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Driving Biology through Inorganic Chemistry

Our research focuses on using light responsive ruthenium compounds to target, treat, or direct biological events.

We use light as our primary trigger for biological events, whether that means creating a biomaterial that stiffens or softens, releasing drugs from a polymeric depot, or caging small molecules.

Light-responsive chemistry enables powerful new research.

Why Light?

Light offers unprecedented control over chemistry and biology.

Millions of people across the world rely on medicines that require daily injections. What if we could eliminate the need for a needle by placing a deposit of drug under the skin and sending patients home with a flashlight they use to dose themselves? In cases like these, patients and doctors need control over when, where, and how much drug to deliver. Light offers that control.

What are the challenges?

Light doesn't penetrate through skin very well.

People have been using light to affect biology for decades, but our dream of eliminating needles is still a dream. Why? Because the chemistries that are usually used only absorb UV light, which barely makes it past your skin, much less into your brain/bone/pancreas. We need new chemistries to allow us to use red or IR light, which gets much deeper into the body.

How do we fix this?

Ruthenium compounds check all the boxes.

Ruthenium polypyridyl compounds absorb visible light very strongly, and break apart cleanly when exposed to light. This means we can use these compounds to make very light sensitive materials to use in the lab and in the clinic. In the Rapp Lab we're exploring three majors ways ruthenium compounds can revolutionize bioengineering: we're making new hydrogel biomaterials for tissue engineering, working on the next generation of drug delivery methods, and photocaging bioactive molecules that have never been caged before.

Research in the Rapp Lab

Our research focuses on using light responsive ruthenium compounds to target, treat, or direct biological events.

Image by Steve Le

Photodynamic Biomaterials

Light responsive hydrogels have revolutionized tissue engineering over the last few decades. We aim to create new materials that allow researchers to study disease progression, accurately test drug targets, and model tissue formation in vitro.

Image by Serge Kutuzov

Self-Illuminated Materials

Light triggered drug delivery is a powerful technique, but hindered by poor light penetration. By coupling RuXlinkers with bioluminescent proteins, we are able to generate self-illuminating materials that release cargo on demand, simply by adding a small molecule.

Image by Hennie Stander


Photocages are a powerful tool in directing and studying biological events. Using inorganic cages allows us to photocage previously impossible motifs, like pyridines, nitriles, and even some click reacting groups.

Sound Interesting?

The Rapp Lab is always looking for excellent trainees at all levels. You could join our team!

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