The literature

Nanoscience in 2001–2002: what the journals were full of

Two years stand out when the nanoscience literature is read in sequence. In 2001 and 2002 the field acquired its first chemistry-society journal, a national funding programme in the United States, and a set of research themes that would dominate the following decade. This page sketches that landscape in general terms and points to the pages that explain each theme in depth.

Anyone who read the physics, chemistry and materials journals week by week in those years would have noticed the same handful of subjects returning again and again, sometimes in three or four journals in a single week. Some were already mature, others only beginning. What follows is an overview of the main strands rather than a list of papers; the only individual papers discussed anywhere on this site are those whose records are cited directly in the text.

Carbon nanotubes, from curiosity to component

By 2001 carbon nanotubes had been a central subject of physics and materials chemistry for a decade. The Wikipedia article on carbon nanotubes notes that much of the literature dates the discovery of hollow graphitic nanotubes to Sumio Iijima's 1991 paper, while also recording that the question of who first saw them is contested. It adds that routes to single-walled tubes were found independently in 1993 by groups at NEC and IBM, and that this set off a wave of work on characterising the tubes and finding uses for them.

The use that drew the most attention in the early 2000s was electronic. Some single-walled tubes behave as metals and others as semiconductors, depending on how the graphene sheet is rolled, and a semiconducting tube can serve as the channel of a transistor. According to the article on carbon nanotube field-effect transistors, such devices were first demonstrated in 1998, and the years that followed brought steady progress. In the journals of 2001 and 2002 that progress showed up as a stream of papers on contacts, doping, logic built from more than one tube, and the stubborn problem of sorting metallic from semiconducting tubes. The broader story is told on the carbon nanotubes page and, for the device side, on molecular electronics and nanowires.

Quantum dots in the chemistry and biology journals

Semiconductor nanocrystals had been studied since the 1980s, but by the turn of the century they were crossing disciplinary borders. The key idea, explained on the quantum dots page, is that a crystal only a few nanometres across confines its electrons so tightly that the colour of light it emits depends on its size. Chemists were refining ways to grow such crystals with narrow size distributions and protective shells, and physicists were studying their blinking and their single-dot spectra.

Biologists were also paying attention. In a 1998 paper in Science, Bruchez and colleagues described preparing semiconductor nanocrystals as fluorescent probes for biological staining. Their abstract reports a narrow, tunable emission spectrum and good photochemical stability compared with conventional dyes, demonstrated in a labelling experiment on mouse fibroblasts, and concludes that the probes were complementary to existing fluorophores and in some cases might be superior. Papers building on that approach, on coating dots so that they stay dispersed in water and on attaching them to biomolecules, were a regular feature of the chemistry and materials journals of the next few years.

Self-assembly and the peptide fibre

Self-assembly, the spontaneous organisation of components into ordered structures through their own local interactions, was already a unifying theme across chemistry and materials science. The Wikipedia article on self-assembly describes the general principle and distinguishes static assembly, which settles towards equilibrium, from dynamic assembly. In 2001 and 2002 the journals carried a great deal of work on self-assembled monolayers on gold, on block copolymers that separate into regular nanoscale domains, and on colloidal particles that pack into ordered films.

One paper from late 2001 marks the moment when biology and materials science met. Writing in Science, Hartgerink and colleagues used a pH change to make a peptide-amphiphile assemble into a fibrous scaffold that they compared to the extracellular matrix. Their abstract reports that the fibres could be reversibly cross-linked and, once cross-linked, could direct the growth of hydroxyapatite crystals aligned along the fibre axes, the same alignment seen between collagen fibrils and mineral in bone. That kind of result, a designed molecule steering the growth of an inorganic crystal, is discussed further on the self-assembly page and on peptides at the nanoscale.

Magnetism, microscopes and fabrication

Three other strands ran steadily through the period. Thin magnetic multilayers and the giant magnetoresistance effect had already moved from the laboratory into computer hard disks, and the physics journals were full of work on spin-polarised transport and magnetic nanoparticles; the spintronics page explains the background. Scanning probe microscopes, two decades after the first scanning tunnelling microscope, had become ordinary laboratory tools, used not only to image surfaces but to move atoms and write patterns; see seeing and touching atoms. And the question of how to make structures smaller than conventional lithography allows fed a steady literature on electron-beam writing, soft lithography and probe-based patterning, described on the nanofabrication page.

A new policy context

The same years changed the field's institutional setting. The Wikipedia article on the National Nanotechnology Initiative records that the initiative was officially launched in 2000 and received its first funding in fiscal year 2001, as a framework for coordinating nanoscale research across United States federal agencies. The same article notes that in December 2003 a law, the 21st Century Nanotechnology Research and Development Act, gave the effort a statutory footing. Other countries set up programmes of their own in the same period, and the phrase "nanoscience and nanotechnology" began to appear in funding calls and conference titles as a field in its own right. The policy page takes up that story.

New journals for a new field

Finally, the literature itself was reorganising. Nano Letters appeared in January 2001, the first dedicated nanoscience journal from a major chemical society, and other titles followed over the next several years. The effect on readers was double-edged: it became easier to find nanoscale work in one place, but the older physics and chemistry journals kept publishing it too, so a complete picture still meant reading across many titles. The journals page maps where each kind of work tends to appear, and keeping up with new papers describes how to follow them today.

Read together, the literature of 2001 and 2002 shows a field in transition: nanotubes and quantum dots moving from discovery towards application, self-assembly reaching into biology, and governments deciding that a science defined by scale deserved its own budget line. Most of the subjects that fill today's nanoscience journals can be traced back to one of those strands.