The world's largest open access publisher, BioMed Central, has been sold to Springer.

BioMed Central (a former sister company of The Scientist) publishes 180 peer-reviewed journals under the open access publishing model, meaning that anyone can read articles for free once they are published, and authors pay a per-page fee to publish in the journals.

There are no plans to change the journal publishing costs or fees, Matt McKay, director of public relations at BioMed Central, told The Scientist. "There are no plans to change the publishing model, as part of the terms and conditions of the agreement of the board of trustees," McKay added. "We are committed to open access and the open access publishing model remains the same."

Springer publishes 1,700 journals in science, technology, and medicine, and is one of three publishing groups that has a green open access policy; authors can pay a processing fee of $3000, and the article becomes immediately open access upon publication. Springer publishes the journal of Microbial Ecology and Functional & Integrative Genomics.

Last year, Yale University dropped its subscription to BioMed Central, citing the rising costs to the university. Flat fees for membership can cost around $30,000 a year.

BioMed Central publisher Matt Cockerill sent an Email to the BioMed journal editors informing them of the acquisition, Scientific American reported. Everything "is 'business as usual' for all BioMed Central staff and journals," he wrote.

McKay declined to say how much Springer paid for the acquisition.

In a statement from Springer, CEO of Science and Business Media Derk Haank said: "This acquisition reinforces the fact that we see open access publishing as a sustainable part of [scientific, technical, and medical] publishing, and not an ideological crusade."