CLARITY, Optogenetics, and Vector Engineering Research Center

Viviana Gradinaru – Principal Investigator
Tim Shay – Director

The mission of the CLARITY, Optogenetics and Vector Engineering Research (CLOVER) Center is to facilitate optogenetic studies, custom viral vector development, and tissue clearing projects across Caltech. In providing infrastructure and reagent sharing, training, and further technology and methodology development, we catalyze high-impact and high-risk research projects. By helping researchers test their hypotheses and obtain the preliminary data necessary to secure additional funding, we drive continued technological development and advance basic science objectives.

Vector-assisted spectral tracing (VAST) using AAV-PHP.eB of mouse cortical neurons.

Technology Development

  • Tissue clearing: We are developing improved methods for imaging through thick intact tissue samples at high resolution by rendering them optically transparent and permeable to stains, antibodies and nucleic acid probes.
  • Opsin engineering: Optogenetics uses light sensitive proteins called opsins to modulate and monitor the activity of neurons and other cellular states. We are working to extend the properties of opsins through protein engineering.
  • Customized gene delivery vehicles: We are developing custom recombinant adeno-associated viruses (AAVs) for more efficient and targeted gene transfer in vivo.

Resources and Outreach

  • One-on-one consultations and training for tissue clearing techniques and viral vector production to jump start research projects
  • Focused workshops for researchers with various backgrounds and experience levels
  • On site use of the CLOVER Center’s tissue clearing facilities and technical support.
  • Collaborative custom vector development.


Prof. Viviana Gradinaru

Principal Investigator

  • Biology and Biological Engineering
  • 258 Alles Laboratory
  • Mail Code 156-29

Dr. Tim Shay


  • 230 Beckman Institute
  • Mail Code 139-74
  • (626) 395-2776