A micro-spherical heart pump powered by cultured cardiomyocytes
Yo Tanaka,ab Kae Sato,c Tatsuya Shimizu,bd Masayuki Yamato,bd Teruo Okanobd and
Takehiko Kitamori*abce
Received 22nd August 2006, Accepted 30th October 2006
First published as an Advance Article on the web 13th November 2006
http://www.rsc.org/ej/LC/2007/b612082b.pdf
There are many effective implanted device. However, majority of them require power source that is either provided through the wire to the device, or has a batter that needed to periodically replace. Therefore, A microfluidic device powered without the need for external energy sources or stimuli is needed. This paper discuss the creation of a micro-spherical heart-like pump powered by spontaneously contracting cardiomyocyte sheets driven without a need for external energy sources or coupled stimuli. This device was fabricated by wrapping a beating cardiomyocyte sheet exhibiting large contractile forces around a fabricated hollow elastomeric sphere (5 mm diameter, 250 mm polymer thickness) fixed with inlet and outlet ports. Fluid
oscillations in a capillary connected to the hollow sphere induced by the synchronously pulsating cardiomyocyte sheet were confirmed, and the device continually worked for at least 5 days in this system.
Cell sheets are obtained routinely utilizing a commercial cell culture system based on the temperatureresponsive polymer, poly(N-isopropylacrylamide) (PIPAAm). Importantly, these living cell sheets are harvested intact, handled, manipulated and transferred to various devices while maintaining their regular and robust pulsating phenotype.
Pumping action is driven with only chemical energy input from culture milieu without any requirement for coupled external energy sources, unlike conventional actuators. However, to mimic the heart of most animals, check valves and multiple chambers are required.
A micro-spherical heart has at least two directions for possible applications: (1) as an electric powerless bio-actuator to drive fluids in implanted micro-chemical or biochemical medical implant devices without using external power sources, and (2) as a component of a cardiovascular circulatory system micro-model to study mechanisms of circulatory physiology, pathology, and developmental biology, or for medical diagnoses of patients using cultured autologous cells.
I choose this article because powering for the any sort of device has always been a great problem. For example the pace maker in heart the battery has life limit, and every time the replace of battery creates a tremendous harm to patience. The ability to utilize biological environment to provide power to the device is indeed ingenious. I like this article also because its creativity and amazed by people’s ability to create cardiomyocyte sheet which can contract upon control and can survive with the nutrient from the environment.
4 comments:
i agree with you...providing power to the device by utilizing the biological environment is a great idea. so far, have the devices made only lasted for at least 5 days? can the pulsating cardiomyocyte sheets last for years?
Pumping action is driven with only chemical energy input from culture milieu without any requirement for coupled external energy sources, unlike conventional actuators.
What kind of chemical energy input are you referring to here? - Is it ATP and Ca++?
It's great to have pumping action without an external energy input. But if the device uses chemical energy from the body, the body has that much less energy to use in different parts of the body. Would this have any negative effect on homeostasis of other functions?
One thing that I would be interested in is whether or not the authors postulated reasons explaining why the cardiomyocyte sheets might have failed after five days. If there was cell death, how could this be provented or delayed? Was the chemical energy input from the "culture milieu" a limiting factor? A removal of the need for an external energy source (electrical or otherwise) is certainly a huge advantage, but if the external chemical environment must be continually replenished, this would introduce new challenges to the tissue engineering microenvironment (i.e. local fluid flows and vascularization issues).
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