Cloudscape

Envision microscopic permanent supermagnets dissolved in water, coated with a material which adheres to water and having a microarchitecture which furthers its absorption of water: perhaps it could then be possible to quickly repel the water itself with a larger magnet. This could be used to dry something or, perhaps, to remove the water from an area around the magnet so as to do something beneath where the water surface had been.

In future, nanorobots could be used to form larger things, like cells form organs, assembling to form a greater whole. Also, however, they could be used to actually create a larger thing outside of themselves, like some cells create the inorganic matrix in bone, or like human builders creating a building. In this way, they could be used to create anything from almost any material.

With enough energy, nanorobots connected to a nanoscale knife could cut through almost anything because in their small size they would meet little resistance. Of course, the effects of this would normally be unnoticeable macroscopically, but suppose that as the nanorobots would cut through the material they would secrete a kind of lubricant, this would allow the microscopic slit to become larger as the parts of the material could slide off one another. For some materials, another method could be to heat it, so that part of it melts or vaporizes so as to lubricate it itself. If the material would be a metal, the nanorobots could instead use magnetism instead of a lubricant to repel the metal.

Suppose that a wall of nanorobots would form in a body part (eg an arm) along the tissues; wherever they are, they imitate the function of the cells next to them; if there are no cells next to them, as in a cavity or vein, there aught not to be any nanorobots at all. In this way, every organic structure retains its normal function, even tendons, veins, and nerves. This wall then thickens, so that it becomes part of the body part, indirectly keeping the two halves together so that it still functions normally. This wall of nanorobots could then keep growing indefinitely, so that the body part would become extendable. In this way, one could, in principle, temporarily extend one's arm for meters. Admittedly, doing this safely would require advanced technology which today can only be carried out in science-fiction.

Rather than having each nanorobot obtain their own energy, nanorobots could energize one another by connecting to one another throughout whatever matrix they are in; on condition, that is, that they are present in sufficient density to form a kind of microscopic "mesh" of concatenated nanorobots. In this way, the energy could evenly be distributed and the collective system could work for a considerably longer time without renewal of energy; furthermore, renewal of energy could happen more easily, and could be done from an external electric source, because rather than having each nanorobot connect to it they could serially connect to it in a chain, like a nanoscale cable or series of branching cables.

Just like Leonardo Da Vinci based his plans of the first working robot ever built in 1495 on the human body, we will base our plans of the first working nanorobots on the human organelles. As nanotechnology already exists in nature, it's obvious that we can steal that technology from her. The only difference is that nanorobots would have to be controlled.

Synthetic organisms were of immense potential in medicine. They were capable of doing things ordinary medicines could not (especially virions), because they could get macromolecules such as proteins into the body, whereas all other medicines were smaller molecules: orally administered macromolecules would be broken down in the digestive tract.
This was so significant because in this way one could directly affect every single substance in the entire body, notably proteins - enzymes, cytokines, and so on. It was wonderful that, just like we could administer medicines, we could now likewise administer enzymes. This broadened our horizon of approaches immensely because through this technique we could influence all the machinery in the body, and therefore all of the body itself.
Whether proteins can still be called "substances" or were, strictly speaking, actually "structures," or a combination of both, was debatable. After all, being nanomedicine, this methodology straddled the line between medicine, the molecular, and nanotechnology, the supramolecular.
The advantage of this approach was that it could be made more balanced: the genes of the virions had a promoter which was regulated by the substance the gene produced. Thus, if there were already sufficient amounts in the body, production was stopped automatically; if there was too little, more was produced. What's more, an excess of a substance could activate other genes producing enzymes which catalyze it. Therefore it was impossible to take an overdose.
In this way the concentration was not simply increased or decreased in the classical brute-force way, but stabilized. The virion ensured that any imbalances were set straight so that the body came closer to a more normal functioning. This also made it possible to target only specific body areas where there were disturbances, which was advantageous, for instance, in the treatment of schizophrenia: schizophrenics have too little dopamine in some brain areas, leading to "negative symptoms" like apathy, and too much dopamine in other areas, leading to "positive symptoms" like delusions. Rather than just decreasing the overall dopamine to control the positive symptoms (which were most dangerous), and in doing so worsening the negative symptoms, synthetic viruses could balance it.
In this way, synthetic viruses could make the functioning of body and mind "normal." Of course, even this could have disadvantages, as our personality is basically a set of abnormalities, so only if it was really needed (as in psychosis), these were applied to the brain. Because the patient of mental illness might actually like some of his symptoms, it was sometimes also possible to only affect some brain areas and rectify those; in other brain areas the virus could either be broken down by substances not present in the targeted brain area, or it could have its genes deactivated by them.
Although a great many of such synthetic organisms were created at first, it was later thought more practical to merge them, or rather their genomes to one. In this way, a universal medicine and at the same time a universal dietary supplement was contrived, and the genus was therefore aptly named Panacea. Later, in addition to affecting substances like proteins, it also affected even larger structures such as organelles and even other bacteria. In this way it was even made to neutralize other pathogens, assisting our own white blood cells.
Panacea had countless functions, and for this reason its genome was also large. However, it had the smallest number of genes it could have while still being viable. Genes it didn't need were removed, so that the genome could still fit in the virion. Based on the Mycoplasma genitalum, which has the smallest known genome (over 500 genes), only the essential genes were included.
As said, by balancing the body's functioning, Panacea made it more normal. Because no-one wanted to be fully normal, however, many of its genes were removed on custom. However, as a dietary supplement it could also optimize it to a supernormal degree, and this was especially so for the brain. Many people choose to be hypomanic, meaning mildly manic, so that they lived much richer lives. Some people also changed their personality from day to day. The morality of this was heavily disputed, however, and most people regarded changing one's personality as wrong. Instead, most people amplified the personality they already had, thus making themselves more emotional or on the contrary more phlegmatic, more sociable or on the contrary more reclusive, more motivated or on the contrary more indifferent.
Because changing one's personality is ego-dystonic, ie not in accordance with one's ego, there were only very few people who experimented with this, and when they did they never let the results be permanent. It was more like a recreational drug, the short-term influence of which can be pleasant but the long-term influence of which can be torture. Some people even used this to temporarily induce mental illnesses, just to know what it feels like, and this was especially done by psychiatrists and relatives of mentally ill people. However, this was nothing new, as drugs had been used for this purpose earlier (eg psychotomimetics, hallucinogens, psychedelics); Panacea was simply a more direct way of doing this, and therefore more safe, and therefore too more often used.

Cells are molecular assemblers, and just like nanorobots, they can produce any material - wood, oil, cheese… It's funny how people should still doubt whether or not nanorobots could be made, if they're themselves made of them.