Insulin Delivery - Microfluidic Systems Have Potential to Help Millions of Diabetics

While "nanotechnology" has been a popular buzzIntegrated Solutions Hold Promise
word among investors and researchers,Leaders in the market for microfluidic insulin pumps,
"microtechnology" has graduated from universitysuch as ISSYS, Eksigent, Debiotech, and Biophan, are
research labs into commercialized realities. MEMSall focusing on integrated solutions that can be
(Micro-Electro Mechanical System) technology hasproduced in volume. They realize that the key to
been around since the late 1970's, and had a hugesuccess will be to provide a low cost, complete
surge in popularity in the 1990's with thesystem that can be implanted in an out-patient
telecommunications industry because it could be usedprocedure, monitored by sensors within the sensor
to make fiber optic switches at the microscopic scale.system, and refilled with insulin by the patient. The
Nowadays, MEMS devices are used commonly formarket for microfluidic insulin pumps is expected to
digital projectors, accelerometers, automotivereach $2 billion by 2010, with substantial continued
sensors, and medical applications. Based on silicongrowth over the following ten years.
wafer integrated circuit (IC) etching technology,Biomedical applications are already the second largest
MEMS devices are actually mechanical actuatorsapplication area for MEMS technologies after
fabricated at the microscopic level.automotive; however, to date commercial success
The Industry Sees Benefitshas been limited to sensors that measure physical
Recently, the pharmaceutical medical device industry(heart rate) rather than biochemical parameters
has recognized the benefits of MEMS, leading to the(glucose). Other than glucose, there are no in vivo
development of a whole new industry of miniaturized,sensors in widespread clinical use for monitoring
microfluidic drug delivery systems. Although manymetabolites, such as cancer cells.
drugs are being used in microfluidic systems, the oneImplantable drug infusion pumps were first used with
that has held the most appeal for consumers andterminally ill cancer patients in the 1980s, but these
industry alike is insulin for diabetics. Withworked on a predetermined drug release schedule
insulin-dependent diabetes on the rise, there is a hugeinto the blood stream with no sensor feedback from
market for implantable, painless, automatic insulinthe patient and no targeting of the drug to the
devices that give precise dosages based oncancerous cells. Now, researchers are beginning to
automatically sensed needs of the patient. As always,use MEMS to improve the delivery of drugs to
these devices need to be cheap, which means thecancer cells.
MEMS fabrication process needs to be able toBreast Cancer, Blood Cells & Pacemakers
produce large volumes, something that has been aThe biochemical signals that guide breast cancer
challenge until recently.tumor cell migration are poorly understood, but new
According to the Centers for Disease Control, frommicrofluidic devices designed specifically to track how
1997 to 2004, the incidence of diabetes among 45-breast cancer cells move in response to chemical
to 79-year-old patients rose 43 percent. Now, aboutsignals are under development. This will allow doctors
12 of every 1000 people over 45 will becometo decrease the amount of cell-killing drugs
diabetic. This means about 3.6 million people in theadministered to the patient and allow the those drugs
United States in 2004 were diabetic. Looking atto target only the cancer cells, rather than any cells
hospital discharges in 2005, over 6.4 million peoplethey contact. For women with breast cancer, this
were hospitalized for diabetes, and a conservativecould mean an end to hair loss, debilitating fatigue,
cost for these hospitalizations was $22 billion.and other detrimental side effects associated with
Obviously, societal costs due to lost wages, lostchemotherapy.
earning years, and other medical conditionsSandia National Labs has created a mechanized
complicated by the presence of diabetes, wouldmicrofluidic device that can ingest red blood cells and
increase this figure dramatically.alter them in a positive fashion. Eventually, they hope
Diabetic patients often complain of how difficult it isto expand their device to work with any cells in the
for them to properly regulate their insulin dosage. Notbody. The ultimate goal of the Sandia device is to
only does it require them to collect a blood samplepuncture cells and inject them with DNA, proteins, or
for analysis, but then they must administer that dosepharmaceuticals to counter biological or chemical
intravenously. In an elderly or obese patient, this isattacks, gene imbalances, and natural bacterial or viral
complicated by poor vision, lack of coordination, andinvasions.
fat, all of which make injecting a proper dose moreElectrical stimulation devices, such as the pacemaker
difficult. Hospitals also make mistakes whenand defibrillator, have been the most successful
administering drug doses, some reports putting theseproducts of microelectronic implants. But now,
mistakes as high as 200,000 serious injuries and 7,000pressure and flow sensors are being added to
deaths in the U.S. each year. Microfluidic drug deliverypacemakers to make them rate-responsive. This will
systems address all these problems and haveenable patients to be more active, as the pacemaker
additional advantages as well.will respond to increased or decreased demands
Configuring Microfluidic Systemsaccording to the needs of the moment.
Microfluidic drug delivery systems have three mainIn another electrical application, Transneuronix, Inc.
components; a needle array, a pump and valvehas made an implantable gastric stimulator that
system, and chemical sensors. The needle array isapplies electrical stimulation to the stomach wall. The
usually hundreds of microscopic silicon wafer etchedcompany is currently conducting clinical trials for the
needles with orifices for the drug to pass through.treatment of severe obesity. Rather than a risky,
Because these needles are so small, they areexpensive surgical procedure such as gastric bypass,
painless, and yet their vast quantity delivers the drugthe stomach will continue to digest food, but the
instantly.stretch and chemical receptors in the wall of the
The pumps and valves are also microfabricated, andstomach will provide neural feedback to the patient
can be integrated with the needle array andthat they are full.
implanted under the skin. The pumps come in twoAnd, Medtronics' "Activa" system delivers a mild
varieties, either passive with some type of electrodeelectrical stimulation to block brain signals that cause
or other stimulating means for fluid flow, or activetremors, such as Parkinson's disease.
with valves that can control the precise dose beingOpportunities Seem Endless
administered at the micro-volume scale.For the medical device industry, this is a wake up call
The third and most important feature of MEMS insulinto seek out MEMS and microfluidic solutions to
delivery systems is the chemical sensor which canlarge-scale problems we face in the United States.
detect the level of blood glucose in the patient andWith the growing epidemics of obesity, diabetes,
automatically administer a precise dose of insulin toheart disease, and cancer, there are countless
correct their glucose levels. Thus, the patient and theopportunities for large and small companies alike to
hospital are removed from the maintenance process.develop sensor-based diagnostic and therapeutic
The patient has a discreet, refillable insulin pouch, anddevices that will help patients live longer, healthier
all of the glucose control is maintained 24 hours a daylives with less invasive procedures.
with no pain, measuring, or administration required.