- A patented
biosensor has now been modified by a research team from the Spanish
National Research Council to detect HIV infection.
- This biosensor
detected very minute quantities of p24 in the blood, which occurs as early
as one week after initial infection.
- The duration of
the test is very short, 4 hours 45 minutes, which allows the results to be
provided the same day.
biosensor has been designed by scientists from The Spanish National Research
Council (Consejo Superior de Investigaciones Científicas (in Spanish- CSIC)
that can be used to detect HIV
after a week of infection.
The sensor consists of mechanical silicon
structures with nanoparticles of gold with p24 present between the
micromechanical silicon structures and the gold nanoparticles. The study titled
"Ultrasensitive detection of HIV-1 p24 antigen by a hybrid
nanomechanical-optoplasmonic platform with potential for detecting HIV-1 at
first week after infection" was published in PLOS recently.
‘Early detection of HIV infection is now possible with recently developed Biosensor.’
from being able to detect the infection within a week, the test takes only 4
hours and 45 minutes that allows the results to be provided the same day.
Structure of the Biosensor
the structure of the biosensor, the gold nanoparticles contain plasmons which
are optical resonances. These plasmons can scatter light, a factor that has
resulted in bringing attention to these structures in the field of optics. The
micromechanical structures detect small intermolecular forces which makes them
these two structures are combines, they produce both optical signals as well as
mechanical structures, resulting in remarkable sensitivity and ability to
detect p24. A patented technology, it is already being used to detect some
forms of cancer.
Javier Tamayo, a CSIC researcher, said that the physical aspect of the chip
used in this study is identical to the one used in biomarker studies. However,
the chemical aspect of the chip like the solutions used would vary depending
upon what is being detected. The
research team involved in the study is trying to identify other possible
applications of this biosensor.
Key Facts About Structure of the Biosensor
microelectronics technology that are well established
- Has lowered
- Is simple to use
- Is ideal for use
in developing nations
Functioning of the Biosensor
- One millilitre of
human serum was added onto the biosensor for a period of one hour at 37
- This is carried
out to facilitate binding of any existing HIV-1 p24 antigens to antibodies
that are present on the surface of the sensor.
- The biosensor is
re-incubated for 15 minutes at 37 °C with gold nanoparticles. This will
allow identification of the p24 proteins.
- The unbound
particles are removed by rinsing.
total time taken for the test is 4 hours and 45 minutes which, according to Dr.
Javier, will allow the test to be repeated the same day. The results of the
study were found to be statistically significant which makes it eligible for
use in medical services.
is the time taken for the HIV virus to result in the detectable presence of
antibodies in the blood of the infected individual. Currently, HIV is detected
- Using the Nucleic
Acid Amplification Tests (NAAT) which identifies the presence of viral RNA
in the blood. This method can detect 20-35 copies of RNA per milliliter,
which is usually found nearly 2 to 3 weeks after the initial HIV
- Using fourth
generation immunoassays which
detect the presence of p24 protein upto 10 picograms per milliliter, which
usually occurs about 3 to 4 weeks after the initial HIV infection.
Advantage of the Biosensor
biosensor can detect low concentrations of p24, up to 100,000 times lower than
that detected by the fourth generation immunoassays and 100 times lower than
methods that are used for identifying the presence of viral RNA.
undetectable phase of the HIV infection is reduced to one week, providing early
detection and better care.
Importance of Early Detection of HIV
The current methods of detection require
approximately 4 weeks for identifying HIV infection. During this time there is
reduction in the CD4 lymphocytes in the gut
of the virus in the central nervous system
- Occurrence of HIV
the initial stages of infection are very critical as the potential to infect
another person is very high. Apart from the risk of spreading the infection,
increased period of infection leads to irreparable damage to the immune system
of the host, therefore early detection will facilitate faster administration of
immunodeficiency virus (HIV) affects the immune system of the host by attacking
the CD4 lymphocytes which are important for fighting infection. This increases
the risk for serious infections as well as for the development of cancer.
(AIDS) is the condition caused by HIV
infection and is considered to be the final stage of infection. It could take
weeks to months for an HIV infected individual to develop AIDS.
spread of HIV infection is mostly through
intercourse with an infected person.
- Sharing needles
- Transmission from
an infected mother to the unborn child.
initial symptoms of the infection are characterized by flu like symptoms as
well as swollen glands. The lowered immunity caused due to the infection
results in the development of associated infections, most common of those is
biosensors will aid in detecting the infection early which can be used to
administer antiretroviral infections before there is complete depletion of the
CD4 cells. This would aid in better health among HIV infected individuals,
lowering the risk of acquiring other severe infections.
- HIV/AIDS - (https://medlineplus.gov/hivaids.html)