of the Central Administrative Board of Research Institute
of Experimental Medicine (Russian Academy of Medical
Sciences) are developing express method for early
detection of diabetic nephropathy. Their effort has
been funded through the grant of the President of
the Russian Federation.
Specialists of the Central Administrative Board
of Research Institute of Experimental Medicine (Russian
Academy of Medical Sciences) are developing biological
microchip that will allow to detect a very early
stage of diabetic nephropathy - one of heavy complications
of insular diabetes. They have created a preliminary
version of biochip, which possesses high sensitivity
and allows to analyze simultaneously at least 30
to 50 tests.
At present, more than one hundred million people worldwide suffer from diabetes,
including more than 2 million people in Russia. According to the World Health
Organization (WHO) data, the number of new morbid events increases annually
by 7 to 12 percent and redoubles every 6 to 7 years.
Every third patient who needs chronic hemodialysis or renal transplantation
is a person suffering from insular diabetes. Early detection and timely medical
treatment are necessary in this case, but diagnostics should be noninvasive,
inexpensive, trustworthy and easy to perform.
Biological microchip technology, which has been commonly applied in recent
years in biology, medicine and biotechnology, meets these requirements.
Biochip is a special carrier where various biological molecules, DNA or albumens
are placed in certain order. A large number of molecules of various substances
are placed on a small square of biochip. When placed in the test, these biological
molecules react with others, and the locations of reaction are marked with
a luminous marker. The information is read off the biochip with the help of
special recording system.
For early detection of diabetic nephropathy physicians need to catch very low
concentrations of albumin in urine (at the pre-clinical stage of the disease,
kidneys excrete from 30 to 300 milligrams of this albumen per day).
A fragment of genetically engineered albumen G, which binds human albumin,
is applied on the microchip (a porous plate, it square being one and a half
centimeter by one and a half centimeter). This albumen is obtained in the Institute
of Experimental Medicine. 30 to 50 albuminous spots can be placed on a plate.
Then a patient's urine test is applied to each spot and the microchip is processed
by labeled albumen, which colors only albumin. If the test is colored, it means
that the patient is ill with nephropathy.
The carrier itself constitutes monolithic macroporous sorbent, the pores'
size being 800 nm, this is a polymer of glycidyl methacrylate, produced at
the Institute of High-Molecular Compounds (Russian Academy of Sciences) under
the guidance of T.B. Tennikova, Doctor of Science (Chemistry). The polymer
contains functional epoxy groups, which allow to bind biological molecules
in mild conditions. That significantly increases sorptive capacity of the material,
which is approximately one hundred times higher than the capacity of a traditional
material- nitrocellulose membrane. Thus, analysis sensitivity would increase.
Pilot experiments have proved that biochip allows to record 20 mkg of albumin
in 1 milliliter of urine. That is sufficient for diagnosing.
However, when treating nephropathy, physicians need to track changing of albumin
content in urine. Then, precise quantitative data logging will be needed, and
to this end, recording system for information read-out from biochip matrix
is required. That is why the researchers intend to create in the future a convenient
and inexpensive carrier reading system, which will allow to precisely assess
the content of albumin in urine. Besides, the system will also be used for
other diagnostic test-systems.
Further information: St. Petersburg; Central Administrative
Board of Research Institute of Experimental Medicine,
Russian Academy of Medical Sciences, E.N. Rakhmatullina,