The first half of the century saw the technology of genetic engineering take off. Tailored retroviruses were used to manipulate the genomes of bacteria, plants and animals. The engineering of custom antibodies and viral inhibitors led the way, eliminating diseases as quickly as they could be fully identified. Geneered high-yield crops, enzyme-rich milk, pollutant consuming bacteria, glowtrees, enhanced immune systems, neo-organs and other more exotic applications soon followed. The owners of patents on the manipulated genes, such companies as Transgene and IM, became the most profitable corporations of the early 21st century.
The wonders of genetic engineering, though, were but a foretaste of the changes wrought by nanotechnology. The Second Industrial Revolution truly began with the building of artificial self-replicating molecular machines. These replicators and assemblers allow the construction of anything that can be designed, given sufficient raw materials and time.
The first simple nanomachines, which were adapted from the machinery of cells, were built in the middle century. These machines could construct systems of proteins, polysaccharides and lipids. Together with the great advances in protein design being made at the time this enabled the construction of both pure bioelectronic circuits (so called biochips) and microfilament-based systems capable of more generalised construction from a wider range of elements. These protein-based systems had the disadvantage of being highly sensitive to environmental changes: they could only operate in liquid suspension, and only in a limited range of temperature and pH.
Nanomachines capable of assembling carefully designed crystalline materials were built in 2063 and over the next few decades revolutionized manufacturing industry by eliminating all unwanted flaws in materials. Diamondoid composites and other exotic materials became cheap to manufacture, allowing the building of the first megastructures. The most impressive achievements of early macroengineering were the corporate arcologies: entire cities contained in single buildings. Even small, mundane objects became much lighter, cheaper and more reliable.
The nanotech revolution proper began with the construction of nanosystems capable of building macroscopic components for larger machines with atomic precision.
The earliest self-reproducing nanosystems were only semireplicators. They could not directly build copies of themselves; instead the nutrient solution bathing them had to be chemically changed to catalyse certain stages in replication. These nanomachines were thus like artificial viruses, with the containing vat acting as a gigantic cell.
The next generation of nanomachines, the true replicators took several decades to develop. The first true artificial replicators were designed and built in 2088 at the Centre for Self-Replicating Technologies, a Eurasian laboratory on Luna. The machines were much more sophisticated than the first generation: they were able to replicate themselves in a nutrient solution of constant composition (i.e. without continual changes in the enzymes present). Nanos were also built from many other types of molecule so that they could be used in a wider range of physical and chemical environments. Such systems were both faster and more robust than the earlier semireplicators and so could be used in a much wider range of applications.
Direct sensory stimulation using implants also became feasible, although as surgical intervention became rare in the treatment of disease, the social acceptability of implantation declined. Therefore the uptake of such technologies was limited to esoteric applications and the disabled. However, the actual mechanics of perception remained quite mysterious, and only limited advances were made in the understanding of human psychology.
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