of a multipurpose close-contact robotic healthcare worker. The arm wields an end-effector that holds swab can be electronically attached/detached using an electromagnet. A camera is also attached to the end-effector so that visual servo will be done from an "eye-in-hand" perspective. The system was validated with a number of human trials conducted at the University of Waterloo, which showed its effectiveness as well as avenues to improve the system.
Alexander Liao, Master's | Kinesiology
Title: Environmental scan of Canadian continuing education courses on exercise and nutrition for older adults
Abstract: Older adults are at risk of many non-communicable chronic diseases that are linked with physical inactivity and malnutrition. Non-medical healthcare professionals are important potential health coaches for helping individuals manage these chronic diseases. However, continuing education (CE) is needed to keep professionals up to date with evidence-based practice. To develop better CE courses, it is important to understand the current landscape of Canadian CE offerings.
Researchers identified current courses through a list of relevant organizations, a Google search using specific terms, and key informant interviews. The courses were analyzed using qualitative frequency analysis to understand their characteristics. A total of 36 courses met the inclusion criteria. The analysis revealed that musculoskeletal conditions and fall risks were well-represented topics. CE on nutrition was scarce, with only 5.7% of courses focusing on nutrition. Additionally, only 54.3% of the identified courses were specifically for older adults.
As Canada moves towards an aging population, it is crucial to adequately train our health professionals on these topics. The development of future courses could be guided by the findings of this environmental scan to address missing topic areas for health professionals.
Nelly Madani, Master's | Electrical and Computer Engineering
Title: Dual Energy X-ray for quantitative analysis of areal bone mineral density (aBMD) using a stacked flat panel detector (FPD)
Abstract: This study focuses on spectral dual-energy X-ray imaging using a stacked detector and its potential to derive areal bone mineral density (aBMD) information. The spectral separation of stacked layers enables quantitative aBMD measurement alongside conventional spectral X-ray imaging, allowing for osteoporosis and osteopenia monitoring in routine X-ray exams. Currently, Dual Energy X-ray Absorptiometry (DEXA) is the gold standard for aBMD evaluation and body composition analysis, however, it faces accessibility limitations and motion artifacts due to its source kVp switching for dual-energy image acquisition. In contrast, a portable stacked flat panel detector (FPD) can be used with a conventional X-ray source and acquire dual-energy images in only a single exposure, with deeper detector layers collecting higher energy X-rays. This ensures precise spatial registration, which is critical for an accurate derivation of BMD. The stacked detector can also be used in a portable setting, potentially improving accessibility and clinical utility in more diverse settings. Simulations of DE spectra were performed with realistic models of x-ray spectra and detector response for the stacked detector configuration as well as DE material decomposition for the derivation of aBMD. A promising correlation has been observed between the derived aBMD using the FPD and the ground truth BMD using a phantom containing calcium inserts with varying simulated bone densities. Experiments have also shown robust quantification across imaging conditions (object placement) critical for a portable setting. Ongoing efforts are underway to minimize scatter for improved decomposition accuracy.
Teresa Marotta, Master's | Mechanical and Mechatronics Engineering
Title: Development of a surgical navigation system for arthroscopic knee ligament reconstruction
Abstract: Background: Knee ligament reconstruction surgery replaces an injured or torn ligament with a graft material that attempts to restore the native joint mechanics. To ensure the graft does not stretch to failure during physiological knee range of motion, graft deformation must remain in the elastic region of the stress-strain curve. Relative change in graft length as a function of knee flexion is influenced by the surgical bone tunnel locations for graft attachment. Choosing a bone tunnel location is challenging as the optimal location is not known for each patient and accurate freehand tunnel drilling can be difficult. Additionally, small errors in the tunnel location can lead to major differences in the strain experienced by the graft and risk for potential graft rupture. To combat these issues, a navigation system using intraoperative knee tracking is proposed.
Objective: To develop a surgical navigation system capable of determining the optimal location of the femoral tunnel and providing visual feedback to the surgeon for accurate tunnel drilling.
Methods: An NDI Polaris optical tracking system was integrated with 3DSlicer to develop a navigation workflow, based on clinician input, on the Tactile Orthopaedics knee model. Key workflow steps included registration to medical images and 3D bone models, surface point collection, knee axis identification, and visual feedback for tracked tool placement.
Next Steps: A cadaver biomechanics study will be performed to analyze the differences in the knee axis location in ACL-deficient and sufficient knees to inform the next stages of the navigation workflow.
Benjamin Masters, Master's | Systems Design Engineering
Title: Analysis of physiological measures around conversational state changes
Abstract: Perhaps the most consequential effect of hearing loss is the impact it has on communication. However, assessing listening effort in interactive environments is difficult, as our attention must be simultaneously divided between listening, speaking, and a variety of other possible contextual demands. The goal of this work is to extend the use of physiological measures of listening effort to interactive conversation. The initial work here investigates variations in pupil dilation around conversational state changes during task-based conversations. Here, conversational state changes are defined as the points in time at which speakers start and stop talking. We derive pupillary temporal response functions to conversational turn-taking and reveal systematic pupil responses that seem to correspond with our expectations around listening and speaking effort in conversation. Our findings, based on data collected from 12 sets of interactive conversations taking place in varying levels of noise and simulated hearing loss, offer insights into how physiological responses during complex interactions can be measured and interpreted to infer how effort is directed throughout conversation.
Christian Mele, PhD | Systems Design Engineering
Title: Biofidelic knee mannequin design for pHRI evaluation of lower-limb exoskeletons
Abstract: Lower limb exoskeletons are wearable assistive robots designed to provide support to a user to improve mobility. Undesirable physical human robot interactions (pHRI) may occur during use, particularly from biomechanical incompatibilities, offsets and misalignments. Undesired shear, normal and moment forces can occur from these interactions, leading to musculoskeletal and skin injuries during use. Measuring interactions from experimental evaluation is difficult due to risks to the user. Modeling approaches are inadequate due to the complex and non-linear interactions present.
The motivation of this study is the development of an anthropometric test device (ATD) or Mannequin to act as an intermediate and reliable testing platform between simulation and user experimentation to study interaction mechanics.
Sadaf Mohsenkhani, PhD | Systems Design Engineering
Title: Towards an in vitro model of the closed-eye environment
Abstract: Contact lens wear, especially overnight, poses risks of vision-compromising complications, linked to increased polymorphonuclear neutrophil (PMN) activity on the ocular surface during nighttime closure. PMNs play a crucial role in the inflammatory response to microbial colonization or tissue damage, pivotal for ocular immunity and defense. Clinical studies have shown tear PMNs (the PMNs found on the ocular surface in the tear film)differ from blood PMNs, presenting unique activation and degranulation profiles. Different activation states and functional responses in tear neutrophil populations is evident from the various profiles of activation markers on the cell membrane. Understanding the factors affecting these response is key to deciphering neutrophil biology in ocular surface health and designing biocompatible ocular materials. To gain a further understanding of ocular and inflammatory cell interactions and material-induced inflammation, an in vitro model that can reproduce the closed eye environment and the phenotype of tear PMNs is needed.
Haresh Patil, PhD | Systems Design Engineering
Title: Bioinspired mandrel-bed 3D printing enhances damage tolerance of nanocomposite
Abstract: Biological materials such as wood, bone, bamboo are natural composites. They have developed remarkable damage tolerance with crack deflection at weak interfaces in their hierarchically organized, concentrically layered, lamellar microstructures. This work demonstrates a novel approach to mimic such concentric layer microstructure with mandrel-bed Direct Ink Writing (DIW) to print robust nanocomposite structures. Since photopolymerization exhibits stiffness transition at the layers of interface bonding in 3D printed parts, a method of controlling damage tolerance of DIW printed structure by tuning interface bonding was discussed.
A photocurable nanocomposite (ink) was prepared by dispersing heat treated hydroxyapatite nano particles (nHA) into a functionalized biopolymer resins composed of Acrylated Epoxidized Soybean Oil (AESO), polyethylene glycol diacrylate (PEGDA) as diluent, and a small volume of tri glycerol diacrylate (TGDA) as a building block monomer. Concentrically layered Crisscross (+/-45°) and twisted ply (Bouligand) microstructures were printed using the mandrel bed 3D printer. Single Edge Notched Beams (SENB) were cut from the printed microstructures. SENB specimens of nanocomposite ink were cast in a machined PTFE mold for isotropic control. Beams were also cast with nanocomposite ink resin by curing in layers. The fracture toughness of all printed and cast nanocomposite specimens was measured using fracture test (based on ASTM-E1820). Stiffness and retraction force at the interfaces of cast resin beams was measured with atomic force microscopy (AFM) to determine the effectiveness of interfaces in controlling the damage tolerance of structures.
Scanning electron microscopy (SEM) images of printed microstructures revealed distinct and differentiable interfaces in the mandrel bed printed microstructures of the nanocomposite. The 3D printed Crisscross microstructure shown reduction in fracture toughness than the isotropic control and Bouligand microstructures improved the fracture toughness over the isotropic control. This work provides valuable insights regarding interfaces developed in DIW printed photocurable nanocomposites structures and their effectiveness in tuning damage tolerance with bioinspired 3D printing.
Mariya Peskova, Undergrad | Systems Design Engineering
Title: Development of decellularized bone as a control for in-vitro biocompatibility testing of novel bone graft materials
Abstract: Various solutions are being developed for bone reconstruction, including synthetic biomaterials. Current studies commonly use hydroxyapatite as a control to evaluate novel biomaterials. While hydroxyapatite is a clinically established material and occurs naturally in bone, it differs significantly in structure and composition compared to bone tissue. Decellularized bone provides a good alternative due to its greater availability, lower cost, and better representation of the bone environment. This project explores whether decellularized bone can be used as a positive control material for bone remodeling in vitro. Discs of bovine bone were decellularized and sterilized using a novel super critical CO2 technology. Preliminary testing with immortalized cells indicates that the decellularized bone supports osteoblast and osteoclast proliferation and differentiation, showing promise as a new control material. Future work will include optimization of protocols with primary cells and identification and quantification of resorption pits.
David Phan, PhD | School of Public Health Sciences
Title: Why brain slices should be used as part of the developmental pipeline when screening a drug’s activity in the central nervous system
Abstract: Due to their relatively inexpensive and high-throughput workflow, in vitro assays are relied upon to predict toxicity and efficacy. However, concerns have been raised over the reliability of the cell-based assays frequently used in drug candidate and toxicity screening. In particular, these assays typically have cells of the same type cultured in a monolayer, which limits cell-cell interaction and cellular differentiation. As well, such models fail to reflect the cellular diversity and microenvironment that exists in vivo, which may significantly alter how cells respond to a drug. Tissue-based models, on the other hand, retain the cellular diversity and architectural complexity of the in vivo microenvironment, which should generate results that more accurately reflect a drug’s behaviour. To illustrate the possibility that a compound may behave differently in cell-based and tissue-based models, I used an example of the latter type (acutely prepared brain slices) to examine an effect that has previously been observed when dissociated neurons are treated with the stress hormone corticosterone. In particular, while an increase in the cell-surface localization of AMPA receptors over time was observed after corticosterone treatment in dissociated neurons, these receptors were downregulated in brain slices. My findings are among several examples that encourage the addition of brain slices in the drug development process, especially for drugs involving the central nervous system. Building on these observations, a method to operationalize the use of brain slices for high-throughput screening using a multi-well format will be discussed.
Yurii Potsiluienko, Master's | Science, Physics and Astronomy
Title: The importance of instrument effects on light polarization when imaging retinal biomarkers of brain diseases
Abstract: Through a combination of experimental measurements and computer modeling, we have characterized the polarization effects of the confocal scanning light ophthalmoscope (CSLO), which will be employed for retinal imaging to detect retinal protein deposits, serving as biomarkers for brain diseases such as Alzheimer's. Subsequently, we identified the optimal settings for the polarization state generator and analyzer to effectively compensate for these polarization effects.
Matthew Robichaud, PhD | Systems Design Engineering
Title: Evaluation of shear-treated platelet and leukocyte reactivity before cardiopulmonary bypass
Abstract: Non-physiological shear is known to induce platelet extracellular vesicle formation and a corresponding loss in adhesive receptors. In the thromboinflammatory environment of cardiopulmonary bypass (CPB), exposure to shear stress may enhance platelet dysfunction and contribute to excessive bleeding and transfusion. The objective of this study is to determine if the platelet response to shear stress in the presence of biomaterials differs between individuals who require blood component replacement and those who do not. Whole blood from patients undergoing CPB were exposed to a shear-biomaterial environment before being activated by platelet or leukocyte agonists. Cell-surface receptors were assessed by flow cytometry. Transfused patients had larger platelets and a higher inflammatory status pre-operatively. Extracellular vesicles correlated to a reduction in platelet size and partially explained the loss of adhesive receptors under increasing shear stress. Platelet vesicles also correlated to neutrophil and monocyte CD11b upregulation in the biomaterial environment.
Erica Rossi, Master's | Mechanical and Mechatronics Engineering
Title: Clinical training for manufacturing of air actuated balloons for dynamic socket-limb interfaces
Abstract: Background: Diabetic pressure ulcers account for up to 80% of all lower limb amputations, a complication exasperated by neuropathy. The prosthetic socket, an interface between the residual limb and the prosthetic, relies on proper fit to maintain the integrity of the skin and comfort of the user. Although sockets are shaped to the unique geometry of the residual limb, limb volume fluctuations (-/+ 10% daily) and loss of limb sensation directly challenge the socket fit. To combat the manual adjustment current dynamic sockets present, a novel prototype self-adjusting in-socket pressure sensing and air microfluidics-based balloon, that acts as an intermediate layer between the socket and limb, has been developed.
Objective: Integrating the manufacturing of air microfluidics-based balloon into clinical practice such that clinicians can incorporate these balloons into their socket creation, enabling further dynamic customization and an increased quality of care.
Methods: Manufacturing documentation was developed and introduced to an undergraduate research assistant such that pitfalls of the communicated steps were identified, and the most effective means of assembly were determined.
Next Steps: Following changes in the fabrication process, the sensors and their means of assembly will be introduced to prosthetists where they will be asked to generate prototypes independently. These prototypes will be returned to the Neural Rehabilitation Engineering lab for testing to examine their quality. In addition, interviews with the prosthetists will be conducted to gain insight into clinical and system level concerns as well as benefits that will be associated with the implementation of the sensors.
Sadegh Sadeghzadeh, PhD | Electrical and Computer Engineering
Title: Multifunctional dopamine-based microneedle biosensor for ketone body monitoring
Abstract:
Ketoacidosis, a severe complication primarily occurring in type1 diabetes due to insulin deficiency, direct the body to utilize fats for energy, leading to excessive ketone production and acidity. Monitoring ßHB levels is crucial for type1 diabetes patients to prevent ketoacidosis1, especially as the rise in the ketone level can be assumed as an
early indicator of insulin deprivation. Hence, monitoring the level of ßHB is important to type1 diabetes patients since they are more prone to experience ketoacidosis2.
Microneedles are a new platform suitable for minimally invasive systems. Some metallic Microneedle systems have
been developed for ketone monitoring; however, there is a high risk of needle breakage and, consequently infection in the insertion area. In contrast, hydrogel microneedles are a potent option for ketone sensing due to their biocompatibility, anti-biofouling features, inherent properties in hydrogels. In the current study, the ß-Hydroxybutyrate Dehydrogenase (ßHBD) enzyme together with its cofactor NAD+ was integrated into the hydrogel microneedle (Dopaminated Hyaluronic acid mixed with PEDOT:PSS). NADH as a secondary product of the enzymatic reaction is electrochemically active making it possible for electrochemical sensing; however, the anodic reaction has an overpotential5. Using a redox mediator is an established technique to decrease the NADH overpotential. Dopamine (dual-functional component) was employed in the current study as a redox mediator and cross-linking agent, the first hydrogel microneedle for continuous ketone body sensing.
The interaction of NADH with dopamine was confirmed in in-vitro studies. By increasing the concentration of NADH, a rise was observed in the anodic peak; conversely, a decrease in quinone. Ex-vivo studies were performed on porcine skin, Microneedle patches were applied on the skin equilibrated with different concentrations of ßHB.
Chronoamperometry current (0.3 V) was recorded for 20 seconds, designated as pre-oxidation current; followed by 10 seconds accumulation time. Then, chronoamperometry (0.3 V) was performed for 50 seconds, designated as detection current. The normalized current was defined as the ratio of detection current to pre-oxidation current. A linear response was observed for ßHB concentration below 1.5 mM with a sensitivity of 0.09/mM.
Additionally, the mechanical properties of the microneedle patch were evaluated by compression mechanical test. The microneedle patch could tolerate forces much higher than the required force (0.3 N/needle) for skin penetration; also, SEM images confirmed the intact structure of Microneedles. Streptozocin-induced diabetic rats were used as animal models for in-vivo studies. Microneedle patches were applied on the back of the rat and fixed with Tegaderm. Then, the ketone level was measured by both the microneedles patch and ketone strips (blood in the tail) using the Freestyle Libre ketone meter. We calculated a MAD (mean absolute difference) of 0.184 mM for ketone levels < 1.5 mM and a MARD (mean absolute relative difference) of 7.68% for ketone levels of ≥ 1.5 mM.
Corin Seelemann, PhD | Engineering
Title: Collagen denaturation correlates with human cortical bone fracture resistance
Abstract: Human cortical bone has toughening mechanisms that provide resistance to crack growth. These behaviors occur because of the hierarchical multiscale order of bone’s primary constituents, collagen protein, and hydroxyapatite mineral. One toughening mechanism is the denaturation of collagen during fracture, which suggests that the energy is absorbed to break the internal hydrogen bonds in collagen rather than extending the crack. Understanding the mechanisms of bone fracture resistance could provide vital information in understanding causes of human bone fragility. Here we test the hypothesis that collagen denatures because of fracture in human cortical bone, and the extent of denaturation positively correlated with the work to fracture.
Five single edge notched beams from human femurs, each from a different donor (aged 19-61), were fractured under 3-point bending with the crack propagating circumferentially on the transverse plane. The work needed to grow the crack by approximately 250 µm was computed for each beam. The fracture surfaces and a negative control were cut from each specimen using a metallurgical saw. These were stained with fluorescently labelled collagen hybridizing peptides (F-CHP) and imaged using laser scanning confocal microscopy. The controls were used to create a threshold level of staining that indicated mechanical denaturation. The percentage of pixels above that threshold within the first 250 µm of crack growth was used to measure the extent of collagen denaturation.
Human bone collagen consistently denatured because of fracture. Every specimen demonstrated increased staining in the region analyzed. Collagen denaturation correlated to work done (R2 = 0.87).
Simran Singh, Undergrad | Systems Design Engineering
Title: Investigating the influence of tear proteins on immortalized human corneal epithelial cells in vitro
Abstract: In vitro models of the ocular surface, specifically the cornea, are developed to test the toxicity and biocompatibility of ophthalmic biomaterials. Corneal epithelial cells (CEC) interact closely with the tear film, containing essential proteins for ocular surface health. This study investigates how two tear proteins, lysozyme and lactoferrin, in artificial tear solution (ATS) influence the adhesive properties of immortalized human corneal epithelial cells (HCEC). ATS variations were prepared with and without these proteins, using Roswell Park Memorial Institute (RPMI), mucin, albumin, and IgG. An HCEC monolayer was cultured in a 48-well plate with keratinocyte medium (KM) refreshed every 72 hours. Following a 6-hour incubation at 37°C, 5% CO₂ in ATS, flow cytometry quantified cell membrane receptors CD49b, CD49c, and CD29, involved in cell adhesion, and CD54, a marker for cell activation and promoting immune cell-interactions. Results show no significant changes in surface membrane receptor expression, indicating that exposing HCEC to tear proteins does not affect their adhesion properties.
Sarah Sparkes, Master's | Systems Design Engineering
Title: Fabrication of soybean oil-based magnetic, helical milli-screws for blood clot removal
Abstract: The formation of blood clots can lead to potentially life-threatening complications, such as stroke or pulmonary embolism. Current clinical approaches for blood clot removal involve surgical intervention and/or the administration of anticoagulant drugs.
The use of 3D-printed, helical, magnetic milli-scale robots for the mechanical disruption of blood clots and local delivery of anticoagulant drugs has been proposed in the literature. The robots are guided to the blood clot via an external, rotating magnetic field and visualized using either ultrasound or x-ray fluoroscopy. Use of these robots allows particularly for the removal of clots in regions of the body that are difficult to access with a catheter.
While many studies in the field of milli- and microrobotics focus on the optimization of robot design, propulsion, and navigation, the research proposed for this MASc thesis instead focuses on improving the hemocompatibility, imaging contrast, and drug delivery capabilities of a milli-scale screw for blood clot removal.
Youchao Teng, PhD | Mechanical and Mechatronics Engineering
Title: Biomass derived nanomaterials based wearable sensors platform for health monitoring
Abstract: Wearable devices capable of detecting vital signs such as pulse, respiratory rate and temperature have great potential for commercialization and integration into daily life. Sweat is an attractive medium that contains multiple molecular biomarkers that wearable sensors can analyze. Continuous monitoring of these biomarkers has the potential to complement laboratory-based blood tests, enabling real-time tracking of daily health and early disease detection and management, especially in the context of the global COVID-19 pandemic.
Currently, the market-available wearable sensors are mainly bulky sensing and energy supply components, inflexible and single stimuli-responsive function, causing unsatisfactory human-machine interface and insufficient data accuracy and awkward wearing experience, which leads to the "wearable is not wearable". In addition, energy supply devices for wearable sensors still face the constraints of requiring frequent charging and replacement. It is urgent to construct similar mechanical properties, superior biocompatibility, multifunctional interfaces between flexible wearable sensors and human tissues, and a flexible and self-charging power supply unit to push the paradigm shift from current wearable 1.0 biosensing technologies to future second-skin-like wearable 2.0 products.
Given the above issues, I propose to fabricate a fully self-powered wearable sensor for multimodal real-time human health monitoring. Soft nature wood-based hydrogel, whose elastic modulus (~kPa) is very similar to natural human skin, will be fabricated as the flexible bionic structures of a highly robust, lightweight, and energy-autonomous wearable platform. Then this wood-based hydrogel is seamlessly integrated with a flexible triboelectric nanogenerator (TENG) which efficient energy extraction from body motion with multiple flexible sweat biosensors and biophysical sensors and puts all of them on the flexible substrate. Lastly, we use this device for real-time human health monitoring and wirelessly transmit data to the user interface by Bluetooth. This data will be analyzed by machine learning to provide feedback on health.
Yue Xu, PhD | Physics and Astronomy
Title: Trehalose sugar protects lipid membrane against amyloid-beta toxicity in Alzheimer's disease
Abstract: The amyloid-beta peptide (Aβ1-42) is one of the main pathogenic factors in Alzheimer’s disease and is known to induce damage to the lipid membrane (Drolle et al. 2017). Trehalose, a naturally existing disaccharide, has been shown to protect plant cellular membranes in extreme conditions and has been attracting attention in neurodegeneration research due to its ability to reduce Aβ misfolding (Khan and Kumar, 2017). We hypothesize that trehalose can also protect the neuronal membrane from amyloid toxicity. In this work, we aimed to explore the potential protective effect of trehalose against Aβ-induced damage in model lipid membranes (DPPC/POPC/Cholesterol in mass ratio of 4:4:2), used to mimic neuronal membranes. We used atomic force microscopy (AFM), Kelvin Probe Force Microscopy (KPFM), Black lipid membrane (BLM) and Localized Surface Plasmon Resonance (LSPR) techniques.
Our AFM and KPFM results demonstrated that trehalose modifies the properties of model lipid membranes and monolayers (both topography and electrical surface potential), especially in combination with NaCl. Our BLM data show that Aβ induced damage to membranes and led to ionic current leakage across membranes due to the formation of various defects and pores. The presence of trehalose reduced the ion current caused by Aβ peptides’ damage to membranes. Our LSPR results revealed that trehalose potentially reduces the binding of Aβ to lipid membranes, indicating the protective effect through suppression of Aβ-membrane interaction.
These findings suggest that trehalose sugar can be useful in protecting neuronal cellular membranes against amyloid toxicity, and thus, this study may contribute to the development of membrane-targeted preventive approaches to overcome AD.
Trevor Yu, Mater's | Systems Design Engineering
Title: Encoding medical ontologies with holographic reduced representations for transformers
Abstract: Transformer models trained on NLP tasks with medical codes often have randomly initialized embeddings that are then adjusted based on training data. For terms appearing infrequently in the dataset, there is little opportunity to improve these representations and learn semantic similarity with other concepts. Medical ontologies represent many biomedical concepts and define a relationship structure between these concepts, making ontologies a valuable source of domain-specific information. Holographic Reduced Representations (HRR) are capable of encoding ontological structure by composing atomic vectors to create structured higher-level concept vectors. We developed an embedding layer that generates concept vectors for clinical diagnostic codes by applying HRR operations that compose atomic vectors based on the SNOMED CT ontology. This approach allows for learning the atomic vectors while maintaining structure in the concept vectors. We trained a Bidirectional Encoder Representations from the Transformers (BERT) model to process sequences of clinical diagnostic codes and used the resulting HRR concept vectors as the embedding matrix for the model. The HRR-based approach modestly improved performance on the masked language modeling (MLM) pre-training task (particularly for rare codes) as well as the fine-tuning tasks of mortality and disease prediction (particularly for patients with many rare codes). This is the first time HRRs have been used to produce structured embeddings for transformer models and we find that this approach maintains semantic similarity between medically related concept vectors and allows better representations to be learned for rare codes in the dataset.
Hanjia Zheng, PhD | Electrical and Computer Engineering
Title: A hydrogel microneedle integrated electrochemical aptamer-based biosensor for multiplexed glucose and lactate quantification
Abstract: Conventional biomarker quantification techniques require invasive sample collection process and laboratory-based assays, which are costly, time-consuming, and require skilled personnel. Transdermal biosensing utilizing skin interstitial fluid (ISF) for biomarker quantification, has great potential to revolutionize the healthcare system by enabling a simple approach to track patient health conditions. In this study, we developed a hydrogel microneedle (HMN)-integrated electrochemical aptamer biosensor, named the Wearable Aptalyzer. This device aligns with the demands of the diabetic healthcare, providing a real-time, continuous, non-invasive, and sensitive approach for glucose and L-lactate monitoring for diabetic patients. Significantly, the Wearable Aptalyzer serves as a universal sensing platform, enabling the tracking of a diverse range of clinically important biomarkers using different aptamers, which cannot be achieved enzymatically. This demonstrates the potential of applying the Wearable Aptalyzer to a broad range of continuous monitoring technologies.
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