A particle that has one of the many dimensions, 100 nm or less is defined as a nanoparticle. As increasing positive results of nanoparticles and nanotechnology studies are put forth, their uses are increasing day by day (right from diagnostics, healthcare to energy production and the IT industry).

As nanoparticles are so small in size they can easily cross the cell barrier. Scientists are interested to find out whether this property of nanoparticles can be used to deliver drugs to remote places. For treating diseases of the CNS, nanosystems are used for generating nano drug delivery systems. They are nanospheres, nanosuspensions, nanoemulsions, carbon nanotubes and nanorobots & solid lipid nanoparticles (SLN).

Nanoparticles have the capability to help in developing newer methods that can alleviate the effects of traumatic, degenerative and neoplastic diseases.

Current applications:

• Neuroscience bioimaging: For tumor targeting and MRI imaging, superparamagnetic inorganic oxides like Fe3O4 are found to be giving positive results in the process. Neuroscience bioimaging also makes use of iron oxides as an alternative. These types of experiments have two things in mind: firstly, to upgrade the MRI signal level and secondly, to see that the drug is delivered to the required cells and tissues. The harmful effects of such materials are high toxicological levels due to heavy metal dissociation. Another method of deriving such nanoparticles is making use of certain microbial species (for example, Rhodopseudomonas capsulata for producing gold nanoparticles).

• Wound dressing: At present, a nanoporous zeolite called QuikClot is used as a wound-dressing material to stop hemorrhage due to traumatic injury. Changing nanostructured surfaces in a very small way to allow neurochemicals that act in different pathways biologically (important neurological functions), would be seen as important in the field of neuroscience and nanobiotechnology. The downside of QuikClot is that it causes dehydration locally and cauterization in situ. Hence, clays or mesoporous bioglass are a better alternative to arrest hemorrhage.

• Delivery of genes: For delivering DNA, gold and silica nanoparticles have been the preferred materials as their physicochemical property and surface chemistry is known all over.

• To change synthesis of proteins by generating unique pathways: microRNAs (miRNAs) play an important part in different neuronal pathways and biology of stem cells. Newer treatment methods that rely on non-viral carrier systems to transfer oligonucleotides inside the cytosol, to get a hold over the process of translation, have gone up many folds.


The positive aspects of nanoparticles in the form of drug delivery systems are:

1. Nanoparticles can be changed conveniently according to their size and surface characteristics, in order to accomplish targeting of the drug after it is given parenterally.

2. Nanoparticles can sustain-release the drug, changing its distribution in the body organs and its resulting clearance from the body. This would give rise to levels of therapeutic efficacy of the drug being raised and a decrease in their respective side effects.

3. The feature of sustained drug release can be changed by altering the matrix components; inclusion of the drugs in the systems is devoid of any chemical reaction. This helps a great deal in keeping the activity of the drug constant.

4. Either targeting ligands or magnetic guidance is the medium to achieve the goal of site-specific targeting.

5. Different routes of drug administration such as oral, nasal, parenteral etc. make use of such systems.

Examples of nanoparticles-nervous system treatment options in clinical trials:

1. Liposomal doxorubicin is being used for soft tissue sarcoma and is currently in Phase I/II.

2. PEG-camptothecin is being used for different types of cancers and is currently in Phase I/II.

Limitations of nanoparticles in neuroscience

1. Generating an immune response due to off target effects.

2. Damaging the CNS by going across the blood brain barrier.

3. Inadequate removal of nanoparticles from the body can cause tissue toxicity.

4. Rise in clinical trial costs due to hurdles in obtaining informed consent from the patients. This would be due to inability of the persons to explain the advantages and disadvantages of nanoparticles, being used for a larger duration, to the patients.

5. Poor patients will not be able to afford such unique treatment options due to their high costs.

Since particular regulatory guidelines to approve such treatment options do not exist, the advice is that risk-based assessment should be done for standalone applications.


The future:

1. To stimulate and record excitable events in neurons and cardiomyocytes.

2. Incorporating calcium phosphosilicate nanoparticles in the treatment of cancer photodynamically.

3. Destroying head and neck cancerous cells in mice through magnetic current and nanoparticles.

4. For diagnosing and treating Alzheimer’s disease through multi-functional nanoparticles.

5. To prevent the immune system from attacking itself through nanoparticles- a multiple sclerosis experiment.

6. Reducing inflammatory effects in mice by spherical gold nanoparticles.


REFERENCES:

1. http://ncbes.eurhost.net/metallic-nanoparticles.aspx

2. http://www.southampton.ac.uk/nanoneuroscience/

3. Khanbabaie R, Jahanshahi M. Revolutionary impact of nanodrug delivery on neuroscience. Current Neuropharmacology. 2012; 10 (4): 370-392.

4. Silva G A. What impact will nanotechnology have on neurology? Nature Clinical Practice Neurology. 2007; 3(4): 180-181.

5. Suh W H, Stucky G D, et al. Nanotechnology, nanotoxicology and neuroscience. Prog Neurobiol. 2009; 87(3): 133-170.

6. Dharmendra J, Prabhala B K. Ethical issues in nanomedicine. The Holistic Approach to Environment 2. 2012; 4: 171-175.

7. http://www.discoverymedicine.com/tag/nanoparticle/

8. http://neurosciencenews.com/nanoparticles-magnetic-current-damage-cancerous-cells/

9. http://boa.unimib.it/bitstream/10281/43984/3/Phd_unimib_063716.pdf

10. http://www.cbsnews.com/news/multiple-sclerosis-study-uses-nanoparticles-to-stop-immune-system-from-attacking/

11. Chen H, Dorrigan A, et al. In vivo study of spherical gold nanoparticles: Inflammatory effects and distribution in mice. PLoS ONE. 2012; 8(2): 1-8.

About Author / Additional Info: