Seagull Nose-on-Chip

Dear Impossible Readers,

I grew up in the heart of Amsterdam, surrounded by colours, culture, pigeons… and seagulls. They are very good at dropping poop or other objects on your head. In fact, when I was in Barcelona a few years ago, one managed to poop on me mid-stroll. Do you know what else they can do? They can drink seawater. Yes, unlike most animals, seabirds such as seagulls, albatrosses, pelicans, terns, and puffins can drink saltwater without dying. Is that not clever?

That tiny, highly efficient salt removal trick could inspire a futuristic chip that manages chloride the way these birds do. Imagine a microfluidic chip lined with avian salt-gland epithelial cells, capable of actively pumping Na⁺ and Cl⁻. Unlike passive membranes, these cells utilise nature’s perfected ion pumps to efficiently remove salt, even under extreme conditions. Such a device could serve as a research tool to test chloride transport in rare ion-channel disorders or function as a specialised cartridge in dialysis systems to regulate electrolyte balance. The advantage of this idea is that the infrastructure to support it is already largely in place. Laboratories routinely grow epithelial monolayers in perfused chips, and bioartificial kidney cartridges have already demonstrated that living cells can be safely integrated into medical devices.

Seagull salt glands are biological powerhouses that act like natural desalination systems. Their cells move sodium (Na⁺), potassium (K⁺), and chloride (Cl⁻) in a sequence that removes salt while allowing water to follow, allowing the bird to drink seawater safely. Impressively, when these cells are cultured in the lab, they maintain the same process, actively removing salt and water. Because these cells are specialised for Na⁺ and Cl⁻ transport, they offer a valuable platform for studying rare diseases affecting chloride channels and ion transport, such as cystic fibrosis, Bartter and Gitelman syndromes, congenital chloride diarrhoea, and some sweat gland disorders. Modelling these conditions on a chip enables researchers to test new drugs and treatments in a controlled environment.

Several experiments already support the feasibility of such a device. Primary cultures of avian salt-gland cells have demonstrated active Cl⁻ transport in laboratory settings, while studies on shark rectal glands and other epithelial models reveal conserved mechanisms for high-volume chloride secretion. Furthermore, bioartificial kidney trials have demonstrated that living epithelial layers can operate safely in extracorporeal circuits (external blood-filtering systems), and organ-on-chip platforms can sustain epithelial cells with continuous flow, nutrients, and oxygen for extended periods. Together, these findings show that the infrastructure needed to develop a salt-gland chip already exists.

Transforming this concept into a working prototype still encounters hurdles. The chip must incorporate perfusion channels to supply oxygen and glucose continuously, mimic hormonal triggers to regulate chloride flux, and guarantee durability and sterility to sustain cell viability over time. Finally, its performance must be tested to measure chloride pumping, ionic selectivity, and long-term operation. Once these challenges are addressed, the initial prototypes could be used as research modules or medical tools. Unlike some of my earlier eccentric posts, the seagull salt gland chip is imminent in our near future. The cells are there, the microfluidic infrastructure is in place, and the proof-of-concept experiments are already documented. Nature has perfected chloride pumping over millions of years. Now it is our turn to develop our own.

Mind your own saltwater,
Yours Possibly