I did a lot of researching when I lived in Rio de Janeiro - where I was born and raised - but couldn't find anything other than vague historical references to the use of straight razors and knives (there are few writen works on the history of the art, and they are anything but complete). It is a fact that Capoeira was outlawed in Brazil during a period of time, supposedly due to its practitioners taking part in street brawls related to opposing political factions.
As far as modern-day "mestres" (instructors) and academies teaching blade techniques, I've never heard of anything. If it happens at all, it's a well-kept secret. Truth is, the carrying of knives, even common pocket folders, is not a common practise in Brazil's big centers (criminals carry firearms in spite of oppressive gun-control laws that affect only the law-abiding).
Leo