You could make the bristles from pigs hair or similar as with other kinds of brushes probably. It would just be really expensive and probably isn't worth it. If you can, do use the correct interdental brushes as they are way more effective. You should consult a dental hygienist for proper sizing. Should you come to Prague, you should contact fulldent.cz as far in advance as you can and arrange an appointment.

(Disclaimer, my GF works there however I and my whole family and some friends who attend there have since then the best dental hygiene possible. They also don't mind English at all.)