Current Laboratory Staff and Personnel

Principal Investigator (PI)


Aijun Wang headshot-1Aijun Wang, Ph.D.

Department of Surgery

Department of Biomedical Engineering

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Laboratory Manager


C.PivettiChris Pivetti, M.S. (

Christopher Pivetti is a scientist for the Department of Surgery, University of California, Davis Health in Sacramento, CA. He received both his bachelor’s degree (2001) and his master’s degree (2004) in general biology from the University of California, San Diego. He serves as the laboratory supervisor and he oversees the daily operations of five principal investigators. His research interests include using stem cell therapy to treat congenital anomalies such as spina bifida, and diaphragmatic hernia.  He also specializes in small animal microsurgery and serves as a microsurgery instructor for the department. 


Project Scientist


priyadarsini kumarPriyadarsini Kumar, Ph.D. (

Priya Kumar is a senior scientist with over 25 years of research experience.  She obtained her PhD from University of California, Davis, and Master’s/Bachelor’s degrees from University of Madras, India. Her research focus is stem cell and stem cell derived extracellular vesicles for treatment of neurodegenerative diseases. She led the GMP production of PMSCs for our team to successfully obtain the IND from FDA for a Phase1/2a spina bifida clinical trial starting in 2021. Her other research focus is in utilizing placenta-derived extracellular vesicles and developing a serum-free cell-free product for clinical applications like adult acquired spinal cord injury. Teaching has always been her passion and loves to mentor aspiring scientists. During her free time, she loves cooking Indian food, watching soap operas in her native language (Tamil), reading books about inspiring personalities, and loves taking care of neighborhood cats.


Postdoctoral Fellows


K.GaoKewa Gao, M.D., Ph.D. (

Kewa is a Shriners Hospitals for Children Postdoctoral Fellow. She was trained as a general and plastic surgeon (MD). Her research is focused on genetic disease treatment such as hemophilia A and sickle cell disease by stem cell transplantation and gene editing. She is also interested in developing biomaterial and stem cell-based treatment for wound healing. In her spare time, Kewa enjoys skiing, scuba diving, and photography.


D.HaoDake Hao, Ph.D. (

Dake is a Shriners Hospitals for Children Postdoctoral Fellow. His research is focused on developing innovative technologies, integrin-based functional and therapeutic molecules and stem cells, biomaterial, and extracellular vesicle engineering for tissue regeneration, such as vascular regeneration, bone regeneration, and fetal regeneration. Besides research, Dake likes sports, especially soccer.


Chaoxing_ZhangChaoxing Zhang, Ph.D. (

Chaoxing is a postdoc fellow at UC Davis. His research is focused on 3D bioprinting of biodegradable biomaterials, stem cells, extracellular vesicles and functional molecules for tissue engineering application, especially fetal tissue engineering, bone regeneration and wound healing. In his free time, Chaoxing likes photographing, playing mobile games and watching NBA.


Research Residents


J.JacksonJordan Elizabeth Jackson, M.D. (

Jordan is a General Surgery Resident at University of California, SF East Bay and she is interested in Pediatric Surgery.  Therefore, she is taking 2 years away from clinical life to do research with Dr. Farmer and Dr. Wang at UC Davis.  She is working with lab members on projects involving MMC animal models. She is also working on a spinal cord injury rodent model, among many other exciting clinical studies.  



Sarah_StokesSarah Calcott Stokes, M.D. (

Sarah is a Surgery Resident spending 2 years doing research at the Surgical Bioengineering Laboratory. She is currently working on a fetal sheep surgical model for spina bifida and a project investigating the properties of stem cells at different gestational ages. In her free time, Sarah likes hiking with her dog and skiing.



Christina T photoChristina Mae Theodorou, M.D. (

Christina is a General Surgery Resident at UC Davis interested in Pediatric Surgery. She is spending two years in the Surgical Bioengineering Lab studying a variety of cellular based therapies for diseases such as myelomeningocele and neuroblastoma. She is also studying interventions to reduce maternal and fetal morbidity and mortality from peripartum hemorrhage. In her free time, Christina enjoys visiting restaurants and wineries around Sacramento and going camping. 



PhD Students


K.ClarkKaitlin Clark, M.A. (

Kasey is a Ph.D. candidate in the Biochemistry, Molecular, Cellular and Developmental Biology (BMCDB) Program, at UC Davis, and is emphasizing in translational research. She received her bachelor’s degree from UC Davis and her master’s degree in Stem Cell biology from CSU Sacramento. Kasey started her research career at the UC Davis School of Veterinary Medicine in 2009 focusing on mesenchymal stem cell (MSC) treatments for animals. She is currently investigating the use of placenta derived MSCs (PMSCs) for the treatment of spina bifida in English Bulldogs. Kasey’s main research focus is the immunoregulatory properties of PMSCs and is also investigating the use of PMSC derived extracellular vesicles for the treatment of multiple sclerosis. In her free time, Kasey enjoys playing sports, riding her horses and spending time with her rescue dogs.


Lalitha R. pictureLalithasri Ramasubramanian, B.S. (

Lalitha is a Ph.D. candidate in Biomedical Engineering (BMEGG). She is developing Extracellular Vesicle (EV) mimicking technologies for vascular repair and regeneration. Outside of lab, she enjoys watching TV, reading, trying new foods, and hiking.



L.Goldbloom-HelznerLeora Goldbloom-Helzner, M.S. (

Leora is a Biomedical Engineering (BMEGG) Ph.D. student. She is working on increasing the yield of extracellular vesicles (EVs) through the use of different culture systems, as well as on the immobilization of EVs on scaffolds using membrane protein-specific aptamers. In her free time, Leora loves to take voice lessons and play volleyball. 



Visiting Scholars


S.HeSiqi He, M.D. (

Siqi is a visiting PhD student (Ph.D. candidate) and a trained plastic surgeon. Her research focuses on using functionalized extracellular matrices with stem cells to promote diabetic wound healing. In her free time, she loves dancing and hiking.



LL.Luu Lu, M.S. (

Lu is a visiting PhD student (Ph.D. candidate). Her research interest is in the study of nanomaterials and drug delivery for tissue regeneration. Her hobbies are listening to music, playing badminton and traveling.



H.SongHengyue Song, M.D. (

Hengyue is a visiting PhD student (Ph.D. candidate) and a trained plastic surgeon. She is now focusing on burn wound healing, tissue engineering, and gene editing research projects. Out of the lab, Hengyue is a photographer, a music aficionado, and a museum lover. 



CIRM Bridges Master’s Students


pic of james gomezJames E. Gomez, B.S. (

James is a HSU-CIRM Bridges Scholar. He completed his Bachelor of Science degree in Biology with an emphasis on Molecular/Cellular Biology from Humboldt State University. His research focuses on increasing production of extracellular vesicles and their subsequent yields through tissue culture. Outside of lab he likes to hike, spend time with family including his pets Mew and Poe, playing music, and learning new hobbies


ryan stagnaroRyan Stagnaro, B.S. (

Ryan is a CIRM Bridges Master’s Student. He graduated with a Bachelor of Science degree in Biology from California State University, Sacramento. His research focuses primarily on the potential treatment of Multiple Sclerosis symptoms in mice utilizing placenta derived mesenchymal stromal cell extracellular vesicles. His interests outside of lab include telling puns and cooking.


tyler sickler picTyler Sickler, B.A. (

Tyler is a CIRM Bridges Master’s Student. He received his Bachelor of Arts degree in Biological Sciences from CSU Sacramento. His research focuses on the targeting efficiency and neuroprotective capability of surface-modified extracellular vesicles (EVs) for the treatment of Myelomeningocele, the most severe form of spina bifida. Outside of research, Tyler participates in competitive running and enjoys spending time with his dog, Kylo.


Junior Specialists


alicia hyllenAlicia Hyllen, M.A. (

Alicia has a Bachelor of Science degree in Cell and Molecular Biology and a Master of Arts in Biological Science from California State University, Sacramento. She works on stem cell production under current Good Manufacturing Practice and IND-enabling studies for FDA approval of a stem cell product for an upcoming clinical trial, for in utero repair of myelomeningocele. In her spare time, Alicia enjoys cooking, baking, and hiking. 


A.IavorovschiAlexandra Maria Iavorovschi, B.S. (

Alex has a Bachelor of Science degree in Human Biology from University of California, San Diego. She also has a background in Marine Biology. Alex is involved in interdisciplinary studies focusing on basic science research and provides high-level technical writing support to the Principal Investigators in the Department of Surgery. Alex enjoys snowboarding, playing tennis, and exploring nature.



lizette reynagaLizette Reynaga, B.S. (

Lizette has a Bachelor of Science in Cellular Molecular Biology from Humboldt State University. She first joined the lab as an intern with the California Institute of Regenerative Medicine in 2017, and was later hired as staff. Lizette is part of the cell culture team responsible for manufacturing and testing stem cells for the in utero repair of myelomeningocele for a future clinical trial. In her spare time, Lizette enjoys painting, hiking and other outdoor activities. 


zach paxtonZachary James Paxton, B.S. (

Zach helps ensure that lab operations run smoothly and performs histology and other tissue analysis for projects concerning various congenital diseases. Outside of lab, Zach loves to ski, swim, play water polo, and be outdoors. He also loves to try new foods and new experiences!




Sabrina pictureSabrina V. Lazar, B.S. ( 

Sabrina earned her Bachelor of Science degree in Cell Biology and minor in Professional Writing from UC Davis. Sabrina is involved in interdisciplinary studies focusing on basic science research and provides high-level technical writing support to the Principal Investigators in the Department of Surgery. She also plays a critical role in composing and editing the quarterly Department of Surgery research newsletter. In her free time, she enjoys Assyrian and Arab cultural dance and plays volleyball and water polo. 


samantha avalloneSamantha Avallone, B.S. (

Samantha has a Bachelor of Science in Biological Sciences and Anthropology from the University of California, Davis. She assists with general lab operations, as well as performs histology and cell culture work. In her spare time, she likes to play flute and alto saxophone, crochet, and bike.