Nanomedicine

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Dr SHOEB MUSTAFA, DEPT. OF MICROBIOLOGY, J.N.MEDICAL COLLEGE AND HOSPITAL,A.M.U, ALIGARH E MAIL:SHOEBMUSTAFA82@INDIATIMES.COM

• Nanomedicine is the medical application of nanotechnology. It covers areas such as nanoparticle drug delivery and possible future applications of molecular nanotechnology (MNT) and nanovaccinology. • The most important innovations are taking place in drug delivery which involves developing nanoscale particles or molecules to improve bioavailability. • In vivo imaging is another area where tools and devices are being developed. Using nanoparticle contrast agents, images such as ultrasound and MRI have a favorable distribution and improved contrast. • The new therapies and surgeries that are being developed might be effective in treating illnesses and diseases such as cancer.

PHARMACOLOGICAL POTENTIAL[edit]

Nanopharmocology is the use of nanotechnology for pharmacology applications such as: the formation of novel nanoscopic entities [1], exploring and matching specific compounds to particular patients for maximum effectiveness; and advanced pharmaceutical delivery systems and discovery of new pharmacological molecular entities; selection of pharmaceuticals for specific individuals to maximize effectiveness and minimize side effects (2), and delivery of pharmaceuticals to targeted locations or tissues within the body. Nanoparticles can render targeted and sustained delivery of biological compounds to specific tissues with a minimum of systemic side effects.

Nanoparticles have unusual properties that can be used to improve drug delivery. • Whereas larger particles would have been cleared from the body, cells take up these nanoparticles because of their size. • The particulates from drug delivery systems lower the volume of distribution and reduce the effect on non-target tissue. • Development of completely new drugs with more useful behavior and less side effects.

Some applications of nanopharmacology[edit]

  • • Diagnose conditions and perceive pathogens.
  • • Identify optimal drug agents to treat the condition or pathogens.
  • • Fuel high-yield production of matched pharmaceuticals.
  • • Locate, attach or enter target tissue, configurations or pathogens.
  • • Dispense the ideal mass of matched biological compound to the target locations.

TARGETTED DRUG DELIVERY-ROLE OF NANOCAPSULES[edit]

• Nanocapsule, means sandy nanoparticle that consists of a shell and a space, in which desired substances may be placed. Drug-filled nanocapsules can be covered with antibodies or cell-surface receptors that bind to cancer or various cells and release their biological compound on contact with that tissue. Nanocapsules have been made using molecules called phospholipids, which are hydrophobic (water-repellant) on one end and hydrophilic (water-loving) on the other. When such molecules are placed in an aqueous environment, they can spontaneously form capsules in which the hydrophobic portions are inside (3), protecting them from contact with water.The walls of our cells are in fact made up of a double layer of such molecules. Inside the cells, similar capsules, called liposomes (literally, fat bodies), are used to transport material.

BIOSENSOR CHIPS[edit]

• Nanotechnology chips with biosensors can find genes, guide drug discovery, monitor body functioning, and identify biologic and chemical pathogens. As nanotechnology and genetics advance, medibots and engineered beneficial microorganisms may be integrated into nanomedibots. Nanomedibots will be used to diagnosis and treat healing conditions that resist diagnosis and curing by current biomedical research. Medibots are robots or robotic systems that provide physicians with greater flexibility, precision of motion, and/or remote procedure capability in the diagnosis or treatment of medical conditions. Concerning macro-scale medibots (4), improvements in the conveyance of visual and directional information with sophisticated consoles and remote-controlled hardware are already enabling surgeons to conduct an increasing array of surgical procedures in a minimally invasive manner.

ONCOLOGY[edit]

1. Nanoparticles of cadmium selenide (quantum dots) glow when exposed to ultraviolet light. When injected, they seep into cancer tumors. The surgeon can see the glowing tumor, and use it as a guide for more accurate tumor removal. 2. Sensor test chips containing thousands of nanowires, able to detect proteins and other biomarkers left behind by cancer cells, could enable the detection and diagnosis of cancer in the early stages from a few drops of a patient's blood. [5] 3. Researchers at Rice University have demonstrated the use of 120nm diameter nanoshells coated with gold to kill cancer tumors in mice. The nanoshells can be targeted to bond to cancerous cells by conjugating antibodies or peptides to the nanoshell surface. By irradiating the area of the tumor with an infrared laser, which passes through flesh without heating it, the gold is heated sufficiently to cause death to the cancer cells [6]. 4. Dendrimer molecule has over a hundred hooks on it that allow it to attach to cells in the body for a variety of purposes. These molecules have also shown potential for targeted chemotherapy against tumor cells.


SURGERY[edit]

• At Rice University, a flesh welder is used to fuse two pieces of chicken meat into a single piece. The two pieces of chicken are placed together touching. A greenish liquid containing gold-coated nanoshells is dribbled along the seam. An infrared laser is traced along the seam, causing the two sides to weld together. • This could solve the difficulties and blood leaks caused when the surgeon tries to restitch the arteries he/she has cut during a kidney or heart transplant. The flesh welder could meld the artery into a perfect seal.


ORTHOPEDIC SURGERY (Arthrobotics)[edit]

· Arthrobotics is the application of robotic technology to help orthopedic surgeons in the healing, repair, and replacement of joint-related conditions. Current applications of arthrobotics involve arthroscopic automation and place enhancements, such as automated motion of the arthroscope, position sensors to guide it, and force sensors for tissue proximity control. Future arthrobotic usages might incorporate complete joint replacement with bionic bionics and neuro-computer interfaces for limb control from neural impulses in the brain.

RADIOLOGY (DIAGNOSTIC AND INTERVENTIONAL) AND NUCLEAR MEDICINE[edit]

• Nanodevices could be observed at work inside the body using MRI, using mostly 13C atoms rather than the natural 12C isotope of carbon, since 13C has a nonzero nuclear magnetic moment. • Medical nanodevices would first be injected into a human body, and would then go to work in a specific organ or tissue mass. • The doctor will monitor the progress, and make certain that the nanodevices have gotten to the correct target treatment region. • The doctor can actually see the nanodevices congregate around their target (a tumor mass, etc.). • Tracking movement can help determine how well drugs are being distributed or how substances are metabolized.

NANOROBOTS[edit]

• There are somewhat speculative claims that using nanorobots [7] [8] in medicine, would totally change the world of medicine once it is realized. • Nanomedicine [9] [10] would make use of these nanorobots, introduced into the body, to repair or detect damages and infections. • According to Robert Freitas of the Institute for Molecular Manufacturing, a typical blood borne medical nanorobot would be between 0.5-3 micrometres in size, because that is the maximum size possible due to capillary passage requirement. • Carbon would be the primary element used to build these nanorobots due to the inherent strength and other characteristics of some forms of carbon (diamond/fullerene composites), and nanorobots would be fabricated in desktop nanofactories [11] specialized for this purpose. • Nanorobots could counter the problem of identifying and isolating cancer cells as they could be introduced into the bloodstream. These nanorobots would search out cancer affected cells using certain molecular markers. Medical nanorobots would then destroy these cells, and only these cells. • Nanomedicines could be a very helpful and hopeful therapy for patients, since current treatments like radiation therapy and chemotherapy often end up destroying more healthy cells than cancerous ones. • Nanorobots could also be useful in precision tissue- and cell-targeted drug delivery [12] [13], in performing nanosurgery [14], and in treatments for hypoxemia and respiratory illness[15] [16], dentistry [17] [18], bacteremic infections[19], physical trauma [20], gene therapy via chromosome replacement therapy [21] [22], and even biological aging [23]. •

RESPIROCYTE[edit]

One very simple nanorobot that was designed a few years ago is, the artificial mechanical red cell, a "respirocyte." (24) that can deliver 236 times more oxygen per unit volume than a natural red cell.

Some possible applications using nanorobots are as follows: • To cure skin diseases, a cream containing nanorobots may be used. • A mouthwash full of smart nanomachines could identify and destroy pathogenic bacteria while allowing normal commensals to grow. • Medical nanodevices could augment the immune system by finding and disabling unwanted bacteria and viruses just like leucocyte. • Devices working in the bloodstream could nibble away at arteriosclerosis deposits, widening the affected blood vessels. • Cell herding devices could restore artery walls and artery linings to prevent most heart attacks.


NEURO-ELECTRONIC INTERFACES (NEUROLOGICAL APPLICATIONS)[edit]

• Neuro-electronic interfaces are a visionary goal dealing with the construction of nanodevices that will permit computers to be joined and linked to the nervous system. • This idea requires the building of a molecular structure that will permit control and detection of nerve impulses by an external computer. • The computers will be able to interpret, register, and respond to signals the body gives off when it feels sensations. • The demand for such structures is huge because many diseases involve the decay of the nervous system (ALS and multiple sclerosis). Also, many injuries and accidents may impair the nervous system resulting in dysfunctional systems and paraplegia. • If computers could control the nervous system through neuro-electronic interface, problems that impair the system could be controlled so that effects of diseases and injuries could be overcome. • PROSPECTS: • Treatment of paraplegia, hemiplegia and spondylosis following accidental injuries, vascular and due to other causes.

CELL REPAIR MACHINES (REGENERATIVE MEDICINE)[edit]

• Using drugs and surgery, doctors can only encourage tissues to repair themselves. With molecular machines, there will be more direct repairs. • The possibilities of these cell repair machines are impressive. Comparable to the size of viruses or bacteria, their compact parts will allow them to be more complex. • As they open and close cell membranes or travel through tissue and enter cells and viruses, machines will only be able to correct a single molecular disorder like DNA damage or enzyme deficiency. • Nanocomputers will be needed to guide these machines. These computers will direct machines to examine, take apart, and rebuild damaged molecular structures.

ENDOCRINOLOGY[edit]

• An example of the state of the nanobiotechnological art is Tejal Desai's(Boston University) artificial pancreas. Dr. Desai has encased her mouse pancreatic cells in a membrane studded with "nanopores" a mere seven nanometres across. As glucose from the blood washes in through the nanopores (25), the enclosed islet cells respond by releasing insulin. At 7 nanometres, the pores are big enough to allow the passage of glucose and insulin,but antibodies, which are significantly larger, cannot squeeze through, and so cannot damage the islet cells.

CARBON NANOTUBE MUSCLE[edit]

Artificial muscles have been made from millions of carbon nanotubes. Like natural muscles, providing an electrical charge causes the individual fibres to expand and the whole structure to move (26). An artificial muscle with strength and speed equal to that of a human muscle may soon be possible. A new wave of technology and medicine is being created and its impact on the world is going to be monumental. From the possible applications such as drug delivery and in vivo imaging to the potential machines of the future, advancements in nanomedicine are being made every day.

Single Molecule Detection in Signaling Pathways[edit]

Novel photon correlation spectroscopy and fluorescence-based techniques allow the visualization of single biomolecules such as specific proteins, enzymes, hormones, nucleic acids, and so on, in living cells and tissues.[2]

References and Notes[edit]

  1. http://www.nanopharmacology.com/
  2. http://wiki.planetphysics.info:8888/index.php/Main_Page#PlanetPhysics.org:_Organizational_Links Nanoscience journals and projects

Bibliography[edit]

J Nanosci Nanotechnol. 2006 Sep-Oct;6(9-10):2769-75.

  • 13. Pharmacytes:An Ideal Vehicle for Targeted Drug Delivery Robert A.Freitas,Jr. Journal of

Nanoscience and NanotechnologyVol.6,2769-2775 2006 14.International Journal of Surgery (2005) - , - e -www.int-journal-surgery.com 15Freitas RA.Exploratory design in medical nanotechnology: a mechanical artificial red cell. Artif Cells Blood Substit Immobil Biotechnol. 1998 Jul;26(4):411-30. PMID: 9663339 [PubMed - indexed for MEDLINE] 16.http://www.foresight.org/Nanomedicine/Respirocytes. 17 Nanodentistry.Freitas RA.Zyvex Corp., Richardson, Texas 75081, USA J Am Dent Assoc. 2000 Nov;131(11):1559-65. 18 Robert A. Freitas Jr., “Nanodentistry,” J. Amer. Dent. Assoc. 131(November 2000):1559-1566. (Cover story) 19 Robert A. Freitas Jr., Journal of Evolution and Technology - Vol. 14 - April 2005 http://jetpress.org/volume14/freitas.html 20 IMM Report Number 18: Nanomedicine In conjunction with Foresight Update 41 Clottocytes: Artificial Mechanical Platelets ByRobertA.Freitas Jr. Research Scientist, Zyvex LLC 21 The future of nanofabrication and molecular scale devices in nanomedicine.Freitas RA. Zyvex Corp, Richardson, Texas, USA Stud Health Technol Inform. 2002;80:45-59 22 The Future of Nanofabrication and Molecular Scale Devices in Nanomedicine Robert A. Freitas Jr.,Research Scientist, Zyvex Corp.published July 2002 http://www.rfreitas.com/Nano/FutureNanofabNMed.htm 23 Death Is An Outrage Robert A. Freitas Jr. Lecture delivered by the author at the Fifth Alcor Conference on Extreme Life Extension, 16 November 2002, Newport Beach, CA, http://www.rfreitas.com/Nano/DeathIsAnOutrage. 24. Robert F. Jr. Nanotechnology Magazine 2 (1996) 8. Robert F. Jr. Artificial Cells 26 (1998) 411. 25. http://www.pnl.gov/energyscience/06-01/ws.htm 26. http://www.mondolithic.com