RiverTide Bio Makes Waves for Peptide-driven Solutions
A Southern California native, Alexander Malinick fell in love with science when he did his first lab experiments in high school. “I was fascinated by how all of life is building blocks of atoms. It drove my enchantment with physical science and STEM.” Those building blocks are now building towards his next breakthrough with RiverTide Bio, a biotechnology startup developing multicyclic peptide platforms designed to selectively detect, deliver, and treat disease.
After receiving a BS in chemistry from the University of La Verne, a small liberal arts school in California, Malinick took a year off to consider next steps. He began tutoring students, and realized he liked the entrepreneurial aspect of providing a service to others. “It was good to be self-employed, but I missed doing experiments,” he said.
Malinick returned to academic life, getting his PhD in analytical chemistry at the University of California Riverside. It was there that he was first introduced to I-Corps.
“We were working on making synthetic lipid membranes, almost like organs on a chip to detect biomarkers, for disease detection,” he said. “We built our biosensor during Covid, and did our first I-Corps, both regional and national.” Malinick and his colleagues named their company On the Spot Biosensors.
“That experience was my first introduction to structured entrepreneurship and stakeholder engagement, and I fell in love with the whole process,” Malinick said.
They were unable to find a large enough market for their technology to be able to spin out a company. “That’s when I started to think about what tech would have a large enough market to demand adoption,” he said.
Around that time, Malinick met Min Xue, who was developing peptide-based technologies and putting them on biosensors to screen for Covid. “I joined his lab as a post doc and then we moved the lab from Riverside to Mt. Sinai in New York,” said Malinick, describing the enormous job of moving a multi-million-dollar lab across the country.
Peptides are short chains of amino acids—the building blocks of proteins. Many serve as messengers in the body, telling cells what to do. For example, insulin is a peptide protein. Malinick’s work with Min Xue on developing peptides eventually led them to co-found RiverTide.
As Malinick describes it, Min always had a vision of developing these peptides and building a company but never had anyone in the lab who was excited to do that, until they partnered.
“Min saw me go through the On the Spot experience; he knew I was passionate about the potential for peptides and the technology,” Malinick added. They started working together in 2023 to develop a modular multicyclic peptide that targets a protease; that is, if a protease is present in high levels in cancer, they could potentially design a peptide that binds to a specific pocket on the protease/protein, using that reaction to activate a treatment.
“When proteases keep increasing in volume in metastatic cancers, they can be very hard to treat,” Malinick added. “We developed a highly selective peptide that targets the protease without significant cross-reactivity, allowing us to target the tumor microenvironment while minimizing interference with other therapies and normal biology. We also generated strong diagnostic data showing that the peptide can accumulate at the tumor site.”
The company has targeted metastatic melanoma as its initial beachhead market through a theragnostic protease-targeting multicyclic peptide, meaning it creates specially engineered small molecules that can find a particular protease and potentially be used both to detect it and to treat disease associated with it.
As Malinick articulated it, there are three treatment options for metastatic cancer patients: immune therapy, genetic market drugs, and current radio therapeutics—radioactive isotopes that destroy both good and bad cells. With their innovation, they are trying to get the “payload” to accumulate at the tumor site, and not impact healthy tissue. To do so would be an enormous breakthrough.
Malinick described the inspiration for naming the company RiverTide. “There’s more awareness today of the potential value of peptides for anti-aging or weight loss, but 20 years ago, they were the black sheep of the medical world,” he said. “I think of it as a giant glacier that’s built up, and now it’s starting to thaw and we can see how integral they are to our lives and sustaining longer lives. It’s a growing river, and the tide is changing for peptides.”
Having been through I-Corps numerous times at the regional and national levels, Malinick has taken important lessons from the experience. “What you think will be the biggest selling point is usually not,” he said. “National I-Corps showed us we had to think differently. We thought you detect the biomarker and then you treat it. That was my bias of focusing on biosensors, since that was my PhD. Actually, the therapeutic is the value driver—that’s what everyone in the ecosystem cares about. Especially for late line metastatic cancer, doctors throw a lot at patients to see what works best. It’s a race against time, and physicians are more inclined to start with a therapeutic option that will potentially increase survival.”
“Our next big lesson from I-Corps began at a regional cohort at CUNY, and was expanded upon in our National cohort, Spring Cohort II 2026, and that was learning about workflow integration,” Malinick added. “No one is going to rewrite how they are going to administer your therapeutic or change the codes for reimbursement for you; you need to follow the existing models. In hindsight, that might seem obvious, but it wasn’t until we spoke to experts that we truly understood how the system works.
“Going through I-Corps changed how I see the world; I view everything through an entrepreneurial lens now,” he said. Malinick is now part of the I-Corps teaching team at Mt. Sinai.
Malinick also discussed the importance of being open to opportunities to pivot, rather than wary of it. “Pivoting is part of the game, and it never ends,” he said. “If you don’t pivot in entrepreneurship, you’re doing something wrong. For RiverTide, we are pivoting hard towards therapeutics.”
RiverTide is developing other technologies with potential and is pursuing grants on all fronts. Next steps will include highly specialized labs and non-human primate testing, a multi-million-dollar effort. “Rather than offering a single peptide or asset, we have a library from which we identify and screen peptides for different applications,” added Malinick. “It’s exciting to establish RiverTide as a platform company with programs spanning drug delivery, theragnostics, and therapeutics.”
As we have progressed, our community has grown,” said Malinick. “I would not be as confident in pursuing this journey if not for the NY I-Corps Hub. I try to go to every workshop they offer, on storytelling, on applying for SBIR and STTR grants. The team there really keeps you going—they make me want to continue even when I’m not sure we can do it. Mt. Sinai has also been incredibly supportive of our work.”
The work of RiverTide is all encompassing, so fortunately for Malinick, he’s pursuing it in partnership with his wife, Desiree, who he met as an undergraduate. She is the co-EL on all of RiverTide’s programs.
“We are very lucky that we work so well together; it’s been an amazing experience,” said Malinick. “Our research and the entrepreneurship encompass my whole life—even sitting at the dining table, we are talking about our work.”
Recently Malinick and his wife got a cat from a rescue, after learning on social media about how the cat had run into someone’s home during a blizzard. They named him Watney, after the main character from the book by Andy Weir, The Martian, because of the cold and stormy weather on Mars. Malinick’s parents have two cats named Rocky and Grace, from one of Weir’s other notable books, Project Hail Mary.
“Watney helps me to manage my time,” joked Malinick. “He’s always watching me on the computer, and if he thinks I’ve been working for too long, he’ll walk on my keyboard and force me to take a break. It’s good for me!”
