T2 Biosystems Inc. raised about $15 million in a Series C funding round it plans to use to bring its benchtop MRI-based diagnostic device to market.

The Cambridge, Mass.-based firm said Physic Ventures led the round, along with new backers Arcus Ventures, RA Capital, Camros Capital, WS Investments and existing investors Flagship Ventures, Polaris Venture Partners, Flybridge Capital Partners and Partners Healthcare.

The device uses a miniaturized version of a magnetic resonance imaging machine to deliver near-instant test results from just about any blood, urine or saliva sample. T2 Biosystems previously raised $10.8 million in a Series B financing in 2008, according to a press release (PDF).

The company said it plans to target immuno-compromised patients with the launch of the first of its commercial products and "will be working with industry partners to develop diagnostic tests for additional applications and to further advance the platform," according to the release.

"The funding will allow us to advance and commercialize our initial menu of diagnostic tests in the decentralized setting, where our unique technical advantages will improve disease diagnosis and treatment," president and CEO John McDonough said in prepared remarks.

In January, T2 Biosystems named Ken Toso vice president of product development.