Nanomedicine: An Emerging Area of Nanotechnology

 

Ritesh Kumar*, Amit Kumar Jha and Surendra Kumar Jain

Ravishankar College of Pharmacy, Bhopal-462010, Madhya Pradesh, India

 

 

ABSTRACT

Nanomedicine is emerging as the most important discipline under the umbrella of nanotechnology. It is concerned with the preservation and improvement of human health, using molecular tools and molecular knowledge of the human body. Simply nanomedicine is the application inside nanotechnology to the medicine. The pharmaceutical nanotechnology market is concerned especially with the diagnostic and carrier for drug, which has been rapidly growing over last decade. Some pharmaceutical nanotechnology based products such as nanoparticles polymer, micelles, dendrimer, monoclonal antibody and other modified nanosystems have been approved by US-FDA and have entered in the market. However, some unknown health risk, unpredictable and undefined safety issues and some clinical as well as regulatory issues still pose formidable challenge. Thus, this review justifies the status, scope and importance of nanomedicine inside the field of nanotechnology.

 

 

KEY WORDS: Nanotechnology, Nanomaterials, Nanoscale devices, Nanomedicine

                 

 

INTRODUCTION

Nanomedicine is the process of diagnosing, treating, and preventing disease and traumatic injury, of relieving pain and of preserving and improving human health, using molecular tools and molecular knowledge of the human body. Nanomedicine is an emerging field of medicine with novel applications. Nanomedicine is a subset of nanotechnology, which uses tiny particles that are more than 10 million times smaller than the human body1. In nanomedicine, these particles are much smaller than living cell. Because of this, nanomedicine presents many revolutionary opportunities in the fight of all types of cancer, neurodegenerative disorders and other diseases. Nanomedicine is beginning to emerge from research in nanotechnology2. Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications3. Encompassing nanoscale science, engineering and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale. Nanoparticles are defined as particulate dispersions or solid particles with a size in the range of 10-1000 nm. The drug is dissolved, entrapped, encapsulated or attached to a nanoparticle matrix4. The major goals in designing nanoparticles as a delivery system are to control particle size, surface properties and release of pharmacologically active agents in order to achieve the site-specific action of the drug at the therapeutically optimal rate and dose regimen5,6.

 

Advantages of Nanoparticles over Nanomedicine

Increased bioavailability, dose proportionality, decrease toxicity, stable dose forms of drugs which are either unstable or have unacceptably low bioavailability in non–nanoparticle dosages forms are the ideal feature of the nanoparticle over nanomedicine. Increased surface area results in a faster dissolution of the active agent in an aqueous environment. Faster dissolution generally equates with greater bioavailability, smaller drug doses, less toxicity, reduction in fed /fasted variability7.

 

 

 

Nanotechnology (Nanomaterials and Nanoscale devices) for diagnosis, treatment and monitoring diseases is a fast developing area of biomedical research. It is an amalgamation of engineering science with pharmaceutical and medical sciences. Nanotech based drug delivery is less toxic as well as inexpensive. Nanomedicine has a limited number of current applications. Academic centers including CalTech and Harvard are using nanowires to create biosensors capable of identifying proteins in a cells as well as viruses in the hopes of developing a new generation of diagnostics.

 

Table 1. Nanomedicine Technologies used in Health Care System

S.N.

Areas of Nanomedicine

Applications in Health Care System

1

Biopharmaceutics

Drug delivery

Drug encapsulation

Functional drug carrier

Drug discovery

2

Implantable material

Tissue repair and replacement

Implant coating

Tissue regeneration scaffolds

3

Structural implant material

 

Bone repair

Bioresorable material smart material

4

Implant device

 

Sensory aids

 

Implantable sensor

Implantable medical device

Retina implant

Cochlear implant

5

Surgical aids

Operating tools

Smart instrument

Surgical robots

6

Diagnostic tools

Genetic testing

Ultra sensitive labeling and detecting technologies

High throughout arrays

7

Imaging

 

Nanoparticle labels

Imaging device

 

Nanotechnology is suited for better drugs delivery to small regions within the human body as such drugs can easily cross biological membrane8. Liposomes are effective for drug targeting by chemotherapeutic agents. The concept of Nanotechnology helps in optimizing a therapy for glioblastoma, the most malignant of brain cancers.

 

As a diagnostic tools, efforts of nanoparticle is directed on utilizing a lab-on-a-chip devices to perform DNA analysis and drug discovery research by reducing the required sample sizes and accelerating the chemical reaction process9. Moreover, imaging technologies such as nanoparticle probes and miniature the imaging devices that could promote early detection and diagnosis of disease.

 

Some examples of application of nanotechnology are:

1.      Intracellular drugs delivery through spontaneously forming nanotubes.

2.      Lipid complexes for i.v. administration of antifungal.

3.      Submicron triglycerides emulsions for parenteral nutrition.

4.      Accelerated wound healing because of silver nanoparticle antimicrobials as dressings.

 

Nanocrystals based drugs are Rapamune (sirolimus), Emend (aprepitant), TriCor (fenofibrate).

 

The Nanotechnology act for understanding basic life processes on using nanoscale devices and materials to learn more about how biological systems self-assemble, self-regulate, and self destroy at the molecular level. Drug delivery is one of the most promising fields of nanotechnology11,12.

 

Medical Nanomaterials and Devices that Signify Nanomedicine

a)      Dendrimers and Dendrimer - Based Devices

Dendrimers represent yet another nanostructured material that may soon find its way into medical therapeutics13. Starburst dendrimers are tree-shaped synthetic molecules with a regular branching structure emanating outward from core that form nanomer by nanometer, with the number of synthetic steps or “generations” dictating the exact size of the particles, typically a few nanometers in spheroid diameter. The cell-surface protein recognition-targeting strategy could be applied against virus-infected cells and parasites. Molecular modeling has been used to determine optimal dendrimer surface modifications for the function of tecto-dendrimer nanodevices and to suggest surface modifications that improve targeting14. Dendrimer represents a new class of controlled structure polymer with nanometric dimensions. They are considered to be basic element for large-scale synthesis of organic and inorganic nanostructure with dimension of 1 to 100 nm, displaying unique properties15.

 

Table 2. Nanoparticles with their Specific Size Range

 

b)      Magnetic Nanoparticle and Immunoassay 

It label the choices so that its interaction with the analyze gives magnetic signals tube used instead of an optical one magnetic nanoparticles. Its detection is possible only by magnetometer. The advantage attributes for detection of subunits modification is in magnetic characters, ability to detect circulation cancer cells and  microorganism16,17.

 

c)      Nanobarcodes

The sequential electrochemical deposition of metal ions to give sub micrometer metallic barcodes whose differential relativity can lead to identification of the unique striping patterns by light microscope. Basically it is used for multiplexed protein assay and single nucleotide variation mapping does not interfere with the use of fluorescent labeling18.

 

Table 3. Different Parameters and Characterization of Nanoparticles

S.N.

Parameters

Characterization Method

1

Particle Size & Size distribution

Photon correlation spectoroscopy,

Scanning electron microscopy (SEM),

Transmission electron microscopy (TEM), Atomic force microscopy (AFM), Mercury porositometry, Laser defractometry

2

Charge Determination

Laser droplet anemometry, Zeta potential

3

Surface Hydrophobicity

Water contact angle measurement, Rose bangle (dye) binding, hydrophobic interaction chromatography, X-ray photoelectron spectroscopy

4

Chemical Analysis of Surface

Static secondary ion mass spectrometry, Sorptometer

5

Carrier Drug Interaction

Differential scanning calorimetry

6

Nanoparticle dispersion stability

Critical flocculation temperature

 

d)      Nanowires

It is similar to the other nanoparticle e.g. gold and QDS but are characterizes by different shapes thus allowing for different interaction with different entities and ore unique optimal signals. It can associated with the almost any chemical or biological  recoginization system which allow real time detection analyst independent ,that can  be conjugated with the almost any bimolecular recoginization entity suitable for the use in vivo diagnostics19.  Nanowires are semiconductive or semiconductive particles with a crystalline structure of a few dozen nm and a high length/diameter ratio. Silicon, cobalt, gold or copper based nanowires have already been produced. They are used to transport electrons in nanoelectronics. It could be composed of different metals, oxides, sulphides and nitrides20.

 

e)      Nanopores

The pores of definite size in the nanoscale range on membrane between two  solutions on application of current, the pores allow only nucleic acids or charged biomolecules or particular size to pass, further these are than directly translated into electric signals on the passage through the pore. Its act as a label less immunoassay for flow system as sensitive enough to detect single base substitution in DNA strands or the length of 30 nucleotides21.

 

f)       Nanocapacitor

It acts with the electrode spacing in the nanoorder with single stranded DNA pores; target hybridization produces a measurable change in capacitance. Its array allow for label less simultaneous detection or nucleic acids22.

 

g)      Nanotubes

The array of Nanotubes e.g. carbon or boron nitride are used electrode with single stranded DNA probes attached to their open end, hybridization or target DNA gives an electrochemical signals, they can also be adapted for analyst other than DNA. The detection technique is sensitivity in the attomole range and reduction of signals to noise radiation and minimize the need for amplification of target DNA23.

 

h)      NanoBiosensors

Based on high specificity of biological reactions for detecting target analyzes, biosensors, which are useful research tools to discover genetic abnormalities and physiological disease. Biosensors couple is a biological recognition element with a physical transducer that translates the bio-recognition event into a measurable effect, such as electrical signal, an optical emission or a mechanical motion. A new class of promising nanobio-sensor to detect bimolecular interaction with great accuracy is the microcantilever. This new class of highly sensitivity biosensors can perform local, high resolution and label-free molecular recognition measurement. Mechanisms of these biosensors are based on cantilever in atomic force microscopy (AFM) 24.

 

The concept of Nanodiagnostics arises the fact that most biological molecules and cell organelles fall within the nanometer scale. For example, the typical protein has a size of 5 nm. The Nanoparticles used for detection can be synthesized to be within this same size domain19,25. Current diagnostic methods measure or determine a particular property as an average of the individual contributions of an ensemble of units or particles. Thus, such methods do not convey any information about the individual members in a heterogeneous population or about the lifespan of the various members within the population26.

Characterization of NanoParticles

The nanoparticles are generally characterized for the particle size, charge determination and surface hydrophobicity. Different parameter and characterization methods for nanoparticles are summarized on the given table 327

 

Expectation from Nanomedicines

Nanotechnology is the beginning to change the scale and methods of vascular imaging and drug delivery. Nanomedicne initiative envisages that nanoscale technologies will begin yielding more miracle benefit within the next 10 years28-31. This includes the development of nanoscale laboratory based diagnostic and drug discovery platform devices such as nanoscale cantilevers for chemical force microscope, microchip devices, and nanopore sequencing32. The Asia-Pacific Economic Cooperation (APEC) Center for Technology Foresight predicts the development of selective nanosensors and drug delivery systems over the next three years, and the application of advanced medical diagnostics and the ability to target human cells for organ repair by 201333. The range of long-term expectations in nanomedicine expands from more cautious forecasts into a realm. Some scientists view as science fiction nanomedicine, which could potentially overthrow traditional notions about disease and health to user in a form of medicine based on prediction and prevention instead of treatment34. In future the field of nanomedicine will become particularly relevant due to the increasing politicization of the nanotechnology debate, and subsequent calls for new regulations by non-governmental organizations. Hence by generating new ideas the expectation of nanomedicine inside the public health sector could uplift inorder to change the life style of the healthy person. By the use of various drug delivery devices it offers direct on site drug delivery effect and provide direct release, and thus increase patient acceptabilty35.

 

 

CONCLUSION

Nanomedicine posses a bright future as if it is the hope that in the first half of the 21st  century, nanomedicine could eliminate virtually all common diseases of the 20th century, and virtually all medical pain and suffering as well. The sort of materials that could be called nanomedicines can include proteins, polymers, dendrimers, micelles, liposomes, emulsions, nanoparticles and nanocapsules. This technology is expected to create innovations and play a vital role in various biomedical applications not only in drug delivery and gene therapy, but also in molecular imaging, biomarkers and biosensors. However as nanomedicine becomes a global movement, it is paramount that the hype be separated from reality. In addition, societal, environmental and ethical concerns will also need to be addressed as breakthroughs in nanomedicne as a source to cure human health.

 

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Received on 01.05.2009

Accepted on 14.06.2009     

© A&V Publication all right reserved

Research Journal . of Pharmaceutical Dosage Forms  and Technology. 1(1): July.-Aug. 2009, 18-21