In this article we will discuss about Nano Medicine:- 1. Meaning of Nano Medicine 2. Advantages of Nano Medicine 3. Disadvantages.

The application of nanotechnology in medicine is often referred to as Nano medicine. Nano medicine is the preservation and improvement of human health using molecular tools and molecular knowledge of the human body. It covers areas such as nanoparticle drug delivery and possible future applications of molecular nanotechnology (MNT) and Nano-vaccinology.

The human body is comprised of molecules. Hence, the availability of molecular nanotechnology will permit dramatic progress in human medical services. More than just an extension of molecular medicine, Nano medicine will help us understand how the biological machinery inside living cells operates at the Nano scale so that it can be employed in molecular machine systems to address complicated medical conditions such as cancer, AIDS, ageing and thereby bring about significant improvement and extension of natural human biological structure and function at the molecular scale.

Nano medical approaches to drug delivery centre on developing Nano scale particles or molecules to improve drug bioavailability that refers to the presence of drug molecules in the body part where they are actually needed and will probably do the most good. It is all about targeting the molecules and delivering drugs with cell precision.

The use of Nano robots in medicine would totally change the world of medicine once it is realized. For instance, by introducing these Nano robots into the body damages and infections can be detected and repaired. In short it holds that capability to change the traditional approach of treating diseases and naturally occurring conditions in the human beings.

1. Advanced therapies with reduced degree of invasiveness.

2. Reduced negative effects of drugs and surgical procedures.

3. Faster, smaller and highly sensitive diagnostic tools.

4. Cost effectiveness of medicines and disease management procedures as a whole.

5. Unsolved medical problems such as cancer, benefiting from the Nano medical approach.

6. Reduced mortality and morbidity rates and increased longevity in return.

1. Lack of proper knowledge about the effect of nanoparticles on biochemical pathways and processes of human body.

2. Scientists are primarily concerned about the toxicity, characterization and exposure pathways associated with Nano medicine that might pose a serious threat to the human beings and environment.

3. The societys ethical use of Nano medicine beyond the concerned safety issues, poses a serious question to the researchers.

Continued here:
Nano Medicine: Meaning, Advantages and Disadvantages - BioTechnology Notes

Both the academic community and the pharmaceutical industry are making increasing investments of time and money in nanotherapeutics. Nearly 50 biomedical products incorporating nanoparticles are already on the market, and many more are moving through the pipeline, with dozens in Phase 2 or Phase 3 clinical trials. Drugmakers are well on their way to realizing the prediction of Christopher Guiffre, chief business officer at the Cambridge, Massachusettsbased nanotherapeutics company Cerulean Pharma, who last November forecast, Five years from now every pharma will have a nano program.

Technologies that enable improved cancer detection are constantly racing against the diseases they aim to diagnose, and when survival depends on early intervention, losing this race can be fatal. While detecting cancer biomarkers is the key to early diagnosis, the number of bona fide biomarkers that reliably reveal the presence of cancerous cells is low. To overcome this challenge, researchers are developing functional nanomaterials for more sensitive detection of intracellular metabolites, tumor cellmembrane proteins, and even cancer cells that are circulating in the bloodstream. (See Fighting Cancer with Nanomedicine, The Scientist, April 2014.)

The extreme brightness, excellent photostability, and ready modulation of silica nanoparticles, along with other advantages, make them particularly useful for molecular imaging and ultrasensitive detection.

Silica nanoparticles are one promising material for detecting specific molecular targets. Dye-doped silica nanoparticles contain a large quantity of dye molecules housed inside a silica matrix, giving an intense fluorescence signal that is up to 10,000 times greater than that of a single organic fluorophore. Taking advantage of Frster Resonance Energy Transfer (FRET), in which a photon emitted by one fluorophore can excite another nearby fluorophore, researchers can synthesize fluorescent silica nanoparticles with emission wavelengths that span a wide spectrum by simply modulating the ratio of the different dyesthe donor chromophore and the acceptor chromophore. The extreme brightness, excellent photostability, and ready modulation of silica nanoparticles, along with other advantages, make them particularly useful for molecular imaging and ultrasensitive detection.

THE NANOMEDICINE CABINET: Scientists are engineering nanometer-size particles made of diverse materials to aid in patient care. The unique properties of these structures are making waves in biomedical analysis and targeted therapy.See full infographic: JPG | PDF TAMI TOLPAOther materials that are under investigation as nanodetectors include graphene oxide (GO), the monolayer of graphite oxide, which has unique electronic, thermal, and mechanical properties. Semiconductor-material quantum dots (QDs), now being developed by Shuming Nies group at Emory University, exhibit quantum mechanical properties when covalently coupled to biomolecules and could improve cancer imaging and molecular profiling.1 Spherical nucleic acids (SNAs), in which nucleic acids are oriented in a spherical geometry, scaffolded on a nanoparticle core (which may be retained or dissolved), are also gaining traction by the pioneering work of Chad Mirkins group at Northwestern University.2 (See illustration.)

Nanoparticles are also proving their worth as probes for various types of bioimaging, including fluorescence, magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET). For instance, Xiaoyuan Chen, now at the National Institutes of Healths National Institute of Biomedical Imaging and Bioengineering, and Hongjie Dai of Stanford University have developed carbon nanotubes for performing PET scans in mice. When modified with the macromolecule polyethylene glycol to improve biocompatibility, the nanotubes were very stable and remained in circulation for days, far longer than the few hours typical of many molecular imaging agents.3 Further modification with a short-peptide targeting ligand called RGD caused the nanotubes to selectively accumulate in tumors that overexpressed integrin, the molecular target of RGD, enabling precise tumor imaging.

To further increase the specificity of nanodetectors, researchers can add recognition probes such as aptamersshort synthetic nucleic acid strands that bind target molecules. For example, we conjugated gold nanoparticles with aptamers that had been identified through iteratively screening DNA probes using living cancer cells.4 Circulating tumor cells (CTCs) are shed into the bloodstream from primary tumors and provide a potential target for early cancer diagnosis. However, CTCs are rare, with blood concentrations of typically fewer than 10 cells per milliliter of blood. Collaborating with physicians to profile samples from leukemia patients, we demonstrated that aptamers are capable of differentiating among different subtypes of leukemia, as well as among patient samples before and after chemotherapy (unpublished data). In addition to leukemia, we have selected aptamers specific to cancers of the lung, liver, ovaries, colon, brain, breast, and pancreas, as well as to bacterial cells. Other researchers have developed nanoparticles with numerous and diverse surface aptamers, enabling them to bind their targets more efficiently and securely.

NANOCAPSULES: A false-color transmission electron micrograph of liposomes, spherical particles composed of a lipid bilayer around a central cavity that can be engineered to deliver both hydrophobic and hydrophilic drugs to specific cells in the body DAVID MCCARTHY/SCIENCE SOURCEThe prototype of targeted drug delivery can be traced back to the concept of a magic bullet, proposed by chemotherapy pioneer and 1908 Nobel laureate Paul Ehrlich. Ehrlich envisioned a drug that could selectively target a disease-causing organism or diseased cells, leaving healthy tissue unharmed. A century later, researchers are developing many types of nanoscale magic bullets that can specifically deliver drugs into target cells or tissues.

Doxil, the first nanotherapeutic approved by the US Food and Drug Administration, is a liposome (~100 nm in diameter) containing the widely used anticancer drug doxorubicin. The therapy takes advantage of the leaky blood vasculature and poor lymphatic drainage in tumor tissues that allow the nanoparticles to squeeze from blood vessels into a tumor and stay there for hours or days. Scientists have also been developing nanotherapeutics capable of targeting specific cell types by binding to surface biomarkers on diseased cells. Targeting ligands range from macromolecules, such as antibodies and aptamers, to small molecules, such as folate, that bind to receptors overexpressed in many types of cancers.

Aptamers in particular are a popular tool for targeting specific cells. Aptamer development is efficient and cost-effective, as automated nucleic acid synthesis allows easy, affordable chemical synthesis and modification of functional moieties. Other advantages include high stability and long shelf life, rapid tissue penetration based on the relatively small molecular weights, low immunogenicity, and ease of antidote development in the case of an adverse reaction to therapy by simply administering an aptamers complementary DNA. We have demonstrated the principle of modifying aptamers on the surfaces of doxorubicin-containing liposomes, which then selectively delivered the drug to cultured cancer cells.5

Recent advances in predicting the secondary structures of a DNA fragment or interactions between multiple DNA strands, as well as in technologies to automatically synthesize predesigned DNA sequences, has opened the door to more advanced applications of aptamers and other DNA structures in nanomedicine. For instance, we have developed aptamer-tethered DNA nanotrains, assembled from multiple copies of short DNA building blocks. On one end, an aptamer moiety allows specific target cell recognition during drug delivery, and a long double-stranded DNA section on the other end forms the boxcars for drug loading. The nanotrains, which can hold a high drug payload and specifically deliver anticancer drugs into target cancer cells in culture and animal models,6 could reduce drug side effects while inhibiting tumor growth. Alternatively, Daniel Anderson of MIT engineered a tetrahedral cage of DNA, often called DNA origami, for folate-mediated targeted delivery of small interfering RNAs (siRNAs) to silence some tumor genes.7 And Mirkins SNAs can similarly transport siRNAs as guided missiles to knock out overexpressed genes in cancer cells. Mirkins group also recently demonstrated that the SNAs were able to penetrate the blood-brain barrier and specifically target genes in the brains of glioblastoma animal models.2 Peng Yin of Harvard Medical School and the Wyss Institute and others are now building even more complex DNA nanostructures with refined functions, such as smart biomedical analysis.8

Conventional assembly of such DNA nanostructures exploits the hybridization of a DNA strand to part of its complementary strand. In addition, we have discovered that DNA nanostructures called nanoflowers because they resemble a ring of nanosize petals, can be self-assembled through liquid crystallization of DNA, which typically occurs at high concentrations of the nucleic acid.9 Importantly, these DNA nanostructures can be readily incorporated with components possessing multiple functionalities, such as aptamers for specific recognition, fluorophores for molecular imaging, and DNA therapeutics for disease therapy.

Another example of novel nanoparticles is DNA micelles, three-dimensional nanostructures that can be readily modified to include aptamers for specific cell-type recognition, or DNA antisense for gene silencing. The lipid core and sphere of projecting nucleic acids can enter cells without any transfection agents and have high resistance to nuclease digestion, making them ideal candidates for drug delivery and cancer therapy.

Researchers are developing many types of nanoscale magic bullets that can specifically deliver drugs into target cells or tissues.

Such advances in targeting are now making it possible to deliver combinations of drugs and ensure that they reach target cells simultaneously. Paula Hammond and Michael Yaffe of MIT recently reported a liposome-based combination chemotherapy delivery system that can simultaneously deliver two synergistic chemotherapeutic drugs, erlotinib and doxorubicin, for enhanced tumor killing.10 Erlotinib, an inhibitor of epidermal growth factor receptor (EGFR), promotes the dynamic rewiring of apoptotic pathways, which then sensitizes cancer cells to subsequent exposure to the DNA-damaging agent doxorubicin. By incorporating erlotinib, a hydrophobic molecule, into the lipid bilayer shell while packaging the hydrophilic doxorubicin inside of the liposomes, the researchers achieved the desired time sequence of drug releasefirst erlotinib, then doxorubicinin a one-two punch against the cancer. They also demonstrated that the efficiency of drug delivery to cancer cells was enhanced by coating the liposomes with folate.

Scientists are also engineering smart nanoparticles, which activate only in the disease microenvironment. For example, George Church of Harvard Medical School and the Wyss Institute and colleagues invented a logic-gated DNA nanocapsule that they programmed to deliver drugs inside cells only when a specific panel of disease biomarkers is overexpressed on the cell surface.11 And Donald Ingbers group, also at Harvard Medical School and the Wyss Institute, developed microscale aggregates of thrombolytic-drug-coated nanoparticles that break apart under the abnormally high fluid shear stress of narrowed blood vessels and then bind and dissolve the problematic clot.12

With these and other nanoplatforms for targeted drug delivery being tested in animal models, medicine is now approaching the prototypic magic bullet, sparing healthy tissue while exterminating disease.

In addition to serving as mere drug carriers that deliver the toxic payload to target cells, nanomaterials can themselves function as therapeutics. For example, thermal energy is emerging as an important means of therapy, and many gold nanomaterials can convert photons into thermal energy for targeted photothermal therapy. Taking advantage of these properties, we conjugated aptamers onto the surfaces of gold-silver nanorods, which efficiently absorb near-infrared light and convert energy from photons to heat. These aptamer-conjugated nanorods were capable of selectively binding to target cells in culture and inducing dramatic cytotoxicity by converting laser light to heat.13

Magnetic nanoparticles are also attractive for their ability to mediate heat induction. Jinwoo Cheon of Yonsei University in Korea developed coreshell magnetic nanoparticles, which efficiently generated thermal energy by a magnetization-reversal process as these nanoparticles returned to their relaxed states under an external, alternating-current magnetic field.14 Using this technology, Cheon and his colleagues saw dramatic tumor regression in a mouse model.A third type of nanosize therapeutic involves cytotoxic polymers. For example, we synthesized a nucleotide-like molecule called an acrydite with an attached DNA aptamer that specifically binds to and enters target cancer cells.15 The acrydite molecules in the resultant acrydite-aptamer conjugates polymerized with each other to form an aptamer-decorated molecular string that led to cytotoxicity in target cancer cells, including those exhibiting multidrug resistance, a common challenge in cancer chemotherapy.

Many other subfields have been advanced by recent developments in nanomedicine, including tissue engineering and regenerative medicine, medical devices, and vaccines. We must proceed with caution until these different technologies prove safe in patients, but nanomedicine is now poised to make a tremendous impact on health care and the practice of clinical medicine.

Guizhi Zhu is a postdoctoral associate in the Department of Chemistry and at the Health Cancer Center of the University of Florida. Weihong Tan is a professor and associate director of the Center for Research at the Bio/Nano Interface at the University of Florida. He also serves as the director of the Molecular Science and Biomedicine Laboratory at Hunan University in China, where Lei Mei is a graduate student.

Read the original post:
http://www.the-scientist.com

After more than 20 years of basic nanoscience research andmore than fifteen years of focused R&D under the NNI, applications of nanotechnology are delivering in both expected and unexpected ways on nanotechnologys promise to benefit society.

Nanotechnology is helping to considerably improve, even revolutionize, many technology and industry sectors: information technology, homeland security, medicine, transportation, energy, food safety, and environmental science, among many others. Described below is a sampling of the rapidly growing list of benefits and applications of nanotechnology.

Many benefits of nanotechnology depend on the fact that it is possible to tailor the structures of materials at extremely small scales to achieve specific properties, thus greatly extending the materials science toolkit. Using nanotechnology, materials can effectively be made stronger, lighter, more durable, more reactive, more sieve-like, or better electrical conductors, among many other traits. Many everyday commercial products are currently on the market and in daily use that rely on nanoscale materials and processes:

Nanotechnology has greatly contributed to major advances in computing and electronics, leading to faster, smaller, and more portable systems that can manage and store larger and larger amounts of information. These continuously evolving applications include:

Nanotechnology is already broadening the medical tools, knowledge, and therapies currently available to clinicians. Nanomedicine, the application of nanotechnology in medicine, draws on the natural scale of biological phenomena to produce precise solutions for disease prevention, diagnosis, and treatment. Below are some examples of recent advances in this area:

Nanotechnology is finding application in traditional energy sources and is greatly enhancing alternative energy approaches to help meet the worlds increasing energy demands. Many scientists are looking into ways to develop clean, affordable, and renewable energy sources, along with means to reduce energy consumption and lessen toxicity burdens on the environment:

In addition to the ways that nanotechnology can help improve energy efficiency (see the section above), there are also many ways that it can help detect and clean up environmental contaminants:

Nanotechnology offers the promise of developing multifunctional materials that will contribute to building and maintaining lighter, safer, smarter, and more efficient vehicles, aircraft, spacecraft, and ships. In addition, nanotechnology offers various means to improve the transportation infrastructure:

Please visit the Environmental, Health, and Safety Issues and the Ethical, Legal, and Societal Issues pages on nano.gov to learn more about how the National Nanotechnology Initiative is committed to responsibly addressing these issues.

Read the original here:
Applications of Nanotechnology - National Nanotechnology Initiative