Nanotechnology is sometimes referred to as “crafting with atoms”, which basically means building up materials atom by atom. It is a bottom-up approach that mimics natural processes, for example how a seed is planted and eventually grows into a large tree. The conventional, and opposite manufacturing approach is the top-down approach, which starts with bulk material, and involves carving or etching out the desired structure from the material. The bottom-up approach can lead to a more efficient use of materials and less waste, and is therefore a promising way to help narrow material loops. In the production of nanoparticles and nanowires it’s easier to use a top-down approach where we start with a large piece of material and grind it down to nanoparticles. But with this technique, a lot of waste material is created, it requires a high energy input, and there is very little control over the final size of the nanoparticles. In comparison, there is a bottom-up approach to creating nanoparticles with a physical method called aerosol generation. This approach starts with a small piece of bulk material that is evaporated in a carrier gas, this can be done by a laser, in a furnace or with a spark or arc process. This vapor is then transported away from the hot zone, by the carrier gas, and starts to nucleate. The small nucleus continues to grow in size into nanoparticles. The size of the particles can be carefully tuned, and the carrier gases can be recycled and reused. The small amount of waste that is created is in the form of material condensation on surfaces in the system, and it can be easily collected and recycled. All this makes aerosol generation a more efficient process than the top-down approach. Semiconductor nanowires are rod-shaped one-dimensional structures with a nanoscale diameter, and they have the potential to radically improve future electronic devices. The top-down approach to create these rods is to start with a bulk piece of the semiconductor crystal and etch out the nanowires, which is not the most material efficient way, and often results in nanowires of lower quality. The bottom-up approach is to grow the nanowires atom layer by atom layer in a process called epitaxy. Instead of a thick bulk semiconductor, the process starts with a thin semiconductor substrate where either seed particles or a mask is deposited. After that, the growth material is supplied and the nanowires are formed under the seed particle or in the hole in the mask, atom layer by atom layer. Another way that can be even more material efficient is an aerosol process called aerotaxy. Here the nanowires are grown in a gas stream, with only a seed particle to initiate the growth. The two main advantages of aerotaxy are that the nanowires are grown in a continuous process, and that there is no substrate. This makes it an extremely material efficient production route. In addition to narrowing material loops, nanotechnology can also help slowing material loops, by trying to prolong the lifetime of products. This can be done by applying different coatings to an existing material. For example, there are nanobased coatings that can make a structure withstand wear better, or make it more resistant to corrosion. And there are also coatings that can make surfaces superhydrophobic, which can be used to create self-cleaning materials, similar to a lotus leaf. Super hydrophobic surfaces are surfaces that don’t like water, where tiny micro or nano structures prevent water droplets from wetting the surface. When it rains, the water droplets will collect any dirt stuck on the surface. Nano-materials can also be used to extend material lifetime. One example is self-healing materials, that are designed to heal themselves from thermal or mechanical damage, with full or partial recovery of its mechanical strength. Common types of self-healing materials are based on polymers that are designed to self-heal their broken bonds. Among different promising materials, researchers have developed both self-healing rubber and self-healing glass. The research on nanotechnology based materials has grown significantly, and there is a wide variety of different applications where nanomaterials can have a huge impact.