Yes, biological research requires a lot of infrastructure and laboratory set-up, so it is indeed expensive. However, YC is an amazing platform to get your technology off the ground and in front of customers. In addition to the funding, advice from YC members has been invaluable in getting a strong business strategy.
The sums YC provides work well for a couple of programmers with laptops - can keep 'em going for a while, but you folks need labs and stuff.