My team and I (UK based) are working with Graphene-based materials and have recently come up with an idea that we want to patent. However, we have not yet developed this idea into a functioning prototype. Is it possible to apply for a patent now, or do we first have to produce a prototype?
First of all, ideas cannot be patented, inventions can; other than in US patent law, it is necessary that an invention solves a technical problem. Concerning your question, you can file a patent application regardless of any existing prototype; this does not usually apply when the invention relates to biological inventions though. Coming back to your question once again, you need to disclose the invention in a manner sufficient so that the person having ordinary skill in the technical field of the invention can reproduce it without undue burden, so as long as you are able to provide such description you are good to go. That said, without any prototyping prior to the drafting of the patent application you may overlook technical details or attempt to patent non-working embodiments of the invention, so it is a good idea to do some prototyping first.