Human powered MEMS-based energy harvest devices
Introduction
Implanted biomedical devices are the potential drug-dosing approach to the patients who are suffer from severe or chronic diseases such as diabetes, colon cancer and heart disease. To supply durable and stable power to implantable biomedical devices (IMDs) is one of the most challenging issues. For most cases, the IMDs have to be replaced owing to the dead batteries inside [1], [2]. Therefore, extracting energy from ambient sources to extend the lifespan of power supply system for IMDs has attracted a lot of attentions of researchers. Extracting power from ambient sources is usually known as energy harvesting, or energy scavenging. Recently, micro-electromechanical systems (MEMSs) based energy harvesters are expected to be one of the potential solutions to supply electrical power to IMDs, owing to its tiny size, light weight and recharge-free attributes.
However, the performance of the micro-energy scavenging devices for biomedical applications is limited by many inherent congenital factors. For instance, micro-energy harvester (MEH) has to preserve anti-infection property owing to the most IMDs are directly employed on human bodies. In addition, the stability and durability of MEH are another two major constraints for IMDs. In order to enhance durability and upgrade performance of MEH, the characteristics of energy sources to be scavenged have to be comprehensively unveiled prior to design of MEHs. For example, expected range of the motion amplitude and frequency have to be firstly defined so that the MEH can be deliberately designed. On the other hand, the size of MEH has to be unobtrusive, in general under 1 cm3 in volume [3]. Besides, the biocompatibility has to be taken into account. In order to integrate with currently available in vivo biomedical devices, the sufficient biocompatibility of MEH is certainly required.
Extracting energy from human body could be one of the most convenient methods to prolong the lifespan of IMDs. Human body provides a rich source of energy. A person, 68 kg (weight) with 15% body fat, approximately stores chemical energy up to 384 MJ [4]. The stored energy is partially consumed by the daily activity as shown in Table 1 [4].
The energy provided by human body can be roughly classified by two types: physical and chemical energy as shown in Fig. 1. The body heat, blood pressure, breathing and human body motions (e.g., walking and arm motion) are all belonged to physical energy. These energies can be intentionally scavenged by the in vitro or in vivo devices like MEHs. On the other hand, a few of chemical energy harvesting MEMS devices have been reported [5], [6]. For instance, a microbial fuel cell is able to convert glucose into electricity by electrochemical reaction [5].
Human powered energy harvesting for IMDs is a topic of substantial and increasing research attention. In this paper, versatile types of physical energy sources to be scavenged from human body are comprehensively studied and characterized in Section 2. The operation principle and design criterion on MEH applied for human body are discussed in Section 3. The major concerns and critical issues on MEH are addressed in Section 4. Finally, the conclusions are presented in Section 5.
Section snippets
Characterization of energy source for IMDs
Scavenging energy from human body is one of the most convenient methods to extend the lifespan of implantable biomedical devices (IMDs). In general, human-generated energy can be scavenged by two ways: physical and chemical. Among them, the microbial fuel cell is the most common device to extract human-generated energy by chemical fashion. On the other hand, the micro-energy harvester (or called micro-generator) is the device to scavenge the physical energy from human body by physical fashion.
MEMS-based energy harvester
The major constraint of currently IMDs is suffered from lifespan of power supply sources (e.g., lithium iodine batteries) [16]. That is, the batteries for implanted biomedical devices cannot be easily replaced or externally recharged. Owing to dramatic progress in micro/nano technologies, MEMS-based energy harvester is expected to be the most significant solution for power sources of the implantable bio-medical micro-devices. Extracting energy from ambient sources or human body could provide
Performance and biocompatibility of MEH
The performance and efficiency of the MEH are significantly limited by the ambient environment so that the development of MEH to extract energy from human body has not been completely mature yet. Some of critical issues for MEH are addressed and discussed below.
Applications of MEHs to IMDs
MEMS Energy harvesting within the human body could be potentially employed to IMDS. In this section, some of the common IMDs, which could be potential integrated with MEH for health care, are addressed and discussed.
Conclusions
The lifespan and biocompatibility are the most seriously issues for most IMDs. In this paper, the energy sources to be scavenged from human body are classified by two types: chemical and physical energy. The bio-chemical transaction is usually required for implantable fuel cell systems. Therefore, the chemical energy harvesting devices have the inherent benefit for IMDs. However, the power density of the chemical energy harvesting system is usually constrained by the types of bio-fuel and the
Acknowledgements
The authors would like to thank the Center for Micro/Nano Technology Research, National Cheng Kung University, Tainan, Taiwan, and National Nano Devices Laboratory (NDL98-C02M3P-107) for equipment access and technical support. This research was partially supported by National Science Council (Taiwan) with Grant NSC 100-2221-E-006-236.
References (67)
- et al.
Biofuel cells – recent advances and applications
Biosens Bioelectron
(2007) - et al.
Thermal comfort, skin temperature distribution, and sensible heat loss distribution in the sitting posture in various asymmetric radiant fields
Build Environ
(2007) - et al.
Review of MEMS-based drug delivery and dosing systems
Sens Actuat A
(2007) - et al.
Integrated power harvesting system including a MEMS generator and a power management circuit
Sens Actuat A
(2008) Thermoelectrics, an environmentally-friendly source of electrical power
Renew Energy
(1999)- et al.
Micromachined CMOS thermoelectric generator as on-chip power supply
Sens Actuat A
(2004) - et al.
Analysis of a micro-electric generator for microsystems
Sens Actuat A
(1996) - et al.
Evaluation of MEMS materials of construction for implantable medical devices
J Biomater
(2002) - et al.
Issues and perspectives on the biocompatibility and immunotoxicity evaluation of implanted controlled release systems
J Control Release
(1999) - et al.
An implantable drug-delivery system based on shape memory alloy micro-actuation
Sens Actuat A
(1997)
The evolution of pacemakers
IEEE Eng Med Biol Mag
Human generated power for mobile electronics
Energy scavenging for mobile and wireless electronics
IEEE Pervasive Comput
Biomechanical energy harvesting: generating electricity during walking with minimal user effort
Science
Principles of anatomy and physiology
Illustrated human and social biology
Non-contact detection of breathing using a microwave sensor
Sensors
A micro electromagnetic low level vibration energy harvester based on MEMS technology
Microsyst Technol
An electromagnetic micro power generator for low-frequency environmental vibrations based on the frequency upconversion technique
J MEMS
A silicon MEMS micro power generator for wearable micro devices
J Chin Inst Eng
Development of an electromagnetic micro-generator
Proc Inst Elect Eng Circ Dev Syst
MEMS inertial power generators for biomedical applications
Microsyst Technol
A batch-fabricated and electret-free silicon electrostatic vibration energy harvester
J Micromech Microeng
Cited by (181)
Integrating self-powered medical devices with advanced energy harvesting: A review
2024, Energy Strategy ReviewsElastic energy storage technology using spiral spring devices and its applications: A review
2023, Energy and Built EnvironmentMEMS-based energy harvesting devices for low-power applications – a review
2023, Results in EngineeringElectromagnetic vibration energy harvester using magnetic fluid as lubricant and liquid spring
2023, Energy Conversion and ManagementTriboelectric Nanogenerator-based smart biomedical sensors for healthcare
2023, Sustainable Energy Technologies and Assessments