What Are Nanotechnology and Nanomedicine? A Brief Overview, Applications, and Examples

Article series

Nanotechnology is the control of matter at the atomic and molecular level and is a relatively new scientific field. It is also defined as "the control of matter with at least one dimension measuring from 1 nanometer to 100 nanometers." Because of the diversity of potential applications, including medical, industrial, and military uses, governments have invested billions of dollars in nanotechnology research. Since nanotechnology is defined by size, it includes fields such as earth science, organic chemistry, molecular biology, semiconductor physics, and microfabrication and is naturally very broad. Related research and applications are equally diverse. Nanotechnology has begun making important contributions to clinical medicine, particularly oncology, for some time.

Nanomaterials have various characteristics ideal for oncology applications. Two properties in particular, "preferential accumulation in tumors and limited distribution in normal tissue," give nanomaterials an advantage over other small molecules. These properties have been well studied in radiation oncology practice and have contributed to imaging, treatment planning, and increasing sensitivity to radiation treatment. In this article series, we aim to discuss nanomaterials suitable for oncology applications and the possible future benefits of nanotechnology in cancer treatment.

History

The first concepts underlying nanotechnology were discussed by the famous physicist Richard Feynman, who also actively participated in building the atomic bomb, in 1959 during his famous talk "There is Plenty of Room at the Bottom," in which he described the possibility of synthesis through direct control of atoms.

While the subject was mostly discussed theoretically until the 1980s, scientific, political, and commercial attention to nanotechnology increased in the early 2000s. Governments began supporting and funding nanotechnology research, starting with the National Nanotechnology Initiative, which established funding for nanoscale research in the United States.

Nanotechnology Applications

Nanotechnology has brought many debates, including the risks of its applications in the food sector and possible health effects of nanoparticle exposure. Meanwhile, products based on advances in nanoscale technologies have begun to be commercialized. These products are limited to bulk applications of nanomaterials rather than atomic control of matter. According to estimates by the Project on Emerging Nanotechnology, more than 1600 nanotechnological products are available to the public. New ones enter the market 3-4 times a week. This project lists all products in a publicly accessible online database. Most applications are limited to "first-generation" passive nanomaterials. These include titanium oxide in sunscreen, cosmetics, surface coatings, and certain food products. Other examples include carbon allotropes used to produce gecko tape; silver in food packaging, clothing, disinfectants, and household appliances; zinc oxide in cosmetics and sunscreen; and cerium oxide as a fuel catalyst. More advanced applications make tennis balls last longer, golf balls fly straighter, and bowling balls more durable with harder surfaces. Nanotechnology is also used in trousers and socks to make them last longer and keep people cool in summer. Silver particles in bandages help wounds heal faster. Cars are also manufactured with nanomaterials and may therefore need less metal and fuel in the future. Video game consoles and personal computers may become cheaper and faster and have more memory thanks to nanotechnology.

The Institute for Global Futures identifies nanotechnology as the field that will have the greatest socioeconomic impact over the next 10 years. In 2010, the value added by nanotechnology-based end products to the global economy was 150 billion USD; in 2014, it reached 2.6 trillion USD.

From Larger to Smaller: The Materials Perspective

Certain phenomena become more prominent as system size decreases. Materials reduced to the nanoscale may exhibit properties different from those at the macroscale, enabling unique applications. For example, opaque materials may become transparent (copper); stable materials may become combustible (aluminum); and insoluble materials may become soluble (gold). A substance such as gold, chemically inert (inactive) at normal scales, may act as a potential chemical catalyst at the nanoscale. Much of the interest in nanotechnology stems from the quantum and surface phenomena matter exhibits at the nanoscale.

From Simple to Complex: The Molecular Perspective

Modern synthetic chemistry has reached a point where small molecules can be prepared in almost any structure. These methods are used to produce many useful chemicals, such as medical products and commercial polymers. These approaches use molecular self-assembly and/or supramolecular chemistry to transform themselves automatically into useful forms through a bottom-up approach.

An Important Application of Nanotechnology: Medicine

Engineering matter at the nanoscale can give us nanoparticles (nanomaterials smaller than 100 nm). These have distinctive properties different from small molecules. These properties have been used to develop new medical diagnostic and therapeutic substances. For example, "iron oxide nanoparticles" have "superparamagnetic" properties absent from other iron oxide materials. In the presence of an external magnetic source, iron oxide nanoparticles can provide paramagnetic signals even at low doses, making them excellent contrast agents for magnetic resonance (MR) imaging.

Nanomaterials also have various characteristics ideal for oncology applications. These include the "enhanced permeability and retention (EPR) effect," different biodistribution, pharmacokinetics, and controlled release. Leaky vessels and inefficient lymphatics specific to tumors allow nanoparticles to flow into tumors but do not permit their return to circulation. This is called the EPR effect and results in preferential nanoparticle accumulation in tumors. This accumulation offers advantages in both diagnostic and therapeutic applications. Nanoparticles also have a distinctive biodistribution compared with small molecules. Unlike small molecules, nanoparticles do not adhere to normal vessels and capillaries. This ensures very little unwanted drug accumulation in normal organs (such as the skin, lungs, and heart). Consequently, many nanoparticles can be designed to release their contents slowly and in a controlled manner. This controlled release increases the likelihood of tumor cells being exposed to anticancer drugs inside the nanoparticles.

Nevertheless, most nanotechnology research in oncology concerns diagnosis and chemotherapy drug delivery. Strong interest has developed in using nanotechnology to advance radiation oncology.

Related Topic

- Fundamentals of Nanotechnology, Article 2: Nanoparticle Platforms, Nanotechnology in Imaging and Diagnosis