Polymers are long molecules comprising repeated chemical units known as monomers. Some polymers, such as polyethylene glycol (PEG), comprising ethylene glycol (Eg) monomers, are very useful parts of sophisticated nanomedicines, because they regulate the way that a medicine is transported around and retained in the body. Other polymers, including oligonucleotides (oligos) are used as therapeutic agents. It is extremely difficult to make polymers such as PEG and oligos accurately, because chemical techniques often add a few more or a few less monomers to the chain. For example, in making Eg112, a PEG polymer with 112 repeated units and a molecular weight close to 5kDa, current processes also make Eg111, Eg113, Eg110, Eg114, and so on, so that the material is known as polydisperse. This is a problem for use as part of a medicine, because the different chain lengths can act in different ways in the body, and analysis of multiple species is harder to do accurately. EXACTMER is a start-up company which has licensed a breakthrough new technology invented at Imperial College London- Nanostar Sieving. A hub molecule with three or more arms is used to form a macromolecular Nanostar. Monomers are added to each of the arms, one by one, to form polymers with an exactly controlled sequence of monomers. After the addition of each monomer, all the debris are removed by molecular sieving through a specially designed membrane. The process is repeated over and over until the desired number of monomers has been added, and then the polymers are cut off the hub and recovered, with all polymer molecules having the same, exact number and sequence of monomers. During 2019 we have sold small quantities (1g) of PEGs, and have carried out paid trials to show that Nanostar Sieving can produce purer oligos than conventional technology. We generated £235K in revenue, indicative of strong interest from a range of customers. Now we must quickly capitalise on this by innovating to make our process more efficient, and using it to make 10-20g batches. Success in this innovation project will provide the technical basis for EXACTMER to invest in 1kg scale manufacturing in 2022, rising to 10kg scale in 2023/24\. It will establish Nanostar Sieving as a competitor to the current state-of-the-art, expensive solid phase synthesis. Exactmer will strive to become the dominant global producer of exact, high value polymers, based in the UK.