The essence of nanotechnology is the use of nanomaterials with diameters less than 100mn.When nanotechnology is applied to biological or life sciences it is called Nanobiotechnology. When nanobiotechnology is applied to proteomics it is called nanoproteomics by which it is possible to even detect a solitary molecule of a protein.
Nanoparticles can be used to track stem cells as for example the supermagnetic iron oxide nanoparticle. Several types of nanoparticles are used in nanobiotechnology.
These could be:
• Gold nanoparticles~ DNA could be attached to these nanoparticles which are usually of diameter less than 13 run.
• QD's (Quantum Dots) ~ these semiconductor nanocrystals are used for whole blood assays and genotyping. QD's are inorganic fluorophores compatible for use as fluorescent markers. They have broad excitation spectra that elicit fluorescence without lasers on just simple excitation. QD's are also used for correlating diagnostics with therapeutic medicines.
• Iron nanoparticles~~ Iron nanoparticles have 15-20 run size. These are usually embedded in styrene and glycidyl methacrylate beads coated with polyGMA through seed polymerization. These beads are called Fe/St-GMA/GMA.
• Biological nanoparticle~an example of a biological nanoparticle is the virus particle. For instance herpes simplex virus can trigger the assembly of magnetic nanobeads as nanosensors.
What is the advantage of using nanoparticles?
• Their small size is helpful for entry into different places.
• They are increasingly resistant to heat and chemicals
• They have large surface area to volume ratio. This helps in diffusion.
Currently nanobiotechnology is used in:
Diagnosis of cancer
Present day diagnostic tests for cancer detection are insufficient in the sense that by the time cancer is detected it becomes too late for meaningful treatment. However, biodegradable nanodevices can be implanted in a patient susceptible to a particular cancer on the basis of genetic profiling although the patient at that point of time may not exhibit any of the manifestations of that cancer. These nanodevices could act as a prophylactic perhaps combining diagnosis with therapeutics also enabling the patient to be monitored continuously on an in vivo basis---as opposed to conventional detection of biomarkers in body fluid samples. So if a nanodevice detects a cancer it would certainly be at an early stage and the patient can be immediately put on therapeutics.
In the diagnoses of other diseases
Nanobiotechnology can be used for detecting microorganisms that are highly infectious and also for biomarker discovery. Nanobiotechnology offers higher resolution in detecting biomarkers especially with polymercoated nanoparticles that can detect biomarkers efficiently as well as aid in separating DNA
Here are some examples of how nanobiotechnology can be used in medical imaging:
Manganese oxide nanoparticles are used to make MRI contrast agents for visual enhancement of MRI imagery aiding the diagnosis of diseases like Parkinsonism and stroke.
Superparamagnetic nanoparticles can be used alongside MRI to detect lymph node metastases.
In MRI, intracranial tumors can be detected by using dextran-coated iron oxide nanoparticle.
Use of perfluorocarbon nanoparticles allows the MRI to detect in vivo progenitor cells. In this case, perfluorocarbon nanoparticles are used to label umbilical cord blood endothelial progenitor cells. When the MRI is set to the fluorocarbon frequency the scan will depict only the nanoparticle containing cells. So the imaging remains unaffected by other signals and the cells could be easily estimated. Various perfluorocarbon nanoparticles could be used to label different compounds and when the MRI is set to those frequencies those compounds will be depicted in the scan. So it can be used as a beacon to track cells and enable treatments.
QD's can be used in combo with magnetic iron oxide nanoparticles to make a single nanoparticle probe which can facilitate dual mode imaging of cancer whereby you can get tumor images as well as the cancer molecule image. A specific example is the use of silica nanoparticles in combo with rhodamine and iron oxide nanoparticle.
Miniaturization of medical devices
Nanobiotechnology is essentially related to miniaturization. Therefore even the heart pacemaker could be miniaturized. This could lower the bar on invasive surgery and also bring about newer uses of the pacemaker such as its use for instance in ventricular resynchronization. Other possibilities include the making of biological fuel cells. There are other currently used bionic devices that benefit from advances in nanobiotechnology. For instance there are bionic pacemaker used for neural interfacing and also bionic pressure controllers.
The use of nanobiotechnology in molecular diagnostics is referred to as nanomolecular diagnostics. Nanodiagnostics involve the interplay of different technologies that are integrated to produce a test result. In nanomolecular diagnostics only very small quantity of sample is needed to conduct the tests.
In nanodiagnostics the time required to get a test result is also considerably less. For example, it would take very little time to detect sexually transmitted diseases in given urine sample and so diagnosis and prescription paradigms can be quickly affected.
As another example, it takes only twenty minutes for bioassays based on bioconjugated nanoparticles to detect pathogenic bacterium and so finds application in detection of infectious diseases.
In nanomolecular diagnostics genetic detection of anthrax pathogenicity is possible by using oligonucleotide-functionalized QDs as nanoprobes.
Cytogenetics finds use to depict the chromosome structure and to find out disease related abnormalities. Normally flouroscence microscopy is used in this field. As it has reached limitations, the adoption of nanobiotechnology through atomic force microscopy and quantum dot FISH have increased the efficiency of molecular cytogenetics.
Atomic force microscopy and scanning near-field optical microscopy can help to:
• Gather G-bands and chromosomal probe information
• It is possible to extract minute quantity of chromosomal DNA using the scanning probe
• Both nanodissection and nanoextraction of chromosomal DNA is possible.
In drug research
Nanoparticles can be used for bioscreening because they serve as labeling molecules.
Already point of care diagnosis at the doctor's clinic and the ability to combine diagnostics with therapeutics is possible with the use of nanobiotechnology in the field of molecular diagnostics. That apart, in future nanomedicine could become a trendsetter in therapeutic methods.
But there are some safety concerns in the use of nanoparticles. Generally there are no safety concerns with in vitro diagnostic use but toxicity could be an area of concern in in vivo use of nanoparticles. As regards in vivo use of nanoparticles questions of safety are generally with regard to nanoparticles lesser than 20 run in diameter that are able to penetrate cells. For example if QDs made with fluorescent labels of calcium selenide or zinc sulfide is introduced in the body it could release cadmium and zinc ions which could be toxic. But whether it affects cell function is a bone of contention.
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