Californian start-up Siren has raised $11.8m to commercialise medical technology that embeds microsensors in fabric, allowing for mass production of affordable, washable smart textiles with remote patient monitoring applications.

Siren’s first commercial product is an FDA-registered temperature-monitoring sock that connects wirelessly to a software application, allowing podiatrists to detect early signs of inflammation in patients at risk of developing diabetic foot ulcers. The onset of diabetic foot ulcers represents a dangerous condition that, when left unchecked, can lead to serious complications, including amputation.

Today, podiatrists largely rely on in-clinic visits to monitor manually the temperature elevations that are the precursor to a diabetic foot ulcer. However, ulcers form in a matter of hours or days and can worsen rapidly between such visits.

Siren enables real-time detection and early intervention, which can prevent the serious complications that result in over 100,000 lower limb amputations every year and cost the US healthcare system over $43bn annually.

Siren’s remote monitoring is particularly valuable during the Covid-19 pandemic, as it allows healthcare practitioners to stay engaged with and care for their patients remotely, limiting in-clinic visits to true emergencies while delivering additional services for physician practices through the recent expansion of Medicare reimbursement for remote patient monitoring services.

“Covid-19 has changed healthcare now and forever,” said Ran Ma, CEO of Siren. “Digitisation and virtual care is no longer a nice-to-have, it’s a need-to-have. Patients need remote patient monitoring to collect and send crucial health data to their physicians. Clinics, by transitioning some medical staff into virtual monitoring, can stay operational, prevent job loss and allow patients continued access to care. Additionally, as a medical device company, we have changed the way that we do business – how we make sales, provide customer support, and how our products work. The companies who not only survive but thrive are the ones best able to evolve and help their customers adapt to this new world.”

The funding round was led by Anathem Ventures, with participation from existing investors DCM, Khosla Ventures, 500 Startups and Peter Thiel’s Founders Fund. In connection with this series B round, Anathem managing partner Crystal McKellar will join Siren as an advisor.

“Technology, at its best, should deliver higher functionality at a fraction of the cost,” said McKellar. “In the healthcare space, this means improving patient outcomes while reducing the financial burden to the system. Siren’s breakthrough technology combines all of these important adoption drivers, and I am thrilled to partner with Siren to help further the company’s growth.”

DCM partner Jason Krikorian will join Siren’s board.

“When we initially invested, what I saw was a resourceful team and a creative and elegant product that would represent an enormous improvement for patient care and cost-effective physician workflows in any environment,” said Krikorian, a long-time Siren investor who co-led Siren’s 2016 seed round. “The current pandemic has made it clear that remote monitoring will be a critical part of any physician’s practice. I’m excited to work even closer with the team on this next phase of growth.”

Since its founding in 2015, Siren has raised $22m across three funding rounds to position itself for commercial expansion, including a previously undisclosed $6.5m series A in 2018 and a $3.4m seed round.

Siren was founded by Ran Ma, Henk Jan Scholten and Jie Fu who have developed proprietary technology to embed microsensors into fabric, allowing for the mass production of affordable, washable smart textiles. Siren’s products seamlessly integrate into their users’ everyday lives while providing real-time biofeedback to patients and their doctors.