Category: Medical devices

According to the definition by World Health Organization, medical device is “An article, instrument, apparatus or machine that is used in the prevention, diagnosis or treatment of illness or disease, or for detecting, measuring, restoring, correcting or modifying the structure or function of the body for some health purpose. …” (www.who.int/medical_devices/definitions/en/).

We collaborate with clinicians to research, develop and experiment mechanical, electromechanical and hybrid medical devices for patient care. Hybrid devices comprise multiple materials including both synthetic and biological components. We also research, develop and apply simulation-based methodologies to design, develop and evaluate medical devices. As manufacturing goes digital, medical devices could be made economically in much smaller numbers, more flexibly and with lower input of labor. I am an advocate of affordable patient-specific medical devices and individualized production.

Patient-Specific Controller for an Implantable Artificial Pancreas by Dr. Yvonne Ho

Posted on by mpecck

The development of an artificial pancreas capable of providing tight blood glucose control for diabetics remains one of the most challenging problems in the field of medical engineering. Dr. Yvonne Ho’s book will serve as an invaluable reference for those engaged in research on diabetes mellitus and artificial pancreas. Following an introductory chapter that provides a concise overview of the research topic, Chapter 2 offers a comprehensive description of diabetes mellitus and its related physiology. Chapter 3 provides a state-of-the-art review of various treatment options. The subsequent chapters primarily focus on presenting novel research and development findings related to an implantable artificial pancreas.

The implantable artificial pancreas aims to regulate blood glucose levels by administering appropriate insulin dosages when required. By directly sensing blood glucose levels and delivering insulin into the vein, this implantable device seeks to eliminate the delays associated with subcutaneous blood glucose sensing and insulin delivery. Preliminary in vitro and in vivo experimental results suggest that the implantable approach to blood glucose control could be a clinically viable alternative to pancreas transplantation. The book demonstrates a deep understanding of blood glucose level modeling and control, as well as the design of implantable devices.

This book will serve as a valuable addition to the libraries of scientists and engineers working at the intersection of engineering and medicine.

Chee-Kong Chui, January 2018

Cyber-medical system for patient-specific medical devices development

Posted on by mpecck

Above is the title of my invited talk in The 13th Annual IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE NEMS 2018), held in Singapore from April 22-26, 2018.

Below is the abstract of my talk:

With increasing demands for quality and affordable healthcare services, organizations in the medical device manufacturing industry are embracing more intelligent and responsive systems through the integration and development of dynamic digital technologies. We propose a Cyber-Physical System (CPS)-based production system with integrated enabling digital technologies and robot assistance. This system has the potential to enhance productivity and sustainability, particularly in the production of patient-specific hybrid medical devices. Hybrid medical devices incorporate multiple components and materials that must function flawlessly over extended periods, often under the demanding conditions of the human body. Examples of hybrid medical devices include artificial tracheas, artificial pancreases for diabetes treatment, and information-delivering microchips.

The proposed CPS-based manufacturing system utilizes an integration of enabling digital technologies, including Augmented Reality (AR), Wireless Sensor Networks (WSN), the Internet of Things (IoT), and Artificial Intelligence (AI), for the fabrication of patient-specific medical devices. Visual and haptic cues are provided to the human operator in a timely manner, allowing for swift intervention. Importance-driven computer graphical rendering of visual cues is embedded into physics-based simulations for haptic rendering.

The study of human centricity in an immersive and robot-assisted environment will provide unique insights into human hand-eye coordination capabilities under external influences. Intriguing scientific questions include the extent to which individuals can learn and develop motor skills with external guidance.

 

Note: There is an IEEE SMC Technical Committee (TC) on Cyber-Medical Systems. More information of the TC can be found here.

Liver tissue properties and frequency-control of RF ablation

Posted on by mpecck

A computational model, consisting of an equivalent circuit of resistors and capacitors, is proposed in [1] to investigate the changes in electrical properties of liver tissue during radio-frequency (RF) ablation.  The variations in tissue mechanical properties are correlated with those of the tissue’s electrical properties. RF ablation, in addition to liver tumor treatment, can be utilized to halt blood flow during liver resection. In [2], we further developed the multi-scale model to study the bioimpedance dispersion of liver tissue. The figure below, taken from [3], compares our model with the Cole-Cole model employed in Gabriel’s study. Both models demonstrate a good fit to the experimental data in the high-frequency region. At the lower frequency region, our model provides a better fit to the data.

Using an accurate multi-scale model and a 3D finite element model, we performed RF ablation simulations at various frequencies in [3]. The size of the ablation region increases with higher frequencies. The frequency-control method may prove to be more effective than the duration-control method in RF ablation.

In [4], we previously conducted preliminary work on the application of a multi-scale/multi-level model for simulating molecular medicine through electroporation.

References:

[1] W-H Huang et al. Multi-scale model for investigating the electrical properties and mechanical properties of liver tissue undergoing ablation, Int J CARS (2011) 6:601-607.

[2] W-H Huang et al. A multiscale model for bioimpedance dispersion of liver tissue, IEEE Trans Biomed Eng (2012) 59(6):1593-1597.

[3] B Duan and CK Chui, Multiscale modeling of liver bio-impedance and frequency control for radiofrequency ablation, 2016 IEEE Region 10 Conference (TENCON) – Proceedings of the International Conference, pp. 1532-1535, November 2016.

[4] Chui et al. A medical simulation system with unified multilevel biomechanical model, Proc of 12th International Conference on Biomedical Engineering ICBME 2002, Singapore, 4-7 December 2002.

Implantable artificial pancreas

Posted on by mpecck

This is a picture of our prototype implantable artificial pancreas that we have been developing. It was exhibited in National University of Singapore Science & Technology Exhibition in March 2015, and later showcased at “The Future of Us” Exhibition organized by the Singapore Government as part of the SG50 celebration, held between between 1 December 2015 and 8 March 2016. This device will require many years of dedicated research and development before it can become a clinically viable alternative to pancreas transplant.