Nanotechnology

Nanotechnology refers to the manipulation, design and application of materials and devices with at least one dimension between 1 and 100 nanometres. At this scale—commonly described as the nanoscale—phenomena governed by quantum mechanics and high surface-area effects begin to dominate the behaviour of matter. These characteristics distinguish nanoscale systems from their larger counterparts and form the basis for a diverse set of scientific and technological developments. The field encompasses a broad range of disciplines, from surface science and molecular biology to semiconductor physics, microfabrication and molecular engineering.

Emergence and historical development

The conceptual origins of nanotechnology can be traced to the late 1950s. In 1959, physicist Richard Feynman outlined the possibility of manipulating atoms directly in his lecture There’s Plenty of Room at the Bottom, an idea that later became central to the field’s development. The term nanotechnology itself was introduced by Norio Taniguchi in 1974, although it remained obscure until the publication of works that popularised nanoscale engineering.
A major turning point came in 1986 with the publication of Engines of Creation by K. Eric Drexler, who envisioned nanoscale assemblers with atom-level precision. Drexler’s writings, along with the founding of the Foresight Institute, raised public and academic interest in molecular-scale fabrication. The 1980s also saw two pivotal experimental advancements: the invention of the scanning tunnelling microscope in 1981, enabling the imaging and manipulation of individual atoms, and the discovery of fullerenes in 1985, followed by carbon nanotubes in 1991. These discoveries provided tangible nanoscale materials that could be studied, modified and engineered.
From the early 2000s, nanotechnology received substantial governmental and industrial support. Initiatives such as the American National Nanotechnology Initiative and European research frameworks formalised size-based definitions and established funding streams. While early debates centred on feasibility and definitions—including high-profile exchanges concerning molecular nanotechnology—practical applications soon expanded across many industries.

Fundamental concepts and nanoscale phenomena

Nanotechnology is defined not only by scale, but also by the distinctive physical and chemical behaviour that emerges at nanometre dimensions. One nanometre is one billionth of a metre. For comparison, a carbon–carbon bond is around 0.1–0.2 nm in length, DNA has a diameter of about 2 nm, and some of the smallest bacteria measure approximately 200 nm.
Two broad methodological approaches underpin nanoscale engineering:

• Bottom-up methods, in which complex structures are assembled from molecular components through processes such as chemical synthesis, molecular self-assembly and supramolecular chemistry. These approaches rely heavily on molecular recognition, non-covalent interactions and templated assembly.
• Top-down methods, in which larger structures are refined or sculpted into nanoscale objects using lithography, etching or precision machining.

Several nanoscale phenomena are central to the field. As dimensions decrease, surface-area-to-volume ratios increase dramatically, influencing mechanical strength, catalytic activity and thermal properties. Quantum confinement may alter electronic structure, enabling unique optical, electrical or magnetic behaviours not present in bulk materials. Enhanced ion transport in nanoscale architectures gives rise to areas such as nanoionics.

Materials, structures and molecular perspectives

Modern chemical synthesis allows the precise design of small molecules and polymers, leading naturally to questions regarding the assembly of these building blocks into larger, ordered structures. Supramolecular systems—assemblies governed by hydrogen bonding, van der Waals interactions or π-stacking—exemplify controlled molecular organisation. Nature provides powerful models of molecular recognition, as seen in base-pairing in DNA or enzyme–substrate specificity.
On larger scales, nanomaterials include nanoparticles, nanowires, nanotubes, quantum dots and thin films. Carbon nanotubes, for example, exhibit exceptional mechanical strength and electrical conductivity; quantum dots possess tunable optical properties based on size. Scanning probe microscopes have revealed atomic arrangements on surfaces, demonstrating the feasibility of atomic-precision manipulation.

Applications across science and technology

Nanotechnology has enabled a wide range of practical applications. Many technologies originate from refined versions of existing methods, while others depend on fundamentally new nanoscale behaviours. Key areas include:

• Nanomedicine, which incorporates drug-delivery systems, imaging agents, diagnostic devices and targeted therapeutics based on nanoparticles and nanostructured materials.
• Nanoelectronics, utilising nanoscale components for high-performance semiconductor devices and quantum-based electronic functions.
• Energy technologies, where nanoscale materials improve battery capacity, catalytic efficiency, hydrogen storage and photovoltaic performance.
• Biomaterials and biotechnology, including biosensors, biocompatible coatings and engineered nanostructures that interface with cells or tissues.
• Agricultural nanotechnology, involving controlled release of nutrients, detection of pathogens and smart delivery systems.
• Consumer products, ranging from textiles treated with nanoparticles for stain resistance to sunscreens incorporating nanoscale metal oxides.

Although early visions centred on molecular nanotechnology with atomically precise assemblers, contemporary developments focus primarily on nanomaterials, nanoscale devices and nanosystems derived from chemical and physical fabrication techniques.

Environmental, ethical and societal considerations

The rapid growth of nanotechnology has raised important questions regarding safety, environmental impact and governance. Nanotoxicology examines how nanoparticles interact with biological systems, recognising that nanoscale dimensions can influence absorption, distribution and bioreactivity. Concerns include environmental accumulation, effects on ecosystems, occupational exposure and the potential for long-term impacts on health.
Broader debates also address potential economic disruption, intellectual property issues and hypothetical risks such as uncontrolled self-replicating nanosystems. Many advocacy groups, regulatory agencies and governments have called for targeted guidelines, risk assessment frameworks and responsible innovation practices.

Future directions and technological trajectories

Nanotechnology continues to evolve through advances in fabrication, characterisation and theoretical understanding. Nanotechnology roadmaps increasingly emphasise atomically precise manufacturing, integrated nanosystems and applications that bridge molecular-scale operations with macro-scale functionality. Emerging areas include quantum materials, nanoscale robotics, advanced nanophotonics and hybrid bio-nano systems.
The field remains central to cutting-edge research due to its potential to transform multiple sectors, from medicine and energy to computing and material design. As understanding deepens, nanotechnology is expected to play an increasingly critical role in shaping scientific progress and technological innovation.