How a Biotech CEO Turned 1,600 Everyday Investors Into Backers—and Raised $4 Million

Nicole Paulk, CEO and Founder of Siren Biotechnology, remembers the objections she heard from board members when she proposed raising money through a public crowdfunding campaign.

“We had investors who were like, ‘This sounds weird,’ and, ‘It doesn’t happen in biotech,’” Paulk said during a recent webinar about her experience. “I said, ‘Let me cook,’ and within a month, we hit a million dollars. All of a sudden, everyone was like, ‘OK!’”

Overall, Siren—a company developing a combination gene and immunotherapy for cancer—raised $4.2 million from more than 1,600 investors. The campaign required Paulk and her team to step outside their comfort zones, promoting themselves and their mission to family, friends, acquaintances, industry contacts, and the broader public across social media.

“You will be uncomfortable,” she said. “You have to be pretty out there in order to get folks aware of who you are and get them pumped about you.”

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The Legal and Operational Setup

Paulk said the legal setup was more involved than expected. Beyond finding specialized regulatory counsel to prepare the Form C filing with the SEC, the company also needed an independent financial audit for the first time.

“We had never been audited before because we’re not a very large company,” Paulk said.

That audit took about three months, though she estimates companies familiar with audits could complete it in half the time. The specialized legal work added another layer of complexity, requiring coordination between Siren’s regular corporate counsel at Cooley and new regulatory specialists.

The paperwork also required radical transparency. The Form C filing is public and reveals details private biotechs typically keep confidential—cash on hand, burn rate, and employee count.

“You have to be very willing to have that information out there,” Paulk said.

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Building Momentum Through Multiple Channels

The company launched its campaign on Wefunder, a platform that lets the public invest in startups in exchange for equity. These arrangements became legal in 2016 after the SEC adopted Regulation Crowdfunding rules.

Siren kept the round private for the first six weeks, raising initial funds from friends, family, and existing investors. Once they surpassed $200,000, they opened the round to the public. Short videos introducing the team, along with award applications, speaking engagements, and regular email updates, proved critical to maintaining interest, Paulk said.

“People want to know the person behind this,” she said. “It humanizes things.”

She also ensured Siren’s website content was accessible to a general audience—using straightforward language and avoiding technical details that might confuse people who haven’t had a science class since high school.

Paid advertising became a major driver as the campaign progressed. Siren started at about $5,000 per month and ramped up to $24,000 per month by the end of the raise. Platform performance varied: Facebook and Instagram delivered strong results, while Google, LinkedIn, and Twitter fell flat.

The team also diversified its outreach—launching email campaigns, speaking at disease-specific conferences, appearing on podcasts, and entering pitch competitions. Paulk even spoke to student investment groups at Stanford, UCSF, and UC Berkeley.

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The Power of Personal Connection

The most effective driver turned out to be personal connection. Paulk opened six hours per week for 15-minute calls with prospective investors and spoke to anyone who signed up. Many conversations weren’t about data or milestones; instead, patients and caregivers wanted to share their own diagnosis stories or talk about loved ones they’d lost to cancer.

“Most of it was really just folks wanting to feel like they were connected to you and that they were part of your journey—and they wanted you to know a little bit about them,” she said. “It was a big reminder how many people are out there looking for a reason to get excited and a reason to have hope.”