Sensors only last two weeks because they use the same enzyme (glucose oxidase) as test strips do - and after a while the stuff just wears out. Otherwise we’d have sensors that last much longer. A sensor consists of not just the very fragile filament (plus a device to implant it into your body) but a printed circuit board, battery and an NFC element that provides data when scanned by an NFC enabled device programmed with the correct algorithm to read the electrical signal. It also needs to be sterile. You can’t just buy “a filament”.
Many of us have, however, linked these sensors with a pump via a Bluetooth transmitter, self-built app, radio link and hackable pump to form a DIY artificial pancreas system that works well, so why try to reinvent the wheel when all the components are relatively simply to acquire? I built mine for less than three hundred quid using an old MacBook and the sensor and pump I am prescribed by the NHS.
However, if your team are proposing you start insulin, you need to learn how to use the drug properly before automating it’s delivery - otherwise if your system were to go wrong, you’ll be in a world of trouble and not know why. First learn injections, then become familiar with a pump before even thinking about building a DIY APS. There isn’t any official support for that sort of system and you need to know the nuts and bolts of it inside out.