Medical robotics startup HistoSonics and its Minnesota-based executive team announced a $54 million Series C fundraising round with backers including proton-beam therapy maker Varian Medical Systems and Dr. Fred Moll, founder of the world's largest medical-robot company, Intuitive Surgical.

HistoSonics is designing and testing a cancer-killing machine that combines robotics, real-time imaging and a novel energy source into a system that can liquefy and destroy cancer cells inside the body using focused acoustic energy.

HistoSonics has strong Midwestern roots. HistoSonics' CEO, Mike Blue, lives in the Minneapolis area and is a former sales vice president with Plymouth's super Dimension, now owned by Medtronic. HistoSonics also has executives in operations, R & D and finance who live in the Twin Cities. The company is headquartered in Michigan, and is based on a technique called histotripsy, invented at the University of Michigan. One of the major investors in this latest funding round was the State of Wisconsin Investment Board.

"HistoSonics plans to expand their operations in the Minneapolis area, where a wealth of med tech engineering and marketing talent resides, while maintaining our presence in Ann Arbor where our R & D has strong roots," Josh King, vice president of marketing for HistoSonics, said in an e-mail Monday.

HistoSonic's key therapy, which it calls robotically assisted sonic therapy, "will offer transformative change for both patients and physicians and will help overcome many of the major limitations and side effects of today's cancer therapies," Blue said in a news release. "It has also shown great promise to work synergistically with other therapies and platforms, such as drug and immunotherapy, a big focus of our preclinical work, as well as with other surgical robotic platforms."

Histotripsy was described in 2015 journal article as "delivery of acoustic energy in the form of short very high intensity pulses, which induces controlled cavitation to mechanically homogenize targeted tissue. Cavitation … occurs when a sufficiently negative pressure is applied to a fluid (or in this case tissue) to cause microbubble formation from fluid vaporization and release of dissolved gas.

Once formed, the microbubbles exhibit highly dynamic patterns of oscillation and inertial collapse which impart severe stresses on surrounding cells and tissues and produces cellular and tissue disruption."

On Monday, HistoSonics announced their Series C funding round, with California's Varian Medical Systems leading the funding raising round. Varian makes advanced proton-beam systems for cancer treatments, as well as systems that perform conventional cancer radiotherapy and oncology treatments including fixed field intensity-modulated radiation therapy and stereotactic radio surgery.

Other investors in the round included the investment arm of Johnson & Johnson, called Johnson & Johnson Innovation — JJDC, Inc., ; Lumira Ventures; Venture Investors; the state of Wisconsin; and existing investors.

The financing included backing from Moll, whose past work includes founding Intuitive Surgical, the Silicon Valley-based company that has ridden the popularity of its robotically assisted da Vinci robotic surgical system to a $66 billion market valuation.

The announcement comes amid robust time for med-tech funding, at least in Minnesota. The state's health-technology trade group, the Medical Alley Association, reports that companies it tracks (not including HistoSonics) raised $167 million during the first three months of 2019, which was well above the previous Q1 record of $112 million.

Joe Carlson • 612-673-4779