In an era of $45 billion private equity deals like the one for energy giant TXU Corp. (TXU ), those worth less than $1 billion rarely merit a mention. Yet a $670 million deal on Feb. 22, led by New York private equity firm New Mountain Capital, is a milestone in the cash-starved world of biotech. The foray, which merges Seattle-based Ikaria Inc. with a spin-off of Germany’s Linde Group Inc., marks one of the biggest moves by private equity in the sector—and signals that more may be in the works. >>> Discuss This Story