Nanotechnology Introduction Series:
The Medical Field

By: Dr Stanley Crawford (Ed.D)

The medical field is rich with opportunity for applications of nanotechnology.  Three areas of nanotechnology are discussed in this article, nanotechnology use in assays, nanotechnology in drug delivery, and nanotechnology based biosensors.  Nanotechnology is the development and use of techniques to study physical phenomena and construct structures in the physical size range of 1-100 nanometers (nm), as well as the incorporation of these structures into applications [1].

stylized medical and nanotechnology symbols of the future

Stylized medical and nanotechnology symbols of the future

Let’s begin with nanotechnology and assays. An assay is a medical procedure that is used to analyze and determine the amount of a particular constituent of a mixture [2].  When nanotechnology is applied to medicine it is often referred to as nanomedicine.  In the field of nanomedicine nanoparticles are used to achieve medical objectives.  The key advantage to nanoparticles when it comes to assays is their sensitivity. Often assays take advantage of being able to detect biomarkers.  Biomarkers are biological indicators of a given state or condition.  This sensitivity to biomarkers helps the assay to make an accurate diagnosis of the problem or disease.  A biomarker that is familiar to some men is the prostate specific antigen (PSA).  The nanoparticle used to detect the presence of the biomarker is able to rapidly and accurately detect biomarkers that are present in very low concentrations [3].  Some of the nanoparticles used in assays are gold nanoparticles, quantum dots, and magnetic nanoparticles [4].

Next, there is the use of nanotechnology in drug delivery.  In the area of cancer treatment nanotechnology has helped to better target medicines to cancerous areas.  This is a big advantage since traditional chemotherapy usually causes collateral damage within the body; often damaging tissue that is healthy and non-cancerous, by not being able to distinguish between good and bad cells.  Some of the clinically approved nanoparticle systems are:

  • Stealth liposomal doxorubicin for Kaposi’s sarcoma, refractory ovarian and breast cancer
  • Albumin-paclitaxel for metastatic breast cancer
  • Megesterol acetate for breast and endometrial cancer
  • Fenofibrate for reduction of cholesterol
  • PEG-L-asparaginase for Leukemia
  • Nanopaclitaxel for breast cancer
  • Aprepitant for suppression of chemotherapy induced nausea and vomiting [5]

The delivery of drugs is accomplished through nanocarriers.  Some of the various nanocarriers are:

  • Lipid-based systems:  composed of amphiphiles that self-assemble into lyotropic liquid crystalline phases that can be dispersed into nanosized particles.
  • Nanotubes: carbon cylinders composed of benzene rings capable of drug encapsulation.
  • Metallic  nanoparticles: commonly gold or iron oxide based systems that can be surface modified and encapsulate drugs.
  • Polymeric nanocarriers: drugs can be encapsulated in or conjugated to random coil polymers.
  • Polymeric micelles:  amphiphilic block copolymers that self-assemble in aqueous solution into a core shell structure.
  • Dendrimers:  composed of multiple highly branched monomers emerging from a central core.  Drugs can be conjugated or complexed to these systems[6].

In addition, nanotechnology based biosensors, called nanosensors; consist of nanostructured particles, or nanoparticles, or nanodevices that respond to physical, chemical, or biological stimuli.  There are many types of nanobiosensors; for example, optical, electrical, electrochemical, nanowire, nanotube, and nanoshell [7].  These biosensors will help to revolutionize the medical field.  The biosensors may be less invasive then some of the medical devices currently in use today.  Some of the biological applications of nanobiosensors are for DNA testing, genetic monitoring; Immunosensors, for HIV, hepatitis and other viral diseases; Cell based, for drug testing; and Enzyme sensors, for diabetics, and drug testing[7].

References

[1] R.N. Kostoff, R.G. Koytcheff, C.G.Y. Lau, Global nanotechnology research literature overview, Technological forecasting & Social Change, 2007, Volume 74, 1733-1747.

[2] The Free Dictionary by Farlex, Retrieved March 9, 2013 from http://medical-dictionary.thefreedictionary.com/assay.

[3] P. Fortina, L.J. Kricka, Nanotechnology: Improving clinical testing? Clinical Chemistry, 2010, Volume 56, Number 9, 1384-1389.

[4] K. Kenwright, L.L.W. Pifer, Nanotechnology: Nanomedicine, Clinical Laboratory Science, 2010, Volume 23, Number 2, 112-116.

[5] R. Ranganathan, S. Madanmohan, A. Kesavan, G. Baskar, Y. Krishnamoorthy, r. Santosham, D. Ponraju, S.D. Rayala, g. Venkatraman, Nanomedicine:  Towards development of patient friendly drug delivery systems for oncological applications.

[6] S. Sagnella, C. Drummond, Drug delivery: a nanomedicine approach, Australian Biochemist, 2012, Volume 43, Number 3, 5-8,20.

[7] S. Ghoshal, D. Mitra, S.Roy, D. Dutta Majumder, Biosensors and biochips for nanomedical applications : a review, Sensors & Transducers, 2010, Volume 113, Issue 2,1-17.


Category: Nanotechnology