Laboratory of Advanced Microfluidic Systems  
  Flexible Intelligent Electrocardiography Jacket Based on Polymer Microengineering  

Heart diseases (mainly coronary heart disease) are the second leading killer disease category in Hong Kong since 1960s. About 12 persons per day were died from the coronary heart disease in 2009. Thus, the long-term and efficient measurement of electrocardiographs (ECG) for chronic heart disease patients is crucial and inevitable. Considering the market demands and the medical significance, we propose to establish an ECG jacket embedded with the measurement electronics (Fig. 1). This ECG jacket appears as regular clothes to record the long-term heart status of patients for tele-health care and medical purposes.

From the user perspective, this product has strict requirements on comfort, non-allergenicity and measurement reliability. In the past two decades, polydimethylsiloxane (PDMS) has emerged as a typical biocompatible structural material for biomedical microdevices. Indeed, applicability of PDMS can be extended to a larger scale as an embedded material for the textile and clothing industries. PDMS can be modified to be electrically conductive by the addition of specific nano-particles. This highly controllable yet easily achievable modification process enables PDMS as an interface material between traditional textile products and highly integrated electronic circuits; and this process potentially opens doors for industry of ‘intelligent clothes’ – the functional wearable products that senses human body’s characteristics.


Figure 1. Concept design of the ECG jacket.
  Bone Reaming System Integrated with Supermedia  

During World War II, Kuntscher created the idea of internal fixation. In 1940, he invented an intramedullary nail to put inside the bone cavity in order to fix the position of fractured bone without opening the fracture site during the healing period. The reaming process of bone cavity can remove the inner cortical bone cell, resulting in the enlargement of the bone cavity for the insertion of an intramedullary nail. However, the reamed internal fixation can enhance bone cavity pressure, temperature, bending stress and torsion shear of the intramedullary nail and causing unnecessary additional injury to patients.

An automated bone reaming system (Fig. 2) was built to monitor heat generation during an internal bone fixation surgery. It consists a temperature sensing system to measure the bone cavity temperature, an automated rotor system to provide the controlled rotational motion to the system, which emulates the rotational motion during a surgical bone-drilling procedure, and a wireless receiver gathering the wireless signal representing the measured temperature. Over-heat in the reaming process of internal bone fixation surgery, which is a widely used clinical operation, can cause unnecessary injury to the patient. To improve the operation safety by limiting the cavity temperature (generated by mechanical friction) and torsion shear. Such automated system can regulate its reaming speed depending on the bone cavity environment (temperature and pressure), measured by embedded physical sensors for real-time multi-sensing information (so-called supermedia). A theoretically model on the heat transfer had also derived to improve the temperature prediction. Moreover, the system supported wireless (range: >10 m) and internet transmission to enable future applications in the remote surgery.


Figure 2. Wearable wireless MIDS prototype. Five motion sensory rings are connected to a wrist watch module, which processes the real-time data analysis and the wireless transmission to a computer terminal.



Laboratory of Advanced Microfluidic Systems | Department of Mechanical and Biomedical Engineering | City University of Hong Kong
Copyright© 2011 - 2013 LAMS Research. All Rights Reserved.