Our Team


CEO, President, co-Founder 

Will is a vascular cell biologist turned entrepreneur. Prior to founding Riparian, he studied at Brigham & Women's Hospital and Harvard Medical School. He received a PhD, MS and a BS in Biomedical Engineering and Applied Math from Harvard University. 

tracy biaco

research specialist

Tracy is a cell biologist who graduated from Wellesley College with a BA in Biochemistry. She previously studied bacterial immunotherapeutic vectors at the Forsyth Dental Institute.

Rafael Gil, PHD


Rafael is a biochemist, cell biologist, and microscopist who graduated from the University of Rochester with a PhD in Pharmacology. During his graduate work, he focused on dissecting a GPCR signaling mechanism involved in cardiac hypertrophy. His postdoctoral work at the University of Michigan looked at the signaling events of alveolar regeneration during acute lung injury.

ron wester, phD


Ron has more than 25 years of leadership experience in the pharmaceutical industry. Most recently, Ron was the founding chemist at Nimbus Therapeutics after a medicinal chemistry career at Pfizer, where he discovered or co-discovered numerous clinical and preclinical candidates including Phase 3 CETP inhibitor torcetrapib (HDL-cholesterol elevation), Phase 2 NHE-1 inhibitor zoniporide (cardioprotection) and Phase 2 renin inhibitor terlakiren (blood pressure reduction). As Executive Director of Cardiovascular & Metabolic Diseases Medicinal Chemistry, Ron led more than 100 chemists, and was responsible for establishing and advancing a diverse portfolio of projects across six therapeutic areas including atherosclerosis, cardiovascular and diabetes. He chaired the CETP Early Clinical Management Team, overcoming numerous development challenges while advancing torcetrapib through preclinical and Phase 1 studies. As Vice President of Exploratory Medicinal Sciences, Ron led up to 325 scientists in providing Pfizer drug discovery projects with integrated technology support, including new lead identification, computational sciences, analytical chemistry, reagent provision, biomarker and functional genomics, and exploratory safety. 

He earned his Ph.D. in synthetic organic chemistry from Yale University with Professor Fred Ziegler. Ron authored or co-authored 26 scientific publications and presentations, and is an inventor on 15 issued U.S. patents.

Advisors & Collaborators


co-Founder, Scientific Advisor, collaborator

Guillermo is an Associate Professor of Pathology at Harvard Medical School and the Director of the Laboratory for Systems Biology at the Center for Excellence in Vascular Biology at Brigham & Women’s Hospital. His expertise in the endothelial biology of cardiovascular diseases is widely recognized as this has been a focus of his laboratory for the past fifteen years.

He received a PhD from Yale University working with Prof. William Sessa on the molecular regulation of nitric oxide production in vascular endothelium. His postdoctoral research with Michael Gimbrone Jr. at Harvard Medical School studied endothelial cell gene expression, hemodynamics, and atherogenesis. He authored 78 scientific publications primarily focused on vascular biology.