Keywords

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Nanomedicine

Nanomedicine is defined as the application of nanobiotechnology to medicine. Its broad scope covers the use of nanoparticles and nanodevices in healthcare for diagnosis as well as therapeutics. Safety, ethical, and regulatory issues are also included.

Basics of Nanobiotechnology

Nanotechnology (Greek word nano means dwarf) is the creation and utilization of materials, devices, and systems through the control of matter on the nanometer-length scale, i.e., at the level of atoms, molecules, and supramolecular structures. Nanotechnology, as defined by the National Nanotechnology Initiative (http://www.nano.gov/), is the understanding and control of matter at dimensions of roughly 1–100 nm, where unique phenomena enable novel applications. Encompassing nanoscale science, engineering, and technology, nanotechnology involves imaging, measuring, modeling, and manipulating matter at this length scale. It is the popular term for the construction and utilization of functional structures with at least one characteristic dimension measured in nanometers – a nanometer is one billionth of a meter (10−9 m). This is roughly four times the diameter of an individual atom, and the bond between two individual atoms is 0.15 nm long. Proteins are 1–20 nm in size. The definition of “small,” another term used in relation to nanotechnology, depends on the application but can range from 1 nm to 1 mm. Nano is not the smallest scale; further down the power of 10 are angstrom (=0.1 nm), pico, femto, atto, and zepto. By weight, the mass of a small virus is about 10 attograms. An attogram is one-thousandth of a femtogram, which is one-thousandth of a picogram, which is one-thousandth of a nanogram. Dimensions of various objects in nanoscale are shown in Table 1.1.

Table 1.1 Dimensions of various objects in nanoscale
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Given the inherent nanoscale functional components of living cells, it was inevitable that nanotechnology will be applied in biotechnology giving rise to the term nanobiotechnology. A brief introduction will be given to basic nanotechnologies from physics and chemistry, which are now being integrated into molecular biology to advance the field of nanobiotechnology. The aim is to understand the biological processes to improve diagnosis and treatment of diseases. Sizes of biologically entities relevant to the brain are shown in Fig. 1.1.

Fig. 1.1
figure 1

Sizes of biologically entities relevant to the brain. (Top row above scale bar) From left to right: (a) X-ray crystal structure of Alzheimer’s disease candidate drug, dehydroevodiamine HCl (DHED); (b and c) porous metal oxide microspheres being endocytosed by BV2 microglia cell (close-up and low magnification) SEM images; (d and e) SEM and fluorescence micrograph of DHED microcrystals (DHED is blue-green luminescent). (Bottom row below the scale bar) Left to right: small molecules, such as dopamine, minocycline, mefenamic acid, DHED, and heme, are ∼1 nm or smaller. The lipid bilayer is a few nanometers thick. Biomolecules such as a microRNA and a protein are only a few nanometers in size. A single cell or neuron is tens or hundreds of microns in size. Size of human brain is tens of centimeters (Reproduced from: Suh WH, et al. Prog Neurobiol 2009;87:133–70 (by permission))

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Relation of Nanobiotechnology to Nanomedicine

Technical achievements in nanotechnology are being applied to improve drug ­discovery, drug delivery, and pharmaceutical manufacturing. A vast range of applications have spawned many new terms, which are defined as they are described in various chapters. Numerous applications in the pharmaceutical industry can also be covered under the term “nanobiopharmaceuticals.”

Landmarks in the Evolution of Nanomedicine

Historical landmarks in the evolution of nanomedicine are shown in Table 1.2.

Table 1.2 Historical landmarks in the evolution of nanomedicine
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Nanomedicine as a Part of Evolution of Medicine

Medicine is constantly evolving, and new technologies are incorporated into the diagnosis and treatment of patients. This process is sometimes slow, and there can be a gap of years before new technologies are integrated in medical practice. The reasons for the delay are:

  • Establishing the safety and efficacy of innovative treatments is a long process, particularly with clinical trials and regulatory reviews.

  • The current generation of medical practitioners are still not well oriented toward biotechnology, and conservative elements of the profession may be slow in accepting and learning about nanobiotechnology, which is at the cutting edge of biotechnology.

  • High cost of new technologies is a concern for the healthcare providers. Cost-benefit studies are needed to convince the skeptics that some of the new technologies may actually reduce the overall cost of healthcare.

Molecular medicine is already a recognized term. It should not be considered a subspecialty of medicine as molecular technologies would have an overall impact on the evolution of medicine. Recognition of the usefulness of biotechnology has enabled progress in the concept of personalized medicine, which again is not a branch of medicine but simply indicates a trend in healthcare and simply means the prescription of specific treatments and therapeutics best suited for an individual (Jain 2009). Various nanomachines and other nano-objects that are currently under investigation in medical research and diagnostics will soon find applications in the practice of medicine. Nanobiotechnologies are being used to create and study models of human disease, particularly immune disorders. Introduction of nanobiotechnologies in medicine will not create a separate branch of medicine but simply implies improvement of diagnosis as well as therapy.

Current research is exploring the fabrication of designed nanostructures, nanomotors, microscopic energy sources, and nanocomputers at the molecular scale, along with the means to assemble them into larger systems, economically and in great numbers. Some of the applications of nanobiotechnology in medicine are shown in Table 1.3.

Table 1.3 Nanomedicine in the twenty-first century
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