Medical Device Daily National Editor
Dracula and blood-letting have given the medical necessity of drawing blood a rather bad name.
Needles are the modern medical equivalents of the scary predecessors, and they don't do much better, image-wise. Though relatively recent inventions, they invade the body through the skin, push things in or suck things out of the body, offer opportunity for infection, hurt – and are also quite scary to many of us.
Making really modern the necessary process of obtaining blood – to examine its many significant and often revealing constituents – medical device manufacturers have long been searching for alternatives that don't pierce the body and so don't come with the possibility of infections, pain – and that anxiety-producing look.
Two companies last week said they are making progress toward that goal.
Electrical engineers at the Schulich School of Engineering at the University of Calgary have patented a device called the Electronic Mosquito, a skin patch for drawing blood to measure glucose for control of diabetes.
And researchers with the National Space Biomedical Research Institute (NSBRI; Houston) are billing as a type of Star Trek medical technology a noninvasive, needle-free system that uses light to measure tissue oxygen and pH.
The e-Mosquito being developed by Schulich researchers is about the size of a deck of playing cards.
It also uses needles, but they are micro-needles and, like a mosquito, they only "bite" a little bit into the skin. The patch contains four micro-needles that sequentially bite at programmed intervals.
Karan Kaler, director of the Schulich School's Bio-Micro Electromechanical Systems (MEMS) Laboratory, told Medical Device Daily that the micro-needles are essentially off-the-shelf products, with the researchers then doing the necessary MEMS engineering to add some protective coating and fit the needles on the patch.
A key challenge, he said, is controlling the depth of skin penetration by the micro-needles – only deep enough to make the necessary draw from a capillary and not deep enough to hit a nerve so there is little or no pain for the patient.
The patch could be worn anywhere on the body, and in less sensitive areas than the fingertip, to obtain readings of capillary blood. A sensor in each cell of the e-Mosquito measures the blood's sugar levels.
This data can then be sent wirelessly to a remote device such a computer or a monitoring instrument worn on the wrist. The system could even be connected to an alarm to alert patients or doctors when blood sugar levels enter the danger zone.
Kaler told MDD that the target application of blood draw for diabetes care was "low-hanging fruit" for the project – meaning the application most easily satisfied by the patch system, with future generations of the device potentially linked to lab chip devices.
Thus, the patches could be used for blood which is then analyzed by an integrated lab-chip product – one of the key technologies being worked on in his lab – and programmed to analyze specific constituents for this or that disease, even cancer, he said.
The university is seeking partners to pursue product development, such as adding all the other sensor and analysis components, and currently available, to the patch. "What I think is going to happen," Kaler said, "is that somebody is going to have all the goodies to put everything in one place."
Martin Mintchev, director of the Low Frequency Instrumentation Lab at the Schulich School of Engineering, emphasized the basic first intent of the patch: a method for reducing the pain and frequent trauma of needle use.
"This is a dramatic improvement over manual poking, particularly for children and elderly patients. Our approach ... offers a reliable, repeatable solution with the minor inconvenience of wearing something similar to an adhesive bandage."
Kaler said the next step for product development is to make the components of the e-Mosquito smaller to fit more needles on the patch.
Currently, there are four needles, so the patch would need to be changed at least once a day. Adding more needles would allow patients to wear the patch for longer periods of time or test their blood more frequently, even while they're asleep. And Mintchev and Kaler said they foresee the possibility of integrating an insulin pump system so that injections can also become autonomous, using data from the e-Mosquito, thus creating an external artificial pancreas.
The needleless system, being developed by the NSBRI for drawing blood, has reached the prototype stage, the researchers said.
Dubbed the Venus, the device can also measure blood and tissue chemistry, metabolic rate and other parameters.
Placed on the skin, the four-inch by two-inch device takes its measurements using near infrared light. Blood in tiny blood vessels absorbs some of the light, but the rest is reflected back to the sensor. The monitor analyzes the reflected light to determine metabolic rate, along with tissue oxygen and pH.
The sensor and portable monitor, under development by Dr. Babs Soller and her colleagues, are funded by NSBRI for use in space. The researchers say that the technology's multiple, real-time applications will be beneficial to astronauts in their day-to-day activities and also to critically ill patients on Earth.
"Tissue and blood chemistry measurements can be used in medical care to assess patients with traumatic injuries and those at risk for cardiovascular collapse," said Soller, who leads NSBRI's Smart Medical Systems and Technology team. "The measurement of metabolic rate will let astronauts know how quickly they are using up the oxygen in their life-support backpacks. If spacewalking astronauts run low on oxygen, the situation can become fatal."
A unique advantage of the near infrared device is that its measurements are not impacted by skin color or body fat, according to the researchers.
A noninvasive system also means a reduced risk of infection due to the lack of needle pricks. Most of the system's development has occurred at the University of Massachusetts Medical School (Boston), where Soller is a professor of anesthesiology. She has worked closely with researchers at NASA Johnson Space Center (Houston) to develop applications of the Venus system for space.
Former NASA astronaut and NSBRI User Panel Chairman Dr. Leroy Chiao said that Soller's sensor system and other technologies being developed for spaceflight are a wise investment.
"The neat thing about the work being done is that it is a two-for-one deal," Chiao said. "Not only is this research going to help future astronaut crews and operations, it has very real benefits to people on the ground, especially to people in more rural areas."
On Earth, there are several areas of healthcare that could benefit from Venus. However, it is patients treated by emergency personnel on ambulances and on the battlefield that could benefit the most from the technology."
"Eventually, we expect first-responders would have these devices, which would provide feedback on the severity of a person's injury," Soller said. "Data can be communicated directly to the hospital. Early access to this type of information may increase a victim's chances of survival."
She cited another intriguing possibility: "Athletes would benefit from using these parameters in developing training programs that will help them improve their endurance and performance. And we suspect the same thing will be true for patients in physical rehabilitation."
Currently, Soller and her collaborators are preparing the sensor for integration into spacesuits by reducing its size, increasing its accuracy in measuring metabolic rate, and developing the capability to run on batteries. She said these activities will also speed applications for patients on Earth.