Mark McDonnell

Principal Scientist - Medicinal Chemistry

Mark McDonnell, Ph.D. leads the medicinal chemistry effort as a Principal Scientist. His research experience encompasses 20 years in the research laboratories of Johnson and Johnson, and Fox Chase Chemical Diversity Center Inc. His expertise lies in the synthesis of small molecule bioactive agents and he has lead several projects from hit identification through lead optimization in the oncologic and CNS therapeutic areas. He is a co-inventor on more than two dozen U.S. patents and applications.


Baiwei Gu

Principal Scientist - Drug Discovery and Gene Therapy

Baiwei Gu, Ph.D. is the Principal Scientist for Drug Discovery and Gene Therapy. His expertise is in translational research in cancer biology, stem cell biology, molecular biology and assay development. His postdoctoral experiences of over 11 years were obtained at Washington University and Children’s Hospital of Philadelphia where he focused on pathogenesis of genetic disorders, and stem cell research respectively. He received Ph.D. training in Dr. Sai-Juan Chen and Dr. Zhu Chen’s laboratory at Shanghai Institute of Hematology.


Ursula Ramirez

Principal Scientist - X-ray Crystallography

Ursula Ramirez, Ph.D. leads X-ray crystallography studies at Vironika.  She is a structural biologist and has experience in computational drug discovery.  Ursula received her Ph.D. in Neuroscience at Northwestern University, where she trained in X-ray crystallography in the laboratory of Dr. Douglas Freymann.  She did her postdoctoral studies in computational biology in the laboratory of Dr. Eileen Jaffe at Fox Chase Cancer Center.  


Scientific advisors


Paul Lieberman

Paul Lieberman, Ph.D. is Founder of Vironika, and is a Professor of the Wistar Institute.  He is the Scientific Director of the Molecular Screening Facility at the Wistar Institute.  His expertise is in viral oncology and viral chromosome biology, and has investigated the biochemical and cellular biological properties of EBV and EBNA1 for over 15 years.  He was trained with Dr. Arnold Berk, Director of the MBI at UCLA, and with Drs. Gary and Diane Hayward at Johns Hopkins University School of Medicine in viral oncology and pharmacology.


Allen Reitz

Allen B. Reitz, Ph.D. received a Ph.D. with Prof. Murray Goodman at UC, San Diego, and conducted research at Johnson & Johnson for ~26 years.  Since 2008, he has been an entrepreneur, founding Fox Chase Chemical Diversity Center, Inc. (, among other small business research ventures.  He is also co-founder and President of the non-profit Pennsylvania Drug Discovery Institute, a regional service and outreach organization to promote biomedical research.  He is co-inventor of eight NCEs that have entered human clinical trials, including trigriluzole and mazapertine.

Nicholas Siciliano

Dr. Siciliano currently serves as the CEO of Invisible Sentinel, a global molecular solutions Company that provides novel microbial detection tools to ensure consumer safety and product quality.  He also serves as the President and co-founder of Paratope Technologies, a life sciences education company, and Immuno-Spy, a consulting company for vaccines and immunotherapies. Dr. Siciliano received a Bachelor of Science degree in Chemistry from Villanova University and a Ph.D. in Immunology and Microbial Pathogenesis from Thomas Jefferson University. He is a member of Invisible Sentinel’s Board of Directors and serves on several biotech start-up Advisory Boards. He is also a lecturer in entrepreneurship at Thomas Jefferson University. He holds multiple utility and design patents for diagnostic technologies, and has published scientific manuscripts in the fields of bacteriology, virology, immunology, molecular biology, and cancer immunotherapy.




Troy Messick

Troy Messick, Ph.D. is a co-founder of Vironika.  His expertise is in structural and molecular biology of cancer.  He has trained with Dr. Ronen Marmorstein at the Wistar Institute in X-ray crystallography, Dr. Roger Greenberg at the University of Pennsylvania, and Dr. Leemor Joshua-Tor at Cold Spring Harbor Laboratory.  He received a Ph.D. from Stonybrook University in Genetics and trained at the Cold Spring Harbor laboratories.