Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Safety of nanotechnology


Published on

Published in: Technology, Business
  • Be the first to comment

Safety of nanotechnology

  1. 1. Safety of NanotechnologyNanotechnology is a powerful tool for combating cancer and is being put to usein other applications that may reduce pollution, energy consumption,greenhouse gas emissions, and help prevent diseases. NCIs Alliance forNanotechnology in Cancer is working to ensure that nanotechnologies forcancer applications are developed responsibly.There is nothing inherently dangerous about being nanosized. Our ability tomanipulate objects at the nanoscale has developed relatively recently, butnanoparticles are as old as the earth. Many nanoparticles occur naturally (forexample, in volcanic ash and sea spray) and as by-products of human activitiessince the Stone Age (nanoparticles are in smoke and soot from fire). There areso many ambient incidental nanoparticles, in fact, that one of the challenges ofnanoparticle exposure studies is that background incidental nanoparticles areoften at order-of-magnitude higher levels than the engineered particles beingevaluated.As with any new technology, the safety of nanotechnology is continuouslybeing tested. The small size, high reactivity, and unique tensile and magneticproperties of nanomaterials—the same properties that drive interest in theirbiomedical and industrial applications—have raised concerns aboutimplications for the environment, health, and safety (EHS). There has beensome as yet unresolved debate recently about the potential toxicity of a specifictype of nanomaterial—carbon nanotubes (CNTs)—which has been associatedwith tissue damage in animal studies. However, the majority of available dataindicate that there is nothing uniquely toxic about nanoparticles as a class ofmaterials.In fact, most engineered nanoparticles are far less toxic than household cleaningproducts, insecticides used on family pets, and over-the-counter dandruffremedies. Certainly, the nanoparticles used as drug carriers forchemotherapeutics are much less toxic than the drugs they carry and aredesigned to carry drugs safely to tumors without harming organs and healthytissue.To insure that potential risks of nanotechnology are thoroughly evaluated, theNCI Alliance for Nanotechnology in Cancer makes the services of
  2. 2. its Nanotechnology Characterization Laboratory (NCL) available to thenanotech and cancer research communities. The NCL, an intramural program ofthe Alliance, performs nanomaterial safety and toxicity testing in vitro (in thelaboratory) and using animal models. The NCL tests are designed tocharacterize nanomaterials that enter the bloodstream, regardless of route. Thistesting is just one part of the NCLs cascade of tests to evaluate thephysicochemical properties, biocompatibility, and efficacy of nanomaterialsintended for cancer therapy and diagnosis. To date, the NCL has evaluated morethan 125 different nanoparticles intended for medical applications.The NCL works closely with the U.S. Food and Drug Administration (FDA)and National Institutes of Standards and Technology (NIST) to deviseexperiments that are relevant to nanomaterials, to validate these tests on avariety of nanomaterial types, and to disseminate its methods to the nanotechand cancer research communities. The NCL also facilitates the development ofvoluntary-consensus standards for reliably and pro-actively measuring andmonitoring environment, health and safety ramifications of nanotechapplications.Whether actual or perceived, the potential health risks associated with themanufacture and use of nanomaterials must be carefully studied in order toadvance our understanding of this field of science and to realize the significantbenefits that nanotechnology has to offer society, such as for cancer research,diagnostics, and therapy. sol-gel process is a wet-chemical technique (also known as chemicalsolution deposition) widely used recently in the fields of materials science andceramic engineering.Such methods are used primarily for the fabrication of materials (typically ametal oxide) starting from a chemical solution (sol, short for solution) whichacts as the precursor for an integrated network (or gel) of either discreteparticles or network polymers.
  3. 3. Typical precursors are metal alkoxides and metal chlorides, which undergohydrolysis and polycondensation reactions to form either a network "elasticsolid" or a colloidal suspension (or dispersion) – a system composed of discrete(often amorphous) submicrometer particles dispersed to various degrees in ahost fluid.Formation of a metal oxide involves connecting the metal centers with oxo (M-O-M) or hydroxo (M-OH-M) bridges, therefore generating metal-oxo or metal-hydroxo polymers in solution. Thus, the sol evolves towards the formation of agel-like diphasic system containing both a liquid phase and solid phase whosemorphologies range from discrete particles to continuous polymer networks.In the case of the colloid, the volume fraction of particles (or particle density)may be so low that a significant amount of fluid may need to be removedinitially for the gel-like properties to be recognized. This can be accomplishedin any number of ways. The most simple method is to allow time forsedimentation to occur, and then pour off the remaining liquid. Centrifugationcan also be used to accelerate the process of phase separation.Removal of the remaining liquid (solvent) phase requires a drying process,which is typically accompanied by a significant amount of shrinkage anddensification. The rate at which the solvent can be removed is ultimatelydetermined by the distribution of porosity in the gel.The ultimate microstructure of the final component will clearly be stronglyinfluenced by changes implemented during this phase of processing.Afterwards, a thermal treatment, or firing process, is often necessary in order tofavor further polycondensation and enhance mechanical properties andstructural stability via final sintering, densification and grain growth. One of thedistinct advantages of using this methodology as opposed to the more traditionalprocessing techniques is that densification is often achieved at a much lowertemperature.The precursor sol can be either deposited on a substrate to form a film (e.g. bydip-coating or spin-coating), cast into a suitable container with the desired shape(e.g. to obtain a monolithic ceramics, glasses, fibers, membranes, aerogels), orused to synthesize powders (e.g. microspheres, nanospheres).
  4. 4. The sol-gel approach is a cheap and low-temperature technique that allows forthe fine control of the product’s chemical composition. Even small quantities ofdopants, such as organic dyes and rare earth metals, can be introduced in the soland end up uniformly dispersed in the final product.It can be used in ceramics processing and manufacturing as an investmentcasting material, or as a means of producing very thin films of metal oxides forvarious purposes. Sol-gel derived materials have diverse applications in optics,electronics, energy, space, (bio)sensors, medicine (e.g. controlled drug release)and separation (e.g. chromatography) technology.IntroductionWith nanotechnology, a large set of materials and improved products rely on achange in the physical properties when the feature sizes are shrunk.Nanoparticles, for example, take advantage of their dramatically increasedsurface area to volume ratio. Their optical properties, e.g. fluorescence, becomea function of the particle diameter. When brought into a bulk material,nanoparticles can strongly influence the mechanical properties of the material,like stiffness or elasticity. For example, traditional polymers can be reinforcedby nanoparticles resulting in novel materials which can be used as lightweightreplacements for metals. Therefore, an increasing societal benefit of suchnanoparticles can be expected. Such nanotechnologically enhanced materialswill enable a weight reduction accompanied by an increase in stability andimproved functionality. Practical nanotechnology is essentially the increasingability to manipulate (with precision) matter on previously impossible scales,presenting possibilities which many could never have imagined - it thereforeseems unsurprising that few areas of human technology are exempt from thebenefits which nanotechnology could potentially bring.Nanomedicine:Nanomedicine is the medical application of nanotechnology.[1] Nanomedicineranges from the medical applications of nanomaterials, to nanoelectronicbiosensors, and even possible future applications of molecular nanotechnology.Current problems for nanomedicine involve understanding the issues related to
  5. 5. toxicity and environmental impact of nanoscale materials. One nanometer isone-millionth of a millimeter.Overview:Nanomedicine seeks to deliver a valuable set of research tools and clinicallyuseful devices in the near future. The National Nanotechnology Initiativeexpects new commercial applications in the pharmaceutical industry that mayinclude advanced drug delivery systems, new therapies, and in vivoimaging.Neuro-electronic interfaces and other nanoelectronics-based sensorsare another active goal of research. Further down the line, the speculative fieldof molecular nanotechnology believes that cell repair machines couldrevolutionize medicine and the medical field.Nanomedicine is a large industry, with nanomedicine sales reaching 6.8 billiondollars in 2004, and with over 200 companies and 38 products worldwide, aminimum of 3.8 billion dollars in nanotechnology R&D is being invested everyyear. As the nanomedicine industry continues to grow, it is expected to have asignificant impact on the economy.Medical use of nanomaterialsTwo forms of nanomedicine that have already been tested in mice and areawaiting human trials are using gold nanoshells to help diagnose and treatcancer, and using liposomes as vaccine adjuvants and as vehicles for drugtransport.[7][8] Similarly, drug detoxification is also another application fornanomedicine which has shown promising results in rats.[9] A benefit of usingnanoscale for medical technologies is that smaller devices are less invasive andcan possibly be implanted inside the body, plus biochemical reaction times aremuch shorter. These devices are faster and more sensitive than typical drugdelivery.Drug deliveryNanomedical approaches to drug delivery center on developing nanoscaleparticles or molecules to improve drug bioavailability. Bioavailability refers tothe presence of drug molecules where they are needed in the body and wherethey will do the most good. Drug delivery focuses on maximizingbioavailability both at specific places in the body and over a period of time.This can potentially be achieved by molecular targeting by nanoengineereddevices.[11][12] It is all about targeting the molecules and delivering drugs withcell precision. More than $65 billion are wasted each year due to poorbioavailability. In vivo imaging is another area where tools and devices are
  6. 6. being developed. Using nanoparticle contrast agents, images such as ultrasoundand MRI have a favorable distribution and improved contrast. The new methodsof nanoengineered materials that are being developed might be effective intreating illnesses and diseases such as cancer. What nanoscientists will be ableto achieve in the future is beyond current imagination. This might beaccomplished by self assembled biocompatible nanodevices that will detect,evaluate, treat and report to the clinical doctor automatically.Drug delivery systems, lipid- or polymer-based nanoparticles, can be designedto improve the pharmacological and therapeutic properties of drugs. Thestrength of drug delivery systems is their ability to alter the pharmacokineticsand biodistribution of the drug. When designed to avoid the bodys defencemechanisms, nanoparticles have beneficial properties that can be used toimprove drug delivery. Where larger particles would have been cleared from thebody, cells take up these nanoparticles because of their size. Complex drugdelivery mechanisms are being developed, including the ability to get drugsthrough cell membranes and into cell cytoplasm. Efficiency is importantbecause many diseases depend upon processes within the cell and can only beimpeded by drugs that make their way into the cell. Triggered response is oneway for drug molecules to be used more efficiently. Drugs are placed in thebody and only activate on encountering a particular signal. For example, a drugwith poor solubility will be replaced by a drug delivery system where bothhydrophilic and hydrophobic environments exist, improving the solubility. [16]Also, a drug may cause tissue damage, but with drug delivery, regulated drugrelease can eliminate the problem. If a drug is cleared too quickly from thebody, this could force a patient to use high doses, but with drug deliverysystems clearance can be reduced by altering the pharmacokinetics of the drug.Poor biodistribution is a problem that can affect normal tissues throughwidespread distribution, but the particulates from drug delivery systems lowerthe volume of distribution and reduce the effect on non-target tissue. Potentialnanodrugs will work by very specific and well-understood mechanisms; one ofthe major impacts of nanotechnology and nanoscience will be in leadingdevelopment of completely new drugs with more useful behavior and less sideeffects.Applications and Reported Studies Abraxane, approved by Food and Drug Administration to treat breast cancer, is the nanoparticle albumin bound paclitaxel. In a mice study, scientists from Rice University and University of Texas MD Anderson Cancer Center reported enhanced effectiveness and reduced toxicity of an existing treatment for head and neck cancer when using the nanoparticles to deliver the drug. The hydrophilic carbonic
  7. 7. clusters functionalized with polyethylene glycol or PEG-HCC are mixed with the chemotherapeutic drug paclitaxel (Taxol) and the epidermal growth factor receptor (EGFR) targeted Cetuximab and injected intravenously. They found the tumors were killed more effectively with radiation and the healthy tissue suffered less toxicity than without the nanotechnology drug delivery. The standard treatment contains Cremophor EL which allows the hydrophobic paclitaxel to be delivered intravenously. Replacing the toxic Cremophor with carbon nanoparticles eliminated its side effect and improved drug targeting which in turn required a lower dose of the toxic paclitaxel.[17]Protein and peptide deliveryProtein and peptides exert multiple biological actions in human body and theyhave been identified as showing great promise for treatment of various diseasesand disorders. These macromolecules are called biopharmaceuticals. Targetedand/or controlled delivery of these biopharmaceuticals using nanomaterials likenanoparticles and Dendrimers is an emerging field callednanobiopharmaceutics, and these products are called nanobiopharmaceuticals.CancerA schematic illustration showing how nanoparticles or other cancer drugs mightbe used to treat cancer.The small size of nanoparticles endows them with properties that can be veryuseful in oncology, particularly in imaging. Quantum dots (nanoparticles withquantum confinement properties, such as size-tunable light emission), when
  8. 8. used in conjunction with MRI (magnetic resonance imaging), can produceexceptional images of tumor sites. These nanoparticles are much brighter thanorganic dyes and only need one light source for excitation. This means that theuse of fluorescent quantum dots could produce a higher contrast image and at alower cost than todays organic dyes used as contrast media. The downside,however, is that quantum dots are usually made of quite toxic elements.Another nanoproperty, high surface area to volume ratio, allows manyfunctional groups to be attached to a nanoparticle, which can seek out and bindto certain tumor cells. Additionally, the small size of nanoparticles (10 to 100nanometers), allows them to preferentially accumulate at tumor sites (becausetumors lack an effective lymphatic drainage system). A very exciting researchquestion is how to make these imaging nanoparticles do more things for cancer.For instance, is it possible to manufacture multifunctional nanoparticles thatwould detect, image, and then proceed to treat a tumor? This question is undervigorous investigation; the answer to which could shape the future of cancertreatment.[18] A promising new cancer treatment that may one day replaceradiation and chemotherapy is edging closer to human trials. Kanzius RFtherapy attaches microscopic nanoparticles to cancer cells and then "cooks"tumors inside the body with radio waves that heat only the nanoparticles and theadjacent (cancerous) cells.Sensor test chips containing thousands of nanowires, able to detect proteins andother biomarkers left behind by cancer cells, could enable the detection anddiagnosis of cancer in the early stages from a few drops of a patients blood.[19]The basic point to use drug delivery is based upon three facts: a) efficientencapsulation of the drugs, b) successful delivery of said drugs to the targetedregion of the body, and c) successful release of that drug there.Researchers at Rice University under Prof. Jennifer West, have demonstratedthe use of 120 nm diameter nanoshells coated with gold to kill cancer tumors inmice. The nanoshells can be targeted to bond to cancerous cells by conjugatingantibodies or peptides to the nanoshell surface. By irradiating the area of thetumor with an infrared laser, which passes through flesh without heating it, thegold is heated sufficiently to cause death to the cancer cells.[20]Nanoparticles of cadmium selenide (quantum dots) glow when exposed toultraviolet light. When injected, they seep into cancer tumors. The surgeon cansee the glowing tumor, and use it as a guide for more accurate tumor removal.In photodynamic therapy, a particle is placed within the body and is illuminatedwith light from the outside. The light gets absorbed by the particle and if theparticle is metal, energy from the light will heat the particle and surrounding
  9. 9. tissue. Light may also be used to produce high energy oxygen molecules whichwill chemically react with and destroy most organic molecules that are next tothem (like tumors). This therapy is appealing for many reasons. It does notleave a ―toxic trail‖ of reactive molecules throughout the body (chemotherapy)because it is directed where only the light is shined and the particles exist.Photodynamic therapy has potential for a noninvasive procedure for dealingwith diseases, growth and tumors.SurgeryAt Rice University, a flesh welder is used to fuse two pieces of chicken meatinto a single piece. The two pieces of chicken are placed together touching. Agreenish liquid containing gold-coated nanoshells is dribbled along the seam.An infrared laser is traced along the seam, causing the two sides to weldtogether. This could solve the difficulties and blood leaks caused when thesurgeon tries to restitch the arteries that have been cut during a kidney or hearttransplant. The flesh welder could weld the artery perfectly.[21]VisualizationTracking movement can help determine how well drugs are being distributed orhow substances are metabolized. It is difficult to track a small group of cellsthroughout the body, so scientists used to dye the cells. These dyes needed to beexcited by light of a certain wavelength in order for them to light up. Whiledifferent color dyes absorb different frequencies of light, there was a need for asmany light sources as cells. A way around this problem is with luminescenttags. These tags are quantum dots attached to proteins that penetrate cellmembranes. The dots can be random in size, can be made of bio-inert material,and they demonstrate the nanoscale property that color is size-dependent. As aresult, sizes are selected so that the frequency of light used to make a group ofquantum dots fluoresce is an even multiple of the frequency required to makeanother group incandesce. Then both groups can be lit with a single lightsource.Nanoparticle targetingIt is greatly observed that[who?] nanoparticles are promising tools for theadvancement of drug delivery, medical imaging, and as diagnostic sensors.However, the biodistribution of these nanoparticles is still imperfect due to thecomplex hosts reactions to nano- and microsized materials[14] and the difficultyin targeting specific organs in the body. Nevertheless, a lot of work is stillongoing to optimize and better understand the potential and limitations ofnanoparticulate systems. For example, current research in the excretory systems
  10. 10. of mice shows the ability of gold composites to selectively target certain organsbased on their size and charge. These composites are encapsulated by adendrimer and assigned a specific charge and size. Positively-charged goldnanoparticles were found to enter the kidneys while negatively-charged goldnanoparticles remained in the liver and spleen. It is suggested that the positivesurface charge of the nanoparticle decreases the rate of opsonization ofnanoparticles in the liver, thus affecting the excretory pathway. Even at arelatively small size of 5 nm, though, these particles can becomecompartmentalized in the peripheral tissues, and will therefore accumulate inthe body over time. While advancement of research proves that targeting anddistribution can be augmented by nanoparticles, the dangers of nanotoxicitybecome an important next step in further understanding of their medical uses.[22]Neuro-electronic interfacesNeuro-electronic interfacing is a visionary goal dealing with the construction ofnanodevices that will permit computers to be joined and linked to the nervoussystem. This idea requires the building of a molecular structure that will permitcontrol and detection of nerve impulses by an external computer. The computerswill be able to interpret, register, and respond to signals the body gives off whenit feels sensations. The demand for such structures is huge because manydiseases involve the decay of the nervous system (ALS and multiple sclerosis).Also, many injuries and accidents may impair the nervous system resulting indysfunctional systems and paraplegia. If computers could control the nervoussystem through neuro-electronic interface, problems that impair the systemcould be controlled so that effects of diseases and injuries could be overcome.Two considerations must be made when selecting the power source for suchapplications. They are refuelable and nonrefuelable strategies. A refuelablestrategy implies energy is refilled continuously or periodically with externalsonic, chemical, tethered, magnetic, or electrical sources. A nonrefuelablestrategy implies that all power is drawn from internal energy storage whichwould stop when all energy is drained.One limitation to this innovation is the fact that electrical interference is apossibility. Electric fields, electromagnetic pulses (EMP), and stray fields fromother in vivo electrical devices can all cause interference. Also, thick insulatorsare required to prevent electron leakage, and if high conductivity of the in vivomedium occurs there is a risk of sudden power loss and ―shorting out.‖ Finally,thick wires are also needed to conduct substantial power levels withoutoverheating. Little practical progress has been made even though research ishappening. The wiring of the structure is extremely difficult because they mustbe positioned precisely in the nervous system so that it is able to monitor andrespond to nervous signals. The structures that will provide the interface must
  11. 11. also be compatible with the body’s immune system so that they will remainunaffected in the body for a long time.[23] In addition, the structures must alsosense ionic currents and be able to cause currents to flow backward. While thepotential for these structures is amazing, there is no timetable for when they willbe available.Medical applications of molecular nanotechnologyMolecular nanotechnology is a speculative subfield of nanotechnologyregarding the possibility of engineering molecular assemblers, machines whichcould re-order matter at a molecular or atomic scale. Molecular nanotechnologyis highly theoretical, seeking to anticipate what inventions nanotechnologymight yield and to propose an agenda for future inquiry. The proposed elementsof molecular nanotechnology, such as molecular assemblers and nanorobots arefar beyond current capabilities.NanorobotsThe somewhat speculative claims about the possibility of using nanorobots[24] inmedicine, advocates say, would totally change the world of medicine once it isrealized. Nanomedicine[1][23] would make use of these nanorobots (e.g.,Computational Genes), introduced into the body, to repair or detect damagesand infections. According to Robert Freitas of the Institute for MolecularManufacturing, a typical blood borne medical nanorobot would be between 0.5-3 micrometres in size, because that is the maximum size possible due tocapillary passage requirement. Carbon could be the primary element used tobuild these nanorobots due to the inherent strength and other characteristics ofsome forms of carbon (diamond/fullerene composites), and nanorobots wouldbe fabricated in desktop nanofactories [25] specialized for this purpose.Nanodevices could be observed at work inside the body using MRI, especiallyif their components were manufactured using mostly 13C atoms rather than thenatural 12C isotope of carbon, since 13C has a nonzero nuclear magneticmoment. Medical nanodevices would first be injected into a human body, andwould then go to work in a specific organ or tissue mass. The doctor willmonitor the progress, and make certain that the nanodevices have gotten to thecorrect target treatment region. The doctor will also be able to scan a section ofthe body, and actually see the nanodevices congregated neatly around theirtarget (a tumor mass, etc.) so that he or she can be sure that the procedure wassuccessful.
  12. 12. Cell repair machines This article may contain original research. Please improve it by verifying the claims made and adding references. Statements consisting only of original research may be removed. More details may be available on the talk page. (January 2009)Using drugs and surgery, doctors can only encourage tissues to repairthemselves. With molecular machines, there will be more direct repairs.[26] Cellrepair will utilize the same tasks that living systems already prove possible.Access to cells is possible because biologists can insert needles into cellswithout killing them. Thus, molecular machines are capable of entering the cell.Also, all specific biochemical interactions show that molecular systems canrecognize other molecules by touch, build or rebuild every molecule in a cell,and can disassemble damaged molecules. Finally, cells that replicate prove thatmolecular systems can assemble every system found in a cell. Therefore, sincenature has demonstrated the basic operations needed to perform molecular-levelcell repair, in the future, nanomachine based systems will be built that are ableto enter cells, sense differences from healthy ones and make modifications tothe structure.The healthcare possibilities of these cell repair machines are impressive.Comparable to the size of viruses or bacteria, their compact parts would allowthem to be more complex. The early machines will be specialized. As they openand close cell membranes or travel through tissue and enter cells and viruses,machines will only be able to correct a single molecular disorder like DNAdamage or enzyme deficiency. Later, cell repair machines will be programmedwith more abilities with the help of advanced AI systems.Nanocomputers will be needed to guide these machines. These computers willdirect machines to examine, take apart, and rebuild damaged molecularstructures. Repair machines will be able to repair whole cells by workingstructure by structure. Then by working cell by cell and tissue by tissue, wholeorgans can be repaired. Finally, by working organ by organ, health is restored tothe body. Cells damaged to the point of inactivity can be repaired because of theability of molecular machines to build cells from scratch. Therefore, cell repairmachines will free medicine from reliance on self repair alone.NanonephrologyNanonephrology is a branch of nanomedicine and nanotechnology that seeks touse nano-materials and nano-devices for the diagnosis, therapy, andmanagement of renal diseases. It includes the following goals:
  13. 13. 1. the study of kidney protein structures at the atomic level 2. nano-imaging approaches to study cellular processes in kidney cells 3. nano medical treatments that utilize nanoparticles to treat various kidney diseasesAdvances in Nanonephrology are expected to be based on discoveries in theabove areas that can provide nano-scale information on the cellular molecularmachinery involved in normal kidney processes and in pathological states. Byunderstanding the physical and chemical properties of proteins and othermacromolecules at the atomic level in various cells in the kidney, noveltherapeutic approaches can be designed to combat major renal diseases. Thenano-scale artificial kidney is a goal that many physicians dream of. Nano-scaleengineering advances will permit programmable and controllable nano-scalerobots to execute curative and reconstructive procedures in the human kidney atthe cellular and molecular levels. Designing nanostructures compatible with thekidney cells and that can safely operate in vivo is also a future goal. The abilityto direct events in a controlled fashion at the cellular nano-level has thepotential of significantly improving the lives of patients with kidney diseases.NANOBIOLOGY:Bionanotechnology, nanobiotechnology, and nanobiology are terms that referto the intersection of nanotechnology and biology.[1] Given that the subject isone that has only emerged very recently, bionanotechnology andnanobiotechnology serve as blanket terms for various related technologies.This discipline helps to indicate the merger of biological research with variousfields of nanotechnology. Concepts that are enhanced through nanobiologyinclude: nanodevices, nanoparticles, and nanoscale phenomena that occurswithin the disciple of nanotechnology. This technical approach to biologyallows scientists to imagine and create systems that can be used for biologicalresearch. Biologically-inspired nanotechnology uses biological systems as theinspirations for technologies not yet created. We can learn from eons ofevolution that have resulted in elegant systems that are naturally created.[2]The most important objectives that are frequently found in nanobiology involveapplying nanotools to relevant medical/biological problems and refining these
  14. 14. applications. Developing new tools for the medical and biological fields isanother primary objective in nanotechnology. New nanotools are often made byrefining the applications of the nanotools that are already being used. Theimaging of native biomolecules, biological membranes, and tissues is also amajor topic for the nanobiology researchers. Other topics concerningnanobiology include the use of cantilever array sensors and the application ofnanophotonics for manipulating molecular processes in living cells.NanobiotechnologyNanobiotechnology (sometimes referred to as nanobiology) is best described ashelping modern medicine progress from treating symptoms to generating curesand regenerating biological tissues. Three American patients have receivedwhole cultured bladders with the help of doctors who use nanobiologytechniques in their practice. Also, it has been demonstrated in animal studiesthat a uterus can be grown outside the body and then placed in the body in orderto produce a baby. Stem cell treatments have been used to fix diseases that arefound in the human heart and are in clinical trials in the United States. There isalso funding for research into allowing people to have new limbs withouthaving to resort to prosthesis. Artificial proteins might also become available tomanufacture without the need for harsh chemicals and expensive machines. Ithas even been surmised that by the year 2055, computers may be made out ofbiochemicals and organic salts.[7]Another example of current nanobiotechnological research involvesnanospheres coated with fluorescent polymers. Researchers are seeking todesign polymers whose fluorescence is quenched when they encounter specificmolecules. Different polymers would detect different metabolites. The polymer-coated spheres could become part of new biological assays, and the technologymight someday lead to particles which could be introduced into the human bodyto track down metabolites associated with tumors and other health problems.Another example, from a different perspective, would be evaluation and therapyat the nanoscopic level, i.e. the treatment of Nanobacteria (25-200 nm sized) asis done by NanoBiotech Pharma.While nanobiology is in its infancy, there are a lot of promising methods thatwill rely on nanobiology in the future. Biological systems are inherently nano inscale; nanoscience must merge with biology in order to deliverbiomacromolecules and molecular machines that are similar to nature.Controlling and mimicking the devices and processes that are constructed frommolecules is a tremendous challenge to face the converging disciplines ofnanotechnology.[8] All living things, including humans, can be considered to benanofoundries. Natural evolution has optimized the "natural" form of
  15. 15. nanobiology over millions of years. In the 21st century, humans have developedthe technology to artificially tap into nanobiology. This process is bestdescribed as "organic merging with synthetic." Colonies of live neurons can livetogether on a biochip device; according to research from Dr. Gunther Gross atthe University of North Texas. Self-assembling nanotubes have the ability to beused as a structural system. They would be composed together with rhodopsins;which would facilitate the optical computing process and help with the storageof biological materials. DNA (as the software for all living things) can be usedas a structural proteomic system - a logical component for molecularcomputing. Ned Seeman - a researcher at New York University - along withother researchers are currently researching concepts that are similar to eachother.[9]Nanobiology may play a role in a radical level of change. Various aspects ofapplied and theoretical nanotechnology could help to function as virtual assetson the Internet; which may become a newly formed socio-economic substratesystem making up the "virtual landscape." Expanding technologies and achanging socio-economic system might reshape every aspect of life that iscurrently understood. A matrix of mass media may come out of all thesetechnological advances related to nanobiology. This could create an interactivebi-directional experiential knowledge conveyance system experience.Biological metaphors in computing are being used to create the biological andphysical materials that are needed in order to guide the next step in humanevolution. The P53 protein, a product of nanobiology, can literally shut downthe metabolism of living cells. This protein is considered to be a primecandidate as a cure for certain cancers. Cancer cells have a genetic identitydifferent from the "host" cell and can be targets for P53 delivery.[10]BionanotechnologyDNA nanotechnology is one important example of bionanotechnology. Theutilization of the inherent properties of nucleic acids like DNA to create usefulmaterials is a promising area of modern research. Another important area ofresearch involves taking advantage of membrane properties to generatesynthetic membranes. Protein folding studies provide a third important avenueof research, but one that has been largely inhibited by our inability to predictprotein folding with a sufficiently high degree of accuracy. Given the myriaduses that biological systems have for proteins, though, research intounderstanding protein folding is of high importance and could prove fruitful forbionanotechnology in the future.
  16. 16. Nanotechnology and constructionsNanotechnology is one of the most active research areas that encompass anumber of disciplines Such as electronics, bio-mechanics and coatings includingcivil engineering and construction materials.[9]The use of nanotechnology in construction involves the development of newconcept and understanding of the hydration of cement particles and the use ofnano-size ingredients such as alumina and silica and other nanoparticles. Themanufactures also investigating the methods of manufacturing of nano-cement.If cement with nano-size particles can be manufactured and processed, it willopen up a large number of opportunities in the fields of ceramics, high strengthcomposites and electronic applications. Since at the nanoscale the properties ofthe material are different from that of their bulk counter parts. When materialsbecomes nano-sized, the proportion of atoms on the surface increases relative tothose inside and this leads to novel properties. Some applications ofnanotechnology in construction are describe below.[9]Nanoparticles and steelSteel has been widely available material and has a major role in the constructionindustry. The use of nanotechnology in steel helps to improve the properties ofsteel. The fatigue, which led to the structural failure of steel due to cyclicloading, such as in bridges or towers.The current steel designs are based on thereduction in the allowable stress, service life or regular inspection regime. Thishas a significant impact on the life-cycle costs of structures and limits theeffective use of resources.The Stress risers are responsible for initiating cracksfrom which fatigue failure results .The addition of copper nanoparticles reducesthe surface un-evenness of steel which then limits the number of stress risersand hence fatigue cracking. Advancements in this technology usingnanoparticles would lead to increased safety, less need for regular inspectionregime and more efficient materials free from fatigue issues for construction.[9]The nano-size steel produce stronger steel cables which can be in bridgeconstruction. Also these stronger cable material would reduce the costs andperiod of construction, especially in suspension bridges as the cables are runfrom end to end of the span. This would require high strength joints which leadsto the need for high strength bolts. The capacity of high strength bolts isobtained through quenching and tempering. The microstructures of suchproducts consist of tempered martensite. When the tensile strength of temperedmartensite steel exceeds 1,200 MPa even a very small amount of hydrogenembrittles the grain boundaries and the steel material may fail during use. Thisphenomenon, which is known as delayed fracture, which hindered the
  17. 17. strengthening of steel bolts and their highest strength is limited to only around1,000 to 1,200 MPa.[9]The use of vanadium and molybdenum nanoparticles improves the delayedfracture problems associated with high strength bolts reducing the effects ofhydrogen embrittlement and improving the steel micro-structure throughreducing the effects of the inter-granular cementite phase.[9]Welds and the Heat Affected Zone (HAZ) adjacent to welds can be brittle andfail without warning when subjected to sudden dynamic loading.The addition ofnanoparticles of magnesium and calcium makes the HAZ grains finer in platesteel and this leads to an increase in weld toughness. The increase in toughnessat would result in a smaller resource requirement because less material isrequired in order to keep stresses within allowable limits.The carbon nanotubesare exciting material with tremendous properties of strength and stiffness, theyhave found little application as compared to steel,because it is difficult to bindthem with bulk material and they pull out easily, Which make them ineffectivein construction materials.[9]Nanoparticles in glassGlass is also an important material in construction. Research is being carried outon the application of nanotechnology to glass. Titanium dioxide (TiO2)nanoparticles are used to coat glazing since it has sterilizing and anti-foulingproperties. The particles catalyze powerful reactions which break down organicpollutants, volatile organic compounds and bacterial membranes. The TiO2 ishydrophilic (attraction to water) which can attract rain drops which then washoff the dirt particles. Thus the introduction of nanotechnology in the Glassindustry, incorporates the self cleaning property of glass.[9]Fire-protective glass is another application of nanotechnology. This is achievedby using a clear intumescent layer sandwiched between glass panels (aninterlayer) formed of silica nanoparticles (SiO2) which turns into a rigid andopaque fire shield when heated. Most of glass in construction is on the exteriorsurface of buildings. So the light and heat entering the building through glasshas to be prevented. The nanotechnology can provide a better solution to blocklight and heat coming through windows.[9]Nanoparticles in coatingsCoatings is an important area in construction coatings are extensively use topaint the walls, doors, and windows. Coatings should provide a protective layerwhich is bound to the base material to produce a surface of the desired
  18. 18. protective or functional properties. The coatings should have self healingcapabilities through a process of ―self-assembly.‖ Nanotechnology is beingapplied to paints to obtained the coatings having self healing capabilities andcorrosion protection under insulation. Since these coatings are hydrophobic andrepels water from the metal pipe and can also protect metal from salt waterattack.[9]Nanoparticle based systems can provide better adhesion and transparency. TheTiO2 coating captures and breaks down organic and inorganic air pollutants bya photocatalytic process, which leads to putting roads to good environmentaluse.[9]