Advanced Research Laboratory for Multifunctional Lightweight Structures (ARL-MLS) Biomedical

Research in Biomedical

Problem Statement

ARL-MLS is now navigating towards bridging the gap between biology and technology with the study of the various aspects of human body and medical care devices. The concepts are concerned with the impact of physical forces on biological structures and materials in the fields of fluid mechanics, solid mechanics, dynamics, and manufacturing, as well as its application to human health. Manufacturing encompasses the research and development of innovative processes for the fabrication of biomedical micro/macro devices, metal and polymer implants and sensors, tissue constructs, scaffolds as well as artificial organs. At ARL-MLS we strive to develop solutions for:

Highly standardized and regulated methodologies.
Human health automation.
Space exploration and sustenance.
Ergonomic and consumer friendly wearable devices.
Energy scarcity for long term medical care products.
Cost effective health care systems and methods for easy assimilation.
Risk management and safety inspired device propagation.
Novel Biocompatible material selection and adoption for higher functionality.

Solutions

To overcome the many global challenges in the field of Biomedical Research, ARL – MLS has been actively developing cutting edge solutions such as:

High Precision interactive computational methods for real-time investigations in biomechanics.
Regulatory Approach towards biomedical product innovation.
Surrogate and smart models for live health monitoring and administration.
Implantable and wearable solutions for sustainable health care infusing human factor studies.
Energy solutions for wearable and implantable devices for long term application.
Advanced Operation Research and Systems design methods towards biomedical product management.
Interdisciplinary approach towards bioengineering solutions for improved user experience and product performance.
Development according to industry best practices using ISO/IEC guidelines (ISO 13485, ISO 14971, IEC 60601, etc.).

Projects

Effect High Speed Gz on the human heart

Abstract

Myocardium generally demonstrates viscoelastic behavior. Since the stress–stain relationships of tissues are pseudo-elastic, their mechanical behavior can be defined as hyperelastic. In this work, mechanical properties of bovine heart were studied. In this study, the experimental technique for testing myocardium is explained and the experimental data are presented. First, the heart was perfused and the specimens were cut from different regions of the heart. Second, the materials preferred direction was identified. Then, a series of uniaxial, biaxial and equibiaxial test were performed on specimens taken from: left ventricle free wall (LVFW), right ventricle free wall (RVFW), left ventricle mid-wall (LVMW) and apex. Test specimens were preconditioned by applying cyclic load to reduce the viscoelastic effect. After preconditioning, the samples were tested at various stretch rates and loading conditions. Finally, a conclusion is made on the experimental data.

Citation

Ghaemi, H., Behdinan, K., & Spence, A. D. (2009). In vitro technique in estimation of passive mechanical properties of bovine heart: Part I. Experimental techniques and data. Medical engineering & physics, 31(1), 76-82.

Reaming of Cancellous Bone of the Femur

Abstract

Reaming of the cancellous bone of the femur is performed in certain orthopaedic procedures, in order to accommodate insertion of implants such as intramedullary nails. In such processes, the reamers spin at a maximum of 250 rev/min resulting in low-frequency vibrations, which can result in the formation of multicornered holes or non-cylindrical holes. These non-cylindrical holes can lead to improper fixation, which increases healing duration. Simulation of low-speed reaming in the femur analogue was conducted by using a finite element model of the reamer with two different models for reamer blade loads: concentrated forces on the tool tip and distributed forces on the engagement length of the reamer. The model of the process is quasi-static in a characteristic form. The specific cutting pressure, an important parameter in the governing equation, was found experimentally for this purpose. The effects of reaming condition, reamer size, and irregular tooth spacing on stability were investigated. An optimum irregular tooth spacing for a common six-flute reamer, resulting in the most stable reaming process was proposed. Hole profiles and tool axis trajectory of the tool were simulated for both regular and optimum irregular tooth spacing cases. The improvements in the hole quality from using the proposed irregular tooth spacing; benefits of which include expedition of post-operative healing, were demonstrated through simulated three-dimensional hole profiles.

Citation

Towfighian, S., Behdinan, K., Papini, M., Saghir, Z., Zalzal, P., & De Beer, J. (2008). Finite element modelling of low-speed femur reaming using reamers with irregular tooth spacing. Journal of sound and vibration, 318(4-5), 868-883.

Finite Element Analysis Middle Cervical Spine

Abstract

The spinal cord may be injured through various spinal column injury patterns. However, the relationship between column injury pattern and cord damage is not well understood. This investigation was conducted to develop a detailed, asymmetric three-dimensional finite element model of the C3-C5 cervical spine. The model was validated by comparing the simulation results obtained in this study with experimental published data. Upon validation of the model, the spinal cord was included into the model the simulation were performed. The disc bulge in the model with spinal cord were measured and compared with the results of the model without spinal cord. The results showed that inclusion of the spinal cord reduced the amount of lateral disc bulged. The results of the analysis of the model with spinal cord showed that in compression, the anterior surface of spinal cord sees more displacement, stress and strain that posterior surface and vice versa for flexion/extension.

Citation

N. Bahramshahi, H. Ghaemi and K. Behdinan, "Finite Element Study of Spinal Cord Mechanics During Biomechanical Response of Middle Cervical Spine", Volume 2: Biomedical and Biotechnology Engineering, 2010.

Force Sensor Performance at Body-device Interfaces

Abstract

Force and pressure sensors are used to monitor fit and inform designers, researchers, and clinicians in various biomedical applications. However, sensor performance at the body-device interface is not well understood. The objective of this thesis was to develop and apply novel approaches to evaluating force sensor performance at clinically-relevant body-device interfaces. This work includes the characterization of existing transducers as well as the development of a novel sensor for assistive device applications. Clinically-relevant static and dynamic loading profiles were applied to two commercial sensors and the prototype sensor via a mechanical testing machine and an apparatus simulating the lower limb. The results of this study provide recommendations for use and summarize the effects of area of applied load, sensor configuration, tissue compliance, and calibration methods. This integration of force sensors is a vital first step towards adaptable, intelligent assistive devices that have the potential to improve fit, comfort, and performance.

Citation

M. Hamilton, H. Sivasambu, K. Behdinan and J. Andrysek, "Evaluating the dynamic performance of interfacial pressure sensors at a simulated body-device interface", Canadian Prosthetics & Orthotics Journal, vol. 4, no. 1, 2021.

Available: 10.33137/cpoj.v4i1.36059.

The design of a piezoelectric nanocomposite diaphragm for insulin delivery micropumps

Abstract

In this work, a lead-free piezoelectric nanocomposite material is proposed to be used as an actuator for electronic devices in microscales. Specifically, use of the novel nanocomposite is examined as a micropump actuator with insulin delivery applications for individuals suffering from diabetes. This novel actuator replaces both the passive substrate and the active layer of traditional diaphragms. The active layer in traditional micropumps usually uses a piezoelectric lead zirconate titanate (PZT) layer due to its strong and desirable properties. PZT contains lead, which is toxic and environmentally hazardous. It is therefore desirable to use lead free materials. The proposed nanocomposite material contains barium titanate (BaTiO3) nanoparticles, as a lead-free piezoelectric material, embedded in a piezoelectric polymeric matrix of Polyvinylidene Fluoride (PVDF). The active nanocomposite’s electromechanical properties were estimated using Eshelby’s approach.

This actuator has been developed and tested with COMSOL Multiphysics, meeting requirements needed for an insulin micropump. The proposed micropump meets the requirements for insulin delivery including a flow rate of 0.1-20 µL/min and a backpressure of greater than 9.8 kPa. Moreover, a comprehensive study on the static, free vibration and dynamic behavior of the proposed diaphragm has been performed. This work shows that a BaTiO3 / PVDF nanocomposite actuator is able to provide means of actuating an insulin delivery micropump. This nanocomposite can be an alternative to traditional lead-containing actuators. The lead-free actuator is also eco-friendly and bio-compatible, which are important considerations when designing a safe and sustainable micropump, especially for medical applications.

Citation

Angelou A, Norman C, Miran N, Albers S, Moradi-Dastjerdi R, Behdinan K. 'An eco-friendly, biocompatible and reliable piezoelectric nanocomposite actuator for the new generation of microelectronic devices'. Eur Phys J Plus 2021;136:678.

Available: https://doi.org/10.1140/epjp/s13360-021-01653-z.