Taye Tolu Mekonnen is a postdoctoral research associate at the University of Sydney, specializing in imaging technologies for diagnosis and treatment. He earned his PhD in Biomedical Engineering from Macquarie University in 2020, where he developed a pioneering imaging technology known as multichannel optical coherence tomography (MC-OCT). This patented device has significant applications in high-speed imaging of upper airway dynamics and non-destructive industrial testing. He was a recipient of the international Macquarie University Research Training Program (iMQRTP) scholarship for his doctoral studies.
After completing his PhD, Dr. Mekonnen began his academic career in Ethiopia as a lecturer at Jimma University. He then moved to the University of Houston as a postdoctoral researcher, where he significantly contributed to the development of optical elastography methods, including a novel form of reverberant optical coherence elastography (OCE), to characterize tissue biomechanical properties. Since January 2023, he has been advancing his research at the University of Sydney, focusing on developing efficient imaging technologies aimed at reducing the cost of inhalers through faster and more effective screening methods.
With a strong foundation in computer engineering (MSc, Addis Ababa University) and electrical engineering (BSc, Bahir Dar University), Dr. Mekonnen is dedicated to enhancing biomedical imaging techniques and their applications in healthcare. His current research interests include advancing and implementing high-resolution optical coherence tomography and optical coherence elastography for drug delivery to the lungs.
Development of an optofluidic system to characterize lower airway fluid dynamics
Understanding the intricate dynamics of respiratory airflow and the transport mechanisms of inhaled aerosols in the airways is crucial for advancing respiratory health. This includes evaluating respiratory risks associated with inhaled airborne aerosols and optimizing inhalation therapy for systemic and topical drug delivery. Extensive research has focused on extra-thoracic fluid dynamics to enhance drug delivery efficacy and comprehend the fate of inhaled aerosols. For instance, the complex geometry and relatively high flow rate in the upper airways leads to flow separation, turbulence, and recirculation zones, which in turn affects the deposition patterns of particles in this region. Particle deposition on airway walls in this region predominantly results from inertia impaction. Conversely, lower airway particle transport and deposition are mainly influenced by gravitational and Brownian motion forces. The slow resident respiratory airflow in regions such as the bronchioles play significant role in determining the fate of microparticles, leading to distinct aerosol transport mechanism and deposition patterns.
Characterization of the fluid dynamics in the narrow lower airway has been mostly limited to computational fluid dynamics (CFD). While CFD is powerful for simulating and understanding fluid flow in various regions of the narrow lower airways, modelling particle dynamics and its interactions with airflow, as well as deposition mechanisms can complicate the simulation. The emergence of microfluidic channel offers an opportunity to assess fluid dynamics in this region in vitro, potentially serving as validation tools for CFD and offer insights into the characteristics of in vivo airflow in these regions.
This study aims to introduce a unique approach for characterizing fluid dynamics in microchannels that mimic lower airway regions using optical coherence tomography (OCT). Unlike high-speed cameras and other microscopic imaging techniques which are limited to focal plane imaging, OCT provides a visualization of microchannel cross-sections, enabling a real-time characterization of flow dynamics. Its high temporal and spatial resolution imaging capacity is vital for accurately quantifying dynamic particle behavior, including tracking its motion and deposition dynamics. We have recently demonstrated the capabilities of OCT in imaging sub-surface microstructures of dry powder depositions and two-phase detection at high resolution (< 5 µm) and substantial penetration depth (~2.5 mm) for the first time. Integrating microscale imaging with microfluidic channels holds promise in providing unparalleled insights into the airflow dynamics in narrow airways. The core aims of this study are to:
• develop an optofluidic system integrating microfluidic system with our existing OCT system;
• examine the dynamic characteristics of aerosols including particle flow patterns, tracking its trajectories, and analysing retention time and deposition behaviour.
As a postdoctoral research associate at the University of Sydney, I have been devoted to advancing optical imaging techniques in the fields of biomedical and respiratory science. In my recent research efforts, I have led the development and optimization of a high-resolution OCT technique designed specifically for analysing the dynamic behaviour of inhalable pharmaceutical powders. Our research, which focuses on characterizing the deposition and dissolution properties of aerosols, with a specific emphasis on applications in inhalation drug delivery, has been provisionally patented.
During my doctoral studies at Macquarie University, I pioneered the development of a novel multichannel optical coherence tomography (MC-OCT) system, a technology which enables the reconstruction of dynamic upper airway geometries during physiological respiration. Subsequently, as a postdoctoral researcher at the University of Houston, I introduced a non-invasive opto-acoustic technique to facilitate a comprehensive assessment of biomechanical properties in soft materials. Building upon these achievements, my current research focus lies in advancing high-resolution optical techniques for evaluating aerosol mechanics relevant to inhalation drug delivery systems. Through this work, I aim to contribute to the development of more effective and targeted drug delivery methods, ultimately improving treatment outcomes.
I am committed to advancing the field of respiratory science through innovative optical techniques. Within this goal, I am exclusively focused on research, specifically dedicated to the development of innovative optical techniques that advance the imaging capabilities of pharmaceutical aerosols. For the next few years, I am committed to establishing myself as a recognized researcher in both Australian and international academic communities. My aim is to build a strong publication record consisting of high-quality and impactful research that is relevant to practitioners both within and outside academia. Securing the DDL Career Development Grant would be of immense value in facilitating this goal, as it would provide me with the necessary resources and dedicated time to further enhance my research output.
In addition to developing my research profile, my short-term goal is to transition into an academic position where I can lead a research group dedicated to advancing optical techniques in the field of inhaled drug delivery. Academic position would provide me with the opportunity to contribute as educator, mentor, and researcher, making significant contributions to scientific knowledge and clinical practice in this domain.
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To achieve my career aspirations, I recognize the importance of continuous learning, skill development, and networking. I plan to pursue additional training opportunities, such as workshops and courses, to enhance my expertise in areas like grant writing, project management, and teaching pedagogy. I will actively seek out collaborations with leading researchers and industry partners to broaden my research scope and impact. Throughout my PhD and beyond, I have had the privilege to work with and learn from distinguished professors across various fields, including biomedical engineering, fluid mechanics, optical imaging and pharmaceutics. The invaluable training I received from these esteemed mentors has equipped me with the necessary knowledge and skills to conduct impactful research, and they continue to be close and reliable mentors. Recognizing the value of collaboration, I seek to leverage my global network to foster additional partnerships beyond my current mentors at the University of Sydney.